A software control system for the ACTS high-burst-rate link evaluation terminal
NASA Technical Reports Server (NTRS)
Reinhart, Richard C.; Daugherty, Elaine S.
1991-01-01
Control and performance monitoring of NASA's High Burst Rate Link Evaluation Terminal (HBR-LET) is accomplished by using several software control modules. Different software modules are responsible for controlling remote radio frequency (RF) instrumentation, supporting communication between a host and a remote computer, controlling the output power of the Link Evaluation Terminal and data display. Remote commanding of microwave RF instrumentation and the LET digital ground terminal allows computer control of various experiments, including bit error rate measurements. Computer communication allows system operators to transmit and receive from the Advanced Communications Technology Satellite (ACTS). Finally, the output power control software dynamically controls the uplink output power of the terminal to compensate for signal loss due to rain fade. Included is a discussion of each software module and its applications.
Ka-Band Phased Array System Characterization
NASA Technical Reports Server (NTRS)
Acosta, R.; Johnson, S.; Sands, O.; Lambert, K.
2001-01-01
Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rates several orders of magnitude higher than currently offered with reflector-based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA-based links. Short spacing of radiating elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2 pi phase errors can add to Inter Symbol Interference (ISI), phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased-array antennas when used in a high data rate modulation link. The tests and evaluations described here uncover the interaction between the electrical characteristics of a PAA and the BER performance of a communication link.
NASA Technical Reports Server (NTRS)
Lowrie, J. W.; Fermelia, A. J.; Haley, D. C.; Gremban, K. D.; Vanbaalen, J.; Walsh, R. W.
1982-01-01
The derivation of the equations is presented, the rate control algorithm described, and simulation methodologies summarized. A set of dynamics equations that can be used recursively to calculate forces and torques acting at the joints of an n link manipulator given the manipulator joint rates are derived. The equations are valid for any n link manipulator system with any kind of joints connected in any sequence. The equations of motion for the class of manipulators consisting of n rigid links interconnected by rotary joints are derived. A technique is outlined for reducing the system of equations to eliminate contraint torques. The linearized dynamics equations for an n link manipulator system are derived. The general n link linearized equations are then applied to a two link configuration. The coordinated rate control algorithm used to compute individual joint rates when given end effector rates is described. A short discussion of simulation methodologies is presented.
DOT National Transportation Integrated Search
1998-10-01
The 1995 crude mortality rate of physician diagnosed traumatic brain injury (TBI) in the New Mexico is estimated to be 21 deaths per 100,000 population and the crude incidence of both hospitalized and fatal TBI is 110 cases per 100,000 population (1,...
ATS-5 millimeter wave propagation measurements
NASA Technical Reports Server (NTRS)
Ippolito, L. J.
1973-01-01
Long term experimental measurements to determine the propagation characteristics of 15 and 32 GHz earth-space links and to evaluate performance characteristics of operational millimeter wave systems are reported. The ATS 5 millimeter wave experimental link experienced attenuation and fading characteristics as a function of rainfall rate and other meteorological parameters. A method of site selection for the lowest attenuation rainfall rate improved reception tremendously.
A Link-Level Simulator of the cdma2000 Reverse-Link Physical Layer
Gharavi, H.; Chin, F.; Ban, K.; Wyatt-Millington, R.
2003-01-01
The cdma2000 system is an evolutionary enhancement of the IS-95 standards which support 3G services defined by the International Telecommunications Union (ITU). cdma2000 comes in two phases: 1XRTT and 3XRTT (1X and 3X indicates the number of 1.25 MHz wide radio carrier channels used and RTT stands for Radio Transmission Technology). The cdma2000 1XRTT, which operates within a 1.25 MHz bandwidth, can be utilized in existing IS-95 CDMA channels as it uses the same bandwidth, while 3XRTT requires the commitment of 5 MHz bandwidth to support higher data rates. This paper describes a software model implementation of the cdma2000 reverse link and its application for evaluating the effect of rake receiver design parameters on the system performance under various multipath fading conditions. The cdma2000 models were developed at the National Institute of Standards and Technology (NIST), using SPW (Signal Processing Worksystem) commercial software tools. The model has been developed in a generic manner that includes all the reverse link six radio configurations and their corresponding data rates, according to cdma2000 specifications. After briefly reviewing the traffic channel characteristics of the cdma2000 reverse link (subscriber to base station), the paper discusses the rake receiver implementation including an ideal rake receiver. It then evaluates the performance of each receiver for a Spreading Rate 3 (3XRTT) operation, which is considered as a true “3G” cdma2000 technology. These evaluations are based on the vehicular IMT-2000 (International Mobile Telecommunication 2000) channel model using the link budget defined in cdma2000 specifications for the reverse link. PMID:27413613
Yield and Failure Behavior Investigated for Cross-Linked Phenolic Resins Using Molecular Dynamics
NASA Technical Reports Server (NTRS)
Monk, Joshua D.; Lawson, John W.
2016-01-01
Molecular dynamics simulations were conducted to fundamentally evaluate the yield and failure behavior of cross-linked phenolic resins at temperatures below the glass transition. Yield stress was investigated at various temperatures, strain rates, and degrees of cross-linking. The onset of non-linear behavior in the cross-linked phenolic structures was caused by localized irreversible molecular rearrangements through the rotation of methylene linkers followed by the formation or annihilation of neighboring hydrogen bonds. The yield stress results, with respect to temperature and strain rate, could be fit by existing models used to describe yield behavior of amorphous glasses. The degree of cross-linking only indirectly influences the maximum yield stress through its influence on glass transition temperature (Tg), however there is a strong relationship between the degree of cross-linking and the failure mechanism. Low cross-linked samples were able to separate through void formation, whereas the highly cross-linked structures exhibited bond scission.
Mondor, Luke; Walker, Kevin; Bai, Yu Qing; Wodchis, Walter P.
2017-01-01
Background: Health Links are a new model of providing care coordination for high-cost, high-needs patients in Ontario. We evaluated use of hospital-related health care services among Health Links patients in the Central Local Health Integration Network (LHIN) of Ontario in the year before versus after program enrolment and compared rates of use with those among similar patients with complex needs not enrolled in the program (comparator group). Methods: We identified all patients who received a Health Links coordinated care plan before Jan. 1, 2015, using linked registry and health administrative data. We used propensity scores to match (1:1) enrollees (registry) with comparator patients (administrative data). Using a difference-in-differences approach with generalized estimating equations, we evaluated 5 measures of Health Link performance: rates of hospital admission, emergency department visits, days in acute care, 30-day readmissions and 7-day postdischarge primary care follow-up. Results: Of the 344 enrollees in the registry, we matched 313 [91.0%] to comparator patients. All measured sociodemographic, comorbidity and health care use characteristics were balanced between the 2 groups (all standardized differences < 0.10). For enrollees, the rate of days in acute care per person-year increased by 35% (incidence rate ratio 1.35 [confidence interval 1.11-1.65]) after versus before the index date, but differences were nonsignificant for all other measures. Difference-in-differences analyses revealed greater reductions in hospital admissions, emergency department visits and acute care days after the index date in the comparator group than among enrollees. Interpretation: Initial implementation of the Health Link program in the Central LHIN did not reduce selected indicators of Health Link performance among enrollees. As the Health Link program evolves and standardization is implemented, future research may reveal effects from the initiative in other outcomes or with longer follow-up. PMID:29025737
ERIC Educational Resources Information Center
Heidemeier, Heike; Staudinger, Ursula M.
2012-01-01
This study demonstrates how self-evaluation processes explain subgroup differences in ratings of life satisfaction (population heterogeneity). Life domains differ with regard to the constraints they impose on beliefs in internal control. We hypothesized that these differences are linked with cognitive biases in ratings of life satisfaction. In…
El-Wakeel, Amr S; Mohammed, Nazmi A; Aly, Moustafa H
2016-09-10
In this work, a free space optical communication (FSO) link is proposed and utilized to explore and evaluate the FSO link performance under the joint occurrence of the atmospheric scattering and turbulence phenomena for 850 and 1550 nm operation. Diffraction and nondiffraction-limited systems are presented and evaluated for both wavelengths' operation, considering far-field conditions under different link distances. Bit error rate, pointing error angles, beam divergence angles, and link distance are the main performance indicators that are used to evaluate and compare the link performance under different system configurations and atmospheric phenomena combinations. A detailed study is performed to provide the merits of this work. For both far-field diffraction-limited and nondiffraction-limited systems, it is concluded that 1550 nm system operation is better than 850 nm for the whole presented joint occurrences of atmospheric scattering and turbulence.
Evaluation of identifier field agreement in linked neonatal records.
Hall, E S; Marsolo, K; Greenberg, J M
2017-08-01
To better address barriers arising from missing and unreliable identifiers in neonatal medical records, we evaluated agreement and discordance among traditional and non-traditional linkage fields within a linked neonatal data set. The retrospective, descriptive analysis represents infants born from 2013 to 2015. We linked children's hospital neonatal physician billing records to newborn medical records originating from an academic delivery hospital and evaluated rates of agreement, discordance and missingness for a set of 12 identifier field pairs used in the linkage algorithm. We linked 7293 of 7404 physician billing records (98.5%), all of which were deemed valid upon manual review. Linked records contained a mean of 9.1 matching and 1.6 non-matching identifier pairs. Only 4.8% had complete agreement among all 12 identifier pairs. Our approach to selection of linkage variables and data formatting preparatory to linkage have generalizability, which may inform future neonatal and perinatal record linkage efforts.
Evaluation of optical up- and downlinks from high altitude platforms using IM/DD
NASA Astrophysics Data System (ADS)
Henniger, Hennes; Giggenbach, Dirk; Horwath, Joachim; Rapp, Christoph
2005-04-01
The advantages of optical links like small, light and power efficient terminals are practical for high data rate services over high altitude platforms (HAPs). However, atmospheric effects can disturb the optical links and must be considered in link design. In this paper we evaluate clear sky and non clear sky attenuation effects and their impact on the link-quality of up- and downlinks from HAPs. As vertical links could be restricted by very large cloud and fog attenuation, investigations of the scattering effects in cloud media has been done. The Mie-theory shows that cloud transmittance is not depending on the wavelength, whereas the attenuation of fog and dust is smaller for longer wavelengths. Satellite cloud data has been used to predict the link availability for a ground station in Germany. A ground station diversity concept is introduced to achieve higher link availability. As high receiver sensitivity helps to reduce terminal mass, power and size, evaluation of receiver sensitivity is shown. Also, a receiver model is developed which enables to calculate for the background light loss in direct detection systems.
Turning up the Heat on Online Teaching Evaluations: Does "Hotness" Matter?
ERIC Educational Resources Information Center
Freng, Scott; Webber, David
2009-01-01
Previous research has linked teachers' physical attractiveness and students' evaluations of teaching. We expanded on this literature by using data from RateMyProfessors.com (RMP), a database popular among college students. Additionally, we examined the unique variance that physical attractiveness explains in student evaluations of teaching while…
Individuals and Environments: Linking Ability and Skill Ratings with Interests
ERIC Educational Resources Information Center
Anthoney, Sarah Fetter; Armstrong, Patrick Ian
2010-01-01
Holland's (1997) theory of corresponding person and work environment structures was evaluated by comparing the integration of individual and occupational ratings of interests, abilities, and skills. Occupational ratings were obtained from the U.S. Department of Labor's O*NET database (U.S. Department of Labor, 2007). College students (494 women,…
Linking Data for Mothers and Babies in De-Identified Electronic Health Data.
Harron, Katie; Gilbert, Ruth; Cromwell, David; van der Meulen, Jan
2016-01-01
Linkage of longitudinal administrative data for mothers and babies supports research and service evaluation in several populations around the world. We established a linked mother-baby cohort using pseudonymised, population-level data for England. Retrospective linkage study using electronic hospital records of mothers and babies admitted to NHS hospitals in England, captured in Hospital Episode Statistics between April 2001 and March 2013. Of 672,955 baby records in 2012/13, 280,470 (42%) linked deterministically to a maternal record using hospital, GP practice, maternal age, birthweight, gestation, birth order and sex. A further 380,164 (56%) records linked using probabilistic methods incorporating additional variables that could differ between mother/baby records (admission dates, ethnicity, 3/4-character postcode district) or that include missing values (delivery variables). The false-match rate was estimated at 0.15% using synthetic data. Data quality improved over time: for 2001/02, 91% of baby records were linked (holding the estimated false-match rate at 0.15%). The linked cohort was representative of national distributions of gender, gestation, birth weight and maternal age, and captured approximately 97% of births in England. Probabilistic linkage of maternal and baby healthcare characteristics offers an efficient way to enrich maternity data, improve data quality, and create longitudinal cohorts for research and service evaluation. This approach could be extended to linkage of other datasets that have non-disclosive characteristics in common.
NASA Technical Reports Server (NTRS)
Shahidi, Anoosh K.; Schlegelmilch, Richard F.; Petrik, Edward J.; Walters, Jerry L.
1991-01-01
A software application to assist end-users of the link evaluation terminal (LET) for satellite communications is being developed. This software application incorporates artificial intelligence (AI) techniques and will be deployed as an interface to LET. The high burst rate (HBR) LET provides 30 GHz transmitting/20 GHz receiving (220/110 Mbps) capability for wideband communications technology experiments with the Advanced Communications Technology Satellite (ACTS). The HBR LET can monitor and evaluate the integrity of the HBR communications uplink and downlink to the ACTS satellite. The uplink HBR transmission is performed by bursting the bit-pattern as a modulated signal to the satellite. The HBR LET can determine the bit error rate (BER) under various atmospheric conditions by comparing the transmitted bit pattern with the received bit pattern. An algorithm for power augmentation will be applied to enhance the system's BER performance at reduced signal strength caused by adverse conditions.
Blangiardo, Marta; Finazzi, Francesco; Cameletti, Michela
2016-08-01
Exposure to high levels of air pollutant concentration is known to be associated with respiratory problems which can translate into higher morbidity and mortality rates. The link between air pollution and population health has mainly been assessed considering air quality and hospitalisation or mortality data. However, this approach limits the analysis to individuals characterised by severe conditions. In this paper we evaluate the link between air pollution and respiratory diseases using general practice drug prescriptions for chronic respiratory diseases, which allow to draw conclusions based on the general population. We propose a two-stage statistical approach: in the first stage we specify a space-time model to estimate the monthly NO2 concentration integrating several data sources characterised by different spatio-temporal resolution; in the second stage we link the concentration to the β2-agonists prescribed monthly by general practices in England and we model the prescription rates through a small area approach. Copyright © 2016 Elsevier Ltd. All rights reserved.
Steventon, Adam; Bardsley, Martin; Billings, John; Georghiou, Theo; Lewis, Geraint Hywel
2012-08-01
To test whether two hospital-avoidance interventions altered rates of hospital use: "intermediate care" and "integrated care teams." Linked administrative data for England covering the period 2004 to 2009. This study was commissioned after the interventions had been in place for several years. We developed a method based on retrospective analysis of person-level data comparing health care use of participants with that of prognostically matched controls. Individuals were linked to administrative datasets through a trusted intermediary and a unique patient identifier. Participants who received the intermediate care intervention showed higher rates of unscheduled hospital admission than matched controls, whereas recipients of the integrated care team intervention showed no difference. Both intervention groups showed higher rates of mortality than did their matched controls. These are potentially powerful techniques for assessing impacts on hospital activity. Neither intervention reduced admission rates. Although our analysis of hospital utilization controlled for a wide range of observable characteristics, the difference in mortality rates suggests that some residual confounding is likely. Evaluation is constrained when performed retrospectively, and careful interpretation is needed. © Health Research and Educational Trust.
Rainfall estimation from microwave links in São Paulo, Brazil.
NASA Astrophysics Data System (ADS)
Rios Gaona, Manuel Felipe; Overeem, Aart; Leijnse, Hidde; Uijlenhoet, Remko
2017-04-01
Rainfall estimation from microwave link networks has been successfully demonstrated in countries such as the Netherlands, Israel and Germany. The path-averaged rainfall intensity can be computed from the signal attenuation between cell phone towers. Although this technique is still in development, it offers great opportunities to retrieve rainfall rates at high spatiotemporal resolutions very close to the ground surface. High spatiotemporal resolutions and closer-to-ground measurements are highly appreciated, especially in urban catchments where high-impact events such as flash-floods develop in short time scales. We evaluate here this rainfall measurement technique for a tropical climate, something that has hardly been done previously. This is highly relevant since many countries with few surface rainfall observations are located in the tropics. The test-bed is the Brazilian city of São Paulo. The performance of 16 microwave links was evaluated, from a network of 200 links, for the last 3 months of 2014. The open software package RAINLINK was employed to obtain link rainfall estimates. The evaluation was done through a dense automatic gauge network. Results are promising and encouraging, especially for short links for which a high correlation (> 0.9) and a low bias (< 5%) were obtained.
Analysis of Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol
NASA Technical Reports Server (NTRS)
Woo, Simon S.
2011-01-01
To synchronize clocks between spacecraft in proximity, the Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol has been proposed. PITS is based on the NTP Interleaved On-Wire Protocol and is capable of being adapted and integrated into CCSDS Proximity-1 Space Link Protocol with minimal modifications. In this work, we will discuss the correctness and liveness of PITS. Further, we analyze and evaluate the performance of time synchronization latency with various channel error rates in different PITS operational modes.
Aperture averaging and BER for Gaussian beam in underwater oceanic turbulence
NASA Astrophysics Data System (ADS)
Gökçe, Muhsin Caner; Baykal, Yahya
2018-03-01
In an underwater wireless optical communication (UWOC) link, power fluctuations over finite-sized collecting lens are investigated for a horizontally propagating Gaussian beam wave. The power scintillation index, also known as the irradiance flux variance, for the received irradiance is evaluated in weak oceanic turbulence by using the Rytov method. This lets us further quantify the associated performance indicators, namely, the aperture averaging factor and the average bit-error rate (
Assessing factorial invariance of two-way rating designs using three-way methods
Kroonenberg, Pieter M.
2015-01-01
Assessing the factorial invariance of two-way rating designs such as ratings of concepts on several scales by different groups can be carried out with three-way models such as the Parafac and Tucker models. By their definitions these models are double-metric factorially invariant. The differences between these models lie in their handling of the links between the concept and scale spaces. These links may consist of unrestricted linking (Tucker2 model), invariant component covariances but variable variances per group and per component (Parafac model), zero covariances and variances different per group but not per component (Replicated Tucker3 model) and strict invariance (Component analysis on the average matrix). This hierarchy of invariant models, and the procedures by which to evaluate the models against each other, is illustrated in some detail with an international data set from attachment theory. PMID:25620936
system aspects of optical LEO-to-ground links
NASA Astrophysics Data System (ADS)
Giggenbach, D.; Shrestha, A.; Fuchs, C.; Schmidt, C.; Moll, F.
2017-09-01
Optical Direct-to-Ground data links for earth-observation satellites will offer channel rates of several Gbps, together with low transmit powers and small terminal mass and also rather small ground receiver antennas. The avoidance of any signal spectrum limitation issues might be the most important advantage versus classical RF-technology. The effects of optical atmospheric signal attenuation, and the fast signal fluctuations induced by atmospheric index-of-refraction turbulence and sporadic miss-pointing-fading, require the use of adaptive signal formats together with fading mitigation techniques. We describe the typical downlink scenario, introduce the four different modes of data rate variation, and evaluate different methods of rate-adaptive modulation formats and repetition coding techniques.
Linking Data for Mothers and Babies in De-Identified Electronic Health Data
Gilbert, Ruth; Cromwell, David; van der Meulen, Jan
2016-01-01
Objective Linkage of longitudinal administrative data for mothers and babies supports research and service evaluation in several populations around the world. We established a linked mother-baby cohort using pseudonymised, population-level data for England. Design and Setting Retrospective linkage study using electronic hospital records of mothers and babies admitted to NHS hospitals in England, captured in Hospital Episode Statistics between April 2001 and March 2013. Results Of 672,955 baby records in 2012/13, 280,470 (42%) linked deterministically to a maternal record using hospital, GP practice, maternal age, birthweight, gestation, birth order and sex. A further 380,164 (56%) records linked using probabilistic methods incorporating additional variables that could differ between mother/baby records (admission dates, ethnicity, 3/4-character postcode district) or that include missing values (delivery variables). The false-match rate was estimated at 0.15% using synthetic data. Data quality improved over time: for 2001/02, 91% of baby records were linked (holding the estimated false-match rate at 0.15%). The linked cohort was representative of national distributions of gender, gestation, birth weight and maternal age, and captured approximately 97% of births in England. Conclusion Probabilistic linkage of maternal and baby healthcare characteristics offers an efficient way to enrich maternity data, improve data quality, and create longitudinal cohorts for research and service evaluation. This approach could be extended to linkage of other datasets that have non-disclosive characteristics in common. PMID:27764135
FSO and quality of service software prediction
NASA Astrophysics Data System (ADS)
Bouchet, O.; Marquis, T.; Chabane, M.; Alnaboulsi, M.; Sizun, H.
2005-08-01
Free-space optical (FSO) communication links constitute an alternative option to radio relay links and to optical cables facing growth needs in high-speed telecommunications (abundance of unregulated bandwidth, rapid installation, availability of low-cost optical components offering a high data rate, etc). Their operationalisation requires a good knowledge of the atmospheric effects which can negatively affect role propagation and the availability of the link, and thus to the quality of service (QoS). Better control of these phenomena will allow for the evaluation of system performance and thus assist with improving reliability. The aim of this paper is to compare the behavior of a FSO link located in south of France (Toulouse: with the following parameters: around 270 meters (0.2 mile) long, 34 Mbps data rate, 850 nm wavelength and PDH frame) with airport meteorological data. The second aim of the paper is to assess in-house FSO quality of service prediction software, through comparing simulations with the optical link data and the weather data. The analysis uses in-house software FSO quality of service prediction software ("FSO Prediction") developed by France Telecom Research & Development, which integrates news fog fading equations (compare to Kim & al.) and includes multiple effects (geometrical attenuation, atmospheric fading, rain, snow, scintillation and refraction attenuation due to atmospheric turbulence, optical mispointing attenuation). The FSO link field trial, intended to enable the demonstration and evaluation of these different effects, is described; and preliminary results of the field trial, from December 2004 to May 2005, are then presented.
ERIC Educational Resources Information Center
Inverness Research, 2008
2008-01-01
Inverness Research studied the American Museum of Natural History's (AMNH) Seminars on Science program for eight years, from its inception in 1998 to 2006. This paper presents teacher survey ratings for "The Link between Dinosaurs and Birds", along with profiles of three teachers who took the course. Course takers report on the annual…
ERIC Educational Resources Information Center
Olver, Mark E.; Wong, Stephen C. P.; Nicholaichuk, Terry; Gordon, Audrey
2007-01-01
The Violence Risk Scale-Sexual Offender version (VRS-SO) is a rating scale designed to assess risk and predict sexual recidivism, to measure and link treatment changes to sexual recidivism, and to inform the delivery of sexual offender treatment. The VRS-SO comprises 7 static and 17 dynamic items empirically or conceptually linked to sexual…
NASA Astrophysics Data System (ADS)
Wang, Max L.; Arbabian, Amin
2017-09-01
We propose and demonstrate an ultrasonic communication link using spatial degrees of freedom to increase data rates for deeply implantable medical devices. Low attenuation and millimeter wavelengths make ultrasound an ideal communication medium for miniaturized low-power implants. While a small spectral bandwidth has drastically limited achievable data rates in conventional ultrasonic implants, a large spatial bandwidth can be exploited by using multiple transducers in a multiple-input/multiple-output system to provide spatial multiplexing gain without additional power, larger bandwidth, or complicated packaging. We experimentally verify the communication link in mineral oil with a transmitter and a receiver 5 cm apart, each housing two custom-designed mm-sized piezoelectric transducers operating at the same frequency. Two streams of data modulated with quadrature phase-shift keying at 125 kbps are simultaneously transmitted and received on both channels, effectively doubling the data rate to 250 kbps with a measured bit error rate below 10-4. We also evaluate the performance and robustness of the channel separation network by testing the communication link after introducing position offsets. These results demonstrate the potential of spatial multiplexing to enable more complex implant applications requiring higher data rates.
An energy-efficient rate adaptive media access protocol (RA-MAC) for long-lived sensor networks.
Hu, Wen; Chen, Quanjun; Corke, Peter; O'Rourke, Damien
2010-01-01
We introduce an energy-efficient Rate Adaptive Media Access Control (RA-MAC) algorithm for long-lived Wireless Sensor Networks (WSNs). Previous research shows that the dynamic and lossy nature of wireless communications is one of the major challenges to reliable data delivery in WSNs. RA-MAC achieves high link reliability in such situations by dynamically trading off data rate for channel gain. The extra gain that can be achieved reduces the packet loss rate which contributes to reduced energy expenditure through a reduced numbers of retransmissions. We achieve this at the expense of raw bit rate which generally far exceeds the application's link requirement. To minimize communication energy consumption, RA-MAC selects the optimal data rate based on the estimated link quality at each data rate and an analytical model of the energy consumption. Our model shows how the selected data rate depends on different channel conditions in order to minimize energy consumption. We have implemented RA-MAC in TinyOS for an off-the-shelf sensor platform (the TinyNode) on top of a state-of-the-art WSN Media Access Control Protocol, SCP-MAC, and evaluated its performance by comparing our implementation with the original SCP-MAC using both simulation and experiment.
Remote-seeded WDM-PON upgrade using linear semiconductor opticalamplifiers
NASA Astrophysics Data System (ADS)
Martínez, J. J.; Merayo, N.; Villafranca, A.; Garcés, I.
2013-05-01
In this work we have assessed the capacity of a linear (gain-clamped) semiconductor optical amplifier to enhance the budget of WDM PON network links for their evolution from FTTC to FTTH access. A wavelength-seeded network architecture has been considered, evaluating the performance improvement obtained by the use of an amplifier for the cases of link reach extension and optical splitting to reach end users. The evaluation measurements have shown that the extra budget is enough to compensate for the losses of a passive splitter up to atleast 1:16 division rate or to highly increment reach of the network.
Pre-configured polyhedron based protection against multi-link failures in optical mesh networks.
Huang, Shanguo; Guo, Bingli; Li, Xin; Zhang, Jie; Zhao, Yongli; Gu, Wanyi
2014-02-10
This paper focuses on random multi-link failures protection in optical mesh networks, instead of single, the dual or sequential failures of previous studies. Spare resource efficiency and failure robustness are major concerns in link protection strategy designing and a k-regular and k-edge connected structure is proved to be one of the optimal solutions for link protection network. Based on this, a novel pre-configured polyhedron based protection structure is proposed, and it could provide protection for both simultaneous and sequential random link failures with improved spare resource efficiency. Its performance is evaluated in terms of spare resource consumption, recovery rate and average recovery path length, as well as compared with ring based and subgraph protection under probabilistic link failure scenarios. Results show the proposed novel link protection approach has better performance than previous works.
NASA Technical Reports Server (NTRS)
Safren, H. G.
1987-01-01
The effect of atmospheric turbulence on the bit error rate of a space-to-ground near infrared laser communications link is investigated, for a link using binary pulse position modulation and an avalanche photodiode detector. Formulas are presented for the mean and variance of the bit error rate as a function of signal strength. Because these formulas require numerical integration, they are of limited practical use. Approximate formulas are derived which are easy to compute and sufficiently accurate for system feasibility studies, as shown by numerical comparison with the exact formulas. A very simple formula is derived for the bit error rate as a function of signal strength, which requires only the evaluation of an error function. It is shown by numerical calculations that, for realistic values of the system parameters, the increase in the bit error rate due to turbulence does not exceed about thirty percent for signal strengths of four hundred photons per bit or less. The increase in signal strength required to maintain an error rate of one in 10 million is about one or two tenths of a db.
Dynamical behavior of susceptible-infected-recovered-susceptible epidemic model on weighted networks
NASA Astrophysics Data System (ADS)
Wu, Qingchu; Zhang, Fei
2018-02-01
We study susceptible-infected-recovered-susceptible epidemic model in weighted, regular, and random complex networks. We institute a pairwise-type mathematical model with a general transmission rate to evaluate the influence of the link-weight distribution on the spreading process. Furthermore, we develop a dimensionality reduction approach to derive the condition for the contagion outbreak. Finally, we analyze the influence of the heterogeneity of weight distribution on the outbreak condition for the scenario with a linear transmission rate. Our theoretical analysis is in agreement with stochastic simulations, showing that the heterogeneity of link-weight distribution can have a significant effect on the epidemic dynamics.
Cicalese, Luca; Raun, Loren; Shirafkan, Ali; Campos, Laura; Zorzi, Daria; Montalbano, Mauro; Rhoads, Colin; Gazis, Valia; Ensor, Katherine; Rastellini, Cristiana
2017-11-01
Primary liver cancer is a significant cause of cancer-related death in both the United States and the world at large. Hepatocellular carcinoma comprises 90% of these primary liver cancers and has numerous known etiologies. Evaluation of these identified etiologies and other traditional risk factors cannot explain the high incidence rates of hepatocellular carcinoma in Texas. Texas is home to the second largest petrochemical industry and agricultural industry in the nation; industrial activity and exposure to pathogenic chemicals have never been assessed as potential links to the state's increased incidence rate of hepatocellular carcinoma. The association between the county-level concentrations of 4 air pollutants known to be linked to liver cancer, vinyl chloride, arsenic, benzene, and 1,3-butadiene, and hepatocellular carcinoma rates was evaluated using nonparametric generalized additive logistic regression and gamma regression models. Hepatocellular carcinoma incidence rates for 2000-2013 were evaluated in comparison to 1996 and 1999 pollution concentrations and hepatocellular carcinoma rates for the subset of 2006-2013 were evaluated in comparison to 2002 and 2005 pollution concentrations, respectively. The analysis indicates that the relationship between the incidence of liver cancer and air pollution and risk factors is nonlinear. There is a consistent significant positive association between the incidence of liver cancer and hepatitis C prevalence rates (gamma all years, p < 0.05) and vinyl chloride concentrations (logistic 2002 and 2005, p < 0.0001; gamma 2002 and 2005, p < 0.05). This study suggests that vinyl chloride is a significant contributor to the incidence of liver cancer in Texas. The relationship is notably nonlinear. Further, the study supports the association between incidence of liver cancer and prevalence of hepatitis B.
Parametric study of intersatellite CO2 laser data links
NASA Astrophysics Data System (ADS)
Bonek, E.; Lutz, H.
The performance capability of current CO2 laser communication tecnology for intersatellite data links is evaluated. The link parameters, such as the distance, bit rate, ac signal-to-noise ratio, are related to the masses and the prime power requirements of satellite laser terminals using variables like the telescope (antenna) aperture diameter and the transmitted laser power. It is found that high data rates could be readily transmitted with telescopes of the order of only 10 cm in diameter, with the complte laser data terminals weighing between 25 kg and 70 kg and consuming prime power in the 90-300 W range. In addition, these terminals would require only about 0.1 cu m or less of volume and a very low movable antenna mass, which would alleviate constraints on satellite attitude control units in remote sensing missions.
Lewin, Adam B.; Peris, Tara S.; Bergman, R. Lindsey; McCracken, James T.; Piacentini, John
2011-01-01
The purpose of this investigation was to examine correlates of parent, child, and therapist treatment expectations and their role in the exposure-based treatment of childhood obsessive compulsive disorder (OCD). Treatment expectations were assessed among 49 youth with primary OCD, their parents, and therapists as part of the baseline evaluation and post-treatment clinical outcomes were determined by blind evaluators. Baseline depressive symptoms, child/parent-rated functional impairment, externalizing behavior problems, number of comorbid psychiatric disorders, and a lower perception of control were associated with lower pre-treatment expectations. Parent expectation was associated with parental OCD symptoms, child depressive symptoms and child-reported impairment. Therapist expectations inversely correlated with child depressive symptoms, externalizing problems, and child-rated impairment. Pre-treatment OCD severity and prior treatment history were not linked to expectancy. Finally, higher treatment expectations were linked to better treatment response, lower attrition, better homework compliance, and reduced impairment. PMID:21723534
The shape-memory effect in ionic elastomers: fixation through ionic interactions.
González-Jiménez, Antonio; Malmierca, Marta A; Bernal-Ortega, Pilar; Posadas, Pilar; Pérez-Aparicio, Roberto; Marcos-Fernández, Ángel; Mather, Patrick T; Valentín, Juan L
2017-04-19
Shape-memory elastomers based on a commercial rubber cross-linked by both ionic and covalent bonds have been developed. The elastomeric matrix was a carboxylated nitrile rubber (XNBR) vulcanized with magnesium oxide (MgO) providing ionic interactions that form hierarchical structures. The so-named ionic transition is used as the unique thermal transition responsible for the shape-memory effect (SME) in these elastomers. These ionic interactions fix the temporary shape due to their behavior as dynamic cross-links with temperature changes. Covalent cross-links were incorporated with the addition of different proportions of dicumyl peroxide (DCP) to the ionic elastomer to establish and recover the permanent shape. In this article, the SME was modulated by modifying the degree of covalent cross-linking, while keeping the ionic contribution constant. In addition, different programming parameters, such as deformation temperature, heating/cooling rate, loading/unloading rate and percentage of tensile strain, were evaluated for their effects on shape-memory behavior.
Linking a young child's activity pattern data with samples that are collected during an exposure assessment is important in evaluating uptake dose rates associated with environmental contaminant exposures. A pilot study (N=9) was performed to test how well categorical activity-le...
NASA Astrophysics Data System (ADS)
Nagpal, Shaina; Gupta, Amit
2017-08-01
Free Space Optics (FSO) link exploits the tremendous network capacity and is capable of offering wireless communications similar to communications through optical fibres. However, FSO link is extremely weather dependent and the major effect on FSO links is due to adverse weather conditions like fog and snow. In this paper, an FSO link is designed using an array of receivers. The disparity of the link for very high attenuation conditions due to fog and snow is analysed using aperture averaging technique. Further effect of aperture averaging technique is investigated by comparing the systems using aperture averaging technique with systems not using aperture averaging technique. The performance of proposed model of FSO link has been evaluated in terms of Q factor, bit error rate (BER) and eye diagram.
Michie, Susan; Carey, Rachel N; Johnston, Marie; Rothman, Alexander J; de Bruin, Marijn; Kelly, Michael P; Connell, Lauren E
2018-05-18
Understanding links between behaviour change techniques (BCTs) and mechanisms of action (the processes through which they affect behaviour) helps inform the systematic development of behaviour change interventions. This research aims to develop and test a methodology for linking BCTs to their mechanisms of action. Study 1 (published explicit links): Hypothesised links between 93 BCTs (from the 93-item BCT taxonomy, BCTTv1) and mechanisms of action will be identified from published interventions and their frequency, explicitness and precision documented. Study 2 (expert-agreed explicit links): Behaviour change experts will identify links between 61 BCTs and 26 mechanisms of action in a formal consensus study. Study 3 (integrated matrix of explicit links): Agreement between studies 1 and 2 will be evaluated and a new group of experts will discuss discrepancies. An integrated matrix of BCT-mechanism of action links, annotated to indicate strength of evidence, will be generated. Study 4 (published implicit links): To determine whether groups of co-occurring BCTs can be linked to theories, we will identify groups of BCTs that are used together from the study 1 literature. A consensus exercise will be used to rate strength of links between groups of BCT and theories. A formal methodology for linking BCTs to their hypothesised mechanisms of action can contribute to the development and evaluation of behaviour change interventions. This research is a step towards developing a behaviour change 'ontology', specifying relations between BCTs, mechanisms of action, modes of delivery, populations, settings and types of behaviour.
Ghafari, Mohsen; Atkinson, John D
2018-06-05
A novel one-step hyper-cross-linking method, using 1,2-dichloroethane (DCE) and 1,6-dichlorohexane (DCH) cross-linkers, expands the micropore volume of commercial styrenic polymers. Performance of virgin and modified polymers was evaluated by measuring hexane, toluene, and methyl-ethyl-ketone (MEK) adsorption capacity, adsorption/desorption kinetics, and desorption efficiency. Hyper-cross-linked polymers have up to 128% higher adsorption capacity than virgin polymers at P/P 0 = 0.05 due to micropore volume increases up to 330%. Improvements are most pronounced with the DCE cross-linker. Hyper-cross-linking has minimal impact on hexane adsorption kinetics, but adsorption rates for toluene and MEK decrease by 6-41%. Desorption rates decreased (3-36%) for all materials after hyper-cross-linking, with larger decreases for DCE hyper-cross-linked polymers due to smaller average pore widths. For room temperature desorption, 20-220% more adsorbate remains in hyper-cross-linked polymers after regeneration compared to virgin materials. DCE hyper-cross-linked polymers have 13-92% more residual adsorbate than DCH counterparts. Higher temperatures were required for DCE hyper-cross-linked polymers to completely desorb VOCs compared to the DCH hyper-cross-linked and virgin counterparts. Results show that the one-step hyper-cross-linking method for modifying styrenic polymers improves adsorption capacity because of added micropores, but decreases adsorption/desorption kinetics and desorption efficiency for large VOCs due to a decrease in average pore width. Copyright © 2018 Elsevier B.V. All rights reserved.
Teacher Evaluation and Classroom Practice: Teacher Perceptions in Northeast Tennessee
ERIC Educational Resources Information Center
Bogart, Christopher Dean
2013-01-01
The purpose of this quantitative study was to investigate the perceptions of K-12 teachers as they relate to the implementation of the Tennessee Educator Acceleration (TEAM) evaluation framework. Survey links were sent to 1,115 K-12 teachers from 4 Northeast Tennessee school districts. The survey achieved a 24% return rate for a total of 270…
Environmental Decisions often rely upon observational data or model estimates. For instance, the evaluation of human health or ecological risks often includes information on pollutant emission rates, environmental concentrations, exposures, and exposure/dose-response data. Whet...
Statistical similarity measures for link prediction in heterogeneous complex networks
NASA Astrophysics Data System (ADS)
Shakibian, Hadi; Charkari, Nasrollah Moghadam
2018-07-01
The majority of the link prediction measures in heterogeneous complex networks rely on the nodes connectivities while less attention has been paid to the importance of the nodes and paths. In this paper, we propose some new meta-path based statistical similarity measures to properly perform link prediction task. The main idea in the proposed measures is to drive some co-occurrence events in a number of co-occurrence matrices that are occurred between the visited nodes obeying a meta-path. The extracted co-occurrence matrices are analyzed in terms of the energy, inertia, local homogeneity, correlation, and information measure of correlation to determine various information theoretic measures. We evaluate the proposed measures, denoted as link energy, link inertia, link local homogeneity, link correlation, and link information measure of correlation, using a standard DBLP network data set. The results of the AUC score and Precision rate indicate the validity and accuracy of the proposed measures in comparison to the popular meta-path based similarity measures.
de Jonge, Linda; Garne, Ester; Gini, Rosa; Jordan, Susan E; Klungsoyr, Kari; Loane, Maria; Neville, Amanda J; Pierini, Anna; Puccini, Aurora; Thayer, Daniel S; Tucker, David; Vinkel Hansen, Anne; Bakker, Marian K
2015-11-01
Research on associations between medication use during pregnancy and congenital anomalies is significative for assessing the safe use of a medicine in pregnancy. Congenital anomaly (CA) registries do not have optimal information on medicine exposure, in contrast to prescription databases. Linkage of prescription databases to the CA registries is a potentially effective method of obtaining accurate information on medicine use in pregnancies and the risk of congenital anomalies. We linked data from primary care and prescription databases to five European Surveillance of Congenital Anomalies (EUROCAT) CA registries. The linkage was evaluated by looking at linkage rate, characteristics of linked and non-linked cases, first trimester exposure rates for six groups of medicines according to the prescription data and information on medication use registered in the CA databases, and agreement of exposure. Of the 52,619 cases registered in the CA databases, 26,552 could be linked. The linkage rate varied between registries over time and by type of birth. The first trimester exposure rates and the agreements between the databases varied for the different medicine groups. Information on anti-epileptic drugs and insulins and analogue medicine use recorded by CA registries was of good quality. For selective serotonin reuptake inhibitors, anti-asthmatics, antibacterials for systemic use, and gonadotropins and other ovulation stimulants, the recorded information was less complete. Linkage of primary care or prescription databases to CA registries improved the quality of information on maternal use of medicines in pregnancy, especially for medicine groups that are less fully registered in CA registries.
NASA Astrophysics Data System (ADS)
Raptis, Nikos; Pikasis, Evangelos; Syvridis, Dimitris
2016-10-01
For several years, it has been examined if the attributes of the wavelengths in C band of the Ultraviolet (UV) spectrum that lie between 200 and 280 nm can be exploited in order to set up short range covert links of low rate in a Non-Line-of-Sight (NLOS) regime. In the present work, it is experimentally investigated and verified that using this band, short range and low rate NLOS links using the same transmitter/receiver pair under different atmospheric conditions without applying extreme power levels can be implemented rather effectively. The transmitter was composed of four Light Emitting Diodes. At the receiving side, an optical filter was followed by a Photo-Multiplier Tube. Initially, we measured the power losses of the channels with and without fog (artificially generated) for ranges up to 20 meters and several transmitters/receiver configurations. Secondly, the performance of Fourth-order Pulse Position Modulation (4-PPM) and Flip Orthogonal Frequency Division Multiplexing (Flip-OFDM) was evaluated for such channels and 10 Kbit/s rate. Applying emissions at 265 nm, NLOS links can operate efficiently especially in harsh environments, as the power losses were lowered when fog appeared. In terms of the modulation formats, 4-PPM performed better in most cases. Better results were obtained for both schemes when the medium became thicker due to the presence of fog. Finally, some initial measurements were realized with a Silicon Carbide PiN photodiode for the same rate but low elevation angles. The performance was exactly the opposite compared to a receiver with inherent gain when the atmosphere thickened.
Degradability of an Acrylate-Linked, Fluorotelomer Polymer in Soil
Fluorotelomer polymers are used in a broad array of products in modern societies worldwide and, if they degrade at significant rates, potentially are a significant source of perfluorooctanoic acid (PFOA) and related compounds to the environment. To evaluate this possibility, we i...
O'Hara, Margaret H; Frazier, Linda M; Stembridge, Travis W; McKay, Robert S; Mohr, Sandra N; Shalat, Stuart L
2013-09-01
This study compares outcomes at a hospital-linked, physician-led, birthing center to a traditional hospital labor and delivery service. Using de-identified electronic medical records, a retrospective cohort design was employed to evaluate 32,174 singleton births during 1998-2005. Compared with hospital service, birth care center delivery was associated with a lower rate of cesarean sections (adjusted Relative Risk = 0.73, 95% confidence interval 0.59-0.91; p < 0.001) without an increased rate of operative vaginal delivery (adjusted Relative Risk = 1.04, 95% confidence interval 0.97-1.13; p = 0.25) and a higher initiation of breastfeeding (adjusted Relative Risk = 1.28, 95% confidence interval 1.25-1.30; p ≤ 0.001). A maternal length of stay greater than 72 hours occurred less frequently in the birth care center (adjusted Relative Risk = 0.60, 95% confidence interval 0.55-0.66; p < 0.001). Comparing only women without major obstetrical risk factors, the differences in outcomes were reduced but not eliminated. Adverse maternal and infant outcomes were not increased at the birth care center. A hospital-linked, physician-led, birth care center has the potential to lower rates of cesarean sections without increasing rates of operative vaginal delivery or other adverse maternal and infant outcomes. © 2013, Copyright the Authors Journal compilation © 2013, Wiley Periodicals, Inc.
Average BER and outage probability of the ground-to-train OWC link in turbulence with rain
NASA Astrophysics Data System (ADS)
Zhang, Yixin; Yang, Yanqiu; Hu, Beibei; Yu, Lin; Hu, Zheng-Da
2017-09-01
The bit-error rate (BER) and outage probability of optical wireless communication (OWC) link for the ground-to-train of the curved track in turbulence with rain is evaluated. Considering the re-modulation effects of raining fluctuation on optical signal modulated by turbulence, we set up the models of average BER and outage probability in the present of pointing errors, based on the double inverse Gaussian (IG) statistical distribution model. The numerical results indicate that, for the same covered track length, the larger curvature radius increases the outage probability and average BER. The performance of the OWC link in turbulence with rain is limited mainly by the rain rate and pointing errors which are induced by the beam wander and train vibration. The effect of the rain rate on the performance of the link is more severe than the atmospheric turbulence, but the fluctuation owing to the atmospheric turbulence affects the laser beam propagation more greatly than the skewness of the rain distribution. Besides, the turbulence-induced beam wander has a more significant impact on the system in heavier rain. We can choose the size of transmitting and receiving apertures and improve the shockproof performance of the tracks to optimize the communication performance of the system.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bhattarai, Bishnu P.; Gentle, Jake P.; Hill, Porter
Abstract—Overhead transmission lines (TLs) are conventionally given seasonal ratings based on conservative environmental assumptions. Such an approach often results in underutilization of the line ampacity as the worst conditions prevail only for a short period over a year/season. We presents dynamic line rating (DLR) as an enabling smart grid technology that adaptively computes ratings of TLs based on local weather conditions to utilize additional headroom of existing lines. In particular, general line ampacity state solver utilizes measured weather data for computing the real-time thermal rating of the TLs. The performance of the presented method is demonstrated from a field studymore » of DLR technology implementation on four TL segments at AltaLink, Canada. The performance is evaluated and quantified by comparing the existing static and proposed dynamic line ratings, and the potential benefits of DLR for enhanced transmission assets utilization. For the given line segments, the proposed DLR results in real-time ratings above the seasonal static ratings for most of the time; up to 95.1% of the time, with a mean increase of 72% over static rating.« less
Socially Anxious and Peer-Victimized Preadolescents: "Doubly Primed" for Distress?
ERIC Educational Resources Information Center
Erath, Stephen A.; Tu, Kelly M.; El-Sheikh, Mona
2012-01-01
We examined independent and interactive associations linking preadolescents' socially anxious feelings and peer victimization experiences with their social behaviors (rated by parents and teachers) and psychophysiological arousal during lab simulations of salient peer stress situations in preadolescence (peer evaluation and peer rebuff).…
NASA Astrophysics Data System (ADS)
Che-Aron, Z.; Abdalla, A. H.; Abdullah, K.; Hassan, W. H.
2013-12-01
In recent years, Cognitive Radio (CR) technology has largely attracted significant studies and research. Cognitive Radio Ad Hoc Network (CRAHN) is an emerging self-organized, multi-hop, wireless network which allows unlicensed users to opportunistically access available licensed spectrum bands for data communication under an intelligent and cautious manner. However, in CRAHNs, a lot of failures can easily occur during data transmission caused by PU (Primary User) activity, topology change, node fault, or link degradation. In this paper, an attempt has been made to evaluate the performance of the Multi-Radio Link-Quality Source Routing (MR-LQSR) protocol in CRAHNs under different path failure rate. In the MR-LQSR protocol, the Weighted Cumulative Expected Transmission Time (WCETT) is used as the routing metric. The simulations are carried out using the NS-2 simulator. The protocol performance is evaluated with respect to performance metrics like average throughput, packet loss, average end-to-end delay and average jitter. From the simulation results, it is observed that the number of path failures depends on the PUs number and mobility rate of SUs (Secondary Users). Moreover, the protocol performance is greatly affected when the path failure rate is high, leading to major service outages.
Duplex Direct Data Distribution System
NASA Technical Reports Server (NTRS)
Greenfield, Israel (Technical Monitor)
2001-01-01
The NASA Glenn Research Center (GRC) is developing and demonstrating communications and network technologies that are helping to enable the near-Earth space Internet. GRC envisions several service categories. The first of these categories is direct data distribution or D3 (pronounced "D-cubed"). Commercially provided D3 will make it possible to download a data set from a spacecraft, like the International Space Station. as easily as one can extract a file from a remote server today, using a file transfer protocol. In a second category, NASA spacecraft will make use of commercial satellite communication (SATCOM) systems. Some of those services will come from purchasing time on unused transponders that cover landmasses. While it is likely there will be gaps in service coverage, Internet services should be available using these systems. This report addresses alternative methods of implementing a full duplex enhancement of the GRC developed experimental Ka-Band Direct Data Distribution (D3) space-to-ground communication link. The resulting duplex version is called the Duplex Direct Data Distribution (D4) system. The D4 system is intended to provide high-data-rate commercial direct or internet-based communications service between the NASA spacecraft in low earth orbit (LEO) and the respective principal investigators associated with these spacecraft. Candidate commercial services were assessed regarding their near-term potential to meet NASA requirements. Candidates included Ka-band and V-band geostationary orbit and non-geostationary orbit satellite relay services and direct downlink ("LEO teleport") services. End-to-end systems concepts were examined and characterized in terms of alternative link layer architectures. Alternatives included a Direct Link, a Relay Link, a Hybrid Link, and a Dual Mode Link. The direct link assessment examined sample ground terminal placements and antenna angle issues. The SATCOM-based alternatives examined existing or proposed commercial SATCOM services that could be available in the 2005 time frame. The alternatives were evaluated and compared in terms of average daily system throughput and cost per bit. Throughput was estimated based on hypothetical scenarios supporting the International Space Station and polar orbiting missions. The feasibility of using standard TCP and a modified TCP was evaluated and risks were identified. An estimate of the TCP acknowledgment data rate required to support a return channel rate of 622 Mbps was developed using OPNET.
Advances in Ka-Band Communication System for CubeSats and SmallSats
NASA Technical Reports Server (NTRS)
Kegege, Obadiah; Wong, Yen F.; Altunc, Serhat
2016-01-01
A study was performed that evaluated the feasibility of Ka-band communication system to provide CubeSat/SmallSat high rate science data downlink with ground antennas ranging from the small portable 1.2m/2.4m to apertures 5.4M, 7.3M, 11M, and 18M, for Low Earth Orbit (LEO) to Lunar CubeSat missions. This study included link analysis to determine the data rate requirement, based on the current TRL of Ka-band flight hardware and ground support infrastructure. Recent advances in Ka-band transceivers and antennas, options of portable ground stations, and various coverage distances were included in the analysis. The link/coverage analysis results show that Cubesat/Smallsat missions communication requirements including frequencies and data rates can be met by utilizing Near Earth Network (NEN) Ka-band support with 2 W and high gain (>6 dBi) antennas.
Stratford, Trisha; Meara, Alan; Psychotherapy, M Gestalt; Lal, Sara
2014-08-01
This exploratory study was designed to investigate the link between a client's heart rate variability (HRV) and the forming of a therapeutic alliance (TA) during psychotherapy. Change in HRV is associated with many psychological and physiological situations, including cardiac mortality. Cardiac effects were evaluated during therapy in 30 symptomatically anxious clients using HRV during six weekly 1-hour therapy sessions (S1-S6). Therapeutic index (TI), a measure of TA, was evaluated using skin conductance resonance between client and therapist. The Working Alliance Inventory provides a subjective measure of TA. State and trait anxiety and mood states were also assessed. Most HRV parameters were highest during S4. The sympathovagal balance was highest in S1 but stabilized after S2. In S4, TI was linked to high HRV parameters. Overall higher anxiety levels seem to be associated to lower HRV parameters. Conversely, in S4, high HRV parameters were linked to higher mood scores. This study found that a subjective measure of TA contradicted the physiological outcome. Results suggest that physiological data collected during therapy are a more accurate barometer of TA forming. These research findings suggest a need for further research identifying physiological markers in clients with a variety of mental health disorders over long-term therapy.
Probing the big five in adolescence: personality and adjustment during a developmental transition.
Graziano, W G; Ward, D
1992-06-01
The present study probed the links among Big Five personality differences, self-reported personality differences, and adjustment to school among young adolescents. We used a multimethod converging analysis, with three sources of data: (a) adolescent self-report on standardized personality inventories; (b) classroom teacher trait ratings and evaluations of adjustment; and (c) school guidance counselor evaluations of adjustment. Evaluations of adolescent adjustment were systematically related to Big Five personality differences, as assessed by both classroom teachers' and school counselors' ratings. For classroom teachers, adjustment was closely related to evaluations on the Big Five dimension of Conscientiousness. Adolescent self-report on several standardized measures was not related to adult evaluation of school adjustment. We suggest that the five-factor model may be a useful tool for probing adjustment during the transition to adolescence.
Tsukamoto, Manabu; Mori, Toshiharu; Ohnishi, Hideo; Uchida, Soshi; Sakai, Akinori
2017-12-01
A number of studies on total hip arthroplasty have compared highly cross-linked polyethylene (HXLPE) with conventional polyethylene (CPE) liners beyond 10 years. However, the impact of HXLPE on the wear-related reoperation rate is unclear. The purpose of this study was to evaluate the clinical advantage of using a single manufacturer's HXLPE in terms of reducing the reoperation rate. The study was a follow-up retrospective cohort study over a mean of 12 years that examined patients aged 45-70 years with cementless total hip arthroplasty using a 26-mm-diameter cobalt-chromium head. Sixty-seven patients (79 hips; HXLPE group = 41 hips, CPE group = 38 hips) were evaluated for a minimum 10-year follow-up. Kaplan-Meier survival analysis was performed, with wear-related reoperations and radiographic osteolysis serving as the end points. The polyethylene wear rate was also assessed. The mean 12-year follow-up rates of survivorship that were evaluated using wear-related reoperations as the end point were 100% and 91.4% in the HXLPE and CPE groups, respectively (P = .007), and the mean 12-year follow-up rates of survivorship with osteolysis as the end point were 100% and 36.2%, respectively (P < .001). Compared with the CPE group, the HXLPE group presented a significantly reduced wear rate (HXLPE group, 0.035 mm/y; CPE group, 0.118 mm/y). A unique strength of this study is that we assessed a single manufacturer's HXLPE while keeping most other implant parameters uniform. This study reveals the clinical advantage of using a single manufacturer's HXLPE in terms of a reduced wear-related reoperation rate at a mean 12-year follow-up. Copyright © 2017 Elsevier Inc. All rights reserved.
Downing, Julia; Batuli, Mwazi; Kivumbi, Grace; Kabahweza, Josephine; Grant, Liz; Murray, Scott A; Namukwaya, Elizabeth; Leng, Mhoira
2016-04-08
Integrating palliative care (PC) and empowering the health care workforce is essential to achieve universal access to PC services. In 2010, 46% of patients in Mulago Hospital, Uganda had a life limiting illness, of whom 96% had PC needs. The university/hospital specialist PC unit (Makerere/Mulago Palliative Care Unit -MPCU) implemented a link-nurse model to empower hospital nurses to provide generalist PC. Over two years, 27 link nurses were trained and mentored and 11 clinical protocols developed. The aim of the study was to evaluate the impact of the palliative care link nurse programme at Mulago Hospital An evaluation approach utilising mixed methods was used integrating qualitative and quantitative data including: pre and post course assessment confidence ratings; course evaluation forms; audit of clinical guidelines availability; review of link-nurse activity sheets/action plans; review of MPCU patient documentation; Most Significant Change (MSC); individual and focus group interviews. A significant difference was seen in nurses' confidence after the training (p < 0.001). From July 2012 to December 2013, link nurses identified 2447 patients needing PC, of whom they cared for 2113 (86%) and referred 334 (14%) to MPCU. Clinical guidelines/protocols were utilised in 50% of wards. Main themes identified include: change in attitude; developing new skills and knowledge; change in relationships; improved outcomes of care, along with the challenges that they experienced in integrating PC. Since the start of the programme there has been an increase in PC patients seen at the hospital (611 in 2011 to 1788 in 2013). The link-nurse programme is a practical model for integrating PC into generalist services. Recommendations have been made for ongoing development and expansion of the programme as an effective health systems strengthening approach in similar healthcare contexts, as well as the improvement in medical and nursing education.
Present state of HDTV coding in Japan and future prospect
NASA Astrophysics Data System (ADS)
Murakami, Hitomi
The development status of HDTV digital codecs in Japan is evaluated; several bit rate-reduction codecs have been developed for 1125 lines/60-field HDTV, and performance trials have been conducted through satellite and optical fiber links. Prospective development efforts will attempt to achieve more efficient coding schemes able to reduce the bit rate to as little as 45 Mbps, as well as to apply coding schemes to automated teller machine networks.
ERIC Educational Resources Information Center
Dee, Thomas S.; Wyckoff, James
2017-01-01
Teachers matter--and some matter more than others. That recognition has driven a tidal wave of controversial policy reforms over the past decade, rooted in new evaluation systems that link teachers' ratings and, in some cases, their pay and advancement to evidence of classroom practice and student learning. Two out of three U.S. states overhauled…
Does Time Management Training Work? An Evaluation
ERIC Educational Resources Information Center
Green, Peter; Skinner, Denise
2005-01-01
In an increasingly competitive business environment, organisations have sought to increase productivity and reduce costs. The consequences of this for many employees include increased workloads, longer working hours and greater time pressures which, the evidence suggests, are linked to stress, high rates of absence and turnover. At the same time…
Wurzelbacher, Steven J; Al-Tarawneh, Ibraheem S; Meyers, Alysha R; Bushnell, P Timothy; Lampl, Michael P; Robins, David C; Tseng, Chih-Yu; Wei, Chia; Bertke, Stephen J; Raudabaugh, Jill A; Haviland, Thomas M; Schnorr, Teresa M
2016-12-01
Workers' compensation (WC) claims data may be useful for identifying high-risk industries and developing prevention strategies. WC claims data from private-industry employers insured by the Ohio state-based workers' compensation carrier from 2001 to 2011 were linked with the state's unemployment insurance (UI) data on the employer's industry and number of employees. National Labor Productivity and Costs survey data were used to adjust UI data and estimate full-time equivalents (FTE). Rates of WC claims per 100 FTE were computed and Poisson regression was used to evaluate differences in rates. Most industries showed substantial claim count and rate reductions from 2001 to 2008, followed by a leveling or slight increase in claim count and rate from 2009 to 2011. Despite reductions, there were industry groups that had consistently higher rates. WC claims data linked to employment data could be used to prioritize industries for injury research and prevention activities among State-insured private employers. Am. J. Ind. Med. 59:1087-1104, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Getting the word out: neural correlates of enthusiastic message propagation.
Falk, Emily B; O'Donnell, Matthew Brook; Lieberman, Matthew D
2012-01-01
What happens in the mind of a person who first hears a potentially exciting idea?We examined the neural precursors of spreading ideas with enthusiasm, and dissected enthusiasm into component processes that can be identified through automated linguistic analysis, gestalt human ratings of combined linguistic and non-verbal cues, and points of convergence/divergence between the two. We combined tools from natural language processing (NLP) with data gathered using fMRI to link the neurocognitive mechanisms that are set in motion during initial exposure to ideas and subsequent behaviors of these message communicators outside of the scanner. Participants' neural activity was recorded as they reviewed ideas for potential television show pilots. Participants' language from video-taped interviews collected post-scan was transcribed and given to an automated linguistic sentiment analysis (SA) classifier, which returned ratings for evaluative language (evaluative vs. descriptive) and valence (positive vs. negative). Separately, human coders rated the enthusiasm with which participants transmitted each idea. More positive sentiment ratings by the automated classifier were associated with activation in neural regions including medial prefrontal cortex; MPFC, precuneus/posterior cingulate cortex; PC/PCC, and medial temporal lobe; MTL. More evaluative, positive, descriptions were associated exclusively with neural activity in temporal-parietal junction (TPJ). Finally, human ratings indicative of more enthusiastic sentiment were associated with activation across these regions (MPFC, PC/PCC, DMPFC, TPJ, and MTL) as well as in ventral striatum (VS), inferior parietal lobule and premotor cortex. Taken together, these data demonstrate novel links between neural activity during initial idea encoding and the enthusiasm with which the ideas are subsequently delivered. This research lays the groundwork to use machine learning and neuroimaging data to study word of mouth communication and the spread of ideas in both traditional and new media environments.
Getting the word out: neural correlates of enthusiastic message propagation
Falk, Emily B.; O'Donnell, Matthew Brook; Lieberman, Matthew D.
2012-01-01
What happens in the mind of a person who first hears a potentially exciting idea?We examined the neural precursors of spreading ideas with enthusiasm, and dissected enthusiasm into component processes that can be identified through automated linguistic analysis, gestalt human ratings of combined linguistic and non-verbal cues, and points of convergence/divergence between the two. We combined tools from natural language processing (NLP) with data gathered using fMRI to link the neurocognitive mechanisms that are set in motion during initial exposure to ideas and subsequent behaviors of these message communicators outside of the scanner. Participants' neural activity was recorded as they reviewed ideas for potential television show pilots. Participants' language from video-taped interviews collected post-scan was transcribed and given to an automated linguistic sentiment analysis (SA) classifier, which returned ratings for evaluative language (evaluative vs. descriptive) and valence (positive vs. negative). Separately, human coders rated the enthusiasm with which participants transmitted each idea. More positive sentiment ratings by the automated classifier were associated with activation in neural regions including medial prefrontal cortex; MPFC, precuneus/posterior cingulate cortex; PC/PCC, and medial temporal lobe; MTL. More evaluative, positive, descriptions were associated exclusively with neural activity in temporal-parietal junction (TPJ). Finally, human ratings indicative of more enthusiastic sentiment were associated with activation across these regions (MPFC, PC/PCC, DMPFC, TPJ, and MTL) as well as in ventral striatum (VS), inferior parietal lobule and premotor cortex. Taken together, these data demonstrate novel links between neural activity during initial idea encoding and the enthusiasm with which the ideas are subsequently delivered. This research lays the groundwork to use machine learning and neuroimaging data to study word of mouth communication and the spread of ideas in both traditional and new media environments. PMID:23189049
Basic test framework for the evaluation of text line segmentation and text parameter extraction.
Brodić, Darko; Milivojević, Dragan R; Milivojević, Zoran
2010-01-01
Text line segmentation is an essential stage in off-line optical character recognition (OCR) systems. It is a key because inaccurately segmented text lines will lead to OCR failure. Text line segmentation of handwritten documents is a complex and diverse problem, complicated by the nature of handwriting. Hence, text line segmentation is a leading challenge in handwritten document image processing. Due to inconsistencies in measurement and evaluation of text segmentation algorithm quality, some basic set of measurement methods is required. Currently, there is no commonly accepted one and all algorithm evaluation is custom oriented. In this paper, a basic test framework for the evaluation of text feature extraction algorithms is proposed. This test framework consists of a few experiments primarily linked to text line segmentation, skew rate and reference text line evaluation. Although they are mutually independent, the results obtained are strongly cross linked. In the end, its suitability for different types of letters and languages as well as its adaptability are its main advantages. Thus, the paper presents an efficient evaluation method for text analysis algorithms.
Basic Test Framework for the Evaluation of Text Line Segmentation and Text Parameter Extraction
Brodić, Darko; Milivojević, Dragan R.; Milivojević, Zoran
2010-01-01
Text line segmentation is an essential stage in off-line optical character recognition (OCR) systems. It is a key because inaccurately segmented text lines will lead to OCR failure. Text line segmentation of handwritten documents is a complex and diverse problem, complicated by the nature of handwriting. Hence, text line segmentation is a leading challenge in handwritten document image processing. Due to inconsistencies in measurement and evaluation of text segmentation algorithm quality, some basic set of measurement methods is required. Currently, there is no commonly accepted one and all algorithm evaluation is custom oriented. In this paper, a basic test framework for the evaluation of text feature extraction algorithms is proposed. This test framework consists of a few experiments primarily linked to text line segmentation, skew rate and reference text line evaluation. Although they are mutually independent, the results obtained are strongly cross linked. In the end, its suitability for different types of letters and languages as well as its adaptability are its main advantages. Thus, the paper presents an efficient evaluation method for text analysis algorithms. PMID:22399932
Massicotte, Luc; Thibeault, Lynda; Roy, André
2015-07-01
During the last decade, improved surgical and anesthetic management, such as better understanding of coagulation defects and the use of the phlebotomy, has reduced intraoperative blood product transfusions during orthotopic liver transplantation (OLT). The goal of this study was to look at the impact of initial conventional coagulation tests on blood loss and blood product requirement and to evaluate the role of the phlebotomy during liver transplantations. A total of 700 consecutive OLTs were studied. The group of patients was split into two according to the median of starting international normalized ratio to study blood losses and transfusion rate. Logistic regression was used to determine the main predictors of blood loss, intraoperative blood transfusion, and survival. There was no intergroup difference for demographic characteristics. The mean blood loss was 1,184 mL with a median of 920 mL. Overall, 77.4% of the patients did not receive any blood product and the mean transfusion rate of red blood cells (RBCs) was 0.5 ± 1.4 units per patient. Severity of recipients' disease did not correlate with blood loss or transfusion rate. Starting hemoglobin value was the only biochemical variable linked to RBC transfusions. Phlebotomy was linked to decrease in blood loss, RBC transfusions, and increased survival rate. It is concluded that bleeding did not correlate with traditional coagulation defects or the severity of recipient's disease. Preemptive phlebotomy was linked to a decreased blood loss, a decreased transfusion rate, and an increased 1-year survival rate. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
Rain rate intensity model for communication link design across the Indian region
NASA Astrophysics Data System (ADS)
Kilaru, Aravind; Kotamraju, Sarat K.; Avlonitis, Nicholas; Sri Kavya, K. Ch.
2016-07-01
A study on rain statistical parameters such as one minute rain intensity, possible number of minute occurrences with respective percentage of time in a year has been evaluated for the purpose of communication link design at Ka, Q, V bands as well as at Free-Space Optical communication links (FSO). To understand possible outage period of a communication links due to rainfall and to investigate rainfall pattern, Automatic Weather Station (AWS) rainfall data is analysed due its ample presence across India. The climates of the examined AWS regions vary from desert to cold climate, heavy rainfall to variable rainfall regions, cyclone effective regions, mountain and coastal regions. In this way a complete and unbiased picture of the rainfall statistics for Indian region is evaluated. The analysed AWS data gives insight into yearly accumulated rainfall, maximum hourly accumulated rainfall, mean hourly accumulated rainfall, number of rainy days and number of rainy hours from 668 AWS locations. Using probability density function the one minute rainfall measurements at KL University is integrated with AWS measurements for estimating number of rain occurrences in terms of one minute rain intensity for annual rainfall accumulated between 100 mm and 5000 mm to give an insight into possible one minute accumulation pattern in an hour for comprehensive analysis of rainfall influence on a communication link for design engineers. So that low availability communications links at higher frequencies can be transformed into a reliable and economically feasible communication links for implementing High Throughput Services (HTS).
Pomes, M.L.; Thurman, E.M.; Aga, D.S.; Goolsby, D.A.
1998-01-01
Triazine and chloroacetanilide concentrations in rainfall samples collected from a 23-state region of the United States were analyzed with microtiter-plate enzyme-linked immunosorbent assay (ELISA). Thirty-six percent of rainfall samples (2072 out of 5691) were confirmed using gas chromatography/mass spectrometry (GC/MS) to evaluate the operating performance of ELISA as a screening test. Comparison of ELISA to GC/MS results showed that the two ELISA methods accurately reported GC/MS results (m = 1), but with more variability evident with the triazine than with the chloroacetanilide ELISA. Bayes's rule, a standardized method to report the results of screening tests, indicated that the two ELISA methods yielded comparable predictive values (80%), but the triazine ELISA yielded a false- positive rate of 11.8% and the chloroacetanilide ELISA yielded a false- negative rate of 23.1%. The false-positive rate for the triazine ELISA may arise from cross reactivity with an unknown triazine or metabolite. The false-negative rate of the chloroacetanilide ELISA probably resulted from a combination of low sensitivity at the reporting limit of 0.15 ??g/L and a distribution characterized by 75% of the samples at or below the reporting limit of 0.15 ??g/L.Triazine and chloroacetanilide concentrations in rainfall samples collected from a 23-state region of the United States were analyzed with microtiter-plate enzyme-linked immunosorbent assay (ELISA). Thirty-six percent of rainfall samples (2072 out of 5691) were confirmed using gas chromatography/mass spectrometry (GC/MS) to evaluate the operating performance of ELISA as a screening test. Comparison of ELISA to GC/MS results showed that the two ELISA methods accurately reported GC/MS results (m = 1), but with more variability evident with the triazine than with the chloroacetanilide ELISA. Bayes's rule, a standardized method to report the results of screening tests, indicated that the two ELISA methods yielded comparable predictive values (80%), but the triazine ELISA yielded a false-positive rate of 11.8% and the chloroacetanilide ELISA yielded a false-negative rate of 23.1%. The false-positive rate for the triazine ELISA may arise from cross reactivity with an unknown triazine or metabolite. The false-negative rate of the chloroacetanilide ELISA probably resulted from a combination of low sensitivity at the reporting limit of 0.15 ??g/L and a distribution characterized by 75% of the samples at or below the reporting limit of 0.15 ??g/L.
Wireless multihop backhauls for rural areas: A preliminary study.
Zaidi, Zainab; Lan, Kun-Chan
2017-01-01
Rural areas have very low revenue potential. The major issue in providing low-cost broadband to rural areas is to provide reliable backhaul connections that spread over tens or even hundreds of miles, connecting villages to the nearest service provider. Along with aerial networks of Google and Facebook, there has been a considerable amount of research toward long-distance terrestrial WiFi links. As a comparison, WiFi routers are easier to be deployed and maintained by non-technical people from the local communities, whereas the aerial networks require professional support to operate. Moreover, they are still in the experimentation phase. However, the long distance WiFi links require high-gain directional antennas and very expensive tall towers for high data rates. On the other hand, multihop paths with stronger links may provide better data rates without the need of tall towers. In this paper, we evaluated the concept of using such multihop WiFi links for long backhaul connections. Our simulation results show that these networks can possibly be a cost-effective and practical solution for rural connectivity. These initial results can serve as a first step to understand the comprehensive feasibility of using multihop WiFi networks for backhaul connections in rural area.
Chang, Ching-Wen; Ho, Hsiu-O; Lo, Yi-June; Lee, Sheng-Yang; Yang, You-Ren; Sheu, Ming-Thau
2012-01-01
In this study, hydrogels composed of polyethyleneimine (PEI) and poly(vinyl pyrrolidone) K90 (PVP) cross-linked with various concentrations (0, 0.125, 0.25 and 0.5%) of glutaraldehyde were evaluated as a hydrogel filler for the local delivery of lidocaine after tooth extraction. The drug-release kinetics, swellability, cytotoxicity and wound healing after tooth extraction of these non-cross-linked and cross-linked PEI-PVP hydrogels were examined in male beagles and compared to values using Spongostan(®). Results demonstrated that the extent of cross-linking influenced the swelling of the resulting hydrogel, but the drug-release rates were similar. No significant changes were observed in gingival fibroblasts in contact with the PEI- PVP hydrogels or Spongostan(®). In the in vivo study, PEI-PVP hydrogels showed good retention in the socket for 2 days and showed comparable wound-healing rates within 2 weeks with those of Spongostan(®). In conclusion, PEI-PVP hydrogels are suitable for use as socket-dressing materials, and the release of local anaesthesia from PEI-PVP hydrogels can be sustained for a desirable period of time to prevent pain after a tooth extraction.
Relationship of Posttreatment Decentering and Cognitive Reactivity to Relapse in Major Depression
ERIC Educational Resources Information Center
Fresco, David M.; Segal, Zindel V.; Buis, Tom; Kennedy, Sydney
2007-01-01
Z. V. Segal et al. (2006) demonstrated that depressed patients treated to remission through either antidepressant medication (ADM) or cognitive-behavioral therapy (CBT), but who evidenced mood-linked increases in dysfunctional thinking, showed elevated rates of relapse over 18 months. The current study sought to evaluate whether treatment response…
What Works in Youth Violence Prevention: A Review of the Literature
ERIC Educational Resources Information Center
Fagan, Abigail A.; Catalano, Richard F.
2013-01-01
Objectives: Given the high rates at which adolescents engage in violence, the strong link between adolescent and adult violence, and the financial and social costs of violence, the prevention of violent behavior is a national priority. Methods: The authors conducted a comprehensive review of evaluations utilizing quasi-experimental or experimental…
Quality of Care Attributions to Employed Versus Stay-at-Home Mothers
ERIC Educational Resources Information Center
Shpancer, Noam; Melick, Katherine M.; Sayre, Pamela S.; Spivey, Aria T.
2006-01-01
The present study was designed to find whether evaluations of maternal competence are linked to mothers' employment status and the quality of maternal care. Participants rated videotaped vignettes, depicting either high-quality or low-quality mother-infant interactions, on various dimensions of care quality. The videotaped mothers were described…
ERIC Educational Resources Information Center
Wang, Guanghai; Ren, Fen; Liu, Zhijun; Xu, Guangxing; Jiang, Fan; Skora, Elizabeth; Lewin, Daniel S.
2016-01-01
Background: Deficient sleep is linked to detrimental outcomes in health and school performance for adolescents. This study characterized sleep patterns in Chinese adolescents preparing for the College Entrance Exam (CEE) and evaluated the association between sleep patterns, self-rated academic performance, and the CEE scores. Methods: A sample of…
NASA Technical Reports Server (NTRS)
Reinhart, Richard C.
1992-01-01
The Experiment Control and Monitor (EC&M) software was developed at NASA Lewis Research Center to support the Advanced Communications Technology Satellite (ACTS) High Burst Rate Link Evaluation Terminal (HBR-LET). The HBR-LET is an experimenter's terminal to communicate with the ACTS for various investigations by government agencies, universities, and industry. The EC&M software is one segment of the Control and Performance Monitoring (C&PM) software system of the HBR-LET. The EC&M software allows users to initialize, control, and monitor the instrumentation within the HBR-LET using a predefined sequence of commands. Besides instrument control, the C&PM software system is also responsible for computer communication between the HBR-LET and the ACTS NASA Ground Station and for uplink power control of the HBR-LET to demonstrate power augmentation during rain fade events. The EC&M Software User's Guide, Version 1.0 (NASA-CR-189160) outlines the commands required to install and operate the EC&M software. Input and output file descriptions, operator commands, and error recovery procedures are discussed in the document.
Kim, Seon Young; Kim, Hyunjin; Park, Yeongchun; Lim, Jinsook; Kim, Jimyung; Koo, Sun Hoe; Kwon, Gye Cheol
2017-06-01
On-site drugs of abuse testing devices have undergone continuous improvement. We evaluated three devices with different designs: an automated reader, the Multi-Drug Screen Test Device with DxLINK (DxLINK; Innovacon, Alere, San Diego, USA) and two colorimetric immunoassays, the One Step Multi-Line Screen Panel with Integrated E-Z Split Key Cup II (E-Z Cup; Innovacon, Alere) and the One Step Multi-Drug Screen Panel card (Multi4 card; Alere, Abon Biopharm, Hangzhou, China). Eleven drugs [amphetamine, secobarbital, oxazepam, buprenorphine, benzoylecgonine, methylenedioxymethamphetamine (MDMA), 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC), methamphetamine, methadone, morphine and nortriptyline] were tested using the DxLINK and E-Z Cup. Four drugs (benzoylecgonine, THC, methamphetamine and morphine) were tested using the Multi4 card using control materials (Detectabuse Stat-Skreen; Biochemical Diagnostics, Edgewood, NY, USA). The concentrations (-50%, -25%, +25%, +50% and 3× cut-off values) of the control materials were confirmed by mass spectrometry. Concordance rates were calculated around cut-offs. All devices showed high overall agreement rates of >90% with a few exceptions: the DxLINK exhibited lower sensitivity for benzoylecgonine, methadone and nortriptyline (60% and 30%, 92% and 40%, and 96% and 60% sensitivity at +50% and +25% cut-off levels, respectively). The E-Z Cup exhibited lower sensitivity for oxazepam and nortriptyline (97% and 50%, and 97% and 40% sensitivity at +50% and +25% cut-off levels, respectively). We additionally evaluated test-band color by visual inspection using a standard color-scale card. When detailed color criteria for determination of positivity were applied for the E-Z Cup, using slightly less stringent criteria, oxazepam, buprenorphine, MDMA and nortriptyline showed increases in sensitivity from 70-80% to 90-100%, all with a specificity above 98%. Overall, all devices exhibited satisfactory performance at ±50% cut-off levels for commonly used drugs, with the exception of lower sensitivity for cocaine testing for DxLINK. Careful evaluation of devices and elaborate calibration of visual interpretation for determining positivity may help improve the performance of these devices. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Jäger, Marcus; van Wasen, Andrea; Warwas, Sebastian; Landgraeber, Stefan; Haversath, Marcel; Group, VITAS
2014-01-01
Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE) is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency) and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale) will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development of the implant material itself over a time period of 15 years. PMID:25002933
NASA Astrophysics Data System (ADS)
Deng, Peng; Kavehrad, Mohsen; Lou, Yan
2017-01-01
Flexible wireless datacenter networks based on free space optical communication (FSO) links are being considered as promising solutions to meet the future datacenter demands of high throughput, robustness to dynamic traffic patterns, cabling complexity and energy efficiency. Robust and precise steerable FSO links over dynamic traffic play a key role in the reconfigurable optical wireless datacenter inter-rack network. In this work, we propose and demonstrate a reconfigurable 10Gbps FSO system incorporated with smart beam acquisition and tracking mechanism based on gimballess two-axis MEMS micro-mirror and retro-reflective film marked aperture. The fast MEMS-based beam acquisition switches laser beam of FSO terminal from one rack to the next for reconfigurable networks, and the precise beam tracking makes FSO device auto-correct the misalignment in real-time. We evaluate the optical power loss and bit error rate performance of steerable FSO links at various directions. Experimental results suggest that the MEMS based beam steerable FSO links hold considerable promise for the future reconfigurable wireless datacenter networks.
Daily weather variables and affective disorder admissions to psychiatric hospitals
NASA Astrophysics Data System (ADS)
McWilliams, Stephen; Kinsella, Anthony; O'Callaghan, Eadbhard
2014-12-01
Numerous studies have reported that admission rates in patients with affective disorders are subject to seasonal variation. Notwithstanding, there has been limited evaluation of the degree to which changeable daily meteorological patterns influence affective disorder admission rates. A handful of small studies have alluded to a potential link between psychiatric admission rates and meteorological variables such as environmental temperature (heat waves in particular), wind direction and sunshine. We used the Kruskal-Wallis test, ARIMA and time-series regression analyses to examine whether daily meteorological variables—namely wind speed and direction, barometric pressure, rainfall, hours of sunshine, sunlight radiation and temperature—influence admission rates for mania and depression across 12 regions in Ireland over a 31-year period. Although we found some very weak but interesting trends for barometric pressure in relation to mania admissions, daily meteorological patterns did not appear to affect hospital admissions overall for mania or depression. Our results do not support the small number of papers to date that suggest a link between daily meteorological variables and affective disorder admissions. Further study is needed.
NASA Technical Reports Server (NTRS)
May, Brian D.
1992-01-01
The experimental NASA satellite, Advanced Communications Technology Satellite (ACTS), introduces new technology for high throughput 30 to 20 GHz satellite services. Contained in a single communication payload is both a regenerative TDMA system and multiple 800 MHz 'bent pipe' channels routed to spot beams by a switch matrix. While only one mode of operation is typical during any experiment, both modes can operate simultaneously with reduced capability due to sharing of the transponder. NASA-Lewis instituted a ground terminal development program in anticipation of the satellite launch to verify the performance of the switch matrix mode of operations. Specific functions are built into the ground terminal to evaluate rain fade compensation with uplink power control and to monitor satellite transponder performance with bit error rate measurements. These functions were the genesis of the ground terminal's name, Link Evaluation Terminal, often referred to as LET. Connectors are included in LET that allow independent experimenters to run unique modulation or network experiments through ACTS using only the RF transmit and receive portions of LET. Test data indicate that LET will be able to verify important parts of ACTS technology and provide independent experimenters with a useful ground terminal. Lab measurements of major subsystems integrated into LET are presented. Bit error rate is measured with LET in an internal loopback mode.
Gadkar, Kapil; Lu, James; Sahasranaman, Srikumar; Davis, John; Mazer, Norman A.; Ramanujan, Saroja
2016-01-01
The recent failures of cholesteryl ester transport protein inhibitor drugs to decrease CVD risk, despite raising HDL cholesterol (HDL-C) levels, suggest that pharmacologic increases in HDL-C may not always reflect elevations in reverse cholesterol transport (RCT), the process by which HDL is believed to exert its beneficial effects. HDL-modulating therapies can affect HDL properties beyond total HDL-C, including particle numbers, size, and composition, and may contribute differently to RCT and CVD risk. The lack of validated easily measurable pharmacodynamic markers to link drug effects to RCT, and ultimately to CVD risk, complicates target and compound selection and evaluation. In this work, we use a systems pharmacology model to contextualize the roles of different HDL targets in cholesterol metabolism and provide quantitative links between HDL-related measurements and the associated changes in RCT rate to support target and compound evaluation in drug development. By quantifying the amount of cholesterol removed from the periphery over the short-term, our simulations show the potential for infused HDL to treat acute CVD. For the primary prevention of CVD, our analysis suggests that the induction of ApoA-I synthesis may be a more viable approach, due to the long-term increase in RCT rate. PMID:26522778
Gadkar, Kapil; Lu, James; Sahasranaman, Srikumar; Davis, John; Mazer, Norman A; Ramanujan, Saroja
2016-01-01
The recent failures of cholesteryl ester transport protein inhibitor drugs to decrease CVD risk, despite raising HDL cholesterol (HDL-C) levels, suggest that pharmacologic increases in HDL-C may not always reflect elevations in reverse cholesterol transport (RCT), the process by which HDL is believed to exert its beneficial effects. HDL-modulating therapies can affect HDL properties beyond total HDL-C, including particle numbers, size, and composition, and may contribute differently to RCT and CVD risk. The lack of validated easily measurable pharmacodynamic markers to link drug effects to RCT, and ultimately to CVD risk, complicates target and compound selection and evaluation. In this work, we use a systems pharmacology model to contextualize the roles of different HDL targets in cholesterol metabolism and provide quantitative links between HDL-related measurements and the associated changes in RCT rate to support target and compound evaluation in drug development. By quantifying the amount of cholesterol removed from the periphery over the short-term, our simulations show the potential for infused HDL to treat acute CVD. For the primary prevention of CVD, our analysis suggests that the induction of ApoA-I synthesis may be a more viable approach, due to the long-term increase in RCT rate. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.
Evolution of Cooperation in Adaptive Social Networks
NASA Astrophysics Data System (ADS)
Segbroeck, Sven Van; Santos, Francisco C.; Traulsen, Arne; Lenaerts, Tom; Pacheco, Jorge M.
Humans are organized in societies, a phenomenon that would never have been possible without the evolution of cooperative behavior. Several mechanisms that foster this evolution have been unraveled over the years, with population structure as a prominent promoter of cooperation. Modern networks of exchange and cooperation are, however, becoming increasingly volatile, and less and less based on long-term stable structure. Here, we address how this change of paradigm aspects the evolution of cooperation. We discuss analytical and numerical models in which individuals can break social ties and create new ones. Interactions are modeled as two-player dilemmas of cooperation. Once a link between two individuals has formed, the productivity of this link is evaluated. Links can be broken off at different rates. This individual capacity of forming new links or severing inconvenient ones can effectively change the nature of the game. We address random formation of new links and local linking rules as well as different individual capacities to maintain social interactions. We conclude by discussing how adaptive social networks can become an important step towards more realistic models of cultural dynamics.
Jamil, Qurratul Ain; Masood, Muhammad Irfan; Jamil, Muhammad Nauman; Masood, Imran; Iqbal, Shahid Muhammad
2017-03-01
Polysaccharide gums because of their biocompatibility, biodegradability and non-immunogenic properties are considered as the best choice for preparing sustained release tablets as compared to their synthetic counterpart. The cross linking of natural gums in matrix tablets increase the sustained release property of matrix tablets. Isoniazid is a first line therapy of tuberculosis, belongs to BCS I with half-life of 3-4 hours. These characteristics make isoniazid a good candidate for sustained release dosage form. Karaya gum crossed linked with trisodium tri metaphosphate was used as release rate retardant for preparing isoniazid cross-linked matrix tablet. Total 8 sustained release formulations were prepared. Both granules and tablets were evaluated under in vitro condition against different parameters. Dissolution studies were performed with all eight formulations for 12 hours using USP apparatus I. Four formulations designated as F1, F2, F3, F4 have drug and karaya gum while other four formulations F5, F6, F7, F8 have drug and crossed linked polymer in ratios of 1:1, 1:2, 1:3 and 1:4 respectively. Dissolution data was analyzed by using different kinetic models. Best fit model for most efficient formulation was zero order while release mechanism was super case I. Formulation 8 showed sufficiently slow release kinetics and about 83% of drug was released in 10 hours, indicating that cross-linked karaya gum proved efficient in preparing sustained release tablets.
Pereira, Laurent; Choquet, Christophe; Perozziello, Anne; Wargon, Mathias; Juillien, Gaelle; Colosi, Luisa; Hellmann, Romain; Ranaivoson, Michel; Casalino, Enrique
2015-01-01
Predictors of unscheduled return visits (URV), best time-frame to evaluate URV rate and clinical relationship between both visits have not yet been determined for the elderly following an ED visit. We conducted a prospective-observational study including 11,521 patients aged ≥75-years and discharged from ED (5,368 patients (53.5%)) or hospitalized after ED visit (6,153 patients). Logistic Regression and time-to-failure analyses including Cox proportional model were performed. Mean time to URV was 17 days; 72-hour, 30-day and 90-day URV rates were 1.8%, 6.1% and 10% respectively. Multivariate analysis indicates that care-pathway and final disposition decisions were significantly associated with a 30-day URV. Thus, we evaluated predictors of 30-day URV rates among non-admitted and hospitalized patient groups. By using the Cox model we found that, for non-admitted patients, triage acuity and diagnostic category and, for hospitalized patients, that visit time (day, night) and diagnostic categories were significant predictors (p<0.001). For URV, we found that 25% were due to closely related-clinical conditions. Time lapses between both visits constituted the strongest predictor of closely related-clinical conditions. Our study shows that a decision of non-admission in emergency departments is linked with an accrued risk of URV, and that some diagnostic categories are also related for non-admitted and hospitalized subjects alike. Our study also demonstrates that the best time frame to evaluate the URV rate after an ED visit is 30 days, because this is the time period during which most URVs and cases with close clinical relationships between two visits are concentrated. Our results suggest that URV can be used as an indicator or quality.
Wear of a 5 megarad cross-linked polyethylene liner: a 6-year RSA study.
Callary, Stuart A; Campbell, David G; Mercer, Graham; Nilsson, Kjell G; Field, John R
2013-07-01
One cross-linked polyethylene (XLPE) liner is manufactured using a lower dose of radiation, 5 Mrad, which may result in less cross-linking. The reported in vivo wear rate of this XLPE liner in patients undergoing THA has varied, and has included some patients in each reported cohort who had greater than 0.1 mm/year of wear, which is an historical threshold for osteolysis. Previous studies have measured wear on plain radiographs, an approach that has limited sensitivity. We therefore measured the amount and direction of wear at 6 years using Radiostereometric analysis (RSA) in patients who had THAs that included a cross-linked polyethylene liner manufactured using 5 Mrad radiation. We prospectively reviewed wear in 30 patients who underwent primary THAs with the same design of cross-linked acetabular liner and a 28-mm articulation. Tantalum markers were inserted during surgery and all patients had RSA radiographic examinations at 1 week, 6 months, 1, 2, and 6 years postoperatively. The mean proximal, two-dimensional (2-D) and three-dimensional (3-D) wear rates calculated between 1 year and 6 years were 0.014, 0.014, and 0.018 mm/per year, respectively. The direction of the head penetration recorded between 1 week and 6 years was in a proximal direction for all patients, proximolateral for 16 of 24 patients, and proximomedial for eight of 24 patients. The proximal, 2-D and 3-D wear of a XLPE liner produced using 5 Mrad of radiation was low but measurable by RSA after 6 years. No patients had proximal 2-D or 3-D wear rates exceeding 0.1 mm/year. Further followup is needed to evaluate the effect of XLPE wear particles on the development of long-term osteolysis.
Putnam-Hornstein, Emily; King, Bryn
2014-04-01
This study used linked foster care and birth records to provide a longitudinal, population-level examination of the incidence of first and repeat births among girls who were in foster care at age 17. Girls in a foster care placement in California at the age of 17 between 2003 and 2007 were identified from statewide child protection records. These records were probabilistically matched to vital birth records spanning the period from 2001 to 2010. Linked data were used to estimate the cumulative percentage of girls who had given birth before age 20. Birth rates and unadjusted risk ratios were generated to characterize foster care experiences correlated with heightened teen birth rates. Between 2003 and 2007 in California, there were 20,222 girls in foster care at age 17. Overall, 11.4% had a first birth before age 18. The cumulative percentage who gave birth before age 20 was 28.1%. Among girls who had a first birth before age 18, 41.2% had a repeat teen birth. Significant variations by race/ethnicity and placement-related characteristics emerged. Expanded data and rigorous research are needed to evaluate prevention efforts and ensure parenting teens are provided with the needed services and supports. Copyright © 2013 Elsevier Ltd. All rights reserved.
Fire management and carbon sequestration in Pine Barren Forests
Kenneth L. Clark; Nicholas Skowronski; Michael Gallagher
2015-01-01
Prescribed burning is the major viable option that land managers have for reducing hazardous fuels and ensuring the regeneration of fire-dependent species in a cost-effective manner in Pine Barren ecosystems. Fuels management activities are directly linked to carbon (C) storage and rates of C sequestration by forests. To evaluate the effects of prescribed burning on...
Wireless multihop backhauls for rural areas: A preliminary study
Zaidi, Zainab; Lan, Kun-chan
2017-01-01
Rural areas have very low revenue potential. The major issue in providing low-cost broadband to rural areas is to provide reliable backhaul connections that spread over tens or even hundreds of miles, connecting villages to the nearest service provider. Along with aerial networks of Google and Facebook, there has been a considerable amount of research toward long-distance terrestrial WiFi links. As a comparison, WiFi routers are easier to be deployed and maintained by non-technical people from the local communities, whereas the aerial networks require professional support to operate. Moreover, they are still in the experimentation phase. However, the long distance WiFi links require high-gain directional antennas and very expensive tall towers for high data rates. On the other hand, multihop paths with stronger links may provide better data rates without the need of tall towers. In this paper, we evaluated the concept of using such multihop WiFi links for long backhaul connections. Our simulation results show that these networks can possibly be a cost-effective and practical solution for rural connectivity. These initial results can serve as a first step to understand the comprehensive feasibility of using multihop WiFi networks for backhaul connections in rural area. PMID:28403167
Children's success at detecting circular explanations and their interest in future learning.
Mills, Candice M; Danovitch, Judith H; Rowles, Sydney P; Campbell, Ian L
2017-10-01
These studies explore elementary-school-aged children's ability to evaluate circular explanations and whether they respond to receiving weak explanations by expressing interest in additional learning. In the first study, 6-, 8-, and 10-year-olds (n = 53) heard why questions about unfamiliar animals. For each question, they rated the quality of single explanations and later selected the best explanation between pairs of circular and noncircular explanations. When judging single explanations, 8- and 10-year-olds, and to some extent 6-year-olds, provided higher ratings for noncircular explanations compared to circular ones. When selecting between pairs of explanations, all age groups preferred noncircular explanations to circular ones, but older children did so more consistently than 6-year-olds. Children who recognized the weakness of the single circular explanations were more interested in receiving additional information about the question topics. In Study 2, all three age groups (n = 87) provided higher ratings for noncircular explanations compared to circular ones when listening to responses to how questions, but older children showed a greater distinction in their ratings than 6-year-olds. Moreover, the link between recognizing circular explanations as weak and interest in future learning could not be accounted for solely by individual differences in verbal intelligence. These findings illustrate the developmental trajectory of explanation evaluation and support that recognition of weak explanations is linked to interest in future learning across the elementary years. Implications for education are discussed.
Evaluating the Role of Small Impoundments in Legacy Sediment Storage
NASA Astrophysics Data System (ADS)
Bain, D. J.; Salant, N.; Green, M. B.; Wreschnig, A. J.; Urbanova, T.
2009-12-01
Recent research highlighting the prevalence of dams built for water power in the mid-1800s has led to suggestions that strategies for managing legacy sediment in the Eastern United States should be re-evaluated. However, the link between reach-scale observations of historic dam sites to processes at the catchment scale have not been examined, nor have the role of other, similar historic changes been evaluated. This presentation will compare dam dynamics, including mill density data and synthetic estimates of beaver populations with sedimentation rates recorded in sediment cores. If low-head dams were a dominant mechanism in sediment storage, we expect to see changes in sedimentation rates with the expatriation of the beaver and the rise and decline of water power. Further, we expect to see spatial variation in these changes as beaver and mill densities and potential sediment yield are spatially heterogeneous. Ultimately, dramatic changes in sediment yield due to land use and hydrological alterations likely drove sedimentation rates; the mechanistic importance of storage likely depends on temporal coincidence.
NASA Technical Reports Server (NTRS)
Iannicca, Dennis; Hylton, Alan; Ishac, Joseph
2012-01-01
Delay-Tolerant Networking (DTN) is an active area of research in the space communications community. DTN uses a standard layered approach with the Bundle Protocol operating on top of transport layer protocols known as convergence layers that actually transmit the data between nodes. Several different common transport layer protocols have been implemented as convergence layers in DTN implementations including User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and Licklider Transmission Protocol (LTP). The purpose of this paper is to evaluate several stand-alone implementations of negative-acknowledgment based transport layer protocols to determine how they perform in a variety of different link conditions. The transport protocols chosen for this evaluation include Consultative Committee for Space Data Systems (CCSDS) File Delivery Protocol (CFDP), Licklider Transmission Protocol (LTP), NACK-Oriented Reliable Multicast (NORM), and Saratoga. The test parameters that the protocols were subjected to are characteristic of common communications links ranging from terrestrial to cis-lunar and apply different levels of delay, line rate, and error.
NASA Astrophysics Data System (ADS)
Wang, Xingle; Kiamilev, Fouad; Gui, Ping; Wang, Xiaoqing; Ekman, Jeremy; Zuo, Yongrong; Blankenberg, Jason; Haney, Michael
2006-06-01
A 2 Gb/s0.5 μm complementary metal-oxide semiconductor optical transceiver designed for board- or backplane level power-efficient interconnections is presented. The transceiver supports optical wake-on-link (OWL), an event-driven dynamic power-on technique. Depending on external events, the transceiver resides in either the active mode or the sleep mode and switches accordingly. The active-to-sleep transition shuts off the normal, gigabit link and turns on dedicated circuits to establish a low-power (~1.8 mW), low data rate (less than 100 Mbits/s) link. In contrast the normal, gigabit link consumes over 100 mW. Similarly the sleep-to-active transition shuts off the low-power link and turns on the normal, gigabit link. The low-power link, sharing the same optical channel with the normal, gigabit link, is used to achieve transmitter/receiver pair power-on synchronization and greatly reduces the power consumption of the transceiver. A free-space optical platform was built to evaluate the transceiver performance. The experiment successfully demonstrated the event-driven dynamic power-on operation. To our knowledge, this is the first time a dynamic power-on scheme has been implemented for optical interconnects. The areas of the circuits that implement the low-power link are approximately one-tenth of the areas of the gigabit link circuits.
The Survival of Total Knee Arthroplasty: Current Data from Registries on Tribology: Review Article.
Civinini, Roberto; Carulli, Christian; Matassi, Fabrizio; Lepri, Andrea Cozzi; Sirleo, Luigi; Innocenti, Massimo
2017-02-01
Polyethylene (PE) wear is a major contributor to implant loosening following total knee arthroplasty (TKA), and advanced bearings in TKA are being investigated with hopes of reducing or eliminate wear-related loosening. Currently, information on knee tribology is available from national joint registries and may be the best tools to evaluate the efficacy and safety of design innovations in joint arthroplasty. We performed a review of national joint registries trying to answer the following questions: "Which is the main factor directly related to revisions rate in TKA?" and "Are there new bearing options better than conventional ones?" A review was performed of all published annual reports of National Joint Registers, as well as of the literature. The search was carried out using and comparing the National Joint Registers. Current data from registries for total knee arthroplasty indicates that age is the major factor affecting the outcome of primary total knee replacement. The 10-year cumulative revision rate for non-cross-linked PE was 5.8% and for XLPE it was 3.5%. The effect of cross-linked polyethylene was more evident in the younger patients. The survival of the oxidized zirconium (OxZr) femoral component appears better when compared to a similar age group of patients with conventional group of prostheses. Our review suggests that the revision rates are half for the OxZr components compared to conventional CoCr femoral components. Age is the most relevant single factor related to revision rate. Cross-linked PE has a statistical lower revision rate at 10 years compared to conventional PE and, in the OxZr group, the revision rate is 2 times lower than Co-Cr in the same group of age.
Higher order mode laser beam intensity fluctuations in strong oceanic turbulence
NASA Astrophysics Data System (ADS)
Baykal, Yahya
2017-05-01
Intensity fluctuations of the higher order mode laser beams are evaluated when these beams propagate in a medium exhibiting strong oceanic turbulence. Our formulation involves the modified Rytov solution that extends the Rytov solution to cover strong turbulence as well, and our recently reported expression that relates the atmospheric turbulence structure constant to the oceanic turbulence parameters and oceanic wireless optical communication link parameters. The variations of the intensity fluctuations are reported against the changes of the ratio of temperature to salinity contributions to the refractive index spectrum, rate of dissipation of kinetic energy per unit mass of fluid, rate of dissipation of mean-squared temperature, viscosity and the source size of the higher order mode laser beam. Our results indicate that under any oceanic turbulence parameters, it is advantageous to employ higher order laser modes in reducing the scintillation noise in wireless optical communication links operating in a strongly turbulent ocean.
Performance improvement on a MIMO radio-over-fiber system by probabilistic shaping
NASA Astrophysics Data System (ADS)
Kong, Miao; Yu, Jianjun
2018-01-01
As we know, probabilistic shaping (PS), as a typical one of modulation format optimization technologies, becomes a promising technology and attracts more and more attention, because of its higher transmission capacity and lower computation complexity. In this paper, we experimentally demonstrated a reliable 8 Gbaud-rate delivery of polarization multiplexed PS 16-QAM single carrier signal in a MIMO radio-over-fiber system with 20-km SMF-28 wire link and 2.5-m wireless link at 60 GHz. The BER performance of PS 16-QAM signals at different baud rate was also evaluated. What is more, PS 16-QAM was also experimentally compared with uniform 16-QAM, and it can be concluded that PS 16-QAM brings a better compromise between effectiveness and reliability performance and a higher capacity than uniform 16-QAM for the radio-over-fiber system.
Norman, Wendy V; Kaczorowski, Janusz; Soon, Judith A; Brant, Rollin; Bryan, Stirling; Trouton, Konia J; Dicus, Lyda
2011-06-14
We describe the rationale and protocol for a randomized controlled trial (RCT) to assess whether intrauterine contraception placed immediately after a second trimester abortion will result in fewer pregnancies than current recommended practice of intended placement at 4 weeks post-abortion. Decision analysis suggests the novel strategy could substantially reduce subsequent unintended pregnancies and abortions. This paper highlights considerations of design, implementation and evaluation of a trial expected to provide rigorous evidence for appropriate insertion timing and health economics of intrauterine contraception after second trimester abortion. Consenting women choosing to use intrauterine contraception after abortion for a pregnancy of 12 to 24 weeks will be randomized to insertion timing groups either immediately (experimental intervention) or four weeks (recommended care) post abortion. Primary outcome measure is pregnancy rate at one year. Secondary outcomes include: cumulative pregnancy rates over five year follow-up period, comprehensive health economic analyses comparing immediate and delayed insertion groups, and device retention rates, complication rates (infection, expulsion) and, contraceptive method satisfaction. Web-based Contraception Satisfaction Questionnaires, clinical records and British Columbia linked health databases will be used to assess primary and secondary outcomes. Enrolment at all clinics in the province performing second trimester abortions began in May 2010 and is expected to complete in late 2011. Data on one year outcomes will be available for analysis in 2014. The RCT design combined with access to clinical records at all provincial abortion clinics, and to information in provincial single-payer linked administrative health databases, birth registry and hospital records, offers a unique opportunity to evaluate such an approach by determining pregnancy rate at one through five years among enrolled women. We highlight considerations of design, implementation and evaluation of a trial expected to provide rigorous evidence for appropriate insertion timing and health economics of intrauterine contraception after second trimester abortion.
2011-01-01
Background We describe the rationale and protocol for a randomized controlled trial (RCT) to assess whether intrauterine contraception placed immediately after a second trimester abortion will result in fewer pregnancies than current recommended practice of intended placement at 4 weeks post-abortion. Decision analysis suggests the novel strategy could substantially reduce subsequent unintended pregnancies and abortions. This paper highlights considerations of design, implementation and evaluation of a trial expected to provide rigorous evidence for appropriate insertion timing and health economics of intrauterine contraception after second trimester abortion. Methods/Design Consenting women choosing to use intrauterine contraception after abortion for a pregnancy of 12 to 24 weeks will be randomized to insertion timing groups either immediately (experimental intervention) or four weeks (recommended care) post abortion. Primary outcome measure is pregnancy rate at one year. Secondary outcomes include: cumulative pregnancy rates over five year follow-up period, comprehensive health economic analyses comparing immediate and delayed insertion groups, and device retention rates, complication rates (infection, expulsion) and, contraceptive method satisfaction. Web-based Contraception Satisfaction Questionnaires, clinical records and British Columbia linked health databases will be used to assess primary and secondary outcomes. Enrolment at all clinics in the province performing second trimester abortions began in May 2010 and is expected to complete in late 2011. Data on one year outcomes will be available for analysis in 2014. Discussion The RCT design combined with access to clinical records at all provincial abortion clinics, and to information in provincial single-payer linked administrative health databases, birth registry and hospital records, offers a unique opportunity to evaluate such an approach by determining pregnancy rate at one through five years among enrolled women. We highlight considerations of design, implementation and evaluation of a trial expected to provide rigorous evidence for appropriate insertion timing and health economics of intrauterine contraception after second trimester abortion. Trial registration Current Controlled Trials ISRCTN19506752 PMID:21672213
Simulator of Space Communication Networks
NASA Technical Reports Server (NTRS)
Clare, Loren; Jennings, Esther; Gao, Jay; Segui, John; Kwong, Winston
2005-01-01
Multimission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) is a suite of software tools that simulates the behaviors of communication networks to be used in space exploration, and predict the performance of established and emerging space communication protocols and services. MACHETE consists of four general software systems: (1) a system for kinematic modeling of planetary and spacecraft motions; (2) a system for characterizing the engineering impact on the bandwidth and reliability of deep-space and in-situ communication links; (3) a system for generating traffic loads and modeling of protocol behaviors and state machines; and (4) a system of user-interface for performance metric visualizations. The kinematic-modeling system makes it possible to characterize space link connectivity effects, including occultations and signal losses arising from dynamic slant-range changes and antenna radiation patterns. The link-engineering system also accounts for antenna radiation patterns and other phenomena, including modulations, data rates, coding, noise, and multipath fading. The protocol system utilizes information from the kinematic-modeling and link-engineering systems to simulate operational scenarios of space missions and evaluate overall network performance. In addition, a Communications Effect Server (CES) interface for MACHETE has been developed to facilitate hybrid simulation of space communication networks with actual flight/ground software/hardware embedded in the overall system.
Blöte, Anke W; Miers, Anne C; Van den Bos, Esther; Westenberg, P Michiel
2018-05-17
Cognitive behavioural therapy (CBT) has relatively poor outcomes for youth with social anxiety, possibly because broad-based CBT is not tailored to their specific needs. Treatment of social anxiety in youth may need to pay more attention to negative social cognitions that are considered a key factor in social anxiety development and maintenance. The aim of the present study was to learn more about the role of performance quality in adolescents' cognitions about their social performance and, in particular, the moderating role social anxiety plays in the relationship between performance quality and self-cognitions. A community sample of 229 participants, aged 11 to 18 years, gave a speech and filled in questionnaires addressing social anxiety, depression, expected and self-evaluated performance, and post-event rumination. Independent observers rated the quality of the speech. The data were analysed using moderated mediation analysis. Performance quality mediated the link between expected and self-evaluated performance in adolescents with low and medium levels of social anxiety. For adolescents with high levels of social anxiety, only a direct link between expected and self-evaluated performance was found. Their self-evaluation was not related to the quality of their performance. Performance quality also mediated the link between expected performance and rumination, but social anxiety did not moderate this mediation effect. Results suggest that a good performance does not help socially anxious adolescents to replace their negative self-evaluations with more realistic ones. Specific cognitive intervention strategies should be tailored to the needs of socially anxious adolescents who perform well.
Cwik, Mary F; Tingey, Lauren; Maschino, Alexandra; Goklish, Novalene; Larzelere-Hinton, Francene; Walkup, John; Barlow, Allison
2016-12-01
We evaluated the impact of a comprehensive, multitiered youth suicide prevention program among the White Mountain Apache of Arizona since its implementation in 2006. Using data from the tribally mandated Celebrating Life surveillance system, we compared the rates, numbers, and characteristics of suicide deaths and attempts from 2007 to 2012 with those from 2001 to 2006. The overall Apache suicide death rates dropped from 40.0 to 24.7 per 100 000 (38.3% decrease), and the rate among those aged 15 to 24 years dropped from 128.5 to 99.0 per 100 000 (23.0% decrease). The annual number of attempts also dropped from 75 (in 2007) to 35 individuals (in 2012). National rates remained relatively stable during this time, at 10 to 13 per 100 000. Although national rates remained stable or increased slightly, the overall Apache suicide death rates dropped following the suicide prevention program. The community surveillance system served a critical role in providing a foundation for prevention programming and evaluation.
High Capacity Communications From Martian Distances. Part 1; Spacecraft Link Design Analysis
NASA Technical Reports Server (NTRS)
Vyas, Hemali N.; Schuchman, Leonard; Orr, Richard; Williams, Wallace Dan; Collins, Michael; Noreen, Gary
2006-01-01
High capacity space communications has been a desire for Human Exploration and Science missions. Current Mars missions operate at data rates of 120 kbps for telemetry downlink and it is desirable to study high rate communication links in the range of 100 Mbps to 1 Gbps data rates from Martian distances. This paper will present some assumed scenarios along with link design assumptions and link analysis for high capacity communications from Mars. The paper will focus on RF subsystems namely antenna and power for the downlink communication from a relay orbiter at Mars. The relay orbiter will communicate with the low orbit spacecrafts at Mars or any Martian surface elements such as robots, and relay the data back to the ground networks on Earth. The study will dive into the spacecraft downlink system design and communication link analysis between the relay orbiter and ground network on Earth for data rates ranging from 100 Mbps to 1 Gbps based on the assumed scenarios and link assumptions. With high rate links at larger distances, there will be a significant impact on the antenna and power requirements and the link design will make an attempt to minimize the mass of the RF subsystem on the spacecraft. The results of this study will be presented for three data rates 1 Gbps, 500 Mbps and 100 Mbps at maximum Mars to Earth distance of 2.67AU. The design will use a Ka-band downlink with 90% link availability, along with various ground network G/T assumptions and possible bandwidth efficient modulations. The paper will conclude with what types of high rate communication links are feasible from Martian distances and also identify a range of requirements for antenna and power technologies for these high capacity communications from Mars.
Prediction and measurement of thermally induced cambial tissue necrosis in tree stems
Joshua L. Jones; Brent W. Webb; Bret W. Butler; Matthew B. Dickinson; Daniel Jimenez; James Reardon; Anthony S. Bova
2006-01-01
A model for fire-induced heating in tree stems is linked to a recently reported model for tissue necrosis. The combined model produces cambial tissue necrosis predictions in a tree stem as a function of heating rate, heating time, tree species, and stem diameter. Model accuracy is evaluated by comparison with experimental measurements in two hardwood and two softwood...
ERIC Educational Resources Information Center
Gould, Madelyn S.; Munfakh, Jimmie L. H.; Kleinman, Marjorie; Lake, Alison M.
2012-01-01
Linking at-risk callers to ongoing mental health care is a key goal of crisis hotline interventions that has not often been addressed in evaluations of hotlines' effectiveness. We conducted telephone interviews with 376 suicidal and 278 nonsuicidal crisis callers to the National Suicide Prevention Lifeline (Lifeline) to assess rates of mental…
Adaptive Wavelet Coding Applied in a Wireless Control System.
Gama, Felipe O S; Silveira, Luiz F Q; Salazar, Andrés O
2017-12-13
Wireless control systems can sense, control and act on the information exchanged between the wireless sensor nodes in a control loop. However, the exchanged information becomes susceptible to the degenerative effects produced by the multipath propagation. In order to minimize the destructive effects characteristic of wireless channels, several techniques have been investigated recently. Among them, wavelet coding is a good alternative for wireless communications for its robustness to the effects of multipath and its low computational complexity. This work proposes an adaptive wavelet coding whose parameters of code rate and signal constellation can vary according to the fading level and evaluates the use of this transmission system in a control loop implemented by wireless sensor nodes. The performance of the adaptive system was evaluated in terms of bit error rate (BER) versus E b / N 0 and spectral efficiency, considering a time-varying channel with flat Rayleigh fading, and in terms of processing overhead on a control system with wireless communication. The results obtained through computational simulations and experimental tests show performance gains obtained by insertion of the adaptive wavelet coding in a control loop with nodes interconnected by wireless link. These results enable the use of this technique in a wireless link control loop.
Mitochondrial DNA variation in human metabolic rate and energy expenditure
Tranah, Gregory J.; Manini, Todd M.; Lohman, Kurt K.; Nalls, Michael A.; Kritchevsky, Stephen; Newman, Anne B.; Harris, Tamara B.; Miljkovic, Iva; Biffi, Alessandro; Cummings, Steven R.; Liu, Yongmei
2014-01-01
The role of climate in driving selection of mtDNA as Homo sapiens migrated out of Africa into Eurasia remains controversial. We evaluated the role of mtDNA variation in resting metabolic rate (RMR) and total energy expenditure (TEE) among 294 older, community-dwelling African and European American adults from the Health, Aging and Body Composition Study. Common African haplogroups L0, L2 and L3 had significantly lower RMRs than European haplogroups H, JT and UK with haplogroup L1 RMR being intermediate to these groups. This study links mitochondrial haplogroups with ancestry-associated differences in metabolic rate and energy expenditure. PMID:21586348
Experimental FSO network availability estimation using interactive fog condition monitoring
NASA Astrophysics Data System (ADS)
Turán, Ján.; Ovseník, Łuboš
2016-12-01
Free Space Optics (FSO) is a license free Line of Sight (LOS) telecommunication technology which offers full duplex connectivity. FSO uses infrared beams of light to provide optical broadband connection and it can be installed literally in a few hours. Data rates go through from several hundreds of Mb/s to several Gb/s and range is from several 100 m up to several km. FSO link advantages: Easy connection establishment, License free communication, No excavation are needed, Highly secure and safe, Allows through window connectivity and single customer service and Compliments fiber by accelerating the first and last mile. FSO link disadvantages: Transmission media is air, Weather and climate dependence, Attenuation due to rain, snow and fog, Scattering of laser beam, Absorption of laser beam, Building motion and Air pollution. In this paper FSO availability evaluation is based on long term measured data from Fog sensor developed and installed at TUKE experimental FSO network in TUKE campus, Košice, Slovakia. Our FSO experimental network has three links with different physical distances between each FSO heads. Weather conditions have a tremendous impact on FSO operation in terms of FSO availability. FSO link availability is the percentage of time over a year that the FSO link will be operational. It is necessary to evaluate the climate and weather at the actual geographical location where FSO link is going to be mounted. It is important to determine the impact of a light scattering, absorption, turbulence and receiving optical power at the particular FSO link. Visibility has one of the most critical influences on the quality of an FSO optical transmission channel. FSO link availability is usually estimated using visibility information collected from nearby airport weather stations. Raw data from fog sensor (Fog Density, Relative Humidity, Temperature measured at each ms) are collected and processed by FSO Simulator software package developed at our Department. Based on FSO link data the FSO link and experimental FSO network availability was estimated for years from 2007 up to 2015. The average FSO network availability up to 98,3378 % was measured (for the BER 10-9). From the experimental data also Hybrid RF/FSO link availability was evaluated. As the weather conditions for FSO and RF link are complementary (FSO works well in rain and RF works well in fog) Hybrid FSO/RF system long time average availability was much better up to 99,9986 %.
Krenek, Kimberly A; Barnes, Ryan C; Talcott, Stephen T
2014-10-01
A detailed characterization of mango pulp polyphenols and other minor phytochemicals was accomplished for the first time in the cultivar 'Keitt' whereby the identification and semiquantification of five hydroxybenzoic acids, four cinnamic acids, two flavonoids, and six apocarotenoids was accomplished. Among the most abundant compounds were two monogalloyl glucosides (MGG) identified as having an ester- or ether-linked glucose, with the ester-linked moiety present in the highest concentration among nontannin polyphenolics. Additionally, the impact of side activities of three commercial cell-wall degrading enzymes during 'Keitt' mango pulp processing was evaluated to determine their role on the hydrolysis of ester- and ether-linked phenolic acids. The use of Crystalzyme 200XL reduced the concentration of ester-linked MGG by 66%, and the use of Rapidase AR 2000 and Validase TRL completely hydrolyzed ether-linked MGG after 4 h of treatment at 50 °C. Fruit quality, in vivo absorption rate, and bioactivity of mango phytochemicals rely on their chemical characterization, and characterizing changes in composition is critical for a complete understanding of in vivo mechanisms.
Postpartum thyroid dysfunction and postpartum depression: are they two linked disorders?
Lucas, A; Pizarro, E; Granada, M L; Salinas, I; Sanmartí, A
2001-12-01
Postpartum has been considered as a period of risk for developing postpartum depression (PD) by some but not all authors, and this PD has been linked with postpartum thyroid dysfunction (PPTD). The major aim of this study was to evaluate the relation between the presence of PPTD and PD. Six hundred and forty-one healthy Caucasian women recruited between their 36th week of pregnancy and fourth day postpartum underwent clinical and laboratory evaluation and were checked again at 1 (n = 605), 3 (n = 552), 6 (n = 574), 9 (n = 431), and 12 (n = 444) months postpartum. At baseline and at each clinical evaluation, Beck Depression Inventory (BDI) was administered to screen PD. The definitive diagnoses of PD was performed by a psychiatrist according to the DSM-III-R criteria. At each visit, we determined serum free T4 and TSH concentrations. Thyroperoxidase and thyroglobulin antibodies were determined only in patients with abnormal hormone concentrations. Postpartum thyroiditis (PPT) was considered to be present in women with overt or subclinical transient hyperthyroidism between 1 and 3 months postpartum and/or overt or subclinical hypothyroidism between 3 and 6 months postpartum. Fifty-six women developed postpartum thyroid dysfunction (PPTD), corresponding to an incidence rate of 11%: 45 with PPT [incidence rate 7.8%; confidence interval (CI) 5.6-10%], eight with Graves' disease (incidence rate 1.5%; CI 0.5-2.5%) and three with nonpalpable toxic thyroid adenoma (incidence rate 0.5%; CI 0-1.5%). Five hundred and eighty of the evaluated women (incidence rate 90.5%; CI 95% 88.2-92.8) presented BDI scores below 21 and therefore the PD diagnoses was excluded. In 50 cases (incidence rate 7.8%; Cl 95% 5.7-9.8), we detected a BDI score over 21 in some evaluations, but the PD diagnosis was not confirmed. Another 11 (incidence rate 1.7%; CI 95% 0.7-2.7) were diagnosed as having PD and required psychiatric treatment. None of the PPTD was diagnosed as having PD. The BDI scores frequency over 21 was similar between healthy women and those with PPTD. Patients with a previous history of depression developed PD more often (P < 0.0001). One hundred and ninety women breast fed their babies for more than 2 months, without observing a higher PD rate or BDI scores over 21 (P = 0.5). We found a general PD incidence rate of 1.7% in our group of patients. This figure is not higher in women with hormone abnormalities caused by PPTD. Women with a past history of depression present a higher risk of PD while those who breast fed did not have an increased risk.
NASA Astrophysics Data System (ADS)
Gupta, Amit; Nagpal, Shaina
2017-05-01
Inter-satellite optical wireless communication (IsOWC) systems can be chosen over existing microwave satellite systems for deploying in space in the future due to their high bandwidth, small size, light weight, low power and low cost. However, the IsOWC system suffers from various attenuations due to weather conditions, turbulence or scintillations which limit its performance and decreases its availability. So, in order to improve the performance, IsOWC system using directly modulated laser source is proposed in this work. The system is designed and evaluated to be suitable for high data rate transmissions up to 10 Gbps. The performance of the system is investigated in order to reduce the cost and complexity of link and improving the quality of information signal. Further the proposed IsOWC system is analysed using BER analyser, power meter and oscilloscope Visualizer.
Motion in partially and fully cross-linked F-actin networks
NASA Astrophysics Data System (ADS)
Morris, Eliza; Ehrlicher, Allen; Weitz, David
2012-02-01
Single molecule experiments have measured stall forces and procession rates of molecular motors on isolated cytoskeletal fibers in Newtonian fluids. But in the cell, these motors are transporting cargo through a highly complex cytoskeletal network. To compare these single molecule results to the forces exerted by motors within the cell, an evaluation of the response of the cytoskeletal network is needed. Using magnetic tweezers and fluorescence confocal microscopy we observe and quantify the relationship between bead motion and filament response in F-actin networks both partially and fully cross-linked with filamin We find that when the transition from full to partial cross-linking is brought about by a decrease in cross-linker concentration there is a simultaneous decline in the elasticity of the network, but the response of the bead remains qualitatively similar. However, when the cross-linking is reduced through a shortening of the F-actin filaments the bead response is completely altered. The characteristics of the altered bead response will be discussed here.
ROMP-based thermosetting polymers from modified castor oil with various cross-linking agents
NASA Astrophysics Data System (ADS)
Ding, Rui
Polymers derived from bio-renewable resources are finding an increase in global demand. In addition, polymers with distinctive functionalities are required in certain advanced fields, such as aerospace and civil engineering. In an attempt to meet both these needs, the goal of this work aims to develop a range of bio-based thermosetting matrix polymers for potential applications in multifunctional composites. Ring-opening metathesis polymerization (ROMP), which recently has been explored as a powerful method in polymer chemistry, was employed as a unique pathway to polymerize agricultural oil-based reactants. Specifically, a novel norbornyl-functionalized castor oil alcohol (NCA) was investigated to polymerize different cross-linking agents using ROMP. The effects of incorporating dicyclopentadiene (DCPD) and a norbornene-based crosslinker (CL) were systematically evaluated with respect to curing behavior and thermal mechanical properties of the polymers. Isothermal differential scanning calorimetry (DSC) was used to investigate the conversion during cure. Dynamic DSC scans at multiple heating rates revealed conversion-dependent activation energy by Ozawa-Flynn-Wall analysis. The glass transition temperature, storage modulus, and loss modulus for NCA/DCPD and NCA/CL copolymers with different cross-linking agent loading were compared using dynamic mechanical analysis. Cross-link density was examined to explain the very different dynamic mechanical behavior. Mechanical stress-strain curves were developed through tensile test, and thermal stability of the cross-linked polymers was evaluated by thermogravimetric analysis to further investigate the structure-property relationships in these systems.
User preference as quality markers of paediatric web sites.
Hernández-Borges, Angel A; Macías-Cervi, Pablo; Gaspar-Guardado, Asunción; Torres-Alvarez De Arcaya, María Luisa; Ruíz-Rabaza, Ana; Jiménez-Sosa, Alejandro
2003-09-01
Little is known about the ability of internet users to distinguish the best medical resources online, and how their preferences, measured by usage and popularity indexes, correlate with established quality criteria. Our objective was to analyse whether the number of inbound links and/or daily visits to a sample of paediatric web pages are reliable quality markers of the pages. Two-year follow-up study of 363 web pages with paediatric information. The number of inbound links and the average number of daily visits to the pages were calculated on a yearly basis. In addition, their rates of compliance with the codes of conduct, guidelines and/or principles of three international organizations were evaluated. The quality code most widely met by the sample web pages was the Health on the Net Foundation Code of Conduct (overall rate, 60.2%). Sample pages showed a low degree of compliance with principles related to privacy, confidentiality and electronic commerce (overall rate less than 45%). Most importantly, we observed a moderate, significant correlation between compliance with quality criteria and the number of inbound links (p < 0.001). However, no correlation was found between the number of daily visits to a page and its degree of compliance with the principles. Some indexes derived from the analysis of webmasters' hyperlinks could be reliable quality markers of medical web resources.
Linking information needs with evaluation: the role of task identification.
Weir, C. R.
1998-01-01
Action Identification Theory was used to explore user's subjective constructions of information tasks in a primary care setting. The first part of the study involved collecting clinician's descriptions of their information tasks. These items were collated and then rated by another larger group of clinicians. Results clearly identified 6 major information tasks, including communication, patient assessment, work monitoring, seeking science information, compliance with policies and procedures, and data integration. Results discussed in terms of implications for evaluation and assessing information needs in a clinical setting. PMID:9929232
Boyer, Cherrie B.; Chiaramonte, Danielle; Lindeman, Peter; Chutuape, Kate; Cooper-Walker, Bendu; Kapogiannis, Bill G.; Wilson, Craig M.; Fortenberry, J. Dennis
2017-01-01
Importance Most human immunodeficiency virus (HIV)–infected youths are unaware of their serostatus (approximately 60%) and therefore not linked to HIV medical or prevention services. The need to identify promising and scalable approaches to promote uptake of HIV testing among youths at risk is critical. Objective To evaluate a multisite HIV testing program designed to encourage localized HIV testing programs focused on self-identified sexual minority males and to link youths to appropriate prevention services after receipt of their test results. Design, Setting, and Participants Testing strategies were evaluated using an observational design during a 9-month period (June 1, 2015, through February 28, 2016). Testing strategies were implemented by 12 adolescent medicine HIV primary care programs and included targeted testing, universal testing, or a combination. Data were collected from local youth at high risk of HIV infection and, specifically, sexual minority males of color. Main Outcomes and Measures Proportion of sexual minority males and sexual minority males of color tested, proportion of previously undiagnosed HIV-positive youths identified, and rates of linkage to prevention services. Results A total of 3301 youths underwent HIV testing. Overall, 35 (3.6%) of those who underwent universal testing in primary care clinical settings, such as emergency departments and community health centers, were sexual minority males (35 [3.6%] were males of color) compared with 236 (46.7%) (201 [39.8%] were males of color) who were tested through targeted testing and 693 (37.8%) (503 [27.4%] were males of color) through combination efforts. Identification of new HIV-positive cases varied by strategy: 1 (0.1%) via universal testing, 39 (2.1%) through combination testing, and 16 (3.2%) through targeted testing. However, when targeted tests were separated from universal testing results for sites using a combined strategy, the rate of newly identified HIV-positive cases identified through universal testing decreased to 1 (0.1%). Rates of new HIV-positive cases identified through targeted testing increased to 49 (6.3%). Youths who tested through targeted testing (416 [85.1%]) were more likely to link successfully to local HIV prevention services, including preexposure prophylaxis, compared with those who underwent universal testing (328 [34.1%]). Conclusions and Relevance The findings suggest that community-based targeted approaches to HIV testing are more effective than universal screening for reaching young sexual minority males (especially males of color), identifying previously undiagnosed HIV-positive youths, and linking HIV-negative youths to relevant prevention services. Targeted, community-based HIV testing strategies hold promise as a scalable and effective means to identify high-risk youths who are unaware of their HIV status. PMID:28418524
De Preter, Géraldine; Neveu, Marie-Aline; Danhier, Pierre; Brisson, Lucie; Payen, Valéry L; Porporato, Paolo E; Jordan, Bénédicte F; Sonveaux, Pierre; Gallez, Bernard
2016-01-19
Glucose fermentation through glycolysis even in the presence of oxygen (Warburg effect) is a common feature of cancer cells increasingly considered as an enticing target in clinical development. This study aimed to analyze the link between metabolism, energy stores and proliferation rates in cancer cells. We found that cell proliferation, evaluated by DNA synthesis quantification, is correlated to glycolytic efficiency in six cancer cell lines as well as in isogenic cancer cell lines. To further investigate the link between glycolysis and proliferation, a pharmacological inhibitor of the pentose phosphate pathway (PPP) was used. We demonstrated that reduction of PPP activity decreases cancer cells proliferation, with a profound effect in Warburg-phenotype cancer cells. The crucial role of the PPP in sustaining cancer cells proliferation was confirmed using siRNAs against glucose-6-phosphate dehydrogenase, the first and rate-limiting enzyme of the PPP. In addition, we found that dichloroacetate (DCA), a new clinically tested compound, induced a switch of glycolytic cancer cells to a more oxidative phenotype and decreased proliferation. By demonstrating that DCA decreased the activity of the PPP, we provide a new mechanism by which DCA controls cancer cells proliferation.
An Evaluation of Spacecraft Pointing Requirements for Optically Linked Satellite Systems
NASA Astrophysics Data System (ADS)
Gunter, B. C.; Dahl, T.
2017-12-01
Free space optical (laser) communications can offer certain advantages for many remote sensing applications, due primarily to the high data rates (Gb/s) and energy efficiences possible from such systems. An orbiting network of crosslinked satellites could potentially relay imagery and other high-volume data at near real-time intervals. To achieve this would require satellites actively tracking one or more satellites, as well as ground terminals. The narrow laser beam width utilized by the transmitting satellites pose technical challenges due to the higher pointing accuracy required for effective signal transmission, in particular if small satellites are involved. To better understand what it would take to realize such a small-satellite laser communication network, this study investigates the pointing requirements needed to support optical data links. A general method for characterizing pointing tolerance, angle rates and accelerations for line of site vectors is devised and applied to various case studies. Comparisons with state-of-the-art small satellite attitude control systems are also made to assess what is possible using current technology. The results help refine the trade space for designs for optically linked networks from the hardware aboard each satellite to the design of the satellite constellation itself.
Impact of window decrement rate on TCP performance in an adhoc network
NASA Astrophysics Data System (ADS)
Suherman; Hutasuhut, Arief T. W.; Badra, Khaldun; Al-Akaidi, Marwan
2017-09-01
Transmission control protocol (TCP) is a reliable transport protocol handling end to end connection in TCP/IP stack. It works well in copper or optical fibre link, but experiences increasing delay in wireless network. Further, TCP experiences multiple retransmissions due to higher collision probability within wireless network. The situation may get worsen in an ad hoc network. This paper examines the impact half window or window reduction rate to the overall TCP performances. The evaluation using NS-2 simulator shows that the smaller the window decrement rate results the smaller end to end delay. Delay is reduced to 17.05% in average when window decrement rate decreases. Average jitter also decreases 4.15%, while packet loss is not affected.
Darwinism for the Genomic Age: Connecting Mutation to Diversification
Hua, Xia; Bromham, Lindell
2017-01-01
A growing body of evidence suggests that rates of diversification of biological lineages are correlated with differences in genome-wide mutation rate. Given that most research into differential patterns of diversification rate have focused on species traits or ecological parameters, a connection to the biochemical processes of genome change is an unexpected observation. While the empirical evidence for a significant association between mutation rate and diversification rate is mounting, there has been less effort in explaining the factors that mediate this connection between genetic change and species richness. Here we draw together empirical studies and theoretical concepts that may help to build links in the explanatory chain that connects mutation to diversification. First we consider the way that mutation rates vary between species. We then explore how differences in mutation rates have flow-through effects to the rate at which populations acquire substitutions, which in turn influences the speed at which populations become reproductively isolated from each other due to the acquisition of genomic incompatibilities. Since diversification rate is commonly measured from phylogenetic analyses, we propose a conceptual approach for relating events of reproductive isolation to bifurcations on molecular phylogenies. As we examine each of these relationships, we consider theoretical models that might shine a light on the observed association between rate of molecular evolution and diversification rate, and critically evaluate the empirical evidence for these links, focusing on phylogenetic comparative studies. Finally, we ask whether we are getting closer to a real understanding of the way that the processes of molecular evolution connect to the observable patterns of diversification. PMID:28224003
Darwinism for the Genomic Age: Connecting Mutation to Diversification.
Hua, Xia; Bromham, Lindell
2017-01-01
A growing body of evidence suggests that rates of diversification of biological lineages are correlated with differences in genome-wide mutation rate. Given that most research into differential patterns of diversification rate have focused on species traits or ecological parameters, a connection to the biochemical processes of genome change is an unexpected observation. While the empirical evidence for a significant association between mutation rate and diversification rate is mounting, there has been less effort in explaining the factors that mediate this connection between genetic change and species richness. Here we draw together empirical studies and theoretical concepts that may help to build links in the explanatory chain that connects mutation to diversification. First we consider the way that mutation rates vary between species. We then explore how differences in mutation rates have flow-through effects to the rate at which populations acquire substitutions, which in turn influences the speed at which populations become reproductively isolated from each other due to the acquisition of genomic incompatibilities. Since diversification rate is commonly measured from phylogenetic analyses, we propose a conceptual approach for relating events of reproductive isolation to bifurcations on molecular phylogenies. As we examine each of these relationships, we consider theoretical models that might shine a light on the observed association between rate of molecular evolution and diversification rate, and critically evaluate the empirical evidence for these links, focusing on phylogenetic comparative studies. Finally, we ask whether we are getting closer to a real understanding of the way that the processes of molecular evolution connect to the observable patterns of diversification.
Kim, Chang-O
2016-10-26
This study aimed to evaluate whether social capital could alleviate health inequality against racial discrimination and identify the critical nature of social capital that generates health inequality differences within the social context of South Korea. Using the data of the 2009 National Survey of Multicultural Families, a nationally representative sample in which 40,430 foreign wives participated, the concentration index (CI) was used to measure the discrimination-related inequalities in self-rated health and was decomposed into contributing factors. The results showed a significant concentration of poor self-rated health unfavorable to foreign wives who were highly discriminated (CI 0.023, standard error [SE] 0.001, p < .001). However, when the CIs were assessed among the subgroups of different social capital, no discrimination-related inequality in health was observed among the group of linking social capital (CI 0.008, SE 0.008, p .332). The total differential decomposition method showed two major factors that generate differences in health inequality between the groups of non-linking and linking social capital: protest against discrimination (35.8 %); experiences of discrimination (28.3 %). The present results indicated that linking social capital can be a useful resource of health resilience factor that equalizes discrimination-related health inequality among marriage migrant women in South Korea. This study provides additional evidence that social capital needs to be placed in its political context.
Facility for the evaluation of space communications and related systems
NASA Technical Reports Server (NTRS)
Kerczewski, Robert J.; Svoboda, James S.; Kachmar, Brian A.
1995-01-01
NASA Lewis Research Center's Communications Projects Branch has developed a facility for the evaluation of space communications systems and related types of systems, called the Advanced Space Communications (ASC) Laboratory. The ASC Lab includes instrumentation, testbed hardware, and experiment control and monitor software for the evaluation of components, subsystems, systems, and networks. The ASC lab has capabilities to perform radiofrequency (RF), microwave, and millimeter-wave characterizations as well as measurements using low, medium, or high data rate digital signals. In addition to laboratory measurements, the ASC Lab also includes integrated satellite ground terminals allowing experimentation and measurements accessing operational satellites through real space links.
A cascaded coding scheme for error control
NASA Technical Reports Server (NTRS)
Shu, L.; Kasami, T.
1985-01-01
A cascade coding scheme for error control is investigated. The scheme employs a combination of hard and soft decisions in decoding. Error performance is analyzed. If the inner and outer codes are chosen properly, extremely high reliability can be attained even for a high channel bit-error-rate. Some example schemes are evaluated. They seem to be quite suitable for satellite down-link error control.
Bernatas, J J; Ali, I M; Ismaël, H A; Matan, A B; Aboubakar, I H
2003-08-01
Decentralisation of directly observed treatment (DOT) for tuberculosis patients in three public centres in Djibouti city from April 2000. To evaluate decentralisation based on the success rate by site of treatment and according to certain critical variables. Comparative evaluation of the success rate of smear-positive patients followed in all treatment centres from 1 May 2000 to 31 March 2001. The success rate was 58% for the main centre, Centre Paul Faure, and 81% for all the peripheral centres together (P < 10.6). It was 80% for the three new centres and 85% for the established centres (P > 0.05). Age under 20 years, female sex and treatment centre were factors linked to success. After stratification, sex was shown to be the confounding variable. Multivariate analysis shows that non-Djibouti nationality is related to treatment success (P = 0.02). In the groups of established and new centres, there is an inverse linear relationship between success rate and workload, with greater capacity in the established centres. Urban decentralisation of DOT increases the chances of treatment success among smear-positive patients. Another centre for supervised treatment needs to be created in one of the public health centres in Djibouti city.
NASA Technical Reports Server (NTRS)
Hinton, David A.; Lohr, Gary W.
1988-01-01
Studies have shown that radio communications between pilots and air traffic control contribute to high pilot workload and are subject to various errors. These errors result from congestion on the voice radio channel, and missed and misunderstood messages. The use of digital data link has been proposed as a means of reducing this workload and error rate. A critical factor, however, in determining the potential benefit of data link will be the interface between future data link systems and the operator of those systems, both in the air and on the ground. The purpose of this effort was to evaluate the pilot interface with various levels of data link capability, in simulated general aviation, single-pilot instrument flight rule operations. Results show that the data link reduced demands on pilots' short-term memory, reduced the number of communication transmissions, and permitted the pilots to more easily allocate time to critical cockpit tasks while receiving air traffic control messages. The pilots who participated unanimously indicated a preference for data link communications over voice-only communications. There were, however, situations in which the pilot preferred the use of voice communications, and the ability for pilots to delay processing the data link messages, during high workload events, caused delays in the acknowledgement of messages to air traffic control.
Bit-error-rate testing of fiber optic data links for MMIC-based phased array antennas
NASA Technical Reports Server (NTRS)
Shalkhauser, K. A.; Kunath, R. R.; Daryoush, A. S.
1990-01-01
The measured bit-error-rate (BER) performance of a fiber optic data link to be used in satellite communications systems is presented and discussed. In the testing, the link was measured for its ability to carry high burst rate, serial-minimum shift keyed (SMSK) digital data similar to those used in actual space communications systems. The fiber optic data link, as part of a dual-segment injection-locked RF fiber optic link system, offers a means to distribute these signals to the many radiating elements of a phased array antenna. Test procedures, experimental arrangements, and test results are presented.
Does the stepwave model predict mica dissolution kinetics?
NASA Astrophysics Data System (ADS)
Kurganskaya, Inna; Arvidson, Rolf S.; Fischer, Cornelius; Luttge, Andreas
2012-11-01
The micas are a unique class of minerals because of their layered structure. A frequent question arising in mica dissolution studies is whether this layered structure radically changes the dissolution mechanism. We address this question here, using data from VSI and AFM experiments involving muscovite to evaluate crystallographic controls on mica dissolution. These data provide insight into the dissolution process, and reveal important links to patterns of dissolution observed in framework minerals. Under our experimental conditions (pH 9.4, 155 °C), the minimal global rate of normal surface retreat observed in VSI data was 1.42 × 10-10 mol/m2/s (σ = 27%) while the local rate observed at deep etch pits reached 416 × 10-10 mol/m2/s (σ = 49%). Complementary AFM data clearly show crystallographic control of mica dissolution, both in terms of step advance and the geometric influence of interlayer rotation (stacking periodicity). These observations indicate that basal/edge surface area ratios are highly variable and change continuously over the course of reaction, thus obviating their utility as characteristic parameters defining mica reactivity. Instead, these observations of overall dissolution rate and the influence of screw dislocations illustrate the link between atomic step movement and overall dissolution rate defined by surface retreat normal to the mica surface. Considered in light of similar observations available elsewhere in the literature, these relationships provide support for application of the stepwave model to mica dissolution kinetics. This approach provides a basic mechanistic link between the dissolution kinetics of phyllosilicates, framework silicates, and related minerals, and suggests a resolution to the general problem of mica reactivity.
Cousineau, Michael R; Stevens, Gregory D; Farias, Albert
2011-02-01
OBJECTIVE AND STUDY SETTING: To evaluate the effectiveness of different approaches to outreach on public health insurance enrollment in 25 California counties with a Children's Health Initiative. Administrative enrollment databases. The use of eight enrollment strategies were identified in each quarter from 2001 to 2007 for each of 25 counties (county quarter). Strategies were categorized as either technology or nontechnology. New enrollments were obtained for Medi-Cal, Healthy Families, and Healthy Kids. Bivariate and multivariate analyses assessed the link between each strategy and new enrollments rates of children. Methods Surveys of key informants determined whether a specific outreach strategy was used in each quarter. These were linked to new enrollments in each county quarter. Between 2001 and 2007, enrollment grew in all three children's health programs. We controlled for the effects of counties, seasons, and county-specific child poverty rates. There was an increase in enrollment rates of 11 percent in periods when technology-based systems were in use compared with when these approaches were inactive. Non-technology-based approaches, including school-linked approaches, yielded a 12 percent increase in new enrollments rates. Deploying seven to eight strategies yielded 54 percent more new enrollments per 10,000 children compared with periods with none of the specific strategies. National health care reform provides new opportunities to expand coverage to millions of Americans. An investment in technology-based enrollment systems will maximize new enrollments, particularly into Medicaid; nontechnological approaches may help identify harder-to-reach populations. Moreover, incorporating several strategies, whether phased in or implemented simultaneously, will enhance enrollments. © Health Research and Educational Trust.
Ku-band signal design study. [for space shuttle orbiter communication links
NASA Technical Reports Server (NTRS)
Lindsey, W. L.; Woo, K. T.
1977-01-01
The acquisition/tracking performance of a practical squaring loop in which the times two multiplier is mechanized as a limiter/multiplier combination is evaluated. This squaring approach serves to produce the absolute value of the arriving signal as opposed to the perfect square law action which is required in order to render acquisition and tracking performance equivalent to that of a Costas loop. The Ku-Band orbiter signal design for the forward link is assessed. Acquisition time results and acquisition and tracking thresholds are summarized. A tradeoff study which pertains to bit synchronization techniques for the high rate Ku-Band channel is included and an optimum selection is made based upon the appropriate design constraints.
FAST TRACK COMMUNICATION: Deposition of amino-rich thin films by RF magnetron sputtering of nylon
NASA Astrophysics Data System (ADS)
Kylián, O.; Hanuš, J.; Choukourov, A.; Kousal, J.; Slavínská, D.; Biederman, H.
2009-07-01
RF magnetron sputtering of a nylon target in different gas mixtures was studied in order to evaluate the capability of this process to deposit amino-rich coatings needed in a wide range of biomedical applications. It has been demonstrated that both the deposition rate of the coatings and the surface density of primary amino groups are strongly linked with working gas mixture composition. From this point of view, a sufficiently high deposition rate as well as the highest amine efficiency reaching a NH2/C value of 18% was observed in the N2/H2 discharge, which leads to the surface exhibiting a high rate of protein adsorption.
Yeon, Pyungwoo; Mirbozorgi, S Abdollah; Lim, Jaemyung; Ghovanloo, Maysam
2017-12-01
This paper presents a feasibility study of wireless power and data transmission through an inductive link to a 1-mm 2 implant, to be used as a free-floating neural probe, distributed across a brain area of interest. The proposed structure utilizes a four-coil inductive link for back telemetry, shared with a three-coil link for wireless power transmission. We propose a design procedure for geometrical optimization of the inductive link in terms of power transmission efficiency (PTE) considering specific absorption rate and data rate. We have designed a low-power pulse-based active data transmission circuit and characterized performance of the proposed inductive link in terms of its data rate and bit error rate (BER). The 1-mm 2 data-Tx/power-Rx coil is implemented using insulated bonding wire with diameter, resulting in measured PTE in tissue media of 2.01% at 131 MHz and 1.8-cm coil separation distance when the resonator coil inner radius is 1 cm. The measured BER at 1-Mbps data rate was and in the air and tissue environments, respectively.
De Rosnay, Marc; Fink, Elian; Begeer, Sander; Slaughter, Virginia; Peterson, Candida
2014-09-01
Links between young children's everyday use of mindful conversational skills and their success on laboratory tests of theory of mind understanding (ToM) were evaluated. Using published scales, teachers rated the conversational behavior and shyness of 129 children aged 60 to 101 months (M = 78·8 months) who were in their first years of primary school. The children also took batteries of first- and second-order false-belief tests along with tests of emotion understanding and general language ability. Correlational and regression analyses showed that performance on false-belief tests of ToM significantly predicted children's competence at reading others' minds in their everyday conversational interactions. Furthermore, these links transcended individual differences in language ability, shy personality, emotion understanding, and age. These findings augment and extend a growing body of evidence linking performance on laboratory ToM tests to socially competent real-world behavior.
NASA Astrophysics Data System (ADS)
Singh, Mehtab
2017-12-01
Optical wireless communication (OWC) systems also known as Free space optics (FSO) are capable of providing high channel bandwidth, high data transmission rates, low power consumption, and high security. OWC links are being considered in different applications such as inter-satellite links, terrestrial links, and inter-aircraft communication links. This paper investigates the impact of different system parameters such as transmission power level, operating wavelength, transmitter pointing error angle, bit transmission rate, atmospheric attenuation, antenna aperture diameter, geometric losses, the responsivity of the photodetector, and link range on the performance of inter-aircraft optical wireless communication link.
Hong, Ha; Solomon, Ethan A.; DiCarlo, James J.
2015-01-01
To go beyond qualitative models of the biological substrate of object recognition, we ask: can a single ventral stream neuronal linking hypothesis quantitatively account for core object recognition performance over a broad range of tasks? We measured human performance in 64 object recognition tests using thousands of challenging images that explore shape similarity and identity preserving object variation. We then used multielectrode arrays to measure neuronal population responses to those same images in visual areas V4 and inferior temporal (IT) cortex of monkeys and simulated V1 population responses. We tested leading candidate linking hypotheses and control hypotheses, each postulating how ventral stream neuronal responses underlie object recognition behavior. Specifically, for each hypothesis, we computed the predicted performance on the 64 tests and compared it with the measured pattern of human performance. All tested hypotheses based on low- and mid-level visually evoked activity (pixels, V1, and V4) were very poor predictors of the human behavioral pattern. However, simple learned weighted sums of distributed average IT firing rates exactly predicted the behavioral pattern. More elaborate linking hypotheses relying on IT trial-by-trial correlational structure, finer IT temporal codes, or ones that strictly respect the known spatial substructures of IT (“face patches”) did not improve predictive power. Although these results do not reject those more elaborate hypotheses, they suggest a simple, sufficient quantitative model: each object recognition task is learned from the spatially distributed mean firing rates (100 ms) of ∼60,000 IT neurons and is executed as a simple weighted sum of those firing rates. SIGNIFICANCE STATEMENT We sought to go beyond qualitative models of visual object recognition and determine whether a single neuronal linking hypothesis can quantitatively account for core object recognition behavior. To achieve this, we designed a database of images for evaluating object recognition performance. We used multielectrode arrays to characterize hundreds of neurons in the visual ventral stream of nonhuman primates and measured the object recognition performance of >100 human observers. Remarkably, we found that simple learned weighted sums of firing rates of neurons in monkey inferior temporal (IT) cortex accurately predicted human performance. Although previous work led us to expect that IT would outperform V4, we were surprised by the quantitative precision with which simple IT-based linking hypotheses accounted for human behavior. PMID:26424887
NASA Astrophysics Data System (ADS)
Pappalardo, Giovanna
2018-03-01
An innovative methodological approach using infrared thermography (IRT) provides a potential contribution to the indirect assessment of hydraulic conductivity of jointed rock masses. This technique proved a suitable tool to evaluate the degree of fracturing of rock masses along with their discontinuity systems, which expedite water flow within the rock mass itself. First, based on the latest scientific outcomes on the application of IRT to the geomechanics of rock systems, rock mass surveys were carried out at different outcrops (dolostone, limestone and porphyroid) and hydraulic conductivity was empirically assessed through approaches well known in the international literature. Then, IRT campaigns were performed at each surveyed rock mass, with the purpose of evaluating the corresponding Cooling Rate Index, strictly linked to the cooling attitude of the rock. Such index was correlated with the assessed hydraulic conductivity and satisfactory regression equations were achieved. The interesting results show that hydraulic conductivity values are likely to be linked with the cooling behavior of rock masses, which, in turn, is affected by spacing, aperture and persistence of discontinuities.
NASA Astrophysics Data System (ADS)
Zhang, Wei; Rao, Qiaomeng
2018-01-01
In order to solve the problem of high speed, large capacity and limited spectrum resources of satellite communication network, a double-layered satellite network with global seamless coverage based on laser and microwave hybrid links is proposed in this paper. By analyzing the characteristics of the double-layered satellite network with laser and microwave hybrid links, an effectiveness evaluation index system for the network is established. And then, the fuzzy analytic hierarchy process, which combines the analytic hierarchy process and the fuzzy comprehensive evaluation theory, is used to evaluate the effectiveness of the double-layered satellite network with laser and microwave hybrid links. Furthermore, the evaluation result of the proposed hybrid link network is obtained by simulation. The effectiveness evaluation process of the proposed double-layered satellite network with laser and microwave hybrid links can help to optimize the design of hybrid link double-layered satellite network and improve the operating efficiency of the satellite system.
Independence of Terminal-Link Entry Rate and Immediacy in Concurrent Chains
ERIC Educational Resources Information Center
Berg, Mark E.; Grace, Randolph C.
2004-01-01
In Phase 1, 4 pigeons were trained on a three-component multiple concurrent-chains procedure in which components differed only in terms of relative terminal-link entry rate. The terminal links were variable-interval schedules and were varied across four conditions to produce immediacy ratios of 4:1, 1:4, 2:1, and 1:2. Relative terminal-link entry…
Evidence of reduced recombination rate in human regulatory domains.
Liu, Yaping; Sarkar, Abhishek; Kheradpour, Pouya; Ernst, Jason; Kellis, Manolis
2017-10-20
Recombination rate is non-uniformly distributed across the human genome. The variation of recombination rate at both fine and large scales cannot be fully explained by DNA sequences alone. Epigenetic factors, particularly DNA methylation, have recently been proposed to influence the variation in recombination rate. We study the relationship between recombination rate and gene regulatory domains, defined by a gene and its linked control elements. We define these links using expression quantitative trait loci (eQTLs), methylation quantitative trait loci (meQTLs), chromatin conformation from publicly available datasets (Hi-C and ChIA-PET), and correlated activity links that we infer across cell types. Each link type shows a "recombination rate valley" of significantly reduced recombination rate compared to matched control regions. This recombination rate valley is most pronounced for gene regulatory domains of early embryonic development genes, housekeeping genes, and constitutive regulatory elements, which are known to show increased evolutionary constraint across species. Recombination rate valleys show increased DNA methylation, reduced doublestranded break initiation, and increased repair efficiency, specifically in the lineage leading to the germ line. Moreover, by using only the overlap of functional links and DNA methylation in germ cells, we are able to predict the recombination rate with high accuracy. Our results suggest the existence of a recombination rate valley at regulatory domains and provide a potential molecular mechanism to interpret the interplay between genetic and epigenetic variations.
Abe, Takeo; Tsunoda, Shinichiro; Nishioka, Aki; Azuma, Kouta; Tsuboi, Kazuyuki; Ogita, Chie; Yokoyama, Yuichi; Furukawa, Tetsuya; Maruoka, Momo; Tamura, Masao; Yoshikawa, Takahiro; Saito, Atsushi; Sekiguchi, Masahiro; Azuma, Naoto; Kitano, Masayasu; Matsui, Kiyoshi; Hosono, Yuji; Nakashima, Ran; Ohmura, Koichiro; Mimori, Tsuneyo; Sano, Hajime
2016-01-01
Anti-aminoacyl-tRNA synthetase (ARS) antibody is one of the myositis-specific autoantibodies to make a diagnosis of polymyositis (PM) and dermatomyositis (DM). Recently a new enzyme-linked immunosorbent assay (ELISA) kit of concurrently detected anti-ARS antibodies (anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ and anti-KS) have become to measure in the clinical setting. To evaluate the reliability of this ELISA kit, we measured anti-ARS antibodies in 75 PM and DM patients using by this ELISA assay and compared them with the results by RNA immunoprecipitation assay. Between the measurements of anti-PL-7, anti-PL-12, anti-EJ and anti-KS autoantibodies by ELISA assay and RNA-IP assay, the concordance rate of reproducibility is 95.1% and the positive agreement rate is 90.9% and negative agreement rate is 96.0% and kappa statistic is 0.841. Between the measurements of existing anti-Jo-1 antibody ELISA kit and anti-ARS antibody ELISA kit, the concordance rate of reproducibility is 96.9%, the positive agreement rate is 100%, negative agreement rate is 96.1% and kappa statistic is 0.909. The lung involvement in patients with PM and DM patients are positive of anti-ARS antibodies and anti-melanoma differentiation associated gene5 (MDA5) antibody at a rate around 70%. Then most life-threatening ILD with anti-MDA5 positive clinically amyopathic dermatomyositis patients could be highly guessed when anti-ARS antibodies are negative.
ERIC Educational Resources Information Center
De Rosnay, Marc; Fink, Elian; Begeer, Sander; Slaughter, Virginia; Peterson, Candida
2014-01-01
Links between young children's everyday use of mindful conversational skills and their success on laboratory tests of theory of mind understanding (ToM) were evaluated. Using published scales, teachers rated the conversational behavior and shyness of 129 children aged 60 to 101 months (M = 78·8 months) who were in their first years of primary…
Casey, Meghan M; Telford, Amanda; Mooney, Amanda; Harvey, Jack T; Eime, Rochelle M; Payne, Warren R
2014-10-06
The purpose of this study was to undertake a process evaluation to examine the reach, adoption and implementation of a school-community linked physical activity (PA) program for girls aged 12 - 15 years (School Years 7 - 9) using the RE-AIM framework. Various approaches were used to assess 'reach', 'adoption' and implementation: (a) a school environment survey of intervention schools (n = 6); (b) teacher feedback regarding the professional development component (91.1% response rate) and lesson implementation (60.8% response rate); and (c) post-intervention focus group interviews with physical education (PE) teachers (n = 29), students (n = 125), coaches (n = 13) and instructors (n = 8) regarding program experiences. Reach and Adoption: Seven schools (n = 1491 Year 7-9 female student enrolment; 70% adoption rate), five tennis clubs, eight football clubs and five leisure centres participated in the program during 2011. Program design and professional development opportunities (training, resource manual and opportunities to work with coaches and instructors during PE classes) supported implementation and student engagement in PA. However, there was a lack of individual and organisational readiness to adopt program principles. For some deliverers there were deeply embedded ideologies that were not aligned with the Game Sense teaching approach upon which the program was based. Further, cognitive components of the program such as self-management were not widely adopted as other components of the program tended to be prioritised. The program design and resources supported the success of the program, however, some aspects were not implemented as intended, which may have affected the likelihood of achieving further positive outcomes. Barriers to program implementation were identified and should be considered when designing school-community linked interventions. In particular, future programs should seek to assess and adjust for organizational readiness within the study design. For example, shared commitment and abilities of program deliverers to implement the program needs to be determined to support program implementation. ACTRN12614000446662. April 30th 2014.
A cascaded coding scheme for error control and its performance analysis
NASA Technical Reports Server (NTRS)
Lin, S.
1986-01-01
A coding scheme for error control in data communication systems is investigated. The scheme is obtained by cascading two error correcting codes, called the inner and the outer codes. The error performance of the scheme is analyzed for a binary symmetric channel with bit error rate epsilon < 1/2. It is shown that, if the inner and outer codes are chosen properly, extremely high reliability can be attained even for a high channel bit error rate. Various specific example schemes with inner codes ranging from high rates to very low rates and Reed-Solomon codes are considered, and their probabilities are evaluated. They all provide extremely high reliability even for very high bit error rates, say 0.1 to 0.01. Several example schemes are being considered by NASA for satellite and spacecraft down link error control.
A cascaded coding scheme for error control and its performance analysis
NASA Technical Reports Server (NTRS)
Lin, Shu; Kasami, Tadao; Fujiwara, Tohru; Takata, Toyoo
1986-01-01
A coding scheme is investigated for error control in data communication systems. The scheme is obtained by cascading two error correcting codes, called the inner and outer codes. The error performance of the scheme is analyzed for a binary symmetric channel with bit error rate epsilon <1/2. It is shown that if the inner and outer codes are chosen properly, extremely high reliability can be attained even for a high channel bit error rate. Various specific example schemes with inner codes ranging form high rates to very low rates and Reed-Solomon codes as inner codes are considered, and their error probabilities are evaluated. They all provide extremely high reliability even for very high bit error rates. Several example schemes are being considered by NASA for satellite and spacecraft down link error control.
Cain, Daniel J.; Croteau, Marie-Noele; Fuller, Christopher C.; Ringwood, Amy H.
2016-01-01
Whereas feeding inhibition caused by exposure to contaminants has been extensively documented, the underlying mechanism(s) are less well understood. For this study, the behavior of several key feeding processes, including ingestion rate and assimilation efficiency, that affect the dietary uptake of Cu were evaluated in the benthic grazer Lymnaea stagnalis following 4–5 h exposures to Cu adsorbed to synthetic hydrous ferric oxide (Cu–HFO). The particles were mixed with a cultured alga to create algal mats with Cu exposures spanning nearly 3 orders of magnitude at variable or constant Fe concentrations, thereby allowing first order and interactive effects of Cu and Fe to be evaluated. Results showed that Cu influx rates and ingestion rates decreased as Cu exposures of the algal mat mixture exceeded 104 nmol/g. Ingestion rate appeared to exert primary control on the Cu influx rate. Lysosomal destabilization rates increased directly with Cu influx rates. At the highest Cu exposure where the incidence of lysosomal membrane damage was greatest (51%), the ingestion rate was suppressed 80%. The findings suggested that feeding inhibition was a stress response emanating from excessive uptake of dietary Cu and cellular toxicity.
Racial and Ethnic Trends in Sudden Unexpected Infant Deaths: United States, 1995-2013.
Parks, Sharyn E; Erck Lambert, Alexa B; Shapiro-Mendoza, Carrie K
2017-06-01
Immediately after the 1994 Back-to-Sleep campaign, sudden unexpected infant death (SUID) rates decreased dramatically, but they have remained relatively stable (93.4 per 100 000 live births) since 2000. In this study, we examined trends in SUID rates and disparities by race/ethnicity since the Back-to-Sleep campaign. We used 1995-2013 US period-linked birth-infant death data to evaluate SUID rates per 100 000 live births by non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic, American Indian/Alaska Native, and Asian/Pacific Islander racial/ethnic groupings. To examine racial/ethnic disparities, we calculated rate ratios with NHWs as the referent group. Unadjusted linear regression was used to evaluate trends ( P < .05) in rates and rate ratios. The distribution and rates of SUID by demographic and birth characteristics were compared for 1995-1997 and 2011-2013, and χ 2 tests were used to evaluate significance. From 1995 to 2013, SUID rates were consistently highest for American Indian/Alaska Natives, followed by NHBs. The rate for NHBs decreased significantly, whereas the rate for NHWs also declined, but not significantly. As a result, the disparity between NHWs and NHBs narrowed slightly. The SUID rates for Hispanics and Asian/Pacific Islanders were lower than the rates for NHWs and showed a significant decrease, resulting in an increase in their advantage over NHWs. Each racial/ethnic group showed a unique trend in SUID rates since the Back-to-Sleep campaign. When implementing risk-reduction strategies, it is important to consider these trends in targeting populations for prevention and developing culturally appropriate approaches for racial/ethnic communities. Copyright © 2017 by the American Academy of Pediatrics.
Racial and Ethnic Trends in Sudden Unexpected Infant Deaths: United States, 1995–2013
Parks, Sharyn E.; Erck Lambert, Alexa B.; Shapiro-Mendoza, Carrie K.
2017-01-01
BACKGROUND AND OBJECTIVES Immediately after the 1994 Back-to-Sleep campaign, sudden unexpected infant death (SUID) rates decreased dramatically, but they have remained relatively stable (93.4 per 100 000 live births) since 2000. In this study, we examined trends in SUID rates and disparities by race/ethnicity since the Back-to-Sleep campaign. METHODS We used 1995–2013 US period-linked birth-infant death data to evaluate SUID rates per 100 000 live births by non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic, American Indian/Alaska Native, and Asian/Pacific Islander racial/ethnic groupings. To examine racial/ethnic disparities, we calculated rate ratios with NHWs as the referent group. Unadjusted linear regression was used to evaluate trends (P < .05) in rates and rate ratios. The distribution and rates of SUID by demographic and birth characteristics were compared for 1995–1997 and 2011–2013, and χ2 tests were used to evaluate significance. RESULTS From 1995 to 2013, SUID rates were consistently highest for American Indian/Alaska Natives, followed by NHBs. The rate for NHBs decreased significantly, whereas the rate for NHWs also declined, but not significantly. As a result, the disparity between NHWs and NHBs narrowed slightly. The SUID rates for Hispanics and Asian/Pacific Islanders were lower than the rates for NHWs and showed a significant decrease, resulting in an increase in their advantage over NHWs. CONCLUSIONS Each racial/ethnic group showed a unique trend in SUID rates since the Back-to-Sleep campaign. When implementing risk-reduction strategies, it is important to consider these trends in targeting populations for prevention and developing culturally appropriate approaches for racial/ethnic communities. PMID:28562272
Preparation of Nanocellulose Reinforced Chitosan Films, Cross-Linked by Adipic Acid
Falamarzpour, Pouria; Behzad, Tayebeh; Zamani, Akram
2017-01-01
Adipic acid, an abundant and nontoxic compound, was used to dissolve and cross-link chitosan. After the preparation of chitosan films through casting technique, the in situ amidation reaction was performed at 80–100 °C as verified by Fourier transform infrared (FT-IR). The reaction was accompanied by the release of water which was employed to investigate the reaction kinetics. Accordingly, the reaction rate followed the first-order model and Arrhenius equation, and the activation energy was calculated to be 18 kJ/mol. Furthermore, the mechanical properties of the chitosan films were comprehensively studied. First, optimal curing conditions (84 °C, 93 min) were introduced through a central composite design. In order to evaluate the effects of adipic acid, the mechanical properties of physically cross-linked (uncured), chemically cross-linked (cured), and uncross-linked (prepared by acetic acid) films were compared. The use of adipic acid improved the tensile strength of uncured and chemically cross-linked films more than 60% and 113%, respectively. Finally, the effect of cellulose nanofibrils (CNFs) on the mechanical performance of cured films, in the presence of glycerol as a plasticizer, was investigated. The plasticized chitosan films reinforced by 5 wt % CNFs showed superior properties as a promising material for the development of chitosan-based biomaterials. PMID:28208822
Preparation of Nanocellulose Reinforced Chitosan Films, Cross-Linked by Adipic Acid.
Falamarzpour, Pouria; Behzad, Tayebeh; Zamani, Akram
2017-02-13
Adipic acid, an abundant and nontoxic compound, was used to dissolve and cross-link chitosan. After the preparation of chitosan films through casting technique, the in situ amidation reaction was performed at 80-100 °C as verified by Fourier transform infrared (FT-IR). The reaction was accompanied by the release of water which was employed to investigate the reaction kinetics. Accordingly, the reaction rate followed the first-order model and Arrhenius equation, and the activation energy was calculated to be 18 kJ/mol. Furthermore, the mechanical properties of the chitosan films were comprehensively studied. First, optimal curing conditions (84 °C, 93 min) were introduced through a central composite design. In order to evaluate the effects of adipic acid, the mechanical properties of physically cross-linked (uncured), chemically cross-linked (cured), and uncross-linked (prepared by acetic acid) films were compared. The use of adipic acid improved the tensile strength of uncured and chemically cross-linked films more than 60% and 113%, respectively. Finally, the effect of cellulose nanofibrils (CNFs) on the mechanical performance of cured films, in the presence of glycerol as a plasticizer, was investigated. The plasticized chitosan films reinforced by 5 wt % CNFs showed superior properties as a promising material for the development of chitosan-based biomaterials.
Methods of linking mothers and infants using health plan data for studies of pregnancy outcomes.
Johnson, Karin E; Beaton, Sarah J; Andrade, Susan E; Cheetham, T Craig; Scott, Pamela E; Hammad, Tarek A; Dashevsky, Inna; Cooper, William O; Davis, Robert L; Pawloski, Pamala A; Raebel, Marsha A; Smith, David H; Toh, Sengwee; Li, De-Kun; Haffenreffer, Katherine; Dublin, Sascha
2013-07-01
Research on medication safety in pregnancy often utilizes health plan and birth certificate records. This study discusses methods used to link mothers with infants, a crucial step in such research. We describe how eight sites participating in the Medication Exposure in Pregnancy Risk Evaluation Program created linkages between deliveries, infants and birth certificates for the 2001-2007 birth cohorts. We describe linkage rates across sites, and for two sites, we compare the characteristics of populations linked using different methods. Of 299,260 deliveries, 256,563 (86%; range by site, 74-99%) could be linked to infants using a deterministic algorithm. At two sites, using birth certificate data to augment mother-infant linkage increased the representation of mothers who were Hispanic or non-White, younger, Medicaid recipients, or had low educational level. A total of 236,460 (92%; range by site, 82-100%) deliveries could be linked to a birth certificate. Tailored approaches enabled linking most deliveries to infants and to birth certificates, even when data systems differed. The methods used may affect the composition of the population identified. Linkages established with such methods can support sound pharmacoepidemiology studies of maternal drug exposure outside the context of a formal registry. Copyright © 2013 John Wiley & Sons, Ltd.
Faster-X evolution: Theory and evidence from Drosophila.
Charlesworth, Brian; Campos, José L; Jackson, Benjamin C
2018-02-12
A faster rate of adaptive evolution of X-linked genes compared with autosomal genes can be caused by the fixation of recessive or partially recessive advantageous mutations, due to the full expression of X-linked mutations in hemizygous males. Other processes, including recombination rate and mutation rate differences between X chromosomes and autosomes, may also cause faster evolution of X-linked genes. We review population genetics theory concerning the expected relative values of variability and rates of evolution of X-linked and autosomal DNA sequences. The theoretical predictions are compared with data from population genomic studies of several species of Drosophila. We conclude that there is evidence for adaptive faster-X evolution of several classes of functionally significant nucleotides. We also find evidence for potential differences in mutation rates between X-linked and autosomal genes, due to differences in mutational bias towards GC to AT mutations. Many aspects of the data are consistent with the male hemizygosity model, although not all possible confounding factors can be excluded. © 2018 John Wiley & Sons Ltd.
Bustos-Vázquez, Eduardo; Fernández-Niño, Julián Alfredo; Astudillo-Garcia, Claudia Iveth
2017-04-01
Self-rated health is an individual and subjective conceptualization involving the intersection of biological, social and psychological factors. It provides an invaluable and unique evaluation of a person's general health status. To propose and evaluate a simple conceptual model to understand self-rated health and its relationship to multimorbidity, disability and depressive symptoms in Mexican older adults. We conducted a cross-sectional study based on a national representative sample of 8,874 adults of 60 years of age and older. Self-perception of a positive health status was determined according to a Likert-type scale based on the question: "What do you think is your current health status?" Intermediate variables included multimorbidity, disability and depressive symptoms, as well as dichotomous exogenous variables (sex, having a partner, participation in decision-making and poverty). The proposed conceptual model was validated using a general structural equation model with a logit link function for positive self-rated health. A direct association was found between multimorbidity and positive self-rated health (OR=0.48; 95% CI: 0.42-0.55), disability and positive self-rated health (OR=0.35; 95% CI: 0.30-0.40), depressive symptoms and positive self-rated health (OR=0.38; 95% CI: 0.34-0.43). The model also validated indirect associations between disability and depressive symptoms (OR=2.25; 95% CI: 2.01- 2.52), multimorbidity and depressive symptoms (OR=1.79; 95% CI: 1.61-2.00) and multimorbidity and disability (OR=1.98; 95% CI: 1.78-2.20). A parsimonious theoretical model was empirically evaluated, which enabled identifying direct and indirect associations with positive self-rated health.
Fathers’ Involvement in Preadolescents’ Diabetes Adherence and Glycemic Control*
Rohan, Jennifer M.; Carle, Adam C.; Pendley, Jennifer Shroff; Delamater, Alan; Drotar, Dennis
2011-01-01
Objective To examine the relationship of paternal involvement in diabetes care with adherence and glycemic control. Methods One hundred and thirty-six mothers and fathers of preadolescents (aged 9–12 years) with type 1 diabetes reported on paternal involvement. Adherence was measured by interview and blood glucose meter downloads. Mothers’ and fathers’ ratings of paternal involvement in diabetes care were compared. We evaluated three structural equation models linking paternal involvement with adherence and glycemic control. Results Mothers and fathers reported similar amounts of paternal involvement, yet mothers rated paternal involvement as more helpful. The data supported a model indicating links between more paternal involvement and higher HbA1c and between lower adherence and higher HbA1c. Mediation and moderation models were not supported. Discussion Although paternal involvement was not directly associated with treatment adherence, it was associated with poorer glycemic control. Some fathers may increase their involvement in response to suboptimal glycemic outcomes. PMID:21515643
NASA Astrophysics Data System (ADS)
Ghimire, B.; Riley, W. J.; Koven, C. D.; Randerson, J. T.; Mu, M.; Kattge, J.; Rogers, A.; Reich, P. B.
2014-12-01
In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However mechanistic representation of nitrogen uptake linked to root traits, and functional nitrogen allocation among different leaf enzymes involved in respiration and photosynthesis is currently lacking in Earth System models. The linkage between nitrogen availability and plant productivity is simplistically represented by potential photosynthesis rates, and is subsequently downregulated depending on nitrogen supply and other nitrogen consumers in the model (e.g., nitrification). This type of potential photosynthesis rate calculation is problematic for several reasons. Firstly, plants do not photosynthesize at potential rates and then downregulate. Secondly, there is considerable subjectivity on the meaning of potential photosynthesis rates. Thirdly, there exists lack of understanding on modeling these potential photosynthesis rates in a changing climate. In addition to model structural issues in representing photosynthesis rates, the role of plant roots in nutrient acquisition have been largely ignored in Earth System models. For example, in CLM4.5, nitrogen uptake is linked to leaf level processes (e.g., primarily productivity) rather than root scale process involved in nitrogen uptake. We present a new plant model for CLM with an improved mechanistic presentation of plant nitrogen uptake based on root scale Michaelis Menten kinetics, and stronger linkages between leaf nitrogen and plant productivity by inferring relationships observed in global databases of plant traits (including the TRY database and several individual studies). We also incorporate improved representation of plant nitrogen leaf allocation, especially in tropical regions where significant over-prediction of plant growth and productivity in CLM4.5 simulations exist. We evaluate our improved global model simulations using the International Land Model Benchmarking (ILAMB) framework. We conclude that mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers leads to overall improvements in CLM4.5's global carbon cycling predictions.
Saccharomyces boulardii for the prevention of hospital onset Clostridium difficile infection.
Flatley, Elizabeth A; Wilde, Ashley M; Nailor, Michael D
2015-03-01
Probiotics, including Saccharomyces boulardii, have been advocated for the prevention of Clostridium difficile infection. The aim of this project was to evaluate the effects of the removal of S. boulardii from an automatic antibiotic order set and hospital formulary on hospital onset C. difficile infection rates. A retrospective chart review was performed on all patients with hospital onset C. difficile infection during the 13 months prior (control group) and the 13 months after (study group) removal of an automatic order set linking S. boulardii capsules to certain broad spectrum antibiotics. A large 800+ bed tertiary hospital. Among all hospitalized patients, the rate of hospital onset C. difficile infection was 0.99 per 1000 patient days while the S. boulardii protocol was active compared with 1.04 per 1000 patient days (p=0.10) after S. boulardii was removed from the formulary. No difference in the rate of hospital onset C. difficile infection was detected in patients receiving the linked broad spectrum antibiotics during and after the removal of the protocol (1.25% vs. 1.51%, respectively; p=0.70). Removal of S. boulardii administration to patients receiving broad spectrum antibiotics and the hospital formulary did not impact the rate of hospital onset C. difficile infection in either the hospital population or patients receiving broad spectrum antibiotics.
Escherichia coli promoter sequences predict in vitro RNA polymerase selectivity.
Mulligan, M E; Hawley, D K; Entriken, R; McClure, W R
1984-01-11
We describe a simple algorithm for computing a homology score for Escherichia coli promoters based on DNA sequence alone. The homology score was related to 31 values, measured in vitro, of RNA polymerase selectivity, which we define as the product KBk2, the apparent second order rate constant for open complex formation. We found that promoter strength could be predicted to within a factor of +/-4.1 in KBk2 over a range of 10(4) in the same parameter. The quantitative evaluation was linked to an automated (Apple II) procedure for searching and evaluating possible promoters in DNA sequence files.
De Vito, David; Al-Aidroos, Naseem; Fenske, Mark J
2017-05-01
Stimuli appearing as visual distractors subsequently receive more negative affective evaluations than novel items or prior targets of attention. Leading accounts question whether this distractor devaluation effect occurs through evaluative codes that become associated with distractors as a mere artefact of attention-task instructions, or through affective consequences of attentional inhibition when applied to prevent distractor interference. Here we test opposing predictions arising from the evaluative-coding and devaluation-by-inhibition hypotheses using an electrophysiological marker of attentional inhibition in a task that requires participants to avoid interference from abstract-shape distractors presented while maintaining a uniquely-colored stimulus in memory. Consistent with prior research, distractors that matched the colour of the stimulus being held in memory elicited a Pd component of the event-related potential waveform, indicating that their processing was being actively suppressed. Subsequent affective evaluations revealed that memory-matching distractors also received more negative ratings than non-matching distractors or previously-unseen shapes. Moreover, Pd magnitude was greater on trials in which the memory-matching distractors were later rated negatively than on trials preceding positive ratings. These results support the devaluation-by-inhibition hypothesis and strongly suggest that fluctuations in stimulus inhibition are closely associated with subsequent affective evaluations. In contrast, none of the evaluative-coding based predictions were confirmed. Copyright © 2017 Elsevier Ltd. All rights reserved.
High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link
NASA Technical Reports Server (NTRS)
Yang, Guangning; Lu, Wei; Krainak, Michael; Sun, Xiaoli
2016-01-01
We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.
Operational evaluation of initial data link air traffic control services, Vol. 1
DOT National Transportation Integrated Search
1990-02-01
This report details the results of an operational evaluation of Initial Data Link Air Traffic Control (ATC) Services. The Operational Evaluation was conducted at the Federal Aviation Administration (FAA) Technical Center utilizing the Data Link test ...
Operational evaluation of initial data link air traffic control services, Vol. 2 - Appendixes
DOT National Transportation Integrated Search
1990-02-01
This report details the results of an operational evaluation of Initial Data : LInk Air Traffic Control (ATC) Services. The Operational Evaluation was : conducted at the Federal Aviation Administration (FAA)Technical Center utilizing : the Data Link ...
Fišar, Z; Hroudová, J; Singh, N; Kopřivová, A; Macečková, D
2016-01-01
Some therapeutic and/or adverse effects of drugs may be related to their effects on mitochondrial function. The effects of simvastatin, resveratrol, coenzyme Q10, acetylcysteine, and acetylcarnitine on Complex I-, Complex II-, or Complex IV-linked respiratory rate were determined in isolated brain mitochondria. The protective effects of these biologically active compounds on the calcium-induced decrease of the respiratory rate were also studied. We observed a significant inhibitory effect of simvastatin on mitochondrial respiration (IC50 = 24.0 μM for Complex I-linked respiration, IC50 = 31.3 μM for Complex II-linked respiration, and IC50 = 42.9 μM for Complex IV-linked respiration); the inhibitory effect of resveratrol was found at very high concentrations (IC50 = 162 μM for Complex I-linked respiration, IC50 = 564 μM for Complex II-linked respiration, and IC50 = 1454 μM for Complex IV-linked respiration). Concentrations required for effective simvastatin- or resveratrol-induced inhibition of mitochondrial respiration were found much higher than concentrations achieved under standard dosing of these drugs. Acetylcysteine and acetylcarnitine did not affect the oxygen consumption rate of mitochondria. Coenzyme Q10 induced an increase of Complex I-linked respiration. The increase of free calcium ions induced partial inhibition of the Complex I+II-linked mitochondrial respiration, and all tested drugs counteracted this inhibition. None of the tested drugs showed mitochondrial toxicity (characterized by respiratory rate inhibition) at drug concentrations achieved at therapeutic drug intake. Resveratrol, simvastatin, and acetylcarnitine had the greatest neuroprotective potential (characterized by protective effects against calcium-induced reduction of the respiratory rate).
Risley, John C.; Hess, Glen W.; Fisher, Bruce J.
2006-01-01
Records of diversion and return flows for water years 1961?2004 along a reach of the Klamath River between Link River and Keno Dams in south-central Oregon were evaluated to determine the cause of a water-balance inconsistency in the hydrologic data. The data indicated that the reach was losing flow in the 1960s and 1970s and gaining flow in the 1980s and 1990s. The absolute mean annual net water-balance difference in flows between the first and second half of the 44-year period (1961-2004) was approximately 103,000 acre-feet per year (acre-ft/yr). The quality of the diversion and return-flow records used in the water balance was evaluated using U.S. Geological Survey (USGS) criteria for accuracy. With the exception of the USGS Klamath River at Keno record, which was rated as 'good' or 'excellent,' the eight other flow records, all from non-USGS flow-measurement sites, were rated as 'poor' by USGS standards due to insufficient data-collection documentation and a lack of direct discharge measurements to verify the rating curves. The record for the Link River site, the most upstream in the study area, included both river and westside power canal flows. Because of rating curve biases, the river flows might have been overestimated by 25,000 acre-ft/yr on average from water years 1961 to 1982 and underestimated by 7,000 acre-ft/yr on average from water years 1983 to 2004. For water years 1984-2004, westside power canal flows might have been underestimated by 11,000 acre-ft/yr. Some diversion and return flows (for mostly agricultural, industrial, and urban use) along the Klamath River study reach, not measured continuously and not included in the water-balance equation, also were evaluated. However, the sum of these diversion and return flows was insufficient to explain the water-balance inconsistency. The possibility that ground-water levels in lands adjacent to the river rose during water years 1961-2004 and caused an increase in ground-water discharge to the river also was evaluated. However, water-level data from local wells did not have a rising trend during the period. The most likely cause of the water-balance inconsistency was flow measurement error in the eight non-USGS flow records. Part of the water-balance inconsistency can be explained by a 43,000 acre-foot error in the river and canal flow portions of the Link River flow record. A remaining 60,000 acre-foot error might have been distributed among the seven other flow records, or much of the remaining 60,000 acre-foot error might have been in the Link River flow record because flows in that record had a greater magnitude than flows in the seven other records. As an additional analysis of the water-balance issue, flow records used in the water balance were evaluated for trends and compared to known changes in water management in the Bureau of Reclamation Klamath Project and Lower Klamath and Tule Lake National Wildlife Refuges over the 44-year period. Many of the water-management changes were implemented in the early 1980s. For three diversion flow records, 1983-2004 mean annual flows were 16,000, 8,000, and 21,000 acre-ft/yr greater than their 1961-82 mean annual flows. Return flows to the Klamath River at two flow-measurement sites decreased by 31,000 and 27,000 acre-ft/yr for 1983-2004 compared with the 1961-82 period.
5.6 Gbps optical intersatellite communication link
NASA Astrophysics Data System (ADS)
Smutny, Berry; Kaempfner, Hartmut; Muehlnikel, Gerd; Sterr, Uwe; Wandernoth, Bernhard; Heine, Frank; Hildebrand, Ulrich; Dallmann, Daniel; Reinhardt, Martin; Freier, Axel; Lange, Robert; Boehmer, Knut; Feldhaus, Thomas; Mueller, Juergen; Weichert, Andreas; Greulich, Peter; Seel, Stefan; Meyer, Rolf; Czichy, Reinhard
2009-02-01
A 5.6 Gbps optical communication link has been verified in-orbit. The intersatellite link uses homodyne BPSK (binary phase shift keying) and allows to transmit data with a duplex data rate of 5.6 Gbps and a bit error rate better than 10-9 between two LEO satellites, NFIRE (U.S.) and TerraSAR-X, Germany). We report on the terminal design and the link performance during the measurement campaign. As an outlook we report on the flight units adapted to LEO-to-GEO intersatellite links that TESAT currently builds and on plans to study GEO-to-ground links.
NASA Astrophysics Data System (ADS)
Odeyemi, Kehinde O.; Owolawi, Pius A.; Srivastava, Viranjay M.
2017-11-01
Dual-hops transmission is a growing interest technique that can be used to mitigate against atmospheric turbulence along the Free Space Optical (FSO) communication links. This paper analyzes the performance of Decode-and-Forward (DF) dual-hops FSO systems in-conjunction with spatial modulation and diversity combiners over a Gamma-Gamma atmospheric turbulence channel using heterodyne detection. Maximum Ratio Combiner (MRC), Equal Gain Combiner (EGC) and Selection Combiner (SC) are considered at the relay and destination as mitigation tools to improve the system error performance. Power series expansion of modified Bessel function is used to derive the closed form expression for the end-to-end Average Pairwise Error Probability (APEP) expressions for each of the combiners under study and a tight upper bound on the Average Bit Error Rate (ABER) per hop is given. Thus, the overall end-to-end ABER for the dual-hops FSO system is then evaluated. The numerical results depicted that dual-hops transmission systems outperformed the direct link systems. Moreover, the impact of having the same and different combiners at the relay and destination are also presented. The results also confirm that the combination of dual hops transmission with spatial modulation and diversity combiner significantly improves the systems error rate with the MRC combiner offering an optimal performance with respect to variation in atmospheric turbulence, change in links average received SNR and link range of the system.
Parental mentalizing as an indirect link between attachment anxiety and parenting satisfaction.
Burkhart, Margaret L; Borelli, Jessica L; Rasmussen, Hannah F; Brody, Robin; Sbarra, David A
2017-03-01
Attachment anxiety in parents is associated with lower quality parent-child relationships. An inhibited capacity to reflect on children's mental states, referred to as prementalizing, may reduce the pleasure parents derive from their relationships. In the current study, we explored the associations among attachment anxiety, prementalizing, and parenting satisfaction in two groups of participants randomly assigned either to reflect on a positive memory with their child (n = 150) or to reflect on a positive memory not involving their child (n = 150). Narratives were evaluated for positive content using two metrics: coder-rated positivity and frequency of positive emotion words. Results revealed that self-reported prementalizing operated indirectly to link attachment anxiety and self-reported parenting satisfaction for both groups. However, prementalizing only served as an indirect link between attachment anxiety and coded measures of positivity among participants who reflected on parenting experiences, suggesting the specificity of prementalizing in linking attachment anxiety and reduced positivity in the parenting role. The results have implications for understanding influences of attachment and mentalization on parents' perception of parent-child relationship quality. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
Era, Vanessa; Candidi, Matteo; Aglioti, Salvatore Maria
2015-11-01
Emotions have a profound influence on aesthetic experiences. Studies using affective priming procedures demonstrate, for example, that inducing a conscious negative emotional state biases the perception of abstract stimuli towards the sublime (Eskine et al. Emotion 12:1071-1074, 2012. doi: 10.1037/a0027200). Moreover, subliminal happy facial expressions have a positive impact on the aesthetic evaluation of abstract art (Flexas et al. PLoS ONE 8:e80154, 2013). Little is known about how emotion influences aesthetic perception of non-abstract, representational stimuli, especially those that are particularly relevant for social behaviour, like human bodies. Here, we explore whether the subliminal presentation of emotionally charged visual primes modulates the explicit subjective aesthetic judgment of body images. Using a forward/backward masking procedure, we presented subliminally positive and negative, arousal-matched, emotional or neutral primes and measured their effect on the explicit evaluation of perceived beauty (high vs low) and emotion (positive vs negative) evoked by abstract and body images. We found that negative primes increased subjective aesthetic evaluations of target bodies or abstract images in comparison with positive primes. No influence of primes on the emotional dimension of the targets was found, thus ruling out an unspecific arousal effect and strengthening the link between emotional valence and aesthetic appreciation. More specifically, that subliminal negative primes increase beauty ratings compared to subliminal positive primes indicates a clear link between negative emotions and positive aesthetic evaluations and vice versa, suggesting a possible link between negative emotion and the experience of sublime in art. The study expands previous research by showing the effect of subliminal negative emotions on the subjective aesthetic evaluation not only of abstract but also of body images.
Using Faculty Learning Communities to Link FYE and High-Risk Core Courses: A Pilot Study
ERIC Educational Resources Information Center
Cuevas, Mo; Campbell, Kendra; Lowery-Hart, Russell D.; Mallard, Jessica; Andersen, Amy
2013-01-01
Can success rates in a gateway course be improved by linking it to a college success course? This article describes the results of a pilot study that linked a first-year biology course that had a high drop-out and failure rate to a college success course that included study skills. The proposal to link courses came from the work of a faculty…
Beckham, Jean C; Flood, Amanda M; Dennis, Michelle F; Calhoun, Patrick S
2009-02-01
The objective of the current study is to evaluate the relationship between hostility and ambulatory cardiovascular activity in women with and without posttraumatic stress disorder (PTSD). One hundred and one women completed 24 hours of ambulatory monitoring and standardized diagnostic and hostility measures. Generalized estimating equations analysis was used to examine the effects of group and hostility factor scores (hostile beliefs, overt hostility, and covert hostility) on ambulatory heart rate (AHR) and ambulatory systolic (ASBP) and diastolic (ADBP) blood pressure. After controlling for covariates, there was an interaction between PTSD and both hostile beliefs and overt hostility for AHR. Increases in hostility were associated with greater increases in heart rate among women with PTSD relative to those without PTSD. There was a similar interaction between hostile beliefs and group for ADBP. Increased AHR and blood pressure have been linked to poor cardiovascular outcomes in nonpsychiatric populations. Individuals with PTSD display increased hostility, a construct that has also been linked to poorer cardiovascular outcomes. Increases in hostile beliefs were associated with a greater increase in ADBP among women with PTSD as compared with control subjects. These data suggest that PTSD might in part moderate the relationship between hostility and cardiovascular outcomes.
GoWeb: a semantic search engine for the life science web.
Dietze, Heiko; Schroeder, Michael
2009-10-01
Current search engines are keyword-based. Semantic technologies promise a next generation of semantic search engines, which will be able to answer questions. Current approaches either apply natural language processing to unstructured text or they assume the existence of structured statements over which they can reason. Here, we introduce a third approach, GoWeb, which combines classical keyword-based Web search with text-mining and ontologies to navigate large results sets and facilitate question answering. We evaluate GoWeb on three benchmarks of questions on genes and functions, on symptoms and diseases, and on proteins and diseases. The first benchmark is based on the BioCreAtivE 1 Task 2 and links 457 gene names with 1352 functions. GoWeb finds 58% of the functional GeneOntology annotations. The second benchmark is based on 26 case reports and links symptoms with diseases. GoWeb achieves 77% success rate improving an existing approach by nearly 20%. The third benchmark is based on 28 questions in the TREC genomics challenge and links proteins to diseases. GoWeb achieves a success rate of 79%. GoWeb's combination of classical Web search with text-mining and ontologies is a first step towards answering questions in the biomedical domain. GoWeb is online at: http://www.gopubmed.org/goweb.
Research in Satellite-Fiber Network Interoperability
NASA Technical Reports Server (NTRS)
Edelson, Burt
1997-01-01
This four part report evaluated the performance of high data rate transmission links using the ACTS satellite, and to provide a preparatory test framework for two of the space science applications that have been approved for tests and demonstrations as part of the overall ACTS program. The test plan will provide guidance and information necessary to find the optimal values of the transmission parameters and then apply these parameters to specific applications. The first part will focus on the satellite-to-earth link. The second part is a set of tests to study the performance of ATM on the ACTS channel. The third and fourth parts of the test plan will cover the space science applications, Global Climate Modeling and Keck Telescope Acquisition Modeling and Control.
Lyssenko, Nathalie; Redies, Christoph; Hayn-Leichsenring, Gregor U
2016-01-01
One of the major challenges in experimental aesthetics is the uncertainty of the terminology used in experiments. In this study, we recorded terms that are spontaneously used by participants to describe abstract artworks and studied their relation to the second-order statistical image properties of the same artworks (Experiment 1). We found that the usage frequency of some structure-describing terms correlates with statistical image properties, such as PHOG Self-Similarity, Anisotropy and Complexity. Additionally, emotion-associated terms correlate with measured color values. Next, based on the most frequently used terms, we created five different rating scales (Experiment 2) and obtained ratings of participants for the abstract paintings on these scales. We found significant correlations between descriptive score ratings (e.g., between structure and subjective complexity), between evaluative and descriptive score ratings (e.g., between preference and subjective complexity/interest) and between descriptive score ratings and statistical image properties (e.g., between interest and PHOG Self-Similarity, Complexity and Anisotropy). Additionally, we determined the participants' personality traits as described in the 'Big Five Inventory' (Goldberg, 1990; Rammstedt and John, 2005) and correlated them with the ratings and preferences of individual participants. Participants with higher scores for Neuroticism showed preferences for objectively more complex images, as well as a different notion of the term complex when compared with participants with lower scores for Neuroticism. In conclusion, this study demonstrates an association between objectively measured image properties and the subjective terms that participants use to describe or evaluate abstract artworks. Moreover, our results suggest that the description of abstract artworks, their evaluation and the preference of participants for their low-level statistical properties are linked to personality traits.
Lyssenko, Nathalie; Redies, Christoph; Hayn-Leichsenring, Gregor U.
2016-01-01
One of the major challenges in experimental aesthetics is the uncertainty of the terminology used in experiments. In this study, we recorded terms that are spontaneously used by participants to describe abstract artworks and studied their relation to the second-order statistical image properties of the same artworks (Experiment 1). We found that the usage frequency of some structure-describing terms correlates with statistical image properties, such as PHOG Self-Similarity, Anisotropy and Complexity. Additionally, emotion-associated terms correlate with measured color values. Next, based on the most frequently used terms, we created five different rating scales (Experiment 2) and obtained ratings of participants for the abstract paintings on these scales. We found significant correlations between descriptive score ratings (e.g., between structure and subjective complexity), between evaluative and descriptive score ratings (e.g., between preference and subjective complexity/interest) and between descriptive score ratings and statistical image properties (e.g., between interest and PHOG Self-Similarity, Complexity and Anisotropy). Additionally, we determined the participants’ personality traits as described in the ‘Big Five Inventory’ (Goldberg, 1990; Rammstedt and John, 2005) and correlated them with the ratings and preferences of individual participants. Participants with higher scores for Neuroticism showed preferences for objectively more complex images, as well as a different notion of the term complex when compared with participants with lower scores for Neuroticism. In conclusion, this study demonstrates an association between objectively measured image properties and the subjective terms that participants use to describe or evaluate abstract artworks. Moreover, our results suggest that the description of abstract artworks, their evaluation and the preference of participants for their low-level statistical properties are linked to personality traits. PMID:27445933
Performance Evaluation of Solar Blind NLOS Ultraviolet Communication Systems
2008-12-01
noise and signal count statistical distributions . Then we further link key system parameters such as path loss and communication bit error rate (BER... quantum noise limited photon-counting detection. These benefits can now begin to be realized based on technological advances in both miniaturized...multiplication gain of 105~107, high responsivity of 62 A/W, large detection area of a few cm2, reasonable quantum efficiency of 15%, and low dark current
Free Space Optical Communication Utilizing Mid-Infrared Interband Cascade Laser
NASA Technical Reports Server (NTRS)
Soibel, A.; Wright, M.; Farr, W.; Keo, S.; Hill, C.; Yang, R. Q.; Liu, H. C.
2010-01-01
A Free Space Optical (FSO) link utilizing mid-IR Interband Cascade lasers has been demonstrated in the 3-5 micron atmospheric transmission window with data rates up to 70 Mb/s and bit-error-rate (BER) less than 10 (exp -8). The performance of the mid-IR FSO link has been compared with the performance of a near-IR link under various fog conditions using an indoor communication testbed. These experiments demonstrated the lower attenuation and scintillation advantages of a mid-IR FSO link through fog than a 1550 nm FSO link.
Adaptive data rate control TDMA systems as a rain attenuation compensation technique
NASA Technical Reports Server (NTRS)
Sato, Masaki; Wakana, Hiromitsu; Takahashi, Takashi; Takeuchi, Makoto; Yamamoto, Minoru
1993-01-01
Rainfall attenuation has a severe effect on signal strength and impairs communication links for future mobile and personal satellite communications using Ka-band and millimeter wave frequencies. As rain attenuation compensation techniques, several methods such as uplink power control, site diversity, and adaptive control of data rate or forward error correction have been proposed. In this paper, we propose a TDMA system that can compensate rain attenuation by adaptive control of transmission rates. To evaluate the performance of this TDMA terminal, we carried out three types of experiments: experiments using a Japanese CS-3 satellite with Ka-band transponders, in house IF loop-back experiments, and computer simulations. Experimental results show that this TDMA system has advantages over the conventional constant-rate TDMA systems, as resource sharing technique, in both bit error rate and total TDMA burst lengths required for transmitting given information.
Delgado, Luis M.; Bayon, Yves; Pandit, Abhay
2015-01-01
Collagen-based devices, in various physical conformations, are extensively used for tissue engineering and regenerative medicine applications. Given that the natural cross-linking pathway of collagen does not occur in vitro, chemical, physical, and biological cross-linking methods have been assessed over the years to control mechanical stability, degradation rate, and immunogenicity of the device upon implantation. Although in vitro data demonstrate that mechanical properties and degradation rate can be accurately controlled as a function of the cross-linking method utilized, preclinical and clinical data indicate that cross-linking methods employed may have adverse effects on host response, especially when potent cross-linking methods are employed. Experimental data suggest that more suitable cross-linking methods should be developed to achieve a balance between stability and functional remodeling. PMID:25517923
Telemetry data via communications relay
NASA Astrophysics Data System (ADS)
Strock, O. J.; Witchey, Michael
This paper responds to a test range engineer's need to relay one or more channels of various types of telemetry data from a remotely-located receiving station to the central telemetry station at range headquarters for real-time processing and display. Several types of data are identified, and specific equipment and technology for multiplexing, transmission, and demultiplexing up to eight streams from a variety of sources is discussed. The widely-used T3 communications link, also known as DS-3, can relay data via satellite, microwave link, or other high-speed path at 44.736 megabits per second, of which about 95 percent can be actual telemetry data; other standard links operate at lower aggregate rates. Several links and rates are discussed, with emphasis in the high-rate T3 link.
DOT National Transportation Integrated Search
1998-10-01
This report uses police-reported motor vehicle crash data linked to Emergency Medical Services data and hospital discharge data to evaluate the relative risk of injury posed by specific roadside objects in Pennsylvania. The report focuses primarily o...
Ribeiro, Pedro Leite; Camacho, Agustín; Navas, Carlos Arturo
2012-01-01
The thermal limits of individual animals were originally proposed as a link between animal physiology and thermal ecology. Although this link is valid in theory, the evaluation of physiological tolerances involves some problems that are the focus of this study. One rationale was that heating rates shall influence upper critical limits, so that ecological thermal limits need to consider experimental heating rates. In addition, if thermal limits are not surpassed in experiments, subsequent tests of the same individual should yield similar results or produce evidence of hardening. Finally, several non-controlled variables such as time under experimental conditions and procedures may affect results. To analyze these issues we conducted an integrative study of upper critical temperatures in a single species, the ant Atta sexdens rubropiosa, an animal model providing large numbers of individuals of diverse sizes but similar genetic makeup. Our specific aims were to test the 1) influence of heating rates in the experimental evaluation of upper critical temperature, 2) assumptions of absence of physical damage and reproducibility, and 3) sources of variance often overlooked in the thermal-limits literature; and 4) to introduce some experimental approaches that may help researchers to separate physiological and methodological issues. The upper thermal limits were influenced by both heating rates and body mass. In the latter case, the effect was physiological rather than methodological. The critical temperature decreased during subsequent tests performed on the same individual ants, even one week after the initial test. Accordingly, upper thermal limits may have been overestimated by our (and typical) protocols. Heating rates, body mass, procedures independent of temperature and other variables may affect the estimation of upper critical temperatures. Therefore, based on our data, we offer suggestions to enhance the quality of measurements, and offer recommendations to authors aiming to compile and analyze databases from the literature. PMID:22384147
Majaj, Najib J; Hong, Ha; Solomon, Ethan A; DiCarlo, James J
2015-09-30
To go beyond qualitative models of the biological substrate of object recognition, we ask: can a single ventral stream neuronal linking hypothesis quantitatively account for core object recognition performance over a broad range of tasks? We measured human performance in 64 object recognition tests using thousands of challenging images that explore shape similarity and identity preserving object variation. We then used multielectrode arrays to measure neuronal population responses to those same images in visual areas V4 and inferior temporal (IT) cortex of monkeys and simulated V1 population responses. We tested leading candidate linking hypotheses and control hypotheses, each postulating how ventral stream neuronal responses underlie object recognition behavior. Specifically, for each hypothesis, we computed the predicted performance on the 64 tests and compared it with the measured pattern of human performance. All tested hypotheses based on low- and mid-level visually evoked activity (pixels, V1, and V4) were very poor predictors of the human behavioral pattern. However, simple learned weighted sums of distributed average IT firing rates exactly predicted the behavioral pattern. More elaborate linking hypotheses relying on IT trial-by-trial correlational structure, finer IT temporal codes, or ones that strictly respect the known spatial substructures of IT ("face patches") did not improve predictive power. Although these results do not reject those more elaborate hypotheses, they suggest a simple, sufficient quantitative model: each object recognition task is learned from the spatially distributed mean firing rates (100 ms) of ∼60,000 IT neurons and is executed as a simple weighted sum of those firing rates. Significance statement: We sought to go beyond qualitative models of visual object recognition and determine whether a single neuronal linking hypothesis can quantitatively account for core object recognition behavior. To achieve this, we designed a database of images for evaluating object recognition performance. We used multielectrode arrays to characterize hundreds of neurons in the visual ventral stream of nonhuman primates and measured the object recognition performance of >100 human observers. Remarkably, we found that simple learned weighted sums of firing rates of neurons in monkey inferior temporal (IT) cortex accurately predicted human performance. Although previous work led us to expect that IT would outperform V4, we were surprised by the quantitative precision with which simple IT-based linking hypotheses accounted for human behavior. Copyright © 2015 the authors 0270-6474/15/3513402-17$15.00/0.
Enhancement of the NMSU Channel Error Simulator to Provide User-Selectable Link Delays
NASA Technical Reports Server (NTRS)
Horan, Stephen; Wang, Ru-Hai
2000-01-01
This is the third in a continuing series of reports describing the development of the Space-to-Ground Link Simulator (SGLS) to be used for testing data transfers under simulated space channel conditions. The SGLS is based upon Virtual Instrument (VI) software techniques for managing the error generation, link data rate configuration, and, now, selection of the link delay value. In this report we detail the changes that needed to be made to the SGLS VI configuration to permit link delays to be added to the basic error generation and link data rate control capabilities. This was accomplished by modifying the rate-splitting VIs to include a buffer the hold the incoming data for the duration selected by the user to emulate the channel link delay. In sample tests of this configuration, the TCP/IP(sub ftp) service and the SCPS(sub fp) service were used to transmit 10-KB data files using both symmetric (both forward and return links set to 115200 bps) and unsymmetric (forward link set at 2400 bps and a return link set at 115200 bps) link configurations. Transmission times were recorded at bit error rates of 0 through 10(exp -5) to give an indication of the link performance. In these tests. we noted separate timings for the protocol setup time to initiate the file transfer and the variation in the actual file transfer time caused by channel errors. Both protocols showed similar performance to that seen earlier for the symmetric and unsymmetric channels. This time, the delays in establishing the file protocol also showed that these delays could double the transmission time and need to be accounted for in mission planning. Both protocols also showed a difficulty in transmitting large data files over large link delays. In these tests, there was no clear favorite between the TCP/IP(sub ftp) and the SCPS(sub fp). Based upon these tests, further testing is recommended to extend the results to different file transfer configurations.
DOT National Transportation Integrated Search
1998-10-01
The report uses police-reported crash data that have been linked to hospital discharge data to evaluate charges for hospital care provided to motor vehicle crash victims in Pennsylvania. Approximately 17,000 crash victims were hospitalized in Pennsyl...
LinkIT: a ludic elicitation game for eliciting risk perceptions.
Cao, Yan; McGill, William L
2013-06-01
The mental models approach, a leading strategy to develop risk communications, involves a time- and labor-intensive interview process and a lengthy questionnaire to elicit group-level risk perceptions. We propose that a similarity ratings approach for structural knowledge elicitation can be adopted to assist the risk mental models approach. The LinkIT game, inspired by games with a purpose (GWAP) technology, is a ludic elicitation tool designed to elicit group understanding of the relations between risk factors in a more enjoyable and productive manner when compared to traditional approaches. That is, consistent with the idea of ludic elicitation, LinkIT was designed to make the elicitation process fun and enjoyable in the hopes of increasing participation and data quality in risk studies. Like the mental models approach, the group mental model obtained via the LinkIT game can hence be generated and represented in a form of influence diagrams. In order to examine the external validity of LinkIT, we conducted a study to compare its performance with respect to a more conventional questionnaire-driven approach. Data analysis results conclude that the two group mental models elicited from the two approaches are similar to an extent. Yet, LinkIT was more productive and enjoyable than the questionnaire. However, participants commented that the current game has some usability concerns. This presentation summarizes the design and evaluation of the LinkIT game and suggests areas for future work. © 2012 Society for Risk Analysis.
NASA Astrophysics Data System (ADS)
Vernon, F. L.; Eakins, J. A.; Busby, R.
2008-12-01
The USArray Transportable Array has deployed over 600 stations in aggregate over the past four years. All stations communicate in near-real time using ip protocols over a variety of communication links including satellite, cell phone, and DSL. Several different communication providers have been used for each type of communication links. In addition, data are being acquired from several regional networks either directly from a data server or after passing through the IRIS DMC BUD system. We will present results about the latency of data arriving at the UCSD Array Network Facility where the real time data are acquired. Under normal operating conditions the median data latency is several seconds. We will also examine the data return rates through the near-real time systems. In addition we will examine the statistics of over 36,000 events which have automatic event locations and associations. We evaluate the timeliness of these results in the context of seismic early warning systems.
Automatic Collision Avoidance Technology (ACAT)
NASA Technical Reports Server (NTRS)
Swihart, Donald E.; Skoog, Mark A.
2007-01-01
This document represents two views of the Automatic Collision Avoidance Technology (ACAT). One viewgraph presentation reviews the development and system design of Automatic Collision Avoidance Technology (ACAT). Two types of ACAT exist: Automatic Ground Collision Avoidance (AGCAS) and Automatic Air Collision Avoidance (AACAS). The AGCAS Uses Digital Terrain Elevation Data (DTED) for mapping functions, and uses Navigation data to place aircraft on map. It then scans DTED in front of and around aircraft and uses future aircraft trajectory (5g) to provide automatic flyup maneuver when required. The AACAS uses data link to determine position and closing rate. It contains several canned maneuvers to avoid collision. Automatic maneuvers can occur at last instant and both aircraft maneuver when using data link. The system can use sensor in place of data link. The second viewgraph presentation reviews the development of a flight test and an evaluation of the test. A review of the operation and comparison of the AGCAS and a pilot's performance are given. The same review is given for the AACAS is given.
A user-centred evaluation framework for the Sealife semantic web browsers
Oliver, Helen; Diallo, Gayo; de Quincey, Ed; Alexopoulou, Dimitra; Habermann, Bianca; Kostkova, Patty; Schroeder, Michael; Jupp, Simon; Khelif, Khaled; Stevens, Robert; Jawaheer, Gawesh; Madle, Gemma
2009-01-01
Background Semantically-enriched browsing has enhanced the browsing experience by providing contextualised dynamically generated Web content, and quicker access to searched-for information. However, adoption of Semantic Web technologies is limited and user perception from the non-IT domain sceptical. Furthermore, little attention has been given to evaluating semantic browsers with real users to demonstrate the enhancements and obtain valuable feedback. The Sealife project investigates semantic browsing and its application to the life science domain. Sealife's main objective is to develop the notion of context-based information integration by extending three existing Semantic Web browsers (SWBs) to link the existing Web to the eScience infrastructure. Methods This paper describes a user-centred evaluation framework that was developed to evaluate the Sealife SWBs that elicited feedback on users' perceptions on ease of use and information findability. Three sources of data: i) web server logs; ii) user questionnaires; and iii) semi-structured interviews were analysed and comparisons made between each browser and a control system. Results It was found that the evaluation framework used successfully elicited users' perceptions of the three distinct SWBs. The results indicate that the browser with the most mature and polished interface was rated higher for usability, and semantic links were used by the users of all three browsers. Conclusion Confirmation or contradiction of our original hypotheses with relation to SWBs is detailed along with observations of implementation issues. PMID:19796398
A user-centred evaluation framework for the Sealife semantic web browsers.
Oliver, Helen; Diallo, Gayo; de Quincey, Ed; Alexopoulou, Dimitra; Habermann, Bianca; Kostkova, Patty; Schroeder, Michael; Jupp, Simon; Khelif, Khaled; Stevens, Robert; Jawaheer, Gawesh; Madle, Gemma
2009-10-01
Semantically-enriched browsing has enhanced the browsing experience by providing contextualized dynamically generated Web content, and quicker access to searched-for information. However, adoption of Semantic Web technologies is limited and user perception from the non-IT domain sceptical. Furthermore, little attention has been given to evaluating semantic browsers with real users to demonstrate the enhancements and obtain valuable feedback. The Sealife project investigates semantic browsing and its application to the life science domain. Sealife's main objective is to develop the notion of context-based information integration by extending three existing Semantic Web browsers (SWBs) to link the existing Web to the eScience infrastructure. This paper describes a user-centred evaluation framework that was developed to evaluate the Sealife SWBs that elicited feedback on users' perceptions on ease of use and information findability. Three sources of data: i) web server logs; ii) user questionnaires; and iii) semi-structured interviews were analysed and comparisons made between each browser and a control system. It was found that the evaluation framework used successfully elicited users' perceptions of the three distinct SWBs. The results indicate that the browser with the most mature and polished interface was rated higher for usability, and semantic links were used by the users of all three browsers. Confirmation or contradiction of our original hypotheses with relation to SWBs is detailed along with observations of implementation issues.
Design of low SWaP optical terminals for free space optical communications
NASA Astrophysics Data System (ADS)
Shubert, P.; Cline, A.; McNally, J.; Pierson, R.
2017-02-01
Along with advantages in higher data rates, spectrum contention, and security, free space optical communications can provide size, weight, and power (SWaP) advantages over radio frequency (RF) systems. SWaP is always an issue in space systems and can be critical in applying free space optical communications to small satellite platforms. The system design of small space-based free space optical terminals with Gbps data rates is addressed. System architectures and requirements are defined to ensure the terminals are capable of acquisition, establishment and maintenance of a free space optical communications link. Design trades, identification of blocking technologies, and performance analyses are used to evaluate the practical limitations to terminal SWaP. Small terminal design concepts are developed to establish their practicality and feasibility. Techniques, such as modulation formats and capacity approaching encoding, are considered to mitigate the disadvantages brought by SWaP limitations, and performance as a function of SWaP is evaluated.
Evaluation of resonances above the proton threshold in 26Si
NASA Astrophysics Data System (ADS)
Chipps, K. A.
2016-09-01
26Al remains an intriguing target for observational gamma-ray astronomy, thanks to its characteristic decay. The 25Al(p, γ)26Si reaction is the crucial link in a sequence that bypasses the production of the observable 26Alg . s . in favor of the isomeric state, and as such has been the focus of many studies. Considerable confusion in this regard has arisen from the use of outdated excitation energies and masses in reaction studies and rate evaluations. Recalibration of existing data from the literature has resulted in updated excitation and resonance energies, but open questions remain, particularly with regard to spin assignments and partial widths/resonance strengths. A discussion of the levels just above the proton threshold in 26Si relevant to the astrophysical 25Al(p, γ)26Si reaction rate will be presented. This work is funded by the US Department of Energy, Office of Science, Office of Nuclear Physics.
SITE project. Phase 1: Continuous data bit-error-rate testing
NASA Technical Reports Server (NTRS)
Fujikawa, Gene; Kerczewski, Robert J.
1992-01-01
The Systems Integration, Test, and Evaluation (SITE) Project at NASA LeRC encompasses a number of research and technology areas of satellite communications systems. Phase 1 of this project established a complete satellite link simulator system. The evaluation of proof-of-concept microwave devices, radiofrequency (RF) and bit-error-rate (BER) testing of hardware, testing of remote airlinks, and other tests were performed as part of this first testing phase. This final report covers the test results produced in phase 1 of the SITE Project. The data presented include 20-GHz high-power-amplifier testing, 30-GHz low-noise-receiver testing, amplitude equalization, transponder baseline testing, switch matrix tests, and continuous-wave and modulated interference tests. The report also presents the methods used to measure the RF and BER performance of the complete system. Correlations of the RF and BER data are summarized to note the effects of the RF responses on the BER.
Decreased plasma neurotrophin-4/5 levels in bipolar disorder patients in mania.
Barbosa, Izabela G; Morato, Isabela B; Huguet, Rodrigo B; Rocha, Fabio L; Machado-Vieira, Rodrigo; Teixeira, Antônio L
2014-01-01
To evaluate two poorly explored neurotrophins (NT), NT-3 and NT-4/5, in bipolar disorder (BD). Forty patients with type I BD (18 in remission and 22 in mania) and 25 healthy controls matched for age, gender, and educational attainment were enrolled in this study. All subjects were assessed by the Mini-International Neuropsychiatric Interview; the Young Mania Rating Scale and the Hamilton Depression Rating Scale were used to evaluate severity of symptoms in BD patients. Plasma levels of NT-3 and NT-4/5 were measured by enzyme-linked immunosorbent assay (ELISA). BD patients in mania presented decreased NT-4/5 plasma levels in comparison with controls (p < 0.05). There were no significant differences in NT-3 plasma levels between BD patients and controls. These findings corroborate the view that neurotrophin dysfunction is associated with mood states in patients with BD.
NASA Technical Reports Server (NTRS)
Reinhart, Richard C.
1992-01-01
The Experiment Control and Monitor (EC&M) software was developed at NASA Lewis Research Center to support the Advanced Communications Technology Satellite (ACTS) High Burst Rate Link Evaluation Terminal (HBR-LET). The HBR-LET is an experimenter's terminal to communicate with the ACTS for various investigations by government agencies, universities, and industry. The EC&M software is one segment of the Control and Performance Monitoring (C&PM) software system of the HBR-LET. The EC&M software allows users to initialize, control, and monitor the instrumentation within the HBR-LET using a predefined sequence of commands. Besides instrument control, the C&PM software system is also responsible for computer communication between the HBR-LET and the ACTS NASA Ground Station and for uplink power control of the HBR-LET to demonstrate power augmentation during rain fade events. The EC&M Software User's Guide, Version 1.0 (NASA-CR-189160) outlines the commands required to install and operate the EC&M software. Input and output file descriptions, operator commands, and error recovery procedures are discussed in the document. The EC&M Software Maintenance Manual, Version 1.0 (NASA-CR-189161) is a programmer's guide that describes current implementation of the EC&M software from a technical perspective. An overview of the EC&M software, computer algorithms, format representation, and computer hardware configuration are included in the manual.
Evaporation estimates from the Dead Sea and their implications on its water balance
NASA Astrophysics Data System (ADS)
Oroud, Ibrahim M.
2011-12-01
The Dead Sea (DS) is a terminal hypersaline water body situated in the deepest part of the Jordan Valley. There is a growing interest in linking the DS to the open seas due to severe water shortages in the area and the serious geological and environmental hazards to its vicinity caused by the rapid level drop of the DS. A key issue in linking the DS with the open seas would be an accurate determination of evaporation rates. There exist large uncertainties of evaporation estimates from the DS due to the complex feedback mechanisms between meteorological forcings and thermophysical properties of hypersaline solutions. Numerous methods have been used to estimate current and historical (pre-1960) evaporation rates, with estimates differing by ˜100%. Evaporation from the DS is usually deduced indirectly using energy, water balance, or pan methods with uncertainty in many parameters. Accumulated errors resulting from these uncertainties are usually pooled into the estimates of evaporation rates. In this paper, a physically based method with minimum empirical parameters is used to evaluate historical and current evaporation estimates from the DS. The more likely figures for historical and current evaporation rates from the DS were 1,500-1,600 and 1,200-1,250 mm per annum, respectively. Results obtained are congruent with field observations and with more elaborate procedures.
A 400 Gbps/100 m free-space optical link
NASA Astrophysics Data System (ADS)
Lin, Chun-Yu; Lu, Hai-Han; Ho, Chun-Ming; Cheng, Ming-Te; Huang, Sheng-Jhe; Wang, Yun-Chieh; Chi, Jing-Kai
2017-02-01
A 400 Gbps/100 m free-space optical (FSO) link with dense-wavelength-division-multiplexing (DWDM)/space-division-multiplexing (SDM) techniques and a doublet lens scheme is proposed. To the best of our knowledge, this is the first time that a link adopting DWDM and SDM techniques and a doublet lens scheme has demonstrated a 400 Gbps/100 m FSO link. The experimental results show that the free-space transmission rate is significantly enhanced by the DWDM and SDM techniques, and the free-space transmission distance is greatly increased by the doublet lens scheme. A 16-channel FSO link with a total transmission rate of 400 Gbps (25 Gbps/λ × 16 λ = 400 Gbps) over a 100 m free-space link is successfully demonstrated. Such a 400 Gbps/100 m DWDM/SDM FSO link provides the advantages of optical wireless communications for high transmission rates and long transmission distances, which is very useful for high-speed and long-haul light-based WiFi (LiFi) applications.
Diversification and the rate of molecular evolution: no evidence of a link in mammals.
Goldie, Xavier; Lanfear, Robert; Bromham, Lindell
2011-10-04
Recent research has indicated a positive association between rates of molecular evolution and diversification in a number of taxa. However debate continues concerning the universality and cause of this relationship. Here, we present the first systematic investigation of this relationship within the mammals. We use phylogenetically independent sister-pair comparisons to test for a relationship between substitution rates and clade size at a number of taxonomic levels. Total, non-synonymous and synonymous substitution rates were estimated from mitochondrial and nuclear DNA sequences. We found no evidence for an association between clade size and substitution rates in mammals, for either the nuclear or the mitochondrial sequences. We found significant associations between body size and substitution rates, as previously reported. Our results present a contrast to previous research, which has reported significant positive associations between substitution rates and diversification for birds, angiosperms and reptiles. There are three possible reasons for the differences between the observed results in mammals versus other clades. First, there may be no link between substitution rates and diversification in mammals. Second, this link may exist, but may be much weaker in mammals than in other clades. Third, the link between substitution rates and diversification may exist in mammals, but may be confounded by other variables.
NASA Technical Reports Server (NTRS)
1972-01-01
A Tracking and Data Relay Satellite System (TDRSS) concept for service of low and medium data rate user spacecraft has been defined. The TDRS system uses two geosynchronous dual spin satellites compatible with Delta 2914 to provide command, tracking, and telemetry service between multiple low earth orbiting users and a centrally located ground station. The low data rate user service capability via each TDRS is as follows: (1) forward link at UHF: voice to one user, commands to 20 users (sequential), range and range rate service, and (2) return link at VHF: voice from one user, data from 20 users (simultaneous), range and range rate return signals. The medium data rate user service via each TDRS is as follows: (1) forward link at S band: voice or command and tracking signals to one user, and (2) return link at S band: voice, data and tracking signals from one user "order wire" for high priority service requests (implemented with an earth coverage antenna).
Tenke, Craig E.; Kayser, Jürgen; Svob, Connie; Miller, Lisa; Alvarenga, Jorge E.; Abraham, Karen; Warner, Virginia; Wickramaratne, Priya; Weissman, Myrna M.; Bruder, Gerard E.
2017-01-01
A prior report (Tenke et al. 2013 Biol. Psychol. 94:426–432) found that participants who rated religion or spirituality (R/S) highly important had greater posterior alpha after 10 years compared to those who did not. Participants who subsequently lowered their rating also had prominent alpha, while those who increased their rating did not. Here we report EEG findings 20 years after initial assessment. Clinical evaluations and R/S ratings were obtained from 73 (52 new) participants in a longitudinal study of family risk for depression. Frequency PCA of current source density transformed EEG concisely quantified posterior alpha. Those who initially rated R/S as highly important had greater alpha compared to those who did not, even if their R/S rating later increased. Furthermore, changes in religious denomination were associated with decreased alpha. Results suggest the possibility of a critical stage in the ontogenesis of R/S that is linked to posterior resting alpha. PMID:28119066
Ethnic variations in immigrant poverty exit and female employment: the missing link.
Kaida, Lisa
2015-04-01
Despite widespread interest in poverty among recent immigrants and female immigrant employment, research on the link between the two is limited. This study evaluates the effect of recently arrived immigrant women's employment on the exit from family poverty and considers the implications for ethnic differences in poverty exit. It uses the bivariate probit model and the Fairlie decomposition technique to analyze data from the Longitudinal Survey of Immigrants to Canada (LSIC), a nationally representative survey of immigrants arriving in Canada, 2000-2001. Results show that the employment of recently arrived immigrant women makes a notable contribution to lifting families out of poverty. Moreover, the wide ethnic variations in the probability of exit from poverty between European and non-European groups are partially explained by the lower employment rates among non-European women. The results suggest that the equal earner/female breadwinner model applies to low-income recent immigrant families in general, but the male breadwinner model explains the low probability of poverty exit among select non-European groups whose female employment rates are notably low.
Wall, Kristin M; Kilembe, William; Inambao, Mubiana; Chen, Yi No; Mchoongo, Mwaka; Kimaru, Linda; Hammond, Yuna Tiffany; Sharkey, Tyronza; Malama, Kalonde; Fulton, T Roice; Tran, Alex; Halumamba, Hanzunga; Anderson, Sarah; Kishore, Nishant; Sarwar, Shawn; Finnegan, Trisha; Mark, David; Allen, Susan A
2015-06-27
Patient identification within and between health services is an operational challenge in many resource-limited settings. When following HIV risk groups for service provision and in the context of vaccine trials, patient misidentification can harm patient care and bias trial outcomes. Electronic fingerprinting has been proposed to identify patients over time and link patient data between health services. The objective of this study was to determine 1) the feasibility of implementing an electronic-fingerprint linked data capture system in Zambia and 2) the acceptability of this system among a key HIV risk group: female sex workers (FSWs). Working with Biometrac, a US-based company providing biometric-linked healthcare platforms, an electronic fingerprint-linked data capture system was developed for use by field recruiters among Zambian FSWs. We evaluated the technical feasibility of the system for use in the field in Zambia and conducted a pilot study to determine the acceptability of the system, as well as barriers to uptake, among FSWs. We found that implementation of an electronic fingerprint-linked patient tracking and data collection system was feasible in this relatively resource-limited setting (false fingerprint matching rate of 1/1000 and false rejection rate of <1/10,000) and was acceptable among FSWs in a clinic setting (2% refusals). However, our data indicate that less than half of FSWs are comfortable providing an electronic fingerprint when recruited while they are working. The most common reasons cited for not providing a fingerprint (lack of privacy/confidentiality issues while at work, typically at bars or lodges) could be addressed by recruiting women during less busy hours, in their own homes, in the presence of "Queen Mothers" (FSW organizers), or in the presence of a FSW that has already been fingerprinted. Our findings have major implications for key population research and improved health services provision. However, more work needs to be done to increase the acceptability of the electronic fingerprint-linked data capture system during field recruitment. This study indicated several potential avenues that will be explored to increase acceptability.
Effect of Link Flexibility on tip position of a single link robotic arm
NASA Astrophysics Data System (ADS)
Madhusudan Raju, E.; Siva Rama Krishna, L.; Mouli, Y. Sharath Chandra; Nageswara Rao, V.
2015-12-01
The flexible robots are widely used in space applications due to their quick response, lower energy consumption, lower overall mass and operation at high speed compared to conventional industrial rigid link robots. These robots are inherently flexible, so that the kinematics of flexible robots can't be solved with rigid body assumptions. The flexibility in links and joints affects end-point positioning accuracy of the robot. It is important to model the link kinematics with precision which in turn simplifies modelling of dynamics of flexible robots. The main objective of this paper is to evaluate the effect of link flexibility on a tip position of a single link robotic arm for a given motion. The joint is assumed to be rigid and only link flexibility is considered. The kinematics of flexible link problem is evaluated by Assumed Modes Method (AMM) using MAT LAB Programming. To evaluate the effect of link flexibility (with and without payload) of robotic arm, the normalized tip deviation is found for flexible link with respect to a rigid link. Finally, the limiting inertia for payload mass is found if the allowable tip deviation is 5%.
Stevenson, Frazier T; Bowe, Connie M; Gandour-Edwards, Regina; Kumari, Vijaya G
2005-02-01
Many studies have evaluated the desirability of expert versus non-expert facilitators in problem-based learning (PBL), but performance differences between basic science and clinical facilitators has been less studied. In a PBL course at our university, pairs of faculty facilitators (1 clinician, 1 basic scientist) were assigned to student groups to maximise integration of basic science with clinical science. This study set out to establish whether students evaluate basic science and clinical faculty members differently when they teach side by side. Online questionnaires were used to survey 188 students about their faculty facilitators immediately after they completed each of 3 serial PBL cases. Overall satisfaction was measured using a scale of 1-7 and yes/no responses were gathered from closed questions describing faculty performance. results: Year 1 students rated basic science and clinical facilitators the same, but Year 2 students rated the clinicians higher overall. Year 1 students rated basic scientists higher in their ability to understand the limits of their own knowledge. Year 2 students rated the clinicians higher in several content expertise-linked areas: preparedness, promotion of in-depth understanding, and ability to focus the group, and down-rated the basic scientists for demonstrating overspecialised knowledge. Students' overall ratings of individual faculty best correlated with the qualities of stimulation, focus and preparedness, but not with overspecialisation, excessive interjection of the faculty member's own opinions, and encouragement of psychosocial issue discussion. When taught by paired basic science and clinical PBL facilitators, students in Year 1 rated basic science and clinical PBL faculty equally, while Year 2 students rated clinicians more highly overall. The Year 2 difference may be explained by perceived differences in content expertise.
The inverse niche model for food webs with parasites
Warren, Christopher P.; Pascual, Mercedes; Lafferty, Kevin D.; Kuris, Armand M.
2010-01-01
Although parasites represent an important component of ecosystems, few field and theoretical studies have addressed the structure of parasites in food webs. We evaluate the structure of parasitic links in an extensive salt marsh food web, with a new model distinguishing parasitic links from non-parasitic links among free-living species. The proposed model is an extension of the niche model for food web structure, motivated by the potential role of size (and related metabolic rates) in structuring food webs. The proposed extension captures several properties observed in the data, including patterns of clustering and nestedness, better than does a random model. By relaxing specific assumptions, we demonstrate that two essential elements of the proposed model are the similarity of a parasite's hosts and the increasing degree of parasite specialization, along a one-dimensional niche axis. Thus, inverting one of the basic rules of the original model, the one determining consumers' generality appears critical. Our results support the role of size as one of the organizing principles underlying niche space and food web topology. They also strengthen the evidence for the non-random structure of parasitic links in food webs and open the door to addressing questions concerning the consequences and origins of this structure.
The Effect of Conditioned Reinforcement Rate on Choice: A Review
Fantino, Edmund; Romanowich, Paul
2007-01-01
We review the nature of conditioned reinforcement, including evidence that conditioned reinforcers maintain choice behavior in concurrent schedules and that they elevate responding in the terminal links of concurrent-chains schedules. A question has resurfaced recently: Do theories of choice in concurrent-chains schedules need to include a term reflecting greater preference for higher rates of conditioned reinforcement? The review of several studies addressing this point suggests that such a term is inappropriate. Elevated rates of conditioned reinforcement (and responding) in the terminal links of concurrent-chains schedules do not lead to greater preference in the initial link leading to the higher rate of conditioned reinforcement. If anything, the opposite preference is likely to occur. This result is not surprising, since the additional putative conditioned reinforcers in the terminal link are not correlated with a reduction in time to primary reinforcement nor with an increase in value. PMID:17575906
Zoder-Martell, Kimberly A; Dufrene, Brad A; Tingstrom, Daniel H; Olmi, D Joe; Jordan, Sara S; Biskie, Erika M; Sherman, Julie C
2014-09-01
This study tested the effects of direct training on direct care staff's initiation of positive interactions with individuals with developmental disabilities who resided in an intermediate care facility. Participants included four direct care staff and their residents. Direct training included real-time prompts delivered via a one-way radio, and data were collected for immediate and sustained increases in rates of direct care staff's positive interactions. Additionally, this study evaluated the link between increased rates of positive interactions and concomitant decreases in residents' challenging behaviors. A multiple baseline design across participants was used and results indicated that all direct care staff increased their rates of positive interactions during direct training. Moreover, all but one participant continued to engage residents in positive interactions at levels above the criterion during the maintenance phase and follow-up phases. The direct care staff member who did not initially meet the criterion improved to adequate levels following one brief performance feedback session. With regard to residents' challenging behaviors, across phases, residents engaged in low levels of challenging behaviors making those results difficult to evaluate. However, improvements in residents' rate of positive interactions were noted. Copyright © 2014 Elsevier Ltd. All rights reserved.
Pricing unit-linked insurance with guaranteed benefit
NASA Astrophysics Data System (ADS)
Iqbal, M.; Novkaniza, F.; Novita, M.
2017-07-01
Unit-linked insurance is an investment-linked insurance, that is, the given benefit is the premium investment out-come. Recently, the most widely marketed insurance in the industry is unit-linked insurance with guaranteed benefit. With guaranteed benefit applied, the insurance benefits form is similar to the payoff form of European call option. Thereby, pricing European call option is involved in pricing unit-linked insurance with guaranteed benefit. The dynamics of investment outcome is assumed to follow stochastic interest rate. Hence, change of measure methods is used in pricing unit-linked insurance. The discount factor with stochastic interest rate needs to be modified as well to be zero coupon bond price. Eventually, the insurance premium is calculated by equivalence principle with guaranteed benefit and insurance period explicitly given.
Lentine, Krista L.; Vijayan, Anitha; Xiao, Huiling; Schnitzler, Mark A.; Davis, Connie L.; Garg, Amit X.; Axelrod, David; Abbott, Kevin C.; Brennan, Daniel C.
2012-01-01
Background Mortality records identify cancer as the leading cause of death among living kidney donors, but information on the burden of cancer outside of death records is limited in this population. Methods We examined a database wherein OPTN identifiers for 4,650 living kidney donors in 1987–2007 were linked to administrative data of a U.S. private health insurer (2000–2007 claims) to identify post-donation cancer diagnoses. Skin and non-skin cancer diagnoses were ascertained from ICD-9-CM codes on billing claims. Donors were also matched one-to-one with general insurance beneficiaries by sex and age when benefits began. Diagnosis rates within observation windows were compared as rate ratios. Results The median time from donation to the end of plan insurance enrollment was 7.7 years, with a median observation period of 2.1 years. Skin cancer rates were similar among prior living donors in the observation period and non-donor controls (rate ratio 0.91, 95% CI 0.59–1.40). In contrast, the rate of total non-skin cancers was significantly less common among donors than controls (rate ratio 0.74, 95% CI 0.55–0.99), although reduced relative risk was limited to donors captured earlier in relation to donation. Several cases of cancer diagnosis (uterine, melanoma, other) were identified within the first year after donation. Prostate cancer was significantly more common among living donors compared with controls (rate ratio 3.80, 95% CI 1.42–10.2). Conclusions Continued study of cancer after kidney donation is warranted to ensure that evaluation, selection, and long-term follow-up support overall good health of the donor. PMID:22825543
NASA Technical Reports Server (NTRS)
Hinrichs, C. A.
1974-01-01
A digital simulation is presented for a candidate modem in a modeled atmospheric scintillation environment with Doppler, Doppler rate, and signal attenuation typical of the radio link conditions for an outer planets atmospheric entry probe. The results indicate that the signal acquisition characteristics and the channel error rate are acceptable for the system requirements of the radio link. The simulation also outputs data for calculating other error statistics and a quantized symbol stream from which error correction decoding can be analyzed.
Effect of prenatal care on infant mortality rates according to birth-death certificate files.
Poma, P A
1999-09-01
Infant mortality has decreased nationwide; however, our national rates still log behind those of other industrialized countries, especially the rates for minority groups. This study evaluates the effect of prenatal care and risk factors on infant mortality rates in Chicago. Using linked infant birth and death certificates of Chicago residents for 1989-1995, a total of 5838 deaths occurring during the first year of life were identified. Birth certificate variables, especially prenatal care, were reviewed. Variables were compared by stratified analysis. Pearson chi 2 analysis and odd ratios (ORs) were computed. Infant mortality rate (IMR) in Chicago decreased from 17 in 1989 to 12.6 in 1995 (P < .0001). Some factors increased IMR several fold: prematurity (OR 17.43), no prenatal care (OR 4.07), inadequate weight gain (OR 2.95), African-American ethnicity (OR 2.55), and inadequate prenatal care (OR 2.03). Compared with no care, prenatal care was associated with lower IMR; however, early care was associated with higher IMR and ORs than later care. These results demonstrate prenatal care is associated with lower IMR; however, compared with late prenatal care, early care does not improve IMR. Further studies should evaluate whether improving the quality of care improves IMRs.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ohta, Shinichi, E-mail: junryuhei@yahoo.co.jp; Nitta, Norihisa, E-mail: r34nitta@belle.shiga-med.ac.jp; Watanabe, Shobu, E-mail: swat@belle.shiga-med.ac.jp
2013-08-01
PurposeTo evaluate the embolic effect and degradability of gelatin microspheres (GMS) using various degrees of cross-linkage and particle sizes in rabbit renal artery embolization.MethodsFour types of GMS were used, as follows: 2 types of cross-linkage and 2 types of particle size. Twenty-four rabbits (6 in each group) were used for the renal artery embolization. Renal angiography was performed before and after embolization of right renal artery. Follow-up renal angiography was performed 2 days (n = 2), 5 days (n = 2), and 15 days (n = 2) after embolization in each group, and then kidneys were removed for histopathological evaluation.more » Vascular areas of the angiography were measured by Image J software, and the reperfusion rate was calculated. In renal specimens, residual GMS were checked and the degree of degradation was classified according to a 4-point scale.ResultsThe mean amounts of large- and small-particle-size GMS injected were 15.0 and 34.3 mg, respectively. Tissue necrosis was confirmed in each group; however, no difference was observed among groups. Renal reperfusion was observed more with small GMS than with large GMS. Renal reperfusion was also observed more with low cross-linked GMS than with high cross-linked GMS. In histopathological specimens, large GMS were confirmed in lobar artery, and small GMS were confirmed in lobular artery. Low cross-linked GMS completely degraded 15 days after embolization. In contrast, high cross-linked GMS were persistent 15 days after embolization.ConclusionDegree of cross-linkage and particle size affected degradability and reperfusion.« less
NASA Astrophysics Data System (ADS)
Zhang, Yong; Papelis, Charalambos; Sun, Pengtao; Yu, Zhongbo
2013-08-01
Particle-based models and continuum models have been developed to quantify mixing-limited bimolecular reactions for decades. Effective model parameters control reaction kinetics, but the relationship between the particle-based model parameter (such as the interaction radius R) and the continuum model parameter (i.e., the effective rate coefficient Kf) remains obscure. This study attempts to evaluate and link R and Kf for the second-order bimolecular reaction in both the bulk and the sharp-concentration-gradient (SCG) systems. First, in the bulk system, the agent-based method reveals that R remains constant for irreversible reactions and decreases nonlinearly in time for a reversible reaction, while mathematical analysis shows that Kf transitions from an exponential to a power-law function. Qualitative link between R and Kf can then be built for the irreversible reaction with equal initial reactant concentrations. Second, in the SCG system with a reaction interface, numerical experiments show that when R and Kf decline as t-1/2 (for example, to account for the reactant front expansion), the two models capture the transient power-law growth of product mass, and their effective parameters have the same functional form. Finally, revisiting of laboratory experiments further shows that the best fit factor in R and Kf is on the same order, and both models can efficiently describe chemical kinetics observed in the SCG system. Effective model parameters used to describe reaction kinetics therefore may be linked directly, where the exact linkage may depend on the chemical and physical properties of the system.
The Safe Yield and Climatic Variability: Implications for Groundwater Management.
Loáiciga, Hugo A
2017-05-01
Methods for calculating the safe yield are evaluated in this paper using a high-quality and long historical data set of groundwater recharge, discharge, extraction, and precipitation in a karst aquifer. Consideration is given to the role that climatic variability has on the determination of a climatically representative period with which to evaluate the safe yield. The methods employed to estimate the safe yield are consistent with its definition as a long-term average extraction rate that avoids adverse impacts on groundwater. The safe yield is a useful baseline for groundwater planning; yet, it is herein shown that it is not an operational rule that works well under all climatic conditions. This paper shows that due to the nature of dynamic groundwater processes it may be most appropriate to use an adaptive groundwater management strategy that links groundwater extraction rates to groundwater discharge rates, thus achieving a safe yield that represents an estimated long-term sustainable yield. An example of the calculation of the safe yield of the Edwards Aquifer (Texas) demonstrates that it is about one-half of the average annual recharge. © 2016, National Ground Water Association.
Fervaha, Gagan; Foussias, George; Takeuchi, Hiroyoshi; Agid, Ofer; Remington, Gary
2016-04-01
Many individuals with major depressive disorder present with prominent motivational deficits; however, the effect of these symptoms on functional outcomes in the illness remains unclear. Individuals with major depression who participated in the Sequenced Treatment Alternatives to Relieve Depression study were included in the present investigation (N=1563). Motivational deficits were evaluated using a derived measure from the Hamilton Depression Rating Scale, while functioning was assessed using the Work and Social Adjustment Scale. Subjective outcomes were also evaluated using the Quality of Life Enjoyment and Satisfaction Questionnaire. After treatment with citalopram, over 70% of participants continued to experience some degree of motivational deficits. These deficits were significantly associated with greater functional impairments both globally and in each domain of functioning evaluated. These symptoms were also linked to worse subjective outcomes such as overall life satisfaction and quality of life. Change in the severity of motivational deficits over time was significantly linked with changes in outcome. Motivational deficits continued to demonstrate a significant association with outcomes, even after controlling for potentially confounding variables such as duration of depressive episode and severity of other depressive symptoms. Motivational deficits are significantly linked to the functional impairment present in many people with major depression, just as they are in other psychiatric illnesses such as schizophrenia. A greater understanding of the underlying mechanisms of these motivational deficits in particular, beyond other depressive symptoms, is critical to the development of strategies aimed at enhancing functional recovery and improved subjective well-being. Copyright © 2015 Elsevier Inc. All rights reserved.
Risson, Valery; Ghodge, Bhaskar; Bonzani, Ian C; Korn, Jonathan R; Medin, Jennie; Saraykar, Tanmay; Sengupta, Souvik; Saini, Deepanshu; Olson, Melvin
2016-09-22
An enormous amount of information relevant to public health is being generated directly by online communities. To explore the feasibility of creating a dataset that links patient-reported outcomes data, from a Web-based survey of US patients with multiple sclerosis (MS) recruited on open Internet platforms, to health care utilization information from health care claims databases. The dataset was generated by linkage analysis to a broader MS population in the United States using both pharmacy and medical claims data sources. US Facebook users with an interest in MS were alerted to a patient-reported survey by targeted advertisements. Eligibility criteria were diagnosis of MS by a specialist (primary progressive, relapsing-remitting, or secondary progressive), ≥12-month history of disease, age 18-65 years, and commercial health insurance. Participants completed a questionnaire including data on demographic and disease characteristics, current and earlier therapies, relapses, disability, health-related quality of life, and employment status and productivity. A unique anonymous profile was generated for each survey respondent. Each anonymous profile was linked to a number of medical and pharmacy claims datasets in the United States. Linkage rates were assessed and survey respondents' representativeness was evaluated based on differences in the distribution of characteristics between the linked survey population and the general MS population in the claims databases. The advertisement was placed on 1,063,973 Facebook users' pages generating 68,674 clicks, 3719 survey attempts, and 651 successfully completed surveys, of which 440 could be linked to any of the claims databases for 2014 or 2015 (67.6% linkage rate). Overall, no significant differences were found between patients who were linked and not linked for educational status, ethnicity, current or prior disease-modifying therapy (DMT) treatment, or presence of a relapse in the last 12 months. The frequencies of the most common MS symptoms did not differ significantly between linked patients and the general MS population in the databases. Linked patients were slightly younger and less likely to be men than those who were not linkable. Linking patient-reported outcomes data, from a Web-based survey of US patients with MS recruited on open Internet platforms, to health care utilization information from claims databases may enable rapid generation of a large population of representative patients with MS suitable for outcomes analysis.
SCAILET - An intelligent assistant for satellite ground terminal operations
NASA Technical Reports Server (NTRS)
Shahidi, A. K.; Crapo, J. A.; Schlegelmilch, R. F.; Reinhart, R. C.; Petrik, E. J.; Walters, J. L.; Jones, R. E.
1992-01-01
Space communication artificial intelligence for the link evaluation terminal (SCAILET) is an experimenter interface to the link evaluation terminal (LET) developed by NASA through the application of artificial intelligence to an advanced ground terminal. The high-burst-rate (HBR) LET provides the required capabilities for wideband communications experiments with the advanced communications technology satellite (ACTS). The HBR-LET terminal consists of seven major subsystems and is controlled and monitored by a minicomputer through an IEEE-488 or RS-232 interface. Programming scripts configure HBR-LET and allow data acquisition but are difficult to use and therefore the full capabilities of the system are not utilized. An intelligent assistant module was developed as part of the SCAILET module and solves problems encountered during configuration of the HBR-LET system. This assistant is a graphical interface with an expert system running in the background and allows users to configure instrumentation, program sequences and reference documentation. The simplicity of use makes SCAILET a superior interface to the ASCII terminal and continuous monitoring allows nearly flawless configuration and execution of HBR-LET experiments.
Maternal exposure to the holocaust and health complaints in offspring.
Flory, Janine D; Bierer, Linda M; Yehuda, Rachel
2011-01-01
Although the link between chronic stress and the development of cardiovascular and metabolic diseases of adulthood has been known for some time, there is growing recognition that early environmental influences may result in developmental programming via epigenetic mechanisms, thereby affecting the developmental trajectory of disease progression. Previous studies support the idea that offspring of Holocaust survivors may have been subjected to early developmental programming. We evaluated the relationship between parental exposure to the Holocaust and self-reported health ratings and disorders made by their adult offspring (i.e., second generation Holocaust survivors). A total of 137 subjects were evaluated. Regression analyses demonstrated that maternal but not paternal exposure to the Holocaust was related to poorer subjective impressions of emotional and physical health. This relationship was diminished when the offspring's own level of trait anxiety was considered. Offspring with maternal, but not paternal, Holocaust exposure also reported greater use of psychotropic and other medications, including medications for the treatment of hypertension and lipid disorders. The mechanism linking these health outcomes and maternal exposure deserves further investigation, including the possibility that fetal or early developmental programming is involved.
Maternal Exposure to the Holocaust and Health Complaints in Offspring
Flory, Janine D.; Bierer, Linda M.; Yehuda, Rachel
2011-01-01
Although the link between chronic stress and the development of cardiovascular and metabolic diseases of adulthood has been known for some time, there is growing recognition that early environmental influences may result in developmental programming via epigenetic mechanisms, thereby affecting the developmental trajectory of disease progression. Previous studies support the idea that offspring of Holocaust survivors may have been subjected to early developmental programming. We evaluated the relationship between parental exposure to the Holocaust and self-reported health ratings and disorders made by their adult offspring (i.e., second generation Holocaust survivors). A total of 137 subjects were evaluated. Regression analyses demonstrated that maternal but not paternal exposure to the Holocaust was related to poorer subjective impressions of emotional and physical health. This relationship was diminished when the offspring’s own level of trait anxiety was considered. Offspring with maternal, but not paternal, Holocaust exposure also reported greater use of psychotropic and other medications, including medications for the treatment of hypertension and lipid disorders. The mechanism linking these health outcomes and maternal exposure deserves further investigation, including the possibility that fetal or early developmental programming is involved. PMID:21508517
Lustenberger, Nadia A; Prodinger, Birgit; Dorjbal, Delgerjargal; Rubinelli, Sara; Schmitt, Klaus; Scheel-Sailer, Anke
2017-09-23
To illustrate how routinely written narrative admission and discharge reports of a rehabilitation program for eight youths with chronic neurological health conditions can be transformed to the International Classification of Functioning, Disability and Health. First, a qualitative content analysis was conducted by building meaningful units with text segments assigned of the reports to the five elements of the Rehab-Cycle ® : goal; assessment; assignment; intervention; evaluation. Second, the meaningful units were then linked to the ICF using the refined ICF Linking Rules. With the first step of transformation, the emphasis of the narrative reports changed to a process oriented interdisciplinary layout, revealing three thematic blocks of goals: mobility, self-care, mental, and social functions. The linked 95 unique ICF codes could be grouped in clinically meaningful goal-centered ICF codes. Between the two independent linkers, the agreement rate was improved after complementing the rules with additional agreements. The ICF Linking Rules can be used to compile standardized health information from narrative reports if prior structured. The process requires time and expertise. To implement the ICF into common practice, the findings provide the starting point for reporting rehabilitation that builds upon existing practice and adheres to international standards. Implications for Rehabilitation This study provides evidence that routinely collected health information from rehabilitation practice can be transformed to the International Classification of Functioning, Disability and Health by using the "ICF Linking Rules", however, this requires time and expertise. The Rehab-Cycle ® , including assessments, assignments, goal setting, interventions and goal evaluation, serves as feasible framework for structuring this rehabilitation program and ensures that the complexity of local practice is appropriately reflected. The refined "ICF Linking Rules" lead to a standardized transformation process of narrative text and thus a higher quality with increased transparency. As a next step, the resulting format of goal codes supplemented by goal-clarifying codes could be validated to strengthen the implementation of the International Classification of Functioning, Disability and Health into rehabilitation routine by respecting the variety of clinical practice.
The Socioemotional Costs and Benefits of Social-Evaluative Concerns: Do Girls Care Too Much?
Rudolph, Karen D.; Conley, Colleen S.
2011-01-01
This research investigated the hypothesis that girls’ heightened concerns about social evaluation contribute to sex differences in depression and interpersonal competence during early adolescence. A short-term longitudinal study was conducted with 474 adolescents to examine the consequences of heightened social-evaluative concerns. Adolescents reported on their levels of social-evaluative concerns and depressive symptoms. Teachers provided ratings of adolescents’ competence with peers (displays of prosocial and aggressive behavior). As anticipated, girls demonstrated higher levels of social-evaluative concerns, depressive symptoms, and interpersonal competence than did boys. Moreover, path analysis confirmed that heightened social-evaluative concerns were associated both concurrently and over time with higher levels of depression, as well as with higher levels of interpersonal competence. Notably, social-evaluative concerns accounted fully for the sex difference in depression and partially for the sex difference in interpersonal competence. These findings highlight the need to consider both the socioemotional costs and benefits of sex-linked relational orientations. PMID:15660675
A study of 60 GHz intersatellite link applications
NASA Technical Reports Server (NTRS)
Anzic, G.; Connolly, D. J.; Haugland, E. J.; Kosmahl, H. G.; Chitwood, J. S.
1983-01-01
Applications of intersatellite links operating at 60 GHz are reviewed. Likely scenarios, ranging from transmission of moderate and high data rates over long distances to low data rates over short distances are examined. A limited parametric tradeoff is performed with system variables such as radiofrequency power, receiver noise temperature, link distance, data rate, and antenna size. Present status is discussed and projections are given for both electron tube and solid state transmitter technologies. Monolithic transmit and receive module technology, already under development at 20 to 30 GHz, is reviewed and its extension to 60 GHz, and possible applicability is discussed.
A study of 60 Gigahertz intersatellite link applications
NASA Astrophysics Data System (ADS)
Anzic, G.; Connolly, D. J.; Haugland, E. J.; Kosmahl, H. G.; Chitwood, J. S.
Applications of intersatellite links operating at 60 GHz are reviewed. Likely scenarios, ranging from transmission of moderate and high data rates over long distances to low data rates over short distances are examined. A limited parametric tradeoff is performed with system variables such as radiofrequency power, receiver noise temperature, link distance, data rate, and antenna size. Present status is discussed and projections are given for both electron tube and solid state transmitter technologies. Monolithic transmit and receive module technology, already under development at 20 to 30 GHz, is reviewed and its extension to 60 GHz, and possible applicability is discussed.
A study of 60 Gigahertz intersatellite link applications
NASA Technical Reports Server (NTRS)
Anzic, G.; Connolly, D. J.; Haugland, E. J.; Kosmahl, H. G.; Chitwood, J. S.
1983-01-01
Applications of intersatellite links operating at 60 GHz are reviewed. Likely scenarios, ranging from transmission of moderate and high data rates over long distances to low data rates over short distances are examined. A limited parametric tradeoff is performed with system variables such as radiofrequency power, receiver noise temperature, link distance, data rate, and antenna size. Present status is discussed and projections are given for both electron tube and solid state transmitter technologies. Monolithic transmit and receive module technology, already under development at 20 to 30 GHz, is reviewed and its extension to 60 GHz, and possible applicability is discussed.
A study of 60 GHz intersatellite link applications
NASA Astrophysics Data System (ADS)
Anzic, G.; Connolly, D. J.; Haugland, E. J.; Kosmahl, H. G.; Chitwood, J. S.
Applications of intersatellite links operating at 60 GHz are reviewed. Likely scenarios, ranging from transmission of moderate and high data rates over long distances to low data rates over short distances are examined. A limited parametric tradeoff is performed with system variables such as radiofrequency power, receiver noise temperature, link distance, data rate, and antenna size. Present status is discussed and projections are given for both electron tube and solid state transmitter technologies. Monolithic transmit and receive module technology, already under development at 20 to 30 GHz, is reviewed and its extension to 60 GHz, and possible applicability is discussed.
A field evaluation of data link flight information services for general aviation pilots
DOT National Transportation Integrated Search
1997-02-01
This report documents a field study of Data Link Flight Information Services : (FIS) designed for use by general aviation (GA) pilots. The Data Link FIS : package that was evaluated in this study included the Traffic Information : Service (TIS), Text...
Controller Evaluation of Initial Data Link Air Traffic Control Services, Mini Study 1, Volume 2
DOT National Transportation Integrated Search
1988-09-01
This report details the results of Mini Study 1. This mini study was conducted : at the Federal Aviation Administration (FAA) Technical Center utilizing the Data : Link testbed. Initial Data Link air traffic control services were evaluated : under pa...
Stress-induced brain activity, brain atrophy, and clinical disability in multiple sclerosis
Weygandt, Martin; Meyer-Arndt, Lil; Behrens, Janina Ruth; Wakonig, Katharina; Bellmann-Strobl, Judith; Ritter, Kerstin; Scheel, Michael; Brandt, Alexander U.; Labadie, Christian; Hetzer, Stefan; Gold, Stefan M.; Paul, Friedemann; Haynes, John-Dylan
2016-01-01
Prospective clinical studies support a link between psychological stress and multiple sclerosis (MS) disease severity, and peripheral stress systems are frequently dysregulated in MS patients. However, the exact link between neurobiological stress systems and MS symptoms is unknown. To evaluate the link between neural stress responses and disease parameters, we used an arterial-spin–labeling functional MRI stress paradigm in 36 MS patients and 21 healthy controls. Specifically, we measured brain activity during a mental arithmetic paradigm with performance-adaptive task frequency and performance feedback and related this activity to disease parameters. Across all participants, stress increased heart rate, perceived stress, and neural activity in the visual, cerebellar and insular cortex areas compared with a resting condition. None of these responses was related to cognitive load (task frequency). Consistently, although performance and cognitive load were lower in patients than in controls, stress responses did not differ between groups. Insula activity elevated during stress compared with rest was negatively linked to impairment of pyramidal and cerebral functions in patients. Cerebellar activation was related negatively to gray matter (GM) atrophy (i.e., positively to GM volume) in patients. Interestingly, this link was also observed in overlapping areas in controls. Cognitive load did not contribute to these associations. The results show that our task induced psychological stress independent of cognitive load. Moreover, stress-induced brain activity reflects clinical disability in MS. Finally, the link between stress-induced activity and GM volume in patients and controls in overlapping areas suggests that this link cannot be caused by the disease alone. PMID:27821732
Ames life science telescience testbed evaluation
NASA Technical Reports Server (NTRS)
Haines, Richard F.; Johnson, Vicki; Vogelsong, Kristofer H.; Froloff, Walt
1989-01-01
Eight surrogate spaceflight mission specialists participated in a real-time evaluation of remote coaching using the Ames Life Science Telescience Testbed facility. This facility consisted of three remotely located nodes: (1) a prototype Space Station glovebox; (2) a ground control station; and (3) a principal investigator's (PI) work area. The major objective of this project was to evaluate the effectiveness of telescience techniques and hardware to support three realistic remote coaching science procedures: plant seed germinator charging, plant sample acquisition and preservation, and remote plant observation with ground coaching. Each scenario was performed by a subject acting as flight mission specialist, interacting with a payload operations manager and a principal investigator expert. All three groups were physically isolated from each other yet linked by duplex audio and color video communication channels and networked computer workstations. Workload ratings were made by the flight and ground crewpersons immediately after completing their assigned tasks. Time to complete each scientific procedural step was recorded automatically. Two expert observers also made performance ratings and various error assessments. The results are presented and discussed.
Frequency Spectrum for New Aviation Data Links: Initial Study Results
NASA Technical Reports Server (NTRS)
Matolak, David W.; Branstetter, James R.
2004-01-01
We describe results from an initial study to assess the suitability of various spectral bands for supporting the deployment of new aviation data links (ADL). The study focused on systems and spectral bands that can deliver VHF data link (VDL)-or-higher data rates in a two-way communication setting, including air-ground, ground-air, and air-air modes of operation. In the first part of our paper, we briefly discuss the current situation regarding communications, navigation, and surveillance (CNS) links and existing spectrum, and the well-known need for new aviation data links. We next provide an overview of related systems, and discuss key factors involved in the use of spectrum in various bands for any future integrated CNS data link, addressing primarily the lower few layers of the communications protocol stack. Desired attributes of a new ADL system are discussed, and the beneficial aspects of a particular transmission technique spread spectrum are summarized. We also provide a short list of several example potential spectral regions, and note that while none of the existing systems will likely meet the full range of desired features of a new ADL, several systems and spectral regions offer promise in terms of one or more characteristics. A detailed discussion and evaluation of these spectral regions is proposed as future work. We include a few brief examples to illustrate initial technical results regarding spread spectrum overlay, also a subject for future work.
Listing Practices for Morbidly Obese Patients at Liver Transplantation Centers in the United States.
Halegoua-De Marzio, Dina L; Wong, She-Yan; Fenkel, Jonathan M; Doria, Cataldo; Sass, David A
2016-12-01
The effect of morbid obesity on liver transplant outcomes has yielded mixed results. The aim of this study was to determine listing practices for morbidly obese patients at liver transplant centers in the United States. A 19-item survey was created to assess liver transplant evaluation and listing practices for morbidly obese patients. All adult liver transplant medical and surgical directors in the United States were contacted by e-mail, which provided an Internet link to an online survey. We sent a total of 187 surveys by e-mail, with responses received from 46 physicians (24.7% response rate). A policy on evaluation and listing of obese patients was present at 70.5% of institutions, with most (54.5%) reporting that their body mass index cutoff for transplant was 40 kg/m2, but a range of 35 kg/m2 to unlimited was noted. Most respondents agreed that patients with high body mass index were less likely to be evaluated for transplant. Respondents reported increased complication rates among obese patients, with the most common being poor wound healing and increased infection rates. Most medical and surgical liver transplant directors have a strong appreciation of the possible morbidity risks associated with performing liver transplants in morbidly obese patients and have policies in effect to minimize these risks.
Controller Evaluation of Initial Data Link Air Traffic Control Services: Mini Study 2 Volume II
DOT National Transportation Integrated Search
1989-03-01
This report details the results of Mini Study 2. This Mini Study was conducted at the Federal Aviation Administration (FAA) Technical Center utilizing the Data Link test bed. Initial Data Link air traffic control services were evaluated under part ta...
Controller Evaluation of Initial Data Link Air Traffic Control Services: Mini Study 2 Volume I
DOT National Transportation Integrated Search
1989-03-01
This report details the results of Mini Study 2. This Mini Study was conducted at the Federal Aviation Administration (FAA) Technical Center utilizing the Data Link test bed. Initial Data Link air traffic control services were evaluated under part ta...
Changes in dynamics of accommodation after accommodative facility training in myopes and emmetropes.
Allen, Peter M; Charman, W Neil; Radhakrishnan, Hema
2010-05-12
This study evaluates the effect of accommodative facility training in myopes and emmetropes. Monocular accommodative facility was measured in nine myopes and nine emmetropes for distance and near. Subjective facility was recorded with automated flippers and objective measurements were simultaneously taken with a PowerRefractor. Accommodative facility training (a sequence of 5 min monocular right eye, 5 min monocular left eye, 5 min binocular) was given on three consecutive days and facility was re-assessed on the fifth day. The results showed that training improved the facility rate in both groups. The improvement in facility rates were linked to the time constants and peak velocity of accommodation. Some changes in amplitude seen in emmetropes indicate an improvement in facility rate at the expense of an accurate accommodation response. Copyright 2010 Elsevier Ltd. All rights reserved.
Carp, Stefan A; Farzam, Parisa; Redes, Norin; Hueber, Dennis M; Franceschini, Maria Angela
2017-09-01
Frequency domain near infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS) have emerged as synergistic techniques for the non-invasive assessment of tissue health. Combining FD-NIRS oximetry with DCS measures of blood flow, the tissue oxygen metabolic rate can be quantified, a parameter more closely linked to underlying physiology and pathology than either NIRS or DCS estimates alone. Here we describe the first commercially available integrated instrument, called the "MetaOx", designed to enable simultaneous FD-NIRS and DCS measurements at rates of 10 + Hz, and offering real-time data evaluation. We show simultaneously acquired characterization data demonstrating performance equivalent to individual devices and sample in vivo measurements of pulsation resolved blood flow, forearm occlusion hemodynamic changes and muscle oxygen metabolic rate monitoring during stationary bike exercise.
Carp, Stefan A.; Farzam, Parisa; Redes, Norin; Hueber, Dennis M.; Franceschini, Maria Angela
2017-01-01
Frequency domain near infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS) have emerged as synergistic techniques for the non-invasive assessment of tissue health. Combining FD-NIRS oximetry with DCS measures of blood flow, the tissue oxygen metabolic rate can be quantified, a parameter more closely linked to underlying physiology and pathology than either NIRS or DCS estimates alone. Here we describe the first commercially available integrated instrument, called the “MetaOx”, designed to enable simultaneous FD-NIRS and DCS measurements at rates of 10 + Hz, and offering real-time data evaluation. We show simultaneously acquired characterization data demonstrating performance equivalent to individual devices and sample in vivo measurements of pulsation resolved blood flow, forearm occlusion hemodynamic changes and muscle oxygen metabolic rate monitoring during stationary bike exercise. PMID:29026684
Zhao, Shuaiyang; Liu, Junlong; Zhao, Hongxi; Li, Youquan; Xie, Junren; Liu, Aihong; Hassan, Muhammad-Adeel; Yin, Hong; Guan, Guiquan; Luo, Jianxun
2017-02-01
Bovine theileriosis, a tick-borne protozoan disease caused by Theileria annulata, Theileria orientalis and Theileria sinensis, is widespread in China and is a serious economic problem for the Chinese livestock industry. In this study, recombinant major piroplasma surface proteins (MPSP) of T. annulata, T. orientalis and T. sinensis based on MPSP genes were expressed in Escherichia coli BL21(DE3). The immunogenicity and specificity of the three purified recombinant MPSP proteins were evaluated with the reference positive sera of T. annulata, T. orientalis, T. sinensis, Babesia bovis, B abesia bigemina, Babesia major, Babesia motasi, Theileria luwenshuni, Theileria uilenbergi and Anaplasma ovis using an enzyme-linked immunosorbent assay (ELISA) or western blotting. The results showed that all three of the rMPSP proteins had a strong reaction with the sera from cattle infected with T. annulata, T. orientalis and T. sinensis via western blotting but not with other piroplasma and Anaplasma species. Then, the rMPSP protein of T. sinensis was used to develop an iELISA for detecting the three Theileria species infections. The specificity and sensitivity were 95.7 and 95.5 %, respectively, with a threshold of 28.8 % of the specific mean antibody rate (AbR). Finally, 2473 field-collected bovine sera, from 42 prefectures of 17 provinces in China, were tested using the ELISA to evaluate the prevalence of bovine theileriosis, and the average positive rate was 43.6 %. The developed iELISA could be a suitable tool to detect the three bovine Theileria species, and the data also provided important information regarding the current prevalence of bovine theileriosis in China.
Gilbert, B K; Mitchell, M P; Bengali, A R; Khandheria, B K
1999-08-01
To describe the development of telemedicine capabilities-application of remote consultation and diagnostic techniques-and to evaluate the feasibility and practicality of such clinical outreach to rural and underserved communities with limited telecommunications infrastructures. In 1992, Mayo Foundation (Rochester, Minn, Jacksonville, Fla, and Scottsdale, Ariz), the National Aeronautics and Space Administration, and the Defense Advanced Research Projects Agency collaborated to create a complex network of fiberoptic landlines, video recording systems, satellite terminals, and specially developed data translators linking Mayo sites with other locations in the continental United States on an on-demand basis. The purpose was to transmit data via the asynchronous transfer mode (ATM) digital communications protocol over the Advanced Communications Technology Satellite. The links were intended to provide a conduit for transmission of data for patient-specific consultations between physicians, evaluation of medical imagery, and medical education for clinical staffs at remote sites. Low-data-rate (LDR) experiments went live late in 1993. Mayo Clinic Rochester successfully provided medical consultation and services to 2 small regional medical facilities. High-data-rate (HDR) experiments included studies of remote digital echocardiography, store-and-forward telemedicine, cardiac catheterization, and teleconsultation for congenital heart disease. These studies combined landline data transmission with use of the satellite. The complexity of the routing paths and network components, immaturity of available software, and inexperience with existing telecommunications caused significant study delays. These experiments demonstrated that next-generation satellite technology can provide batch and real-time imagery for telemedicine. The first-generation of the ATM and satellite network technology used in these experiments created several technical problems and inconveniences that should be overcome as the network infrastructure matures.
Yaeger, Jeffrey P; Temte, Jonathan L; Hanrahan, Lawrence P; Martinez-Donate, P
2015-11-01
Prior studies have evaluated factors predictive of inappropriate antibiotic prescription for upper respiratory tract infections (URIs). Community factors, however, have not been examined. The aim of this study was to evaluate the roles of patient, clinician, and community factors in predicting appropriate management of URIs in children. We used a novel database exchange, linking electronic health record data with community statistics, to identify all patients aged 3 months to 18 years in whom URI was diagnosed in the period from 2007 to 2012. We followed the Healthcare Effectiveness Data and Information Set (HEDIS) quality measurement titled "Appropriate treatment for children with upper respiratory infection" to determine the rate of appropriate management of URIs. We then stratified data across individual and community characteristics and used multiple logistic regression modeling to identify variables that independently predicted antibiotic prescription. Of 20,581 patients, the overall rate for appropriate management for URI was 93.5%. Family medicine clinicians (AOR = 1.5; 95% CI 1.31, 1.71; reference = pediatric clinicians), urgent care clinicians (AOR = 2.23; 95% CI 1.93, 2.57; reference = pediatric clinicians), patients aged 12 to 18 years (AOR = 1.44; 95% CI 1.25, 1.67; reference = age 3 months to 4 years), and patients of white race/ ethnicity (AOR = 1.83; 95% CI 1.41, 2.37; reference = black non-Hispanic) were independently predictive of antibiotic prescription. No community factors were independently predictive of antibiotic prescription. Results correlate with prior studies in which non-pediatric clinicians and white race/ethnicity were predictive of antibiotic prescription, while association with older patient age has not been previously reported. Findings illustrate the promise of linking electronic health records with community data to evaluate health care disparities. © 2015 Annals of Family Medicine, Inc.
Space Communications Artificial Intelligence for Link Evaluation Terminal (SCAILET)
NASA Technical Reports Server (NTRS)
Shahidi, Anoosh
1991-01-01
A software application to assis end-users of the Link Evaluation Terminal (LET) for satellite communication is being developed. This software application incorporates artificial intelligence (AI) techniques and will be deployed as an interface to LET. The high burst rate (HBR) LET provides 30 GHz transmitting/20 GHz receiving, 220/110 Mbps capability for wideband communications technology experiments with the Advanced Communications Technology Satellite (ACTS). The HBR LET and ACTS are being developed at the NASA Lewis Research Center. The HBR LET can monitor and evaluate the integrity of the HBR communications uplink and downlink to the ACTS satellite. The uplink HBR transmission is performed by bursting the bit-pattern as a modulated signal to the satellite. By comparing the transmitted bit pattern with the received bit pattern, HBR LET can determine the bit error rate BER) under various atmospheric conditions. An algorithm for power augmentation is applied to enhance the system's BER performance at reduced signal strength caused by adverse conditions. Programming scripts, defined by the design engineer, set up the HBR LET terminal by programming subsystem devices through IEEE488 interfaces. However, the scripts are difficult to use, require a steep learning curve, are cryptic, and are hard to maintain. The combination of the learning curve and the complexities involved with editing the script files may discourage end-users from utilizing the full capabilities of the HBR LET system. An intelligent assistant component of SCAILET that addresses critical end-user needs in the programming of the HBR LET system as anticipated by its developers is described. A close look is taken at the various steps involved in writing ECM software for a C&P, computer and at how the intelligent assistant improves the HBR LET system and enhances the end-user's ability to perform the experiments.
A digitally implemented communications experiment utilizing the Hermes (CTS) satellite
NASA Technical Reports Server (NTRS)
Jackson, H. D.; Fiala, J. L.
1977-01-01
The Hermes (CTS) experiment program made possible a significant effort directed toward new developments which will reduce the costs associated with the distribution of satellite services. Advanced satellite transponder technology and small inexpensive earth terminals were demonstrated as part of the Hermes program. Another system element that holds promise for reduced transmission cost is associated with the communication link implementation. An experiment is described which uses CTS to demonstrate digital link implementation and its advantages over conventional analog systems. A Digitally Implemented Communications experiment which demonstrates the flexibility and efficiency of digital transmission of television video and audio, telephone voice and high-bit-rate data is also described. Presentation of the experiment concept which concentrates on the evaluation of full-duplex digital television in the teleconferencing environment is followed by a description of unique equipment that was developed.
VanScoy, Brian; Liu, Weiguo; Kulawy, Robert; Drusano, G. L.
2013-01-01
Amoxicillin is considered an option for postexposure prophylaxis of Bacillus anthracis in pregnant and postpartum women who are breastfeeding and in children because of the potential toxicities of ciprofloxacin and doxycycline to the fetus and child. The amoxicillin regimen that effectively kills B. anthracis and prevents resistance is unknown. Fourteen-day dose range and dose fractionation studies were conducted in in vitro pharmacodynamic models to identify the exposure intensity and pharmacodynamic index of amoxicillin that are linked with optimized killing of B. anthracis and resistance prevention. Studies with dicloxacillin, a drug resistant to B. anthracis beta-lactamase, evaluated the role of beta-lactamase production in the pharmacodynamic indices for B. anthracis killing and resistance prevention. Dose fractionation studies showed that trough/MIC and not time above MIC was the index for amoxicillin that was linked to successful outcome through resistance prevention. Failure of amoxicillin regimens was due to inducible or stable high level expression of beta-lactamases. Studies with dicloxacillin demonstrated that a time above MIC of ≥94% was linked with treatment success when B. anthracis beta-lactamase activity was negated. Recursive partitioning analysis showed that amoxicillin regimens that produced peak concentrations of <10.99 μg/ml and troughs of >1.75 μg/ml provided a 100% success rate. Other amoxicillin peak and trough values produced success rates of 28 to 67%. For postpartum and pregnant women and children, Monte Carlo simulations predicted success rates for amoxicillin at 1 g every 8 h (q8h) of 53, 33, and 44% (30 mg/kg q8h), respectively. We conclude that amoxicillin is suboptimal for postexposure prophylaxis of B. anthracis in pregnant and postpartum women and in children. PMID:24041894
Chandler, Kevin Brown; Pompach, Petr; Goldman, Radoslav
2013-01-01
Glycosylation is a common protein modification with a significant role in many vital cellular processes and human diseases, making the characterization of protein-attached glycan structures important for understanding cell biology and disease processes. Direct analysis of protein N-glycosylation by tandem mass spectrometry of glycopeptides promises site-specific elucidation of N-glycan microheterogeneity, something which detached N-glycan and de-glycosylated peptide analyses cannot provide. However, successful implementation of direct N-glycopeptide analysis by tandem mass spectrometry remains a challenge. In this work, we consider algorithmic techniques for the analysis of LC-MS/MS data acquired from glycopeptide-enriched fractions of enzymatic digests of purified proteins. We implement a computational strategy which takes advantage of the properties of CID fragmentation spectra of N-glycopeptides, matching the MS/MS spectra to peptide-glycan pairs from protein sequences and glycan structure databases. Significantly, we also propose a novel false-discovery-rate estimation technique to estimate and manage the number of false identifications. We use a human glycoprotein standard, haptoglobin, digested with trypsin and GluC, enriched for glycopeptides using HILIC chromatography, and analyzed by LC-MS/MS to demonstrate our algorithmic strategy and evaluate its performance. Our software, GlycoPeptideSearch (GPS), assigned glycopeptide identifications to 246 of the spectra at false-discovery-rate 5.58%, identifying 42 distinct haptoglobin peptide-glycan pairs at each of the four haptoglobin N-linked glycosylation sites. We further demonstrate the effectiveness of this approach by analyzing plasma-derived haptoglobin, identifying 136 N-linked glycopeptide spectra at false-discovery-rate 0.4%, representing 15 distinct glycopeptides on at least three of the four N-linked glycosylation sites. The software, GlycoPeptideSearch, is available for download from http://edwardslab.bmcb.georgetown.edu/GPS. PMID:23829323
KnowledgeLink: Impact of Context-Sensitive Information Retrieval on Clinicians' Information Needs
Maviglia, Saverio M.; Yoon, Catherine S.; Bates, David W.; Kuperman, Gilad
2006-01-01
Objective: Infobuttons are message-based content search and retrieval functions embedded within other applications that dynamically return information relevant to the clinical task at hand. The objective of this study was to determine whether infobuttons effectively answer providers' questions about medications or affect patient care decisions. Design: The authors implemented and evaluated a medication infobutton application called KnowledgeLink. Health care providers at 18 outpatient clinics were randomized to one of two versions of KnowledgeLink, one that linked to information from Micromedex (Thomson Micromedex, Greenwood Village, Co) and the other to material from SkolarMD (Wolters Kluwer Health, Palo Alto, CA). Measurements: Data were collected about the frequency of use and demographics of users, patients, and drugs that were queried. Users were periodically surveyed with short questionnaires and then with a more extensive survey at the end of one year. Results: During the first year, KnowledgeLink was used 7,972 times by 359 users to look up information about 1,723 medications for 4,961 patients. Clinicians used KnowledgeLink twice a month on average, and during an average of 1.2% of patient encounters. KnowledgeLink was used by a wide variety of medical staff, not just physicians and nurse practitioners. The frequency of usage and the questions asked varied with user role (primary care physician, specialist physician, nurse practitioner). Although the median KnowledgeLink session was brief (21 seconds), KnowledgeLink answered users' queries 84% of the time, and altered patient care decisions 15% of the time. Users rated KnowledgeLink favorably on multiple scales, recommended extending KnowledgeLink to other content domains, and suggested enhancing the interface to allow refinement of the query and selection of the target resource. Conclusion: An infobutton can satisfy information needs about medications. Although used infrequently and for brief sessions, KnowledgeLink was positively received, answered most users' questions, and had a significant impact on medical decision making. The next steps would be to broaden the domains that KnowledgeLink covers to more specifically tailor results to the user type, to provide options when queries are not immediately answered, and to implement KnowledgeLink within other electronic clinical applications. PMID:16221942
Simons, Jessica M.; Maybery, Murray T.; Leung, Doris; Ng, Honey L. H.; Whitehouse, Andrew J. O.
2015-01-01
The Extreme Male Brain (EMB) theory posits that autistic traits are linked to excessive exposure to testosterone in utero. While findings from a number of studies are consistent with this theory, other studies have produced contradictory results. For example, some findings suggest that rather than being linked to hypermasculinization for males, or defeminization for females, elevated levels of autistic traits are instead linked to more androgynous physical features. The current study provided further evidence relevant to the EMB and androgony positions by comparing groups of males selected for high or low scores on the Autism-spectrum Quotient (AQ) as to the rated masculinity of their faces and voices, and comparable groups of females as to the rated femininity of their faces and voices. The voices of High-AQ males were rated as more masculine than those of Low-AQ males, while the faces of High-AQ females were rated as less feminine than those of Low-AQ females. There was no effect of AQ group on femininity ratings for female voices or on masculinity ratings for male faces. The results thus provide partial support for a link between high levels of autistic-like traits and hypermasculinization for males and defeminization for females, consistent with the EMB theory. PMID:26186689
Reliable Broadcast under Cascading Failures in Interdependent Networks
DOE Office of Scientific and Technical Information (OSTI.GOV)
Duan, Sisi; Lee, Sangkeun; Chinthavali, Supriya
Reliable broadcast is an essential tool to disseminate information among a set of nodes in the presence of failures. We present a novel study of reliable broadcast in interdependent networks, in which the failures in one network may cascade to another network. In particular, we focus on the interdependency between the communication network and power grid network, where the power grid depends on the signals from the communication network for control and the communication network depends on the grid for power. In this paper, we build a resilient solution to handle crash failures in the communication network that may causemore » cascading failures and may even partition the network. In order to guarantee that all the correct nodes deliver the messages, we use soft links, which are inactive backup links to non-neighboring nodes that are only active when failures occur. At the core of our work is a fully distributed algorithm for the nodes to predict and collect the information of cascading failures so that soft links can be maintained to correct nodes prior to the failures. In the presence of failures, soft links are activated to guarantee message delivery and new soft links are built accordingly for long term robustness. Our evaluation results show that the algorithm achieves low packet drop rate and handles cascading failures with little overhead.« less
Damos, Petros
2015-08-01
In this study, we use entropy related mixing rate modules to measure the effects of temperature on insect population stability and demographic breakdown. The uncertainty in the age of the mother of a randomly chosen newborn, and how it is moved after a finite act of time steps, is modeled using a stochastic transformation of the Leslie matrix. Age classes are represented as a cycle graph and its transitions towards the stable age distribution are brought forth as an exact Markov chain. The dynamics of divergence, from a non equilibrium state towards equilibrium, are evaluated using the Kolmogorov-Sinai entropy. Moreover, Kullback-Leibler distance is applied as information-theoretic measure to estimate exact mixing times of age transitions probabilities towards equilibrium. Using empirically data, we show that on the initial conditions and simulated projection's trough time, that population entropy can effectively be applied to detect demographic variability towards equilibrium under different temperature conditions. Changes in entropy are correlated with the fluctuations of the insect population decay rates (i.e. demographic stability towards equilibrium). Moreover, shorter mixing times are directly linked to lower entropy rates and vice versa. This may be linked to the properties of the insect model system, which in contrast to warm blooded animals has the ability to greatly change its metabolic and demographic rates. Moreover, population entropy and the related distance measures that are applied, provide a means to measure these rates. The current results and model projections provide clear biological evidence why dynamic population entropy may be useful to measure population stability. Copyright © 2015 Elsevier Inc. All rights reserved.
Chen, He; Meng, Tianguang
2015-01-01
Three main opposing camps exist over how social capital relates to population health, namely the social support perspective, the inequality thesis, and the political economy approach. The distinction among bonding, bridging, and linking social capital probably helps close the debates between these three camps, which is rarely investigated in existing literatures. Moreover, although self-rated health is a frequently used health indicator in studies on the relationship between social capital and health, the interpersonal incomparability of this measure has been largely neglected. This study has two main objectives. Firstly, we aim to investigate the relationship between bonding, bridging, and linking social capital and self-rated health among Chinese adults. Secondly, we aim to improve the interpersonal comparability in self-rated health measurement. We use data from a nationally representative survey in China. Self-rated health was adjusted using the anchoring vignettes technique to improve comparability. Two-level ordinal logistic regression was performed to model the association between social capital and self-rated health at both individual and community levels. The interaction between residence and social capital was included to examine urban/rural disparities in the relationship. We found that most social capital indicators had a significant relationship with adjusted self-rated health of Chinese adults, but the relationships were mixed. Individual-level bonding, linking social capital, and community-level bridging social capital were positively related with health. Significant urban/rural disparities appeared in the association between community-level bonding, linking social capital, and adjusted self-rated health. For example, people living in communities with higher bonding social capital tended to report poorer adjusted self-rated health in urban areas, but the opposite tendency held for rural areas. Furthermore, the comparison between multivariate analyses results before and after the anchoring vignettes adjustment showed that the relationship between community-level social capital and self-rated health might be distorted if comparability problems are not addressed. In conclusion, the framework of bonding, bridging, and linking social capital helps us better understand the mechanism between social capital and self-rated health. Cultural and socioeconomic factors should be considered when designing health intervention policies using social capital. Moreover, we recommend that more studies improve the comparability of self-rated health by using the anchoring vignettes technique.
Chen, He; Meng, Tianguang
2015-01-01
Three main opposing camps exist over how social capital relates to population health, namely the social support perspective, the inequality thesis, and the political economy approach. The distinction among bonding, bridging, and linking social capital probably helps close the debates between these three camps, which is rarely investigated in existing literatures. Moreover, although self-rated health is a frequently used health indicator in studies on the relationship between social capital and health, the interpersonal incomparability of this measure has been largely neglected. This study has two main objectives. Firstly, we aim to investigate the relationship between bonding, bridging, and linking social capital and self-rated health among Chinese adults. Secondly, we aim to improve the interpersonal comparability in self-rated health measurement. We use data from a nationally representative survey in China. Self-rated health was adjusted using the anchoring vignettes technique to improve comparability. Two-level ordinal logistic regression was performed to model the association between social capital and self-rated health at both individual and community levels. The interaction between residence and social capital was included to examine urban/rural disparities in the relationship. We found that most social capital indicators had a significant relationship with adjusted self-rated health of Chinese adults, but the relationships were mixed. Individual-level bonding, linking social capital, and community-level bridging social capital were positively related with health. Significant urban/rural disparities appeared in the association between community-level bonding, linking social capital, and adjusted self-rated health. For example, people living in communities with higher bonding social capital tended to report poorer adjusted self-rated health in urban areas, but the opposite tendency held for rural areas. Furthermore, the comparison between multivariate analyses results before and after the anchoring vignettes adjustment showed that the relationship between community-level social capital and self-rated health might be distorted if comparability problems are not addressed. In conclusion, the framework of bonding, bridging, and linking social capital helps us better understand the mechanism between social capital and self-rated health. Cultural and socioeconomic factors should be considered when designing health intervention policies using social capital. Moreover, we recommend that more studies improve the comparability of self-rated health by using the anchoring vignettes technique. PMID:26569107
Brockett, Claire L; Abdelgaied, Abdellatif; Haythornthwaite, Tony; Hardaker, Catherine; Fisher, John; Jennings, Louise M
2016-01-01
Advancements in knee replacement design, material and sterilisation processes have provided improved clinical results. However, surface wear of the polyethylene leading to osteolysis is still considered the longer-term risk factor. Experimental wear simulation is an established method for evaluating the wear performance of total joint replacements. The aim of this study was to investigate the influence of simulation input conditions, specifically input kinematic magnitudes, waveforms and directions of motion and position of the femoral centre of rotation, on the wear performance of a fixed-bearing total knee replacement through a combined experimental and computational approach. Studies were completed using conventional and moderately cross-linked polyethylene to determine whether the influence of these simulation input conditions varied with material. The position of the femoral centre of rotation and the input kinematics were shown to have a significant influence on the wear rates. Similar trends were shown for both the conventional and moderately cross-linked polyethylene materials, although lower wear rates were found for the moderately cross-linked polyethylene due to the higher level of cross-linking. The most important factor influencing the wear was the position of the relative contact point at the femoral component and tibial insert interface. This was dependent on the combination of input displacement magnitudes, waveforms, direction of motion and femoral centre of rotation. This study provides further evidence that in order to study variables such as design and material in total knee replacement, it is important to carefully control knee simulation conditions. This can be more effectively achieved through the use of displacement control simulation. PMID:27160561
DOT National Transportation Integrated Search
1999-09-01
A deterministic algorithm was developed which allowed data from Department of Transportation motor vehicle crash records, state mortality registry records, and hospital admission and emergency department records to be linked for analysis of the impac...
Architecture Studies Done for High-Rate Duplex Direct Data Distribution (D4) Services
NASA Technical Reports Server (NTRS)
2002-01-01
A study was sponsored to investigate a set of end-to-end system concepts for implementing a high-rate duplex direct data distribution (D4) space-to-ground communications link. The NASA Glenn Research Center is investigating these systems (both commercial and Government) as a possible method of providing a D4 communications service between NASA spacecraft in low Earth orbit and the respective principal investigators using or monitoring instruments aboard these spacecraft. Candidate commercial services were assessed regarding their near-term potential to provide a D4 type of service. The candidates included K-band and V-band geostationary orbit and nongeostationary orbit satellite relay services and direct downlink (D3) services. Internet protocol (IP) networking technologies were evaluated to enable the user-directed distribution and delivery of science data. Four realistic, near-future concepts were analyzed: 1) A duplex direct link (uplink plus downlink communication paths) between a low-Earth-orbit spacecraft and a principal-investigator-based autonomous Earth station; 2) A space-based relay using a future K-band nongeosynchronous-orbit system to handle both the uplink and downlink communication paths; 3) A hybrid link using both direct and relay services to achieve full duplex capability; 4) A dual-mode concept consisting of both a duplex direct link and a space relay duplex link operating independently. The concepts were analyzed in terms of contact time between the NASA spacecraft and the communications service and the achievable data throughput. Throughput estimates for the D4 systems were based on the infusion of advanced communications technology products (single and multibeam K-band phased-arrays and digital modems) being developed by Glenn. Cost estimates were also performed using extrapolated information from both terrestrial and current satellite communications providers. The throughput and cost estimates were used to compare the concepts.
Champagne, Claude P; Raymond, Yves; Pouliot, Yves; Gauthier, Sylvie F; Lessard, Martin
2014-05-01
The aim of this study is to evaluate the effects of defatted colostrum (Col), defatted decaseinated colostrum whey, cheese whey, and spray-dried porcine plasma (SDPP) as supplements of a growth medium (de Man - Rogosa - Sharpe (MRS) broth) on the multiplication of lactic acid bacteria, probiotic bacteria, and potentially pathogenic Escherichia coli. Using automated spectrophotometry (in vitro system), we evaluated the effect of the 4 supplements on maximum growth rate (μ(max)), lag time (LagT), and biomass (OD(max)) of 12 lactic acid bacteria and probiotic bacteria and of an E. coli culture. Enrichment of MRS broth with a Col concentration of 10 g/L increased the μ(max) of 5 of the 12 strains by up to 55%. Negative effects of Col or SDPP on growth rates were also observed with 3 probiotic strains; in one instance μ(max) was reduced by 40%. The most effective inhibitor of E. coli growth was SDPP, and this effect was not linked to its lysozyme content. The positive effect of enrichment with the dairy-based ingredient might be linked to enrichment in sugars and increased buffering power of the medium. These in vitro data suggest that both Col and SDPP could be considered as supplements to animal feeds to improve intestinal health because of their potential to promote growth of probiotic bacteria and to inhibit growth of pathogenic bacteria such as E. coli.
Cherkas, Andriy; Eckl, Peter; Guéraud, Françoise; Abrahamovych, Orest; Serhiyenko, Victoria; Yatskevych, Ostap; Pliatsko, Mykhailo; Golota, Sergii
2016-01-01
Aim To compare anthropometric parameters, body composition, hormonal and inflammatory profiles, oxidative stress indices, and heart rate variability (HRV) in Heliobacter pylori (H.pylori) positive and negative healthy sedentary participants. Methods Among 30 recruited apparently healthy male participants (age between 20 and 40) enrolled in this cross-sectional study, 18 were H.pylori negative and 12 were positive (stool antigen test). Participants underwent routine physical examination and body composition determination. The following biochemical parameters were determined in blood: fasting whole blood glucose, glycated hemoglobin, insulin, C-peptide, cortisol, aldosterone, testosterone, thyroid stimulating hormone, C-reactive protein, interleukins 6 and 10, tumor necrosis factor-α, and the urinary level of 1,4-dihydroxynonane mercapturic acid. For HRV evaluation, electrocardiogram in supine position and in orthostatic test was performed. Results H.pylori contamination was not significantly associated with any changes in anthropometric parameters, body composition, blood pressure, fasting glucose, or glycated hemoglobin levels. No significant difference was found for inflammatory markers as well as 1,4-dihydroxynonane mercapturic acid. H.pylori-positive participants, however, had significantly higher heart rate (P = 0.009), sympathetic/parasympathetic balance in orthostatic test (P = 0.029), fasting insulin level (P = 0.037), and HOMA-index (P = 0.047). Conclusions H.pylori contamination is linked to a significantly higher heart rate, sympathetic activation, and increased insulin resistance, while inflammatory and oxidative stress markers remain unaffected in healthy sedentary male subjects. PMID:27106356
[Characteristics of Dupuytren's disease in women. A study of 67 cases].
Ferry, N; Lasserre, G; Pauchot, J; Lepage, D; Tropet, Y
2013-12-01
The aim of this study was to identify the clinical differences of the Dupuytren's disease in gender. Testosterone induces an increase of the Dupuytren's fibroblast proliferation via androgen's receptors. Testosterone rate increases during pregnancy and menopausis. We also reached a link between this factors and the clinical aspects of Dupuytren' disease in the women of our study. This retrospective, comparative study was about all women and a randomized number of men, who underwent surgery for Dupuytren' disease between 1980 and 2010. We analysed all the epidemiologic and clinical data, the surgery procedures and the complications. Pre- and postoperative measurements of the extension lack of all the joints were performed with a manual goniometer. Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire was used to evaluate the patients function. This specific data of women were reached. Sixty-seven women and 69 men were compared. The complex regional pain syndrome was significantly more common in women and the correction of the proximal interphalangeal joint was significantly lower in women. Recurrence rate and mean follow up were not statistically different. Mean DASH score was higher in women. We have not found any association between menopausis, pregnancy and the average age at presentation of the disease, the recurrence rate or the extension rate. The prognosis of the Dupuytren's disease is worse in women than in men. Other studies are necessary to reach the link between the testosterone and the clinical history of the disease in women. Copyright © 2012 Elsevier Masson SAS. All rights reserved.
Global Fund grant programmes: an analysis of evaluation scores.
Radelet, Steven; Siddiqi, Bilal
2007-05-26
The Global Fund to Fight AIDS, Tuberculosis and Malaria evaluates programme performance after 2 years to help decide whether to continue funding. We aimed to identify the correlation between programme evaluation scores and characteristics of the programme, the health sector, and the recipient country. We obtained data on the first 140 Global Fund grants evaluated in 2006, and analysed 134 of these. We used an ordered probit multivariate analysis to link evaluation scores to different characteristics, allowing us to record the association between changes in those characteristics and the probability of a programme receiving a particular evaluation score. Programmes that had government agencies as principal recipients, had a large amount of funding, were focused on malaria, had weak initial proposals, or were evaluated by the accounting firm KPMG, scored lowest. Countries with a high number of doctors per head, high measles immunisation rates, few health-sector donors, and high disease-prevalence rates had higher evaluation scores. Poor countries, those with small government budget deficits, and those that have or have had socialist governments also received higher scores. Our results show associations, not causality, and they focus on evaluation scores rather than actual performance of the programmes. Yet they provide some early indications of characteristics that can help the Global Fund identify and monitor programmes that might be at risk. The results should not be used to influence the distribution of funding, but rather to allocate resources for oversight and risk management.
Riall, Taylor S; Sheffield, Kristin M; Kuo, Yong-Fang; Townsend, Courtney M; Goodwin, James S
2011-04-01
To evaluate time trends in surgical resection rates and operative mortality in older adults diagnosed with locoregional pancreatic cancer and to determine the effect of age on surgical resection rates and 2-year survival after surgical resection. Retrospective cohort study using data from the Surveillance, Epidemiology, and End Results (SEER) and linked Medicare claims database (1992-2005). Secondary data analysis of population-based tumor registry and linked claims data. Medicare beneficiaries aged 66 and older diagnosed with locoregional pancreatic cancer (N=9,553), followed from date of diagnosis to time of death or censorship. Percentage of participants undergoing surgical resection, 30-day operative mortality after resection, and 2-year survival according to age group. Surgical resection rates increased significantly, from 20% in 1992 to 29% in 2005, whereas 30-day operative mortality rates decreased from 9% to 5%. After controlling for multiple factors, participants were less likely to be resected with older age. Resection was associated with lower hazard of death, regardless of age, with hazard ratios of 0.46, 0.51, 0.47, 0.43, and 0.35 for resected participants younger than 70, 70 to 74, 75 to 79, 80 to 84, and 85 and older respectively compared with unresected participants younger than 70 (P<.001). With older age, fewer people with pancreatic cancer undergo surgical resection, even after controlling for comorbidity and other factors. This study demonstrated increased resection rates over time in all age groups, along with lower surgical mortality rates. Despite previous reports of greater morbidity and mortality after pancreatic resection in older adults, the benefit of resection does not diminish with older age in selected people. © 2011, Copyright the Authors. Journal compilation © 2011, The American Geriatrics Society.
Performance evaluation of NASA/KSC CAD/CAE graphics local area network
NASA Technical Reports Server (NTRS)
Zobrist, George
1988-01-01
This study had as an objective the performance evaluation of the existing CAD/CAE graphics network at NASA/KSC. This evaluation will also aid in projecting planned expansions, such as the Space Station project on the existing CAD/CAE network. The objectives were achieved by collecting packet traffic on the various integrated sub-networks. This included items, such as total number of packets on the various subnetworks, source/destination of packets, percent utilization of network capacity, peak traffic rates, and packet size distribution. The NASA/KSC LAN was stressed to determine the useable bandwidth of the Ethernet network and an average design station workload was used to project the increased traffic on the existing network and the planned T1 link. This performance evaluation of the network will aid the NASA/KSC network managers in planning for the integration of future workload requirements into the existing network.
ACTS Ka-Band Earth Stations: Technology, Performance, and Lessons Learned
NASA Technical Reports Server (NTRS)
Reinhart, Richard C.; Struharik, Steven J.; Diamond, John J.; Stewart, David
2000-01-01
The Advanced Communications Technology Satellite (ACTS) Project invested heavily in prototype Ka-band satellite ground terminals to conduct an experiments program with the ACTS satellite. The ACTS experiment's program proposed to validate Ka-band satellite and ground station technology. demonstrate future telecommunication services. demonstrate commercial viability and market acceptability of these new services, evaluate system networking and processing technology, and characterize Ka-band propagation effects, including development of techniques to mitigate signal fading. This paper will present a summary of the fixed ground terminals developed by the NASA Glenn Research Center and its industry partners, emphasizing the technology and performance of the terminals (Part 1) and the lessons learned throughout their six year operation including the inclined orbit phase of operations (Full Report). An overview of the Ka-band technology and components developed for the ACTS ground stations is presented. Next. the performance of the ground station technology and its evolution during the ACTS campaign are discussed to illustrate the technical tradeoffs made during the program and highlight technical advances by industry to support the ACTS experiments program and terminal operations. Finally. lessons learned during development and operation of the user terminals are discussed for consideration of commercial adoption into future Ka-band systems. The fixed ground stations used for experiments by government, academic, and commercial entities used reflector based offset-fed antenna systems ranging in size from 0.35m to 3.4m antenna diameter. Gateway earth stations included two systems, referred to as the NASA Ground Station (NGS) and the Link Evaluation Terminal (LET). The NGS provides tracking, telemetry, and control (TT&C) and Time Division Multiple Access (TDMA) network control functions. The LET supports technology verification and high data rate experiments. The ground stations successfully demonstrated many services and applications at Ka-band in three different modes of operation: circuit switched TDMA using the satellite on-board processor, satellite switched SS-TDMA applications using the on-board Microwave Switch Matrix (MSM), and conventional transponder (bent-pipe) operation. Data rates ranged from 4.8 kbps up to 622 Mbps. Experiments included: 1) low rate (4.8- 1 00's kbps) remote data acquisition and control using small earth stations, 2) moderate rate (1-45 Mbps) experiments included full duplex voice and video conferencing and both full duplex and asymmetric data rate protocol and network evaluation using mid-size ground stations, and 3) link characterization experiments and high data rate (155-622 Mbps) terrestrial and satellite interoperability application experiments conducted by a consortium of experimenters using the large transportable ground stations.
Heitmar, R; Varma, C; De, P; Lau, Y C; Blann, A D
2016-11-01
To test the hypothesis of a significant relationship between systemic markers of renal and vascular function (processes linked to cardiovascular disease and its development) and retinal microvascular function in diabetes and/or cardiovascular disease. Ocular microcirculatory function was measured in 116 patients with diabetes and/or cardiovascular disease using static and continuous retinal vessel responses to three cycles of flickering light. Endothelial function was evaluated by von Willebrand factor (vWf), endothelial microparticles and soluble E selectin, renal function by serum creatinine, creatinine clearance and estimated glomerular filtration rate (eGFR). HbA1c was used as a control index. Central retinal vein equivalence and venous maximum dilation to flicker were linked to HbA1c (both p < 0.05). Arterial reaction time was linked to serum creatinine (p = 0.036) and eGFR (p = 0.039); venous reaction time was linked to creatinine clearance (p = 0.018). Creatinine clearance and eGFR were linked to arterial maximum dilatation (p < 0.001 and p = 0.003, respectively) and the dilatation amplitude (p = 0.038 and p = 0.048, respectively) responses in the third flicker cycle. Of venous responses to the first flicker cycle, HbA1c was linked to the maximum dilation response (p = 0.004) and dilatation amplitude (p = 0.017), vWf was linked to the maximum constriction response (p = 0.016), and creatinine clearance to the baseline diameter fluctuation (p = 0.029). In the second flicker cycle, dilatation amplitude was linked to serum creatinine (p = 0.022). Several retinal blood vessel responses to flickering light are linked to glycaemia and renal function, but only one index is linked to endothelial function. Renal function must be considered when interpreting retinal vessel responses.
NASA Technical Reports Server (NTRS)
1973-01-01
The report contains data on antenna configurations for the low data rate users of the Tracking and Data Relay Satellite System (TDRSS). It treats the coverage and mutual visibility considerations between the user satellites and the relay satellites and relates these considerations to requirements of antenna beamwidth and fractional user orbital coverage. A final section includes user/TDRS telecommunication link budgets and forward and return link data rate tradeoffs.
Link Analysis of High Throughput Spacecraft Communication Systems for Future Science Missions
NASA Technical Reports Server (NTRS)
Simons, Rainee N.
2015-01-01
NASA's plan to launch several spacecrafts into low Earth Orbit (LEO) to support science missions in the next ten years and beyond requires down link throughput on the order of several terabits per day. The ability to handle such a large volume of data far exceeds the capabilities of current systems. This paper proposes two solutions, first, a high data rate link between the LEO spacecraft and ground via relay satellites in geostationary orbit (GEO). Second, a high data rate direct to ground link from LEO. Next, the paper presents results from computer simulations carried out for both types of links taking into consideration spacecraft transmitter frequency, EIRP, and waveform; elevation angle dependent path loss through Earths atmosphere, and ground station receiver GT.
Link Analysis of High Throughput Spacecraft Communication Systems for Future Science Missions
NASA Technical Reports Server (NTRS)
Simons, Rainee N.
2015-01-01
NASA's plan to launch several spacecraft into low Earth Orbit (LEO) to support science missions in the next ten years and beyond requires down link throughput on the order of several terabits per day. The ability to handle such a large volume of data far exceeds the capabilities of current systems. This paper proposes two solutions, first, a high data rate link between the LEO spacecraft and ground via relay satellites in geostationary orbit (GEO). Second, a high data rate direct to ground link from LEO. Next, the paper presents results from computer simulations carried out for both types of links taking into consideration spacecraft transmitter frequency, EIRP, and waveform; elevation angle dependent path loss through Earths atmosphere, and ground station receiver GT.
Results from the DOLCE (Deep Space Optical Link Communications Experiment) project
NASA Astrophysics Data System (ADS)
Baister, Guy; Kudielka, Klaus; Dreischer, Thomas; Tüchler, Michael
2009-02-01
Oerlikon Space AG has since 1995 been developing the OPTEL family of optical communications terminals. The optical terminals within the OPTEL family have been designed so as to be able to position Oerlikon Space for future opportunities open to this technology. These opportunities range from commercial optical satellite crosslinks between geostationary (GEO) satellites, deep space optical links between planetary probes and the Earth, as well as optical links between airborne platforms (either between the airborne platforms or between a platform and GEO satellite). The OPTEL terminal for deep space applications has been designed as an integrated RF-optical terminal for telemetry links between the science probe and Earth. The integrated architecture provides increased TM link capacities through the use of an optical link, while spacecraft navigation and telecommand are ensured by the classical RF link. The optical TM link employs pulsed laser communications operating at 1058nm to transmit data using PPM modulation to achieve a robust link to atmospheric degradation at the optical ground station. For deep space links from Lagrange (L1 / L2) data rates of 10 - 20 Mbps can be achieved for the same spacecraft budgets (mass and power) as an RF high gain antenna. Results of an inter-island test campaign to demonstrate the performance of the pulsed laser communications subsystem employing 32-PPM for links through the atmosphere over a distance of 142 km are presented. The transmitter of the communications subsystem is a master oscillator power amplifier (MOPA) employing a 1 W (average power) amplifier and the receiver a Si APD with a measured sensitivity of -70.9 dBm for 32-PPM modulation format at a user data rate of 10 Mbps and a bit error rate (BER) of 10-6.
DOT National Transportation Integrated Search
1999-09-01
A deterministic algorithm was developed which allowed data from Department of Transportation motor vehicle crash records, state mortality registry records, and hospital admission and emergency department records to be linked for analysis of the finan...
A High Speed, Long-Range Mobile Communications Link for use in Polar Regions
NASA Astrophysics Data System (ADS)
Chalishazar, N.; Prescott, G.; Braaten, D.
2003-12-01
The Polar Radar for Ice Sheet Measurements (PRISM) project has developed a high bandwidth, wireless communications link between an autonomous rover and a manned vehicle deployed on a polar ice sheet to exchange real-time video, timing signals for a bistatic radar, and rover sensory data. The PRISM project is developing advanced intelligent remote sensing technology that involves radar systems, an autonomous rover, and communications systems to measure detailed ice sheet characteristics, and to determine bed conditions (frozen or wet) below active ice sheets in both Greenland and Antarctica. While this wireless communications link is being developed to fill a need within the PRISM Project, the same technology will allow polar researchers separated by moderate distances ( ˜10 km) to exchange data. The communications link is based on a high data rate 802.11b wireless technology, and a prototype system has been tested and evaluated during field experiments conducted at the NorthGRIP ice core drilling camp in Greenland (75° 06\\'\\ N, 42° 20\\'\\ W) from June 23-July 17, 2003. The IEEE 802.11b standard works in the 2.4-2.483 GHz band and has been widely used for high-speed data transfer in a WLAN (Wireless Local Area Network). It typically has a range of a few hundred meters and theoretical data rates on the order of 11 Mbps. It has been used for a number of applications in home and office environments. We modified a 802.11b system to operate up to a maximum distance of about 8 km and investigated the radio propagation environment over the flat terrain of the Greenland ice sheet. We evaluated its performance along three different tracks of 8 km in length, and made throughput measurements at intervals of 0.5 km. We measured the received signal strength and noise level in 2-s intervals along these 8 km tracks. Also we conducted experiments for four different antenna heights (1, 2, 3 and 5 m) for developing a radio propagation model for WLAN communication over the ice sheet. We found that peer-to-peer communication between nodes on the ice had data rates varying from 4.5 Mbps at close range to 2.5 Mbps at a distance of 8 km from the base station. The design, propagation model, throughput and coverage of this peer-to-peer communications system in Greenland are presented in this paper. This WLAN system has numerous applications in polar field camps. We tested the transfer of real-time video segments across this link for our educational outreach efforts in the field. These video segments were subsequently uploaded using an Iridium-based Internet link, and sent back to the University of Kansas. The wireless Internet connectivity was also made available to members of the North Grip camp, who were able to access e-mail and the Internet from their tents and common areas. However, throughput for wireless access to the Internet was limited by the Iridium-based Internet connection that had a maximum bandwidth of 9.6 Kbps.
NASA Technical Reports Server (NTRS)
Noble, Viveca K.
1993-01-01
There are various elements such as radio frequency interference (RFI) which may induce errors in data being transmitted via a satellite communication link. When a transmission is affected by interference or other error-causing elements, the transmitted data becomes indecipherable. It becomes necessary to implement techniques to recover from these disturbances. The objective of this research is to develop software which simulates error control circuits and evaluate the performance of these modules in various bit error rate environments. The results of the evaluation provide the engineer with information which helps determine the optimal error control scheme. The Consultative Committee for Space Data Systems (CCSDS) recommends the use of Reed-Solomon (RS) and convolutional encoders and Viterbi and RS decoders for error correction. The use of forward error correction techniques greatly reduces the received signal to noise needed for a certain desired bit error rate. The use of concatenated coding, e.g. inner convolutional code and outer RS code, provides even greater coding gain. The 16-bit cyclic redundancy check (CRC) code is recommended by CCSDS for error detection.
Evaluation of email alerts in practice: Part 2. Validation of the information assessment method.
Pluye, Pierre; Grad, Roland M; Johnson-Lafleur, Janique; Bambrick, Tara; Burnand, Bernard; Mercer, Jay; Marlow, Bernard; Campbell, Craig
2010-12-01
The information assessment method (IAM) permits health professionals to systematically document the relevance, cognitive impact, use and health outcomes of information objects delivered by or retrieved from electronic knowledge resources. The companion review paper (Part 1) critically examined the literature, and proposed a 'Push-Pull-Acquisition-Cognition-Application' evaluation framework, which is operationalized by IAM. The purpose of the present paper (Part 2) is to examine the content validity of the IAM cognitive checklist when linked to email alerts. A qualitative component of a mixed methods study was conducted with 46 doctors reading and rating research-based synopses sent on email. The unit of analysis was a doctor's explanation of a rating of one item regarding one synopsis. Interviews with participants provided 253 units that were analysed to assess concordance with item definitions. The content relevance of seven items was supported. For three items, revisions were needed. Interviews suggested one new item. This study has yielded a 2008 version of IAM. © 2010 Blackwell Publishing Ltd.
de Aquino, Luciana Cristina Lins; de Sousa, Heloisa Ribeiro Tunes; Miranda, Everson Alves; Vilela, Luciano; Bueno, Sônia Maria Alves
2006-04-13
Inabilities to process particulate material and to allow the use of high flow rates are limitations of conventional chromatography. Membranes have been suggested as matrix for affinity separation due to advantages such as allowing high flow rates and low-pressure drops. This work evaluated the feasibility of using an iminodiacetic acid linked poly(ethylenevinyl alcohol) membrane in the immobilized metal ion affinity chromatography (IMAC) purification of a human proinsulin(His)(6) of an industrial insulin production process. The screening of metal ions showed Ni(2+) as metal with higher selectivity and capacity among the Cu(2+), Ni(2+), Zn(2+) and Co(2+). The membrane showed to be equivalent to conventional chelating beads in terms of selectivity and had a lower capacity (3.68 mg/g versus 12.26 mg/g). The dynamic adsorption capacity for human proinsulin(His)(6) was unaffected by the mode of operation (dead-end and cross-flow filtration).
Laméris, Joran; Hipp, John R; Tolsma, Jochem
2018-05-01
This study examines the effects of neighborhood racial in-group size, economic deprivation and the prevalence of crime on neighborhood cohesion among U.S. whites. We explore to what extent residents' perceptions of their neighborhood mediate these macro-micro relationships. We use a recent individual-level data set, the American Social Fabric Study (2012/2013), enriched with contextual-level data from the U.S. Census Bureau (2010) and employ multi-level structural equation models. We show that the racial in-group size is positively related to neighborhood cohesion and that neighborhood cohesion is lower in communities with a high crime rate. Individuals' perceptions of the racial in-group size partly mediate the relationship between the objective racial in-group size and neighborhood cohesion. Residents' perceptions of unsafety from crime also appear to be a mediating factor, not only for the objective crime rate but also for the objective racial in-group size. This is in line with our idea that racial stereotypes link racial minorities to crime whereby neighborhoods with a large non-white population are perceived to be more unsafe. Residents of the same neighborhood differ in how they perceive the degree of economic decay of the neighborhood and this causes them to evaluate neighborhood cohesion differently, however perceptions of neighborhood economic decay do not explain the link between the objective neighborhood context and neighborhood cohesion. Copyright © 2018. Published by Elsevier Inc.
Chen, Wei-Yu; Liao, Chung-Min
2012-11-01
The purpose of this study was to link toxicokinetics/toxicodynamics (TK/TD) and bioavailability-based metal uptake kinetics to assess arsenic (As) uptake and bioaccumulation in three common farmed species of tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), and freshwater clam (Corbicula fluminea). We developed a mechanistic framework by linking damage assessment model (DAM) and bioavailability-based Michaelis-Menten model for describing TK/TD and As uptake mechanisms. The proposed model was verified with published acute toxicity data. The estimated TK/TD parameters were used to simulate the relationship between bioavailable As uptake and susceptibility probability. The As toxicity was also evaluated based on a constructed elimination-recovery scheme. Absorption rate constants were estimated to be 0.025, 0.016, and 0.175 mL g(-1) h(-1) and As uptake rate constant estimates were 22.875, 63.125, and 788.318 ng g(-1) h(-1) for tilapia, milkfish, and freshwater clam, respectively. Here we showed that a potential trade-off between capacities of As elimination and damage recovery was found among three farmed species. Moreover, the susceptibility probability can also be estimated by the elimination-recovery relations. This study suggested that bioavailability-based uptake kinetics and TK/TD-based DAM could be integrated for assessing metal uptake and toxicity in aquatic organisms. This study is useful to quantitatively assess the complex environmental behavior of metal uptake and implicate to risk assessment of metals in aquaculture systems.
Design and Operation of the Transformed National Healthy Start Evaluation.
Banks, Jamelle E; Dwyer, Maura; Hirai, Ashley; Ghandour, Reem M; Atrash, Hani K
2017-12-01
Purpose Improving pregnancy outcomes for women and children is one of the nation's top priorities. The Healthy Start (HS) program was created to address factors that contribute to high infant mortality rates (IMRs) and persistent disparities in IMRs. The program began in 1991 and was transformed in 2014 to apply lessons from emerging research, past evaluation findings, and expert recommendations. To understand the implementation and impact of the transformed program, there is a need for a robust and comprehensive evaluation. Description The national HS evaluation will include an implementation evaluation, which will describe program components that affect outcomes; a utilization evaluation, which will examine the characteristics of women and infants who did and did not utilize the program; and an outcome evaluation, which will assess the program's effectiveness with regard to producing expected outcomes among the target population. Data sources include the National HS Program Survey, a HS participant survey, and individual-level program data linked to vital records and the Pregnancy Risk Assessment Monitoring System (PRAMS) survey. Assessment Descriptive analyses will be used to examine differences in risk profiles between participants and non-participants, as well as to calculate penetration rates for high-risk women in respective service areas. Multivariable analyses will be used to determine the impact of the program on key outcomes and will explore variation by dose, type of services received, and grantee characteristics. Conclusion Evaluation findings are expected to inform program decisions and direction, including identification of effective program components that can be spread and scaled.
Allen, Michael H; Daniel, David G; Revicki, Dennis A; Canuso, Carla M; Turkoz, Ibrahim; Fu, Dong-Jing; Alphs, Larry; Ishak, K Jack; Bartko, John J; Lindenmayer, Jean-Pierre
2012-01-01
The Clinical Global Impression for Schizoaffective Disorder scale is a new rating scale adapted from the Clinical Global Impression scale for use in patients with schizoaffective disorder. The psychometric characteristics of the Clinical Global Impression for Schizoaffective Disorder are described. Content validity was assessed using an investigator questionnaire. Inter-rater reliability was determined with 12 sets of videotaped interviews rated independently by two trained individuals. Test-retest reliability was assessed using 30 randomly selected raters from clinical trials who evaluated the same videos on separate occasions two weeks apart. Convergent and divergent validity and effect size were evaluated by comparing scores between the Clinical Global Impression for Schizoaffective Disorder and the Positive and Negative Syndrome Scale, 21-item Hamilton Rating Scale for Depression, and Young Mania Rating Scale scales using pooled patient data from two clinical trials. Clinical Global Impression for Schizoaffective Disorder scores were then linked to corresponding Positive and Negative Syndrome Scale scores. Content validity was strong. Inter-rater agreement was good to excellent for most scales and subscales (intra-class correlation coefficient ≥ 0.50). Test-retest showed good reproducibility, with intraclass correlation coefficients ranging from 0.444 to 0.898. Spearman correlations between Clinical Global Impression for Schizoaffective Disorder domains and corresponding symptom scales were 0.60 or greater, and effect sizes for Clinical Global Impression for Schizoaffective Disorder overall and domain scores were similar to Positive and Negative Syndrome Scale Young Mania Rating Scale, and 21-item Hamilton Rating Scale for Depression scores. Raters anticipated that the scale might be less effective in distinguishing negative from depressive symptoms, and, in fact, the results here may reflect that clinical reality. Multiple lines of evidence support the reliability and validity of the Clinical Global Impression for Schizoaffective Disorder for studies in schizoaffective disorder.
[Experimental realization of minimally invasive techniques of scleral collagen cross-linking].
Iomdina, Е N; Tarutta, Е P; Semchishen, V А; Korigodskiy, А R; Zakharov, I D; Khoroshilova-Maslova, I P; Ignat'eva, N Yu; Kiseleva, Т N; Sianosyan, А А; Milash, S V
To realize two minimally invasive techniques of scleral collagen cross-linking (SXL) at the equator and posterior pole of the eye: 1) targeted irradiation of the region with ultraviolet A (UVA) and 2) sub-Tenon injection of Sklerateks. To perform UVA-SXL, a tool was developed that includes a UV-LED light source (370 nm, 3 mW/cm2) and a polymer-coated silica multimode optical fiber located in one of the two channels of a detachable metal tip. The other channel is used to deliver riboflavin to the scleral surface. The study included 8 Chinchillas' eyes. Intact fellow eyes served as the controls. Scleral echodensity was measured in vivo with Voluson 730 Pro (Kretz) prior to the procedure and then 2 days and 1 month after. After enucleation, the elastic modulus and the degree of scleral cross-linking were established at the same time-points. A placebo-controlled study on the safety and effectiveness of sub-Tenon Sklerateks injections (solution of amino acid salts in the form of succinates) was conducted on 47 Chinchilla rabbits (94 eyes). Sklerateks or placebo (0.1 ml) was injected below the Tenon's capsule of either eye once a week for 1 month (4 injections; 1st series) or 3 months (12 injections; 2nd series). After the end of the course, 22 eyes were studied morphologically. In 72 eyes, scleral samples were obtained in order to evaluate the elastic modulus (Autograph AGS-H tester, SHIMADZU, Japan) and the rate of cross-linking (judging from the denaturation temperature) by differential scanning calorimetry (Phoenix DSC 204 calorimeter, Netzsch, Germany). After UVA irradiation, the scleral echodensity increased from 86.7±5.1 to 98±4.9 dB. The elastic modulus appeared 1.5 times higher than that of the control samples. The denaturation temperature also increased indicating the rate of scleral cross-linking as high as 15-18%. Weekly Sklerateks for 1-3 months has been shown to induce neither clinical, nor morphological signs of local irritative, damaging, or toxic effect. The findings also include: a 1.8 times higher rate of scleral cross-linking, activation of cellular elements, neoformation of connective tissue on the scleral surface, and vascular growth, which together indicate a pronounced metabolic and strengthening effect of Sklerateks on the sclera. Experimental results on minimally invasive techniques of SXL allow to recommend them for further clinical investigation as a promising treatment of progressive myopia.
Tenke, Craig E; Kayser, Jürgen; Svob, Connie; Miller, Lisa; Alvarenga, Jorge E; Abraham, Karen; Warner, Virginia; Wickramaratne, Priya; Weissman, Myrna M; Bruder, Gerard E
2017-03-01
A prior report (Tenke et al., 2013 Biol. Psychol. 94:426-432) found that participants who rated religion or spirituality (R/S) highly important had greater posterior alpha after 10 years compared to those who did not. Participants who subsequently lowered their rating also had prominent alpha, while those who increased their rating did not. Here we report EEG findings 20 years after initial assessment. Clinical evaluations and R/S ratings were obtained from 73 (52 new) participants in a longitudinal study of family risk for depression. Frequency PCA of current source density transformed EEG concisely quantified posterior alpha. Those who initially rated R/S as highly important had greater alpha compared to those who did not, even if their R/S rating later increased. Furthermore, changes in religious denomination were associated with decreased alpha. Results suggest the possibility of a critical stage in the ontogenesis of R/S that is linked to posterior resting alpha. Copyright © 2017 Elsevier B.V. All rights reserved.
NASA Technical Reports Server (NTRS)
Spence, Rodney L.
1993-01-01
The important principles of direct- and heterodyne-detection optical free-space communications are reviewed. Signal-to-noise-ratio (SNR) and bit-error-rate (BER) expressions are derived for both the direct-detection and heterodyne-detection optical receivers. For the heterodyne system, performance degradation resulting from received-signal and local oscillator-beam misalignment and laser phase noise is analyzed. Determination of interfering background power from local and extended background sources is discussed. The BER performance of direct- and heterodyne-detection optical links in the presence of Rayleigh-distributed random pointing and tracking errors is described. Finally, several optical systems employing Nd:YAG, GaAs, and CO2 laser sources are evaluated and compared to assess their feasibility in providing high-data-rate (10- to 1000-Mbps) Mars-to-Earth communications. It is shown that the root mean square (rms) pointing and tracking accuracy is a critical factor in defining the system transmitting laser-power requirements and telescope size and that, for a given rms error, there is an optimum telescope aperture size that minimizes the required power. The results of the analysis conducted indicate that, barring the achievement of extremely small rms pointing and tracking errors (less than 0.2 microrad), the two most promising types of optical systems are those that use an Nd:YAG laser (lambda = 1.064 microns) and high-order pulse position modulator (PPM) and direct detection, and those that use a CO2 laser (lambda = 10.6 microns) and phase shifting keying homodyne modulation and coherent detection. For example, for a PPM order of M = 64 and an rms pointing accuracy of 0.4 microrad, an Nd:YAG system can be used to implement a 100-Mbps Mars link with a 40-cm transmitting telescope, a 20-W laser, and a 10-m receiving photon bucket. Under the same conditions, a CO2 system would require 3-m transmitting and receiving telescopes and a 32-W laser to implement such a link. Other types of optical systems, such as a semiconductor laser systems, are impractical in the presence of large rms pointing errors because of the high power requirements of the 100-Mbps Mars link, even when optimal-size telescopes are used.
Shuttle Ku-band and S-band communications implementation study
NASA Technical Reports Server (NTRS)
Dodds, J. G.; Huth, G. K.; Nilsen, P. W.; Polydoros, A.; Simon, M. K.; Weber, C. L.
1980-01-01
Various aspects of the shuttle orbiter S-band network communication system, the S-band payload communication system, and the Ku-band communication system are considered. A method is proposed for obtaining more accurate S-band antenna patterns of the actual shuttle orbiter vehicle during flight because the preliminary antenna patterns using mock-ups are not realistic that they do not include the effects of additional appendages such as wings and tail structures. The Ku-band communication system is discussed especially the TDRS antenna pointing accuracy with respect to the orbiter and the modifications required and resulting performance characteristics of the convolutionally encoded high data rate return link to maintain bit synchronizer lock on the ground. The TDRS user constraints on data bit clock jitter and data asymmetry on unbalanced QPSK with noisy phase references are included. The S-band payload communication system study is outlined including the advantages and experimental results of a peak regulator design built and evaluated by Axiomatrix for the bent-pipe link versus the existing RMS-type regulator. The nominal sweep rate for the deep-space transponder of 250 Hz/s, and effects of phase noise on the performance of a communication system are analyzed.
Unveiling Spatial Epidemiology of HIV with Mobile Phone Data
NASA Astrophysics Data System (ADS)
Brdar, Sanja; Gavrić, Katarina; Ćulibrk, Dubravko; Crnojević, Vladimir
2016-01-01
An increasing amount of geo-referenced mobile phone data enables the identification of behavioral patterns, habits and movements of people. With this data, we can extract the knowledge potentially useful for many applications including the one tackled in this study - understanding spatial variation of epidemics. We explored the datasets collected by a cell phone service provider and linked them to spatial HIV prevalence rates estimated from publicly available surveys. For that purpose, 224 features were extracted from mobility and connectivity traces and related to the level of HIV epidemic in 50 Ivory Coast departments. By means of regression models, we evaluated predictive ability of extracted features. Several models predicted HIV prevalence that are highly correlated (>0.7) with actual values. Through contribution analysis we identified key elements that correlate with the rate of infections and could serve as a proxy for epidemic monitoring. Our findings indicate that night connectivity and activity, spatial area covered by users and overall migrations are strongly linked to HIV. By visualizing the communication and mobility flows, we strived to explain the spatial structure of epidemics. We discovered that strong ties and hubs in communication and mobility align with HIV hot spots.
Linking performance decline to choking: players' perceptions in basketball.
Fryer, Ashley Marie; Tenenbaum, Gershon; Chow, Graig M
2018-02-01
This study was aimed at examining how basketball players view unexpected performance errors in basketball, and under what conditions they perceive them as choking. Fifty-three basketball players were randomly assigned into 2 groups (game half) to evaluate the linkage between performance decline and choking as a function of game-time, score gap and game half. Within each group, players viewed 8 scenario clips, which featured a different player conducting an error, and subsequently rated the extent of performance decline, the instance of choking and the salience of various performance attributions regarding the error. The analysis revealed that choking was most salient in the 2nd half of the game, but an error was perceived as choking more saliently in the beginning of the 2nd half. This trend was also shown for players' perception of performance decline. Players' ratings of the attributions assigned to errors, however, revealed that during the end of the 2nd half, time pressure and lack of concentration were the causes of errors. Overall, the results provide evidence towards a conceptual framework linking performance decline to the perception of choking, and that errors conducted by players are perceived as choking when there is not a salient reason to suggest its occurrence.
Unveiling Spatial Epidemiology of HIV with Mobile Phone Data
Brdar, Sanja; Gavrić, Katarina; Ćulibrk, Dubravko; Crnojević, Vladimir
2016-01-01
An increasing amount of geo-referenced mobile phone data enables the identification of behavioral patterns, habits and movements of people. With this data, we can extract the knowledge potentially useful for many applications including the one tackled in this study - understanding spatial variation of epidemics. We explored the datasets collected by a cell phone service provider and linked them to spatial HIV prevalence rates estimated from publicly available surveys. For that purpose, 224 features were extracted from mobility and connectivity traces and related to the level of HIV epidemic in 50 Ivory Coast departments. By means of regression models, we evaluated predictive ability of extracted features. Several models predicted HIV prevalence that are highly correlated (>0.7) with actual values. Through contribution analysis we identified key elements that correlate with the rate of infections and could serve as a proxy for epidemic monitoring. Our findings indicate that night connectivity and activity, spatial area covered by users and overall migrations are strongly linked to HIV. By visualizing the communication and mobility flows, we strived to explain the spatial structure of epidemics. We discovered that strong ties and hubs in communication and mobility align with HIV hot spots. PMID:26758042
Porting Inition and Failure to Linked Cheetah
DOE Office of Scientific and Technical Information (OSTI.GOV)
Vitello, P; Souers, P C
2007-07-18
Linked CHEETAH is a thermo-chemical code coupled to a 2-D hydrocode. Initially, a quadratic-pressure dependent kinetic rate was used, which worked well in modeling prompt detonation of explosives of large size, but does not work on other aspects of explosive behavior. The variable-pressure Tarantula reactive flow rate model was developed with JWL++ in order to also describe failure and initiation, and we have moved this model into Linked CHEETAH. The model works by turning on only above a pressure threshold, where a slow turn-on creates initiation. At a higher pressure, the rate suddenly leaps to a large value over amore » small pressure range. A slowly failing cylinder will see a rapidly declining rate, which pushes it quickly into failure. At a high pressure, the detonation rate is constant. A sequential validation procedure is used, which includes metal-confined cylinders, rate-sticks, corner-turning, initiation and threshold, gap tests and air gaps. The size (diameter) effect is central to the calibration.« less
Canary, Jana D; Blizzard, Leigh; Barry, Ronald P; Hosmer, David W; Quinn, Stephen J
2016-05-01
Generalized linear models (GLM) with a canonical logit link function are the primary modeling technique used to relate a binary outcome to predictor variables. However, noncanonical links can offer more flexibility, producing convenient analytical quantities (e.g., probit GLMs in toxicology) and desired measures of effect (e.g., relative risk from log GLMs). Many summary goodness-of-fit (GOF) statistics exist for logistic GLM. Their properties make the development of GOF statistics relatively straightforward, but it can be more difficult under noncanonical links. Although GOF tests for logistic GLM with continuous covariates (GLMCC) have been applied to GLMCCs with log links, we know of no GOF tests in the literature specifically developed for GLMCCs that can be applied regardless of link function chosen. We generalize the Tsiatis GOF statistic originally developed for logistic GLMCCs, (TG), so that it can be applied under any link function. Further, we show that the algebraically related Hosmer-Lemeshow (HL) and Pigeon-Heyse (J(2) ) statistics can be applied directly. In a simulation study, TG, HL, and J(2) were used to evaluate the fit of probit, log-log, complementary log-log, and log models, all calculated with a common grouping method. The TG statistic consistently maintained Type I error rates, while those of HL and J(2) were often lower than expected if terms with little influence were included. Generally, the statistics had similar power to detect an incorrect model. An exception occurred when a log GLMCC was incorrectly fit to data generated from a logistic GLMCC. In this case, TG had more power than HL or J(2) . © 2015 John Wiley & Sons Ltd/London School of Economics.
A guide to evaluating linkage quality for the analysis of linked data.
Harron, Katie L; Doidge, James C; Knight, Hannah E; Gilbert, Ruth E; Goldstein, Harvey; Cromwell, David A; van der Meulen, Jan H
2017-10-01
Linked datasets are an important resource for epidemiological and clinical studies, but linkage error can lead to biased results. For data security reasons, linkage of personal identifiers is often performed by a third party, making it difficult for researchers to assess the quality of the linked dataset in the context of specific research questions. This is compounded by a lack of guidance on how to determine the potential impact of linkage error. We describe how linkage quality can be evaluated and provide widely applicable guidance for both data providers and researchers. Using an illustrative example of a linked dataset of maternal and baby hospital records, we demonstrate three approaches for evaluating linkage quality: applying the linkage algorithm to a subset of gold standard data to quantify linkage error; comparing characteristics of linked and unlinked data to identify potential sources of bias; and evaluating the sensitivity of results to changes in the linkage procedure. These approaches can inform our understanding of the potential impact of linkage error and provide an opportunity to select the most appropriate linkage procedure for a specific analysis. Evaluating linkage quality in this way will improve the quality and transparency of epidemiological and clinical research using linked data. © The Author 2017. Published by Oxford University Press on behalf of the International Epidemiological Association.
NASA Technical Reports Server (NTRS)
Fines, P.; Aghvami, A. H.
1990-01-01
The performance of a low bit rate (64 Kb/s) all digital 16-ary Differentially Encoded Quadrature Amplitude Modulation (16-DEQAM) demodulator operating over a mobile satellite channel, is considered. The synchronization and detection techniques employed to overcome the Rician channel impairments, are described. The acquisition and steady state performance of this modem, are evaluated by computer simulation over AWGN and RICIAN channels. The results verify the suitability of the 16-DEQAM transmission over slowly faded and/or mildly faded channels.
NASA Technical Reports Server (NTRS)
Davidson, Frederic M.; Field, Christopher T.; Sun, Xiaoli
1996-01-01
We report here the design and the performance measurements of the breadboard receiver of the Geoscience Laser Altimeter System (GLAS). The measured ranging accuracy was better than 2 cm and 10 cm for 5 ns and 30 ns wide received laser pulses under the expected received signal level, which agreed well with the theoretical analysis. The measured receiver sensitivity or the link margin was also consistent with the theory. The effects of the waveform digitizer sample rate and resolution were also measured.
NASA Astrophysics Data System (ADS)
Zdravković, Nemanja; Cvetkovic, Aleksandra; Milic, Dejan; Djordjevic, Goran T.
2017-09-01
This paper analyses end-to-end packet error rate (PER) of a free-space optical decode-and-forward cooperative network over a gamma-gamma atmospheric turbulence channel in the presence of temporary random link blockage. Closed-form analytical expressions for PER are derived for the cases with and without transmission links being prone to blockage. Two cooperation protocols (denoted as 'selfish' and 'pilot-adaptive') are presented and compared, where the latter accounts for the presence of blockage and adapts transmission power. The influence of scintillation, link distance, average transmitted signal power, network topology and probability of an uplink and/or internode link being blocked are discussed when the destination applies equal gain combining. The results show that link blockage caused by obstacles can degrade system performance, causing an unavoidable PER floor. The implementation of the pilot-adaptive protocol improves performance when compared to the selfish protocol, diminishing internode link blockage and lowering the PER floor, especially for larger networks.
Quality and Readability of English-Language Internet Information for Voice Disorders.
Dueppen, Abigail J; Bellon-Harn, Monica L; Radhakrishnan, Nandhakumar; Manchaiah, Vinaya
2017-12-15
The purpose of this study is to evaluate the readability and quality of English-language Internet information related to vocal hygiene, vocal health, and prevention of voice disorders. This study extends recent work because it evaluates readability, content quality, and website origin across broader search criteria than previous studies evaluating online voice material. Eighty-five websites were aggregated using five different country-specific search engines. Websites were then analyzed using quality and readability assessments. The entire web page was evaluated; however, no information or links beyond the first page was reviewed. Statistical calculations were employed to examine website ratings, differences between website origin and quality and readability scores, and correlations between readability instruments. Websites exhibited acceptable quality as measured by the DISCERN. However, only one website obtained the Health On the Net certification. Significant differences in quality were found among website origin, with government websites receiving higher quality ratings. Approximate educational levels required to comprehend information on the websites ranged from 8 to 9 years of education. Significant differences were found between website origin and readability measures with higher levels of education required to understand information on websites of nonprofit organizations. Current vocal hygiene, vocal health, and prevention of voice disorders websites were found to exhibit acceptable levels of quality and readability. However, highly rated Internet information related to voice care should be made more accessible to voice clients through Health On the Net certification. Published by Elsevier Inc.
ERIC Educational Resources Information Center
Craig, Alan; And Others
Link courses and other cooperative educational programs designed for secondary school students in New South Wales were evaluated in 1979. Link courses/programs are instructional sessions in which secondary students attend a postsecondary institution, or in which postsecondary faculty give lessons to students at the secondary school. The study was…
NASA Technical Reports Server (NTRS)
Shambayati, Shervin; Davarian, Faramaz; Morabito, David
2004-01-01
NASA is planning an engineering telemetry demonstration with Mars Reconnaissance Orbiter (MRO). Capabilities of Ka-band (32 GHz) for use with deep space mission are demonstrated using the link optimization algorithms and weather forecasting. Furthermore, based on the performance of previous deep space missions with Ka-band downlink capabilities, experiment plans are developed for telemetry operations during superior solar conjunction. A general overview of the demonstration is given followed by a description of the mission planning during cruise, the primary science mission and superior conjunction. As part of the primary science mission planning the expected data return for various data optimization methods is calculated. These results indicate that, given MRO's data rates, a link optimized to use of at most two data rates, subject to a minimum availability of 90%, performs almost as well as a link with no limits on the number of data rates subject to the same minimum availability.
Advanced Communications Architecture Demonstration Made Significant Progress
NASA Technical Reports Server (NTRS)
Carek, David Andrew
2004-01-01
Simulation for a ground station located at 44.5 deg latitude. The Advanced Communications Architecture Demonstration (ACAD) is a concept architecture to provide high-rate Ka-band (27-GHz) direct-to-ground delivery of payload data from the International Space Station. This new concept in delivering data from the space station targets scientific experiments that buffer data onboard. The concept design provides a method to augment the current downlink capability through the Tracking Data Relay Satellite System (TDRSS) Ku-band (15-GHz) communications system. The ACAD concept pushes the limits of technology in high-rate data communications for space-qualified systems. Research activities are ongoing in examining the various aspects of high-rate communications systems including: (1) link budget parametric analyses, (2) antenna configuration trade studies, (3) orbital simulations (see the preceding figure), (4) optimization of ground station contact time (see the following graph), (5) processor and storage architecture definition, and (6) protocol evaluations and dependencies.
Li, Ming; Cvijetic, Milorad
2015-02-20
We evaluate the performance of the coherent free space optics (FSO) employing quadrature array phase-shift keying (QPSK) modulation over the maritime atmosphere with atmospheric turbulence compensated by use of adaptive optics (AO). We have established a comprehensive FSO channel model for maritime conditions and also made a comprehensive comparison of performance between the maritime and terrestrial atmospheric links. The FSO links are modeled based on the intensity attenuation resulting from scattering and absorption effects, the log-amplitude fluctuations, and the phase distortions induced by turbulence. The obtained results show that the FSO system performance measured by the bit-error-rate (BER) can be significantly improved when the optimization of the AO system is achieved. Also, we find that the higher BER is observed in the maritime FSO channel with atmospheric turbulence, as compared to the terrestrial FSO systems if they experience the same turbulence strength.
Radiation Resistant Electrical Insulation Materials for Nuclear Reactors: Final Report
DOE Office of Scientific and Technical Information (OSTI.GOV)
Duckworth, Robert C.; Aytug, Tolga; Paranthaman, M. Parans
The instrument and control cables in future nuclear reactors will be exposed to temperatures, dose rates, and accumulated doses exceeding those originally anticipated for the 40-year operational life of the nuclear power plant fleet. The use of nanocomposite dielectrics as insulating material for such cables has been considered a route to performance improvement. In this project, nanoparticles were developed and successfully included in three separate material systems [cross-linked polyvinyl alcohol (PVA/XLPVA), cross-linked polyethylene (PE/XLPE), and polyimide (PI)], and the chemical, electrical, and mechanical performance of each was analyzed as a function of environmental exposure and composition. Improvements were found inmore » each material system; however, refinement of each processing pathway is needed, and the consequences of these refinements in the context of thermal, radiation, and moisture exposures should be evaluated before transferring knowledge to industry.« less
Zhao, Yanyan; Kuai, Long; Liu, Yanguo; Wang, Pengpeng; Arandiyan, Hamidreza; Cao, Sufeng; Zhang, Jie; Li, Fengyun; Wang, Qing; Geng, Baoyou; Sun, Hongyu
2015-01-01
A facile one-step solution reaction route for growth of novel MoS2 nanorose cross-linked by 3D rGO network, in which the MoS2 nanorose is constructed by single-layered or few-layered MoS2 nanosheets, is presented. Due to the 3D assembled hierarchical architecture of the ultrathin MoS2 nanosheets and the interconnection of 3D rGO network, as well as the synergetic effects of MoS2 and rGO, the as-prepared MoS2-NR/rGO nanohybrids delivered high specific capacity, excellent cycling and good rate performance when evaluated as an anode material for lithium-ion batteries. Moreover, the nanohybrids also show excellent hydrogen-evolution catalytic activity and durability in an acidic medium, which is superior to MoS2 nanorose and their nanoparticles counterparts. PMID:25735416
Anguita, Jaime A; Neifeld, Mark A; Vasic, Bane V
2007-09-10
By means of numerical simulations we analyze the statistical properties of the power fluctuations induced by the incoherent superposition of multiple transmitted laser beams in a terrestrial free-space optical communication link. The measured signals arising from different transmitted optical beams are found to be statistically correlated. This channel correlation increases with receiver aperture and propagation distance. We find a simple scaling rule for the spatial correlation coefficient in terms of the propagation distance and we are able to predict the scintillation reduction in previously reported experiments with good accuracy. We propose an approximation to the probability density function of the received power of a spatially correlated multiple-beam system in terms of the parameters of the single-channel gamma-gamma function. A bit-error-rate evaluation is also presented to demonstrate the improvement of a multibeam system over its single-beam counterpart.
EasyDIAg: A tool for easy determination of interrater agreement.
Holle, Henning; Rein, Robert
2015-09-01
Reliable measurements are fundamental for the empirical sciences. In observational research, measurements often consist of observers categorizing behavior into nominal-scaled units. Since the categorization is the outcome of a complex judgment process, it is important to evaluate the extent to which these judgments are reproducible, by having multiple observers independently rate the same behavior. A challenge in determining interrater agreement for timed-event sequential data is to develop clear objective criteria to determine whether two raters' judgments relate to the same event (the linking problem). Furthermore, many studies presently report only raw agreement indices, without considering the degree to which agreement can occur by chance alone. Here, we present a novel, free, and open-source toolbox (EasyDIAg) designed to assist researchers with the linking problem, while also providing chance-corrected estimates of interrater agreement. Additional tools are included to facilitate the development of coding schemes and rater training.
2008-12-01
The effective two-way tactical data rate is 3,060 bits per second. Note that there is no parity check or forward error correction (FEC) coding used in...of 1800 bits per second. With the use of FEC coding , the channel data rate is 2250 bits per second; however, the information data rate is still the...Link-11. If the parity bits are included, the channel data rate is 28,800 bps. If FEC coding is considered, the channel data rate is 59,520 bps
Extending the data rate of non-line-of-sight UV communication with polarization modulation
NASA Astrophysics Data System (ADS)
Yin, Hongwei; Jia, Honghui; Zhang, Hailiang; Wang, Xiaofeng; Chang, Shengli; Yang, Juncai
2012-10-01
With low radiation background of solar-blind UV and strong scattering of UV photons by atmospheric particles, UV communication can be made use of to set up a non-line-of-sight (NLOS) free-space optical communication link. Polarization modulation, besides the traditional intensity modulation, is presented to enhance the data rate of the UV communication system. The configuration and the working process of the dually modulated UV communication system with intensity modulation and polarization, the theoretical evaluation of polarization modulation, and a numerical of the scattering matrix are presented, with the conclusion that polarization modulation is achievable. By adding the polarizing devices and changing the coding procedures, the existing singly-modulated UV communication systems with intensity modulation are easily modified to be dually-modulated ones with polarization modulation and intensity modulation. Ideally speaking, the data rate of the dually-modulated UV communication system is the product of the data rate of the singly modulated system and the number of polarization modulation.
Airborne Data Link Study Report
DOT National Transportation Integrated Search
1996-01-01
This report represents evaluations of Data Link products and services in a simulated aviation opearation. The study addresses key issues related to alerting schemes for Data Link messages, positioning of Data Link displays, and mode of presentation o...
Using Link Disconnection Entropy Disorder to Detect Fast Moving Nodes in MANETs.
Alvarez, Carlos F; Palafox, Luis E; Aguilar, Leocundo; Sanchez, Mauricio A; Martinez, Luis G
2016-01-01
Mobile ad-hoc networks (MANETs) are dynamic by nature; this dynamism comes from node mobility, traffic congestion, and other transmission conditions. Metrics to evaluate the effects of those conditions shine a light on node's behavior in an ad-hoc network, helping to identify the node or nodes with better conditions of connection. In this paper, we propose a relative index to evaluate a single node reliability, based on the link disconnection entropy disorder using neighboring nodes as reference. Link disconnection entropy disorder is best used to identify fast moving nodes or nodes with unstable communications, this without the need of specialized sensors such as GPS. Several scenarios were studied to verify the index, measuring the effects of Speed and traffic density on the link disconnection entropy disorder. Packet delivery ratio is associated to the metric detecting a strong relationship, enabling the use of the link disconnection entropy disorder to evaluate the stability of a node to communicate with other nodes. To expand the utilization of the link entropy disorder, we identified nodes with higher speeds in network simulations just by using the link entropy disorder.
Link Adaptation for Mitigating Earth-To-Space Propagation Effects on the NASA SCaN Testbed
NASA Technical Reports Server (NTRS)
Kilcoyne, Deirdre K.; Headley, William C.; Leffke, Zach J.; Rowe, Sonya A.; Mortensen, Dale J.; Reinhart, Richard C.; McGwier, Robert W.
2016-01-01
In Earth-to-Space communications, well-known propagation effects such as path loss and atmospheric loss can lead to fluctuations in the strength of the communications link between a satellite and its ground station. Additionally, the typically unconsidered effect of shadowing due to the geometry of the satellite and its solar panels can also lead to link degradation. As a result of these anticipated channel impairments, NASA's communication links have been traditionally designed to handle the worst-case impact of these effects through high link margins and static, lower rate, modulation formats. The work presented in this paper aims to relax these constraints by providing an improved trade-off between data rate and link margin through utilizing link adaptation. More specifically, this work provides a simulation study on the propagation effects impacting NASA's SCaN Testbed flight software-defined radio (SDR) as well as proposes a link adaptation algorithm that varies the modulation format of a communications link as its signal-to-noise ratio fluctuates. Ultimately, the models developed in this work will be utilized to conduct real-time flight experiments on-board the NASA SCaN Testbed.
Wu, Hung-Yi
2012-08-01
This study presents a structural evaluation methodology to link key performance indicators (KPIs) into a strategy map of the balanced scorecard (BSC) for banking institutions. Corresponding with the four BSC perspectives (finance, customer, internal business process, and learning and growth), the most important evaluation indicators of banking performance are synthesized from the relevant literature and screened by a committee of experts. The Decision Making Trial and Evaluation Laboratory (DEMATEL) method, a multiple criteria analysis tool, is then employed to determine the causal relationships between the KPIs, to identify the critical central and influential factors, and to establish a visualized strategy map with logical links to improve banking performance. An empirical application is provided as an example. According to the expert evaluations, the three most essential KPIs for banking performance are customer satisfaction, sales performance, and customer retention rate. The DEMATEL results demonstrate a clear road map to assist management in prioritizing the performance indicators and in focusing attention on the strategy-related activities of the crucial indicators. According to the constructed strategy map, management could better invest limited resources in the areas that need improvement most. Although these strategy maps of the BSC are not universal, the research results show that the presented approach is an objective and feasible way to construct strategy maps more justifiably. The proposed framework can be applicable to institutions in other industries as well. Copyright © 2011 Elsevier Ltd. All rights reserved.
Interface between authorship, industry and science in the domain of therapeutics.
Healy, David; Cattell, Dinah
2003-07-01
Changes in the character of medical authorship. Aims To compare the impact of industry-linked and non-industry linked articles. We compared articles on sertraline being coordinated by a medical writing agency with articles not coordinated in this way. We calculated numbers of Medline-listed articles per author, journal impact factors, literature profiles and citation rates of both sets of articles. Non-agency-linked articles on sertraline had an average of 2.95 authors per article, a mean length of 3.4 pages, a mean Medline listing of 37 articles per author (95% CI 27-47) and a mean literature profile of 283 per article (95% CI 130-435). Agency-linked articles on sertraline had an average of 6.6 authors per article, a mean length of 10.7 pages, a mean Medline listing of 70 articles per author (95% CI 62-79) and a mean literature profile of 1839 per article (95% CI 1076-2602). The citation rate for agency articles was 20.2 (95% CI 13.4-27.0) and for non-agency articles it was 3.7 (95% CI 3.3-8.1). The literature profiles and citation rates of industry-linked and non-industry-linked articles differ. The emerging style of authorship in industry-linked articles can deliver good-quality articles, but it raises concerns for the scientific base of therapeutics.
Saraceni, Valeria; Pereira, Gerson Fernando Mendes; da Silveira, Mariangela Freitas; Araujo, Maria Alix Leite; Miranda, Angelica Espinosa
2017-06-08
To describe the epidemiological profile of reported cases of syphilis in pregnancy and congenital syphilis in five states (Amazonas, Ceará, Espírito Santo, Rio de Janeiro, and Rio Grande do Sul) and the Federal District using data from the Reportable Disease Information System (SINAN). This descriptive study including an ecological and cross-sectional evaluation employed data from SINAN Net. The syphilis detection rate in pregnancy and the congenital syphilis incidence rate per 1 000 live births were calculated. To identify pregnant women with syphilis who had an outcome of congenital syphilis, the two SINAN databases were linked using the RecLink software. Because the data were representative at the state (not national) level, comparisons were made between the units of the federation and not with the sum of cases. A growth in the syphilis detection rate in pregnancy was detected, ranging from 21% (Amazonas) to 75% (Rio de Janeiro) during the study period. The incidence of congenital syphilis followed the same trend of growth (ranging from 35.6% in the Federal District to 63.9% in Rio Grande do Sul), except for a 0.7% decline in Amazonas. The proportion of women with an outcome of congenital syphilis who had prenatal care ranged from 67.3% in Amazonas to 83.3% in the Federal District. Of the pregnant women with syphilis, 43% had an outcome of congenital syphilis. In pregnant women with syphilis and an outcome of congenital syphilis, maternal diagnosis was made prenatally in 74% and at delivery in 18%. The moment of diagnosis was ignored in 8% of the women. The increase in the syphilis detection rate may have resulted from an increase in the report rate. Ongoing monitoring of pregnant women is essential to eliminate syphilis.
Gronke, W.K.; Chipps, S.R.; Bandas, S.J.; Higgins, K.F.
2006-01-01
In western painted turtles (Chrysemys picta bellii), males often exhibit one of two morphs: (1) a reticulated form, characterized by an intricate network of dark markings on the carapace or (2) a non-reticulated form. Although several hypotheses have been proposed to explain the adaptive significance of reticulate melanism (RM) on western painted turtles, no attempts have been made to document whether RM is linked to habitat conditions or if the presence of melanism affects heating rates. To evaluate these questions, we compared the frequency of adult male turtles with RM across three different habitats: riverine (rivers), lacustrine (lakes) and palustrine (wetland) habitats. Using manipulative experiments, we also tested the hypothesis that body heating rates are higher in turtles with RM. Reticulate melanism occurred on 99 (31%) of 320 male turtles captured in South Dakota from 2002 to 2003. Turtles with reticulate melanism were significantly larger than non-reticulated turtles; RM was not observed on male turtles with carapace lengths 15 cm carapace length) with RM was similar among river (0.54), lake (0.50) and wetland (0.64) habitats, implying that RM is not a habitat-linked trait. Heating rates for turtles with RM were similar to those measured for non-reticulated individuals. Body size, however, influenced heating rates; larger-bodied turtles with lower surface area-to-volume ratio heated more slowly than smaller turtles. Whether RM is a by-product of hormonal regulation or serves an adaptive purpose remains unclear. However, other hypotheses, especially those involving communication (e.g., courtship behavior) and/or gamete protection remain untested for western painted turtles and warrant further investigation.
NASA Astrophysics Data System (ADS)
Lowman, Lauren E. L.; Barros, Ana P.
2014-06-01
Prior studies evaluated the interplay between climate and orography by investigating the sensitivity of relief to precipitation using the stream power erosion law (SPEL) for specified erosion rates. Here we address the inverse problem, inferring realistic spatial distributions of erosion rates for present-day topography and contemporaneous climate forcing. In the central Andes, similarities in the altitudinal distribution and density of first-order stream outlets and precipitation suggest a direct link between climate and fluvial erosion. Erosion rates are estimated with a Bayesian physical-statistical model based on the SPEL applied at spatial scales that capture joint hydrogeomorphic and hydrometeorological patterns within five river basins and one intermontane basin in Peru and Bolivia. Topographic slope and area data were generated from a high-resolution (˜90 m) digital elevation map, and mean annual precipitation was derived from 14 years of Tropical Rainfall Measuring Mission 3B42v.7 product and adjusted with rain gauge data. Estimated decadal-scale erosion rates vary between 0.68 and 11.59 mm/yr, with basin averages of 2.1-8.5 mm/yr. Even accounting for uncertainty in precipitation and simplifying assumptions, these values are 1-2 orders of magnitude larger than most millennial and million year timescale estimates in the central Andes, using various geological dating techniques (e.g., thermochronology and cosmogenic nuclides), but they are consistent with other decadal-scale estimates using landslide mapping and sediment flux observations. The results also reveal a pattern of spatially dependent erosion consistent with basin hypsometry. The modeling framework provides a means of remotely estimating erosion rates and associated uncertainties under current climate conditions over large regions. 2014. American Geophysical Union. All Rights Reserved.
DOT National Transportation Integrated Search
1999-09-01
A deterministic algorithm was developed which allowed data from Department of Transportation motor vehicle crash records, state mortality registry records, and hospital admission and emergency department records to be linked for analysis of the types...
Sarfan, Laurel D; Cody, Meghan W; Clerkin, Elise M
2018-03-16
Although social anxiety symptoms are robustly linked to biased self-evaluations across time, the mechanisms of this relation remain unclear. The present study tested three maladaptive emotion regulation strategies - state post-event processing, state experiential avoidance, and state expressive suppression - as potential mediators of this relation. Undergraduate participants (N = 88; 61.4% Female) rated their social skill in an impromptu conversation task and then returned to the laboratory approximately two days later to evaluate their social skill in the conversation again. Consistent with expectations, state post-event processing and state experiential avoidance mediated the relation between social anxiety symptoms and worsening self-evaluations of social skill (controlling for research assistant evaluations), particularly for positive qualities (e.g. appeared confident, demonstrated social skill). State expressive suppression did not mediate the relation between social anxiety symptoms and changes in self-evaluation bias across time. These findings highlight the role that spontaneous, state experiential avoidance and state post-event processing may play in the relation between social anxiety symptoms and worsening self-evaluation biases of social skill across time.
Linking Job-Embedded Professional Development and Mandated Teacher Evaluation: Teacher as Learner
ERIC Educational Resources Information Center
Derrington, Mary Lynne; Kirk, Julia
2017-01-01
This study explores the link between individualized, job-embedded professional development and teacher evaluation. Moreover, the study explores and describes job-embedded strategies that principals used to facilitate teacher development while working within a state-mandated evaluation system. The theoretical frame utilized four elements of…
Influence of heat treatment on structural, mechanical and wear properties of crosslinked UHMWPE.
Chiesa, R; Moscatelli, M; Giordano, C; Siccardi, F; Cigada, A
2004-01-01
New crosslinked ultra high molecular weight polyethylenes (UHMWPEs) have recently been developed, characterized and introduced in clinical applications. UHMWPE cross-linking treatments are very promising for reducing osteolysis induced by wear debris. The irradiation type, gamma or beta, the dosage and the thermal treatment performed during or following the irradiation process are all factors affecting polyethylene wear resistance. Thermal stabilization treatments performed after or during the irradiation process at a temperature above melting point (i.e. >130 degrees C) have been proven to effectively remove the free radicals generated during irradiation from UHMWPE, but their effect on the mechanical properties of UHMWPE are not completely clear. In addition to wear rate reduction, maintaining good mechanical properties is fundamental aspect in designing the new generation of crosslinked UHMWPE for artificial load bearing materials, especially considering the application in total knee replacements. In this study, we investigated the influence of different stabilization treatments, performed after gamma irradiation, on structural, wear and mechanical properties of UHMWPE. We performed four different stabilization treatments, with different temperatures and cooling rates, on 100 kGy gamma irradiated UHMWPE. Structural properties of UHMWPE were assessed by differential scanning calorimetry (DSC). To assess the mechanical performance of the materials, uni-axial tensile tests were performed according to the ASTM D638 standard, bi-axial tension performance was evaluated by small punch tests (ASTM F2183-02), toughness resistance was evaluated by the Izod method (ASTM F648), and cold flow resistance was analysed by a dynamic compressive test. Evaluation of wear resistance was by a multidirectional pin-on-disk screening machine. Materials considered were in "aged" and "non-aged" conditions. Results confirmed that cross-linking greatly enhances UHMWPE wear resistance, but introduces some detrimental effects on the mechanical properties. In this study, we found that the negative ef-fects on the mechanical properties of crosslinked UHMWPE can be modulated, to some extent, by choosing a thermal stabiliza-tion treatment at a correct temperature and cooling rate. (Journal of Applied Biomaterials & Biomechanics 2004; 2: 20-8).
Temporal context, preference, and resistance to change.
Podlesnik, Christopher A; Jimenez-Gomez, Corina; Thrailkill, Eric A; Shahan, Timothy A
2011-09-01
According to behavioral momentum theory, preference and relative resistance to change in concurrent-chains schedules are correlated and reflect the relative conditioned value of discriminative stimuli. In the present study, we explore the generality of this relation by manipulating the temporal context within a concurrent-chains procedure through changes in the duration of the initial links. Consistent with previous findings, preference for a richer terminal link was less extreme with longer initial links across three experiments with pigeons. In Experiment 1, relative resistance to change and preference were related inversely when responding was disrupted with response-independent food presentations during initial links, replicating a previous finding with rats. However, more food was presented with longer initial links, confounding the disrupter and initial-link duration. In Experiment 2, presession feeding was used instead and eliminated the negative relation between relative resistance to change and preference, but relative resistance to change was not sensitive to relative terminal-link reinforcement rates. In Experiment 3, with more extreme relative terminal-link reinforcement rates, increasing initial-link duration similarly decreased preference and relative resistance to change for the richer terminal link. Thus, when conditions of disruption are equal and assessed under the appropriate reinforcement conditions, changes in temporal context impact relative resistance to change and preference similarly.
Freshwater processing of terrestrial dissolved organic matter: What governs lability?
NASA Astrophysics Data System (ADS)
D'Andrilli, J.; Smith, H. J.; Junker, J. R.; Scholl, E. A.; Foreman, C. M.
2016-12-01
Aquatic and terrestrial ecosystems are linked through the transfer of energy and materials. Allochthonous organic matter (OM) is central to freshwater ecosystem function, influencing local food webs, trophic state, and nutrient availability. In order to understand the nature and fate of OM from inland headwaters to the open ocean, it is imperative to understand the links between OM lability and ecosystem function. Thus, biological, chemical, and physical factors need to be evaluated together to inform our understanding of environmental lability. We performed a laboratory processing experiment on naturally occurring OM leachates from riparian leaves, grasses, and pine needles. Measures of water chemistry, OM optical and molecular characterization, bacterial abundances, microbial assemblage composition, respiration, and C:N:P were integrated to discern the nature and fate of labile and recalcitrant OM in a freshwater stream. Peak processing of all OM sources in the stream water occurred after two days, with spikes in bacterial cell abundances, respiration rates, microbial assemblage shifts, and maximum C utilization. Respiration rates and microbial assemblages were dependent on the degree of lability of the OM molecular composition. Within the first few days, no differences in respiration rates were observed between leachate sources, however, beyond day five, the rates diverged with C processing efficiency correlated with OM lability. Originally comprised of amino acid-like, labile fluorescent species, the inoculated stream water OM became more recalcitrant after 16 days, indicating humification processing over time. Our study highlights the importance of interdisciplinary approaches for understanding the processing and fate of OM in aquatic ecosystems.
High-Performance CCSDS AOS Protocol Implementation in FPGA
NASA Technical Reports Server (NTRS)
Clare, Loren P.; Torgerson, Jordan L.; Pang, Jackson
2010-01-01
The Consultative Committee for Space Data Systems (CCSDS) Advanced Orbiting Systems (AOS) space data link protocol provides a framing layer between channel coding such as LDPC (low-density parity-check) and higher-layer link multiplexing protocols such as CCSDS Encapsulation Service, which is described in the following article. Recent advancement in RF modem technology has allowed multi-megabit transmission over space links. With this increase in data rate, the CCSDS AOS protocol implementation needs to be optimized to both reduce energy consumption and operate at a high rate.
NASA Technical Reports Server (NTRS)
Brooks, David E.; Gassman, Holly; Beering, Dave R.; Welch, Arun; Hoder, Douglas J.; Ivancic, William D.
1999-01-01
Transmission Control Protocol (TCP) is the underlying protocol used within the Internet for reliable information transfer. As such, there is great interest to have all implementations of TCP efficiently interoperate. This is particularly important for links exhibiting long bandwidth-delay products. The tools exist to perform TCP analysis at low rates and low delays. However, for extremely high-rate and lone-delay links such as 622 Mbps over geosynchronous satellites, new tools and testing techniques are required. This paper describes the tools and techniques used to analyze and debug various TCP implementations over high-speed, long-delay links.
A Frequency Agile, Self-Adaptive Serial Link on Xilinx FPGAs
NASA Astrophysics Data System (ADS)
Aloisio, A.; Giordano, R.; Izzo, V.; Perrella, S.
2015-06-01
In this paper, we focused on the GTX transceiver modules of Xilinx Kintex 7 field-programmable gate arrays (FPGAs), which provide high bandwidth, low jitter on the recovered clock, and an equalization system on the transmitter and the receiver. We present a frequency agile, auto-adaptive serial link. The link is able to take care of the reconfiguration of the GTX parameters in order to fully benefit from the available link bandwidth, by setting the highest line rate. It is designed around an FPGA-embedded microprocessor, which drives the programmable ports of the GTX in order to control the quality of the received data and to easily calculate the bit-error rate in each sampling point of the eye diagram. We present the self-adaptive link project, the description of the test system, and the main results.
Optical deep space communication via relay satellite
NASA Technical Reports Server (NTRS)
Gagliardi, R. M.; Vilnrotter, V. A.; Dolinar, S. J., Jr.
1981-01-01
The possible use of an optical for high rate data transmission from a deep space vehicle to an Earth-orbiting relay satellite while RF links are envisioned for the relay to Earth link was studied. A preliminary link analysis is presented for initial sizing of optical components and power levels, in terms of achievable data rates and feasible range distances. Modulation formats are restricted to pulsed laser operation, involving bot coded and uncoded schemes. The advantage of an optical link over present RF deep space link capabilities is shown. The problems of acquisition, pointing and tracking with narrow optical beams are presented and discussed. Mathematical models of beam trackers are derived, aiding in the design of such systems for minimizing beam pointing errors. The expected orbital geometry between spacecraft and relay satellite, and its impact on beam pointing dynamics are discussed.
Traffic management mechanism for intranets with available-bit-rate access to the Internet
NASA Astrophysics Data System (ADS)
Hassan, Mahbub; Sirisena, Harsha R.; Atiquzzaman, Mohammed
1997-10-01
The design of a traffic management mechanism for intranets connected to the Internet via an available bit rate access- link is presented. Selection of control parameters for this mechanism for optimum performance is shown through analysis. An estimate for packet loss probability at the access- gateway is derived for random fluctuation of available bit rate of the access-link. Some implementation strategies of this mechanism in the standard intranet protocol stack are also suggested.
Foreign exchange market as a lattice gauge theory
NASA Astrophysics Data System (ADS)
Young, K.
1999-10-01
A simple model of the foreign exchange market is exactly a lattice gauge theory. Exchange rates are the exponentials of gauge potentials defined on spatial links while interest rates are related to gauge potentials on temporal links. Arbitrage opportunities are given by nonzero values of the gauge-invariant field tensor or curvature defined on closed loops. Arbitrage opportunities involving cross-rates at one time are "magnetic fields," while arbitrage opportunities involving future contracts are "electric fields."
Tuan, Shu-Jen; Yeh, Chih-Chun; Atlihan, Remzi; Chi, Hsin
2016-02-01
To better understand the predator-prey relationship and to compare predation rates, we studied the life table and predation rate of the predator Eocanthecona furcellata Wolff (Hemiptera: Pentatomidae) when reared on two major crucifer pests, Spodoptera litura (F.) (Lepidoptera: Noctuidae) and Plutella xylostella L. (Lepidoptera: Plutellidae). The net reproductive rate, intrinsic rate of increase, finite rate, and net predation rates of E. furcellata reared on P. xylostella were 292.4 offspring, 0.1389 d(-1), 1.1490 d(-1), and 644.1 third instars of P. xylostella, respectively. These values are significantly higher than those reared on S. litura, i.e., 272.3 offspring, 0.1220 d(-1), 1.1298 d(-1), and 863.1 third instars of S. litura. To evaluate the predation potential of E. furcellata fed on P. xylostella and S. litura, we combined both the growth rate and predation rate to calculate the finite predation rate (ω); our results showed that E. furcellata is an effective predator of both S. litura (ω = 1.6029) and P. xylostella (ω = 1.4277). © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Llopart, Ana
2018-05-01
The hemizygosity of the X (Z) chromosome fully exposes the fitness effects of mutations on that chromosome and has evolutionary consequences on the relative rates of evolution of X and autosomes. Specifically, several population genetics models predict increased rates of evolution in X-linked loci relative to autosomal loci. This prediction of faster-X evolution has been evaluated and confirmed for both protein coding sequences and gene expression. In the case of faster-X evolution for gene expression divergence, it is often assumed that variation in 5' noncoding sequences is associated with variation in transcript abundance between species but a formal, genomewide test of this hypothesis is still missing. Here, I use whole genome sequence data in Drosophila yakuba and D. santomea to evaluate this hypothesis and report positive correlations between sequence divergence at 5' noncoding sequences and gene expression divergence. I also examine polymorphism and divergence in 9,279 noncoding sequences located at the 5' end of annotated genes and detected multiple signals of positive selection. Notably, I used the traditional synonymous sites as neutral reference to test for adaptive evolution, but I also used bases 8-30 of introns <65 bp, which have been proposed to be a better neutral choice. X-linked genes with high degree of male-biased expression show the most extreme adaptive pattern at 5' noncoding regions, in agreement with faster-X evolution for gene expression divergence and a higher incidence of positively selected recessive mutations. © 2018 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.
Parkes, M. J.
2013-01-01
Only the carotid chemoreceptors stimulate breathing during hypoxia in Man. They are also ideally located to warn if the brain's oxygen supply falls, or if hypercapnia occurs. Since their discovery ~80 years ago stimulation, ablation, and recording experiments still leave 3 substantial difficulties in establishing how important the carotid chemoreceptors are in controlling breathing during exercise in Man: (i) they are in the wrong location to measure metabolic rate (but are ideally located to measure any mismatch), (ii) they receive no known signal during exercise linking them with metabolic rate and no overt mismatch signals occur and (iii) their denervation in Man fails to prevent breathing matching metabolic rate in exercise. New research is needed to enable recording from carotid chemoreceptors in Man to establish whether there is any factor that rises with metabolic rate and greatly increases carotid chemoreceptor activity during exercise. Available evidence so far in Man indicates that carotid chemoreceptors are either one of two mechanisms that explain breathing matching metabolic rate or have no importance. We still lack key experimental evidence to distinguish between these two possibilities. PMID:24236297
Low validity of Google Trends for behavioral forecasting of national suicide rates.
Tran, Ulrich S; Andel, Rita; Niederkrotenthaler, Thomas; Till, Benedikt; Ajdacic-Gross, Vladeta; Voracek, Martin
2017-01-01
Recent research suggests that search volumes of the most popular search engine worldwide, Google, provided via Google Trends, could be associated with national suicide rates in the USA, UK, and some Asian countries. However, search volumes have mostly been studied in an ad hoc fashion, without controls for spurious associations. This study evaluated the validity and utility of Google Trends search volumes for behavioral forecasting of suicide rates in the USA, Germany, Austria, and Switzerland. Suicide-related search terms were systematically collected and respective Google Trends search volumes evaluated for availability. Time spans covered 2004 to 2010 (USA, Switzerland) and 2004 to 2012 (Germany, Austria). Temporal associations of search volumes and suicide rates were investigated with time-series analyses that rigorously controlled for spurious associations. The number and reliability of analyzable search volume data increased with country size. Search volumes showed various temporal associations with suicide rates. However, associations differed both across and within countries and mostly followed no discernable patterns. The total number of significant associations roughly matched the number of expected Type I errors. These results suggest that the validity of Google Trends search volumes for behavioral forecasting of national suicide rates is low. The utility and validity of search volumes for the forecasting of suicide rates depend on two key assumptions ("the population that conducts searches consists mostly of individuals with suicidal ideation", "suicide-related search behavior is strongly linked with suicidal behavior"). We discuss strands of evidence that these two assumptions are likely not met. Implications for future research with Google Trends in the context of suicide research are also discussed.
Parallel evolution of early and late feathering in turkey and chicken, same gene, different mutation
USDA-ARS?s Scientific Manuscript database
The sex-linked slow (SF) and fast (FF) feathering rate at hatch has been widely used in poultry breeding for autosexing at hatching. In chicken, the sex-linked K (SF), and k+ (FF) alleles are responsible for the feathering rate phenotype in chicken. The K allele is dominant and a partial duplication...
The Gender-Linked Language Effect: An Empirical Test of a General Process Model
ERIC Educational Resources Information Center
Mulac, Anthony; Giles, Howard; Bradac, James J.; Palomares, Nicholas A.
2013-01-01
The gender-linked language effect (GLLE) is a phenomenon in which transcripts of female communicators are rated higher on Socio-Intellectual Status and Aesthetic Quality and male communicators are rated higher on Dynamism. This study proposed and tested a new general process model explanation for the GLLE, a central mediating element of which…
Hammond, Lucinda; Papadopoulos, Spyridon; Johnson, Candice F; MaWhinney, Samantha; Nelson, Bernard; Todd, James K
2002-03-01
We designed an Internet-based surveillance network that linked community clinic diagnoses with viral isolation rates and admission patterns at a related children's hospital. We hypothesized that community surveillance would successfully predict subsequent hospital admissions and laboratory viral isolations. Secondarily, we expected the network to monitor trends in disease and that posting this information on a Web site would be useful to physicians in daily practice. Data were collected from December 1999 through August 2000. Information was summarized and posted weekly on a Web site. Active public piloting of the site took place during August 2000, after which the project was evaluated through an electronic mail survey. The predictive ability of the community surveillance data was evaluated by multivariate linear regression. Increases in the community diagnosis of most syndromes under surveillance, including lower respiratory infections (adjusted R(2) = 0.7086) and gastroenteritis (adjusted R(2) = 0.6532) successfully predicted an increase in subsequent hospital admissions. Community surveillance also successfully predicted laboratory isolation of associated viral organisms. Physicians completing the evaluation (N = 11) indicated that the site provided information useful in daily practice for both physician and parent education. An Internet-based surveillance network linking a hospital with community physicians is beneficial to the hospital in predicting waves of severe cases requiring admission and reciprocally provides useful information to physicians in daily practice regarding the incidence and cause of seasonal disease in the community.
[Social representations of TB patients on treatment discontinuation].
Chirinos, Narda Estela Calsin; Meirelles, Betina Hörner Schlindwein; Bousfield, Andréa Barbará Silva
2015-01-01
To understand the social representations of people with TB who discontinued treatment in a Program of Tuberculosis Control. a descriptive study of qualitative approach conducted in the city of Lima, Peru. Data were collected from October to November 2012, through semi-structured interviews with eight individuals and the method used was thematic content analysis. The categories led to the construction of the social representation that the disease and the treatment bring suffering. This representation influences non-adherence to treatment and may increase the rates of treatment discontinuation. Educational strategies linked to social interaction processes, to subjectivity and to the patient context are needed to reduce the rates of discontinuation of tuberculosis treatment, relapses and multi-drug resistance. The evaluations point to new challenges that must be faced to achieve the Millennium Development Goals.
Whose idea was that? Source monitoring for idea ownership following elaboration.
Stark, Louisa-Jayne; Perfect, Timothy J
2007-10-01
Unconscious plagiarism (UP) occurs when an individual claims a previously experienced idea as their own. Previous studies have explored the cognitive precursors of such errors by manipulating the ways that ideas are thought about between initial idea exposure and later test. While imagining other's ideas does not increase rates of UP relative to control on either a recall-own or generate-new task, improving others' ideas substantially increases such errors in the recall-own task. This study explored the effects of elaboration on rates of UP when a source-monitoring test replaced the recall-own test. Plagiarism was again observed following idea improvement but not idea imagery even though participants engaged explicit source evaluation. Thus the probability of plagiarising another's idea appears linked to the generative nature of the idea processing performed.
Evaluation of communication in wireless underground sensor networks
NASA Astrophysics Data System (ADS)
Yu, X. Q.; Zhang, Z. L.; Han, W. T.
2017-06-01
Wireless underground sensor networks (WUSN) are an emerging area of research that promises to provide communication capabilities to buried sensors. In this paper, experimental measurements have been conducted with commodity sensor motes at the frequency of 2.4GHz and 433 MHz, respectively. Experiments are run to examine the received signal strength of correctly received packets and the packet error rate for a communication link. The tests show the potential feasibility of the WUSN with the use of powerful RF transceivers at 433MHz frequency. Moreover, we also illustrate a classification for wireless underground sensor network communication. Finally, we conclude that the effects of burial depth, inter-node distance and volumetric water content of the soil on the signal strength and packet error rate in communication of WUSN.
Marican, Adolfo; Avila-Salas, Fabián; Valdés, Oscar; Wehinger, Sergio; Villaseñor, Jorge; Fuentealba, Natalia; Arenas-Salinas, Mauricio; Argandoña, Yerko; Carrasco-Sánchez, Verónica; Durán-Lara, Esteban F
2018-03-07
This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN.
Marican, Adolfo; Valdés, Oscar; Wehinger, Sergio; Villaseñor, Jorge; Fuentealba, Natalia; Argandoña, Yerko; Carrasco-Sánchez, Verónica
2018-01-01
This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN. PMID:29518980
Coded throughput performance simulations for the time-varying satellite channel. M.S. Thesis
NASA Technical Reports Server (NTRS)
Han, LI
1995-01-01
The design of a reliable satellite communication link involving the data transfer from a small, low-orbit satellite to a ground station, but through a geostationary satellite, was examined. In such a scenario, the received signal power to noise density ratio increases as the transmitting low-orbit satellite comes into view, and then decreases as it then departs, resulting in a short-duration, time-varying communication link. The optimal values of the small satellite antenna beamwidth, signaling rate, modulation scheme and the theoretical link throughput (in bits per day) have been determined. The goal of this thesis is to choose a practical coding scheme which maximizes the daily link throughput while satisfying a prescribed probability of error requirement. We examine the throughput of both fixed rate and variable rate concatenated forward error correction (FEC) coding schemes for the additive white Gaussian noise (AWGN) channel, and then examine the effect of radio frequency interference (RFI) on the best coding scheme among them. Interleaving is used to mitigate degradation due to RFI. It was found that the variable rate concatenated coding scheme could achieve 74 percent of the theoretical throughput, equivalent to 1.11 Gbits/day based on the cutoff rate R(sub 0). For comparison, 87 percent is achievable for AWGN-only case.
Arch, Joanna J.; Brown, Kirk Warren; Dean, Derek J.; Landy, Lauren N.; Brown, Kimberley; Laudenslager, Mark L.
2014-01-01
A growing body of research has revealed that social evaluative stressors trigger biological and psychological responses that in chronic forms have been linked to aging and disease. Recent research suggests that self-compassion may protect the self from typical defensive responses to evaluation. We investigated whether brief training in self-compassion moderated biopsychological responses to the Trier Social Stress Test (TSST) in women. Compared to attention (placebo) and no-training control conditions, brief self-compassion training diminished sympathetic (salivary alpha-amylase), cardiac parasympathetic, and subjective anxiety responses, though not HPA-axis (salivary cortisol) responses to the TSST. Self-compassion training also led to greater self-compassion under threat relative to the control groups. In that social stress pervades modern life, self-compassion represents a promising approach to diminishing its potentially negative psychological and biological effects. PMID:24636501
Evaluation of a pilot promotora program for Latino forest workers in southern Oregon.
Bush, Diane E; Wilmsen, Carl; Sasaki, Timothy; Barton-Antonio, Dinorah; Steege, Andrea L; Chang, Charlotte
2014-07-01
Forest work, an occupation with some of the highest injury and illness rates, is conducted primarily by Latino immigrant workers. This study evaluates a pilot program where promotoras (lay community health educators) provided occupational health and safety trainings for Latino forest workers. Evaluation methods included a focus group, post-tests, and qualitative feedback. Community capacity to address working conditions increased through (i) increased leadership and community access to information and resources; and (ii) increased worker awareness of workplace health and safety rights and resources. Fear of retaliation remains a barrier to workers taking action; nevertheless, the promotoras supported several workers in addressing-specific workplace issues. For working conditions to significantly improve, major structural influences need to be addressed. A long-term, organizationally supported promotora program can play a key role in linking and supporting change at the individual, interpersonal and community levels, contributing to and supporting structural change. © 2014 Wiley Periodicals, Inc.
Evaluation of linking pavement related databases.
DOT National Transportation Integrated Search
2007-03-01
In general, the objectives of this study were to identify and solve various issues in linking pavement performance related database. The detailed objectives were: to evaluate the state-of-the-art in information technology for data integration and dat...
30 pJ/b, 67 Mbps, Centimeter-to-Meter Range Data Telemetry With an IR-UWB Wireless Link.
Ebrazeh, Ali; Mohseni, Pedram
2015-06-01
This paper reports an energy-efficient, impulse radio ultra wideband (IR-UWB) wireless link operating in 3-5 GHz for data telemetry over centimeter-to-meter range distances at rates extended to tens of Mbps. The link comprises an all-digital, integrated transmitter (TX) fabricated in 90 nm 1P/9M CMOS that incorporates a waveform-synthesis pulse generator and a timing generator for on-off-keying (OOK) pulse modulation and phase scrambling. The link also incorporates an energy-detection receiver (RX) realized with commercial off-the-shelf (COTS) components that performs radio-frequency (RF) filtering, amplification, logarithmic power detection for data demodulation and automatic level control for robust operation in the presence of distance variations. Employing a miniaturized, UWB, chip antenna for the TX and RX, wireless transmission of pseudo-random binary sequence (PRBS) data at rates up to 50 Mbps over 10 cm-1 m is shown. Further, employing a high-gain horn antenna for the RX, wireless transmission of PRBS data at rates up to 67 Mbps over 50 cm-4 m is shown with a TX energy consumption of 30 pJ/b (i.e., power consumption of 2 mW) from 1.2 V. The measured bit error rate (BER) in both cases is < 10(-7) . Results from wireless recording of the background current of a carbon-fiber microelectrode (CFM) in one fast-scan cyclic voltammetry (FSCV) scan using the IR-UWB link are also included, exhibiting excellent match with those obtained from a conventional frequency-shift-keyed (FSK) link at ~433 MHz.
Alpine, Lucy M; Caldas, Francieli Tanji; Barrett, Emer M
2018-04-02
The objective of the study was to investigate student and practice educator evaluations of practice placements using a structured 2 to 1 supervision and implementation model. Cross-sectional pilot study set in clinical sites providing placements for physiotherapy students in Ireland. Students and practice educators completing a 2.1 peer placement between 2013 and 2015 participated. A self-reported questionnaire which measured indicators linked to quality assured placements was used. Three open-ended questions captured comments on the benefits and challenges associated with the 2 to 1 model. Ten students (10/20; 50% response rate) and 10 practice educators (10/10; 100% response rate) responded to the questionnaire. Student responses included four pairs of students and one student from a further two pairs. There was generally positive agreement with the questionnaire indicating that placements using the 2 to 1 model were positively evaluated by participants. There were no significant differences between students and practice educators. The main benefits of the 2 to 1 model were shared learning experiences, a peer supported environment, and the development of peer evaluation and feedback skills by students. A key component of the model was the peer scripting process which provided time for reflection, self-evaluation, and peer review. 2 to 1 placements were positively evaluated by students and educators when supported by a structured supervision model. Clear guidance to students on the provision of peer feedback and support for educators providing feedback to two different students is recommended.
Szekalska, Marta; Sosnowska, Katarzyna; Zakrzeska, Agnieszka; Kasacka, Irena; Lewandowska, Alicja; Winnicka, Katarzyna
2017-01-22
Sodium alginate is a polymer with unique ability to gel with different cross-linking agents in result of ionic and electrostatic interactions. Chitosan cross-linked alginate provides improvement of swelling and mucoadhesive properties and might be used to design sustained release dosage forms. Therefore, the aim of this research was to develop and evaluate possibility of preparing chitosan cross-linked alginate microparticles containing metformin hydrochloride by the spray-drying method. In addition, influence of cross-linking agent on the properties of microparticles was evaluated. Formulation of microparticles prepared by the spray drying of 2% alginate solution cross-linked by 0.1% chitosan was characterized by good mucoadhesive properties, high drug loading and prolonged metformin hydrochloride release. It was shown that designed microparticles reduced rat glucose blood level, delayed absorption of metformin hydrochloride and provided stable plasma drug concentration. Additionally, histopathological studies of pancreas, liver and kidneys indicated that all prepared microparticles improved degenerative changes in organs of diabetic rats. Moreover, no toxicity effect and no changes in rats behavior after oral administration of chitosan cross-linked alginate microparticles were noted.
Using Link Disconnection Entropy Disorder to Detect Fast Moving Nodes in MANETs
Palafox, Luis E.; Aguilar, Leocundo; Sanchez, Mauricio A.; Martinez, Luis G.
2016-01-01
Mobile ad-hoc networks (MANETs) are dynamic by nature; this dynamism comes from node mobility, traffic congestion, and other transmission conditions. Metrics to evaluate the effects of those conditions shine a light on node’s behavior in an ad-hoc network, helping to identify the node or nodes with better conditions of connection. In this paper, we propose a relative index to evaluate a single node reliability, based on the link disconnection entropy disorder using neighboring nodes as reference. Link disconnection entropy disorder is best used to identify fast moving nodes or nodes with unstable communications, this without the need of specialized sensors such as GPS. Several scenarios were studied to verify the index, measuring the effects of Speed and traffic density on the link disconnection entropy disorder. Packet delivery ratio is associated to the metric detecting a strong relationship, enabling the use of the link disconnection entropy disorder to evaluate the stability of a node to communicate with other nodes. To expand the utilization of the link entropy disorder, we identified nodes with higher speeds in network simulations just by using the link entropy disorder. PMID:27219671
The self as a mediator between personality and adjustment.
Graziano, W G; Jensen-Campbell, L A; Finch, J F
1997-08-01
The self can be conceptualized as a mediating agent that translates personality into situated goal-directed activities and adaptation. This research used a level-of-analysis approach to link personality dimensions (Level I) to self-systems (Level II) and to teacher ratings of adjustment in African American, Mexican American, and European American students (N = 317). The authors hypothesized that links among aspects of self-esteem and teacher ratings of adjustment would be domain specific, and those links to dimensions of the 5-factor model would reflects the domain specificity. Structural equation modeling corroborated hypotheses about domain specificity in links between adjustment and 5-factor dimensions. Results were discussed in terms of levels of analysis for personality structure, personality development, and age-related adaptations to social contexts.
Using global unique identifiers to link autism collections.
Johnson, Stephen B; Whitney, Glen; McAuliffe, Matthew; Wang, Hailong; McCreedy, Evan; Rozenblit, Leon; Evans, Clark C
2010-01-01
To propose a centralized method for generating global unique identifiers to link collections of research data and specimens. The work is a collaboration between the Simons Foundation Autism Research Initiative and the National Database for Autism Research. The system is implemented as a web service: an investigator inputs identifying information about a participant into a client application and sends encrypted information to a server application, which returns a generated global unique identifier. The authors evaluated the system using a volume test of one million simulated individuals and a field test on 2000 families (over 8000 individual participants) in an autism study. Inverse probability of hash codes; rate of false identity of two individuals; rate of false split of single individual; percentage of subjects for which identifying information could be collected; percentage of hash codes generated successfully. Large-volume simulation generated no false splits or false identity. Field testing in the Simons Foundation Autism Research Initiative Simplex Collection produced identifiers for 96% of children in the study and 77% of parents. On average, four out of five hash codes per subject were generated perfectly (only one perfect hash is required for subsequent matching). The system must achieve balance among the competing goals of distinguishing individuals, collecting accurate information for matching, and protecting confidentiality. Considerable effort is required to obtain approval from institutional review boards, obtain consent from participants, and to achieve compliance from sites during a multicenter study. Generic unique identifiers have the potential to link collections of research data, augment the amount and types of data available for individuals, support detection of overlap between collections, and facilitate replication of research findings.
Huybrecht, Sabine; Loeckx, Wim; Quaeyhaegens, Yvo; De Tobel, Danielle; Mistiaen, Wilhelm
2011-04-01
This paper presents the initial research results of mentorship in Flanders, Belgium. A validated questionnaire has been used as well as a semi-structured interview, to investigate perceived characteristics, advantages and drawbacks of mentorship, as well as practical aspects in mentoring education. The questionnaire has been validated for the Dutch language. The response rate of 62% has been rather high. The ability to give feedback, experience, availability of time and a positive attitude were the elements considered important for mentors. In spite of workload, lack of time and drawbacks such as adverse effects on the team work on the ward, transferring of enthusiasm onto students was still possible. Benefits for mentors were immaterial and included closer follow-up of new developments, teaching and sharing of experiences. The benefits outweighed the drawbacks. Support by mentoring courses, additional study and especially of link lecturers proved to be beneficial. Especially the help of link lecturers proved to be necessary in problems and in evaluation of "unsafe" students. In the latter case, the link lecturer helps to solve the inherent conflict of interest by being mentor and assessor at the same time. Copyright © 2010 Elsevier Ltd. All rights reserved.
An underwater optical wireless communication network
NASA Astrophysics Data System (ADS)
Arnon, Shlomi
2009-08-01
The growing need for underwater observation and sub-sea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, bio-geochemical, evolutionary and ecological changes in the sea, ocean and lake environments and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. We present models of three kinds of optical wireless communication links a) a line-of-sight link, b) a modulating retro-reflector link and c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered lighted it was possible to mitigate this decrease in some cases. We conclude from the analysis that a high data rate underwater optical wireless network is a feasible solution for emerging applications such as UUV to UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.
Underwater optical wireless communication network
NASA Astrophysics Data System (ADS)
Arnon, Shlomi
2010-01-01
The growing need for underwater observation and subsea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, biogeochemical, evolutionary, and ecological changes in the sea, ocean, and lake environments, and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. Models are presented for three kinds of optical wireless communication links: (a) a line-of-sight link, (b) a modulating retroreflector link, and (c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered light it was possible to mitigate this decrease in some cases. It is concluded from the analysis that a high-data-rate underwater optical wireless network is a feasible solution for emerging applications such as UUV-to-UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.
Why Data Linkage? The Importance of CODES (Crash Outcome Data Evaluation System)
DOT National Transportation Integrated Search
1996-06-01
This report briefly explains the computerized linked data system, Crash Outcome : Data Evaluation System (CODES) that provides greater depth accident data : analysis. The linking of data helps researchers to understand the nature of : traffic acciden...
[Chemotherapeutic characterization of new nitrosourea compounds].
Zeller, W J; Berger, M R; Eisenbrand, G; Petru, E
1988-01-01
The development of new nitrosoureas is described using selected examples. Results obtained with water-soluble analogs and with compounds linked to biomolecules as for instance amino acids, oligopeptides and steroids, are presented. The pronounced antineoplastic effect of some water-soluble analogs is paralleled by an increased rate of DNA-interstrand cross-links and by an increased suppression of hematopoietic stem cells. The suppression of bone marrow stem cells is followed by their rapid regeneration. Water-soluble nitrosoureas induce significant less inhibition of glutathione reductase as compared with established compounds. With regard to long-term toxicity and carcinogenicity water-soluble are superior to established compounds as for instance BCNU. Linking of the nitrosourea moiety to amino acids and oligopeptides led to some analogs with outstanding therapeutic ratio. Out of a group of steroid-linked nitrosoureas, CNC-L-alanine-estradiol-17-ester (CNC-ala-17-E2) is chosen to demonstrate the possibility of reducing bone marrow toxicity despite unchanged or increased therapeutic activity by attachment of the nitrosourea moiety to a steroid. Results of a comparative interspecies in vitro evaluation of CNC-ala-17-E2 in transplanted MXT mammary carcinoma of the mouse, MNU-induced autochthonous rat mammary carcinoma and primary human mammary carcinomas are presented and the question is discussed to what extent in vitro activity of such receptor agents using the tumor stem cell assay reflects their in vivo activity.
Optimizing performance of hybrid FSO/RF networks in realistic dynamic scenarios
NASA Astrophysics Data System (ADS)
Llorca, Jaime; Desai, Aniket; Baskaran, Eswaran; Milner, Stuart; Davis, Christopher
2005-08-01
Hybrid Free Space Optical (FSO) and Radio Frequency (RF) networks promise highly available wireless broadband connectivity and quality of service (QoS), particularly suitable for emerging network applications involving extremely high data rate transmissions such as high quality video-on-demand and real-time surveillance. FSO links are prone to atmospheric obscuration (fog, clouds, snow, etc) and are difficult to align over long distances due the use of narrow laser beams and the effect of atmospheric turbulence. These problems can be mitigated by using adjunct directional RF links, which provide backup connectivity. In this paper, methodologies for modeling and simulation of hybrid FSO/RF networks are described. Individual link propagation models are derived using scattering theory, as well as experimental measurements. MATLAB is used to generate realistic atmospheric obscuration scenarios, including moving cloud layers at different altitudes. These scenarios are then imported into a network simulator (OPNET) to emulate mobile hybrid FSO/RF networks. This framework allows accurate analysis of the effects of node mobility, atmospheric obscuration and traffic demands on network performance, and precise evaluation of topology reconfiguration algorithms as they react to dynamic changes in the network. Results show how topology reconfiguration algorithms, together with enhancements to TCP/IP protocols which reduce the network response time, enable the network to rapidly detect and act upon link state changes in highly dynamic environments, ensuring optimized network performance and availability.
71-Mbit/s ultraviolet-B LED communication link based on 8-QAM-OFDM modulation.
Sun, Xiaobin; Zhang, Zhenyu; Chaaban, Anas; Ng, Tien Khee; Shen, Chao; Chen, Rui; Yan, Jianchang; Sun, Haiding; Li, Xiaohang; Wang, Junxi; Li, Jinmin; Alouini, Mohamed-Slim; Ooi, Boon S
2017-09-18
A demonstration of ultraviolet-B (UVB) communication link is implemented utilizing quadrature amplitude modulation (QAM) orthogonal frequency-division multiplexing (OFDM). The demonstration is based on a 294-nm UVB-light-emitting-diode (UVB-LED) with a full-width at half-maximum (FWHM) of 9 nm and light output power of 190 μW, at 7 V, with a special silica gel lens on top of it. A -3-dB bandwidth of 29 MHz was measured and a high-speed near-solar-blind communication link with a data rate of 71 Mbit/s was achieved using 8-QAM-OFDM at perfect alignment. 23.6 Mbit/s using 2-QAM-OFDM when the angle subtended by the pointing directions of the UVB-LED and photodetector (PD) is 12 degrees, thus establishing a diffuse-line-of-sight (LOS) link. The measured bit-error rate (BER) of 2.8 ×10 -4 and 2.4 ×10 -4 , respectively, are well below the forward error correction (FEC) criterion of 3.8 ×10 -3 . The demonstrated high data-rate OFDM-based UVB communication link paves the way for realizing high-speed non-line-of-sight free-space optical communications.
Fiber optic data link for data acquisition and analysis
NASA Astrophysics Data System (ADS)
Saulsberry, Garen
A data link has been designed and developed for use with fiber optics as a transmission medium, though coaxial and twisted pair cable might also be used. Multiple data types may be transferred at various rates up to 100 Mbits per second and data word width may be programmed to obtain the highest level of efficiency from the bit rate.
Early Communication System (ECOMM) for ISS
NASA Technical Reports Server (NTRS)
Gaylor, Kent; Tu, Kwei
1999-01-01
The International Space Station (ISS) Early Communications System (ECOMM) was a Johnson Space Center (JSC) Avionic Systems Division (ASD) in-house developed communication system to provide early communications between the ISS and the Mission Control Center-Houston (MCC-H). This system allows for low rate commands (link rate of 6 kbps) to be transmitted through the Tracking and Data Relay Satellite System (TDRSS) from MCC-H to the ISS using TDRSS's S-band Single Access Forward (SSA/) link service. This system also allows for low rate telemetry (link rate of 20.48 kbps) to be transmitted from ISS to MCC-H through the TDRSS using TDRSS's S-band Single Access Return (SSAR) link service. In addition this system supports a JSC developed Onboard Communications Adapter (OCA) that allows for a two-way data exchange of 128 kbps between MCC-H and the ISS through TDRSS. This OCA data can be digital video/audio (two-way videoconference), and/or file transfers, and/or "white board". The key components of the system, the data formats used by the system to insure compatibility with the future ISS S-Band System, as well as how other vehicles may be able to use this system for their needs are discussed in this paper.
Carter, Stephen J; Hunter, Gary R; McAuley, Edward; Courneya, Kerry S; Anton, Philip M; Rogers, Laura Q
2016-10-01
Research showing a link between exercise-induced changes in aerobic fitness and reduced fatigue after a cancer diagnosis has been inconsistent. We evaluated associations of fatigue and rate-pressure product (RPP), a reliable index of myocardial oxygen demand, at rest and during submaximal walking following a physical activity intervention among post-primary treatment breast cancer survivors (BCS). Secondary analyses of 152 BCS in a randomized controlled trial testing a physical activity intervention (INT) versus usual care (UC) were performed. The INT group completed counseling/group discussions along with supervised exercise sessions tapered to unsupervised exercise. Evaluations were made at baseline and immediately post-intervention (M3) on measures of physical activity (accelerometry), graded walk test, and average fatigue over the previous 7 days. RPP was calculated by dividing the product of heart rate and systolic blood pressure by 100. Resting and submaximal RPPs were significantly improved in both groups at M3; however, the magnitude of change (∆) was greater in the INT group from stage 1 (∆RPP1; INT -13 ± 17 vs. UC -7 ± 18; p = 0.03) through stage 4 (∆RPP4; INT -21 ± 26 vs. UC -9 ± 24; p < 0.01) of the walk test. The INT group reported significantly reduced fatigue (INT -0.7 ± 2.0 vs. UC +0.1 ± 2.0; p = 0.02) which was positively associated with ∆RPP during stages 2-4 of the walk test but not ∆aerobic fitness. Lower RPP during submaximal walking was significantly associated with reduced fatigue in BCS. Exercise/physical activity training programs that lower the physiological strain during submaximal walking may produce the largest improvements in reported fatigue.
Janjua, Naveed Zafar; Kuo, Margot; Chong, Mei; Yu, Amanda; Alvarez, Maria; Cook, Darrel; Armour, Rosemary; Aiken, Ciaran; Li, Karen; Mussavi Rizi, Seyed Ali; Woods, Ryan; Godfrey, David; Wong, Jason; Gilbert, Mark; Tyndall, Mark W.; Krajden, Mel
2016-01-01
Background The British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals. Methods The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992) of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals. Results Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54%) were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90–100%). Conclusion Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV. PMID:26954020
Janjua, Naveed Zafar; Kuo, Margot; Chong, Mei; Yu, Amanda; Alvarez, Maria; Cook, Darrel; Armour, Rosemary; Aiken, Ciaran; Li, Karen; Mussavi Rizi, Seyed Ali; Woods, Ryan; Godfrey, David; Wong, Jason; Gilbert, Mark; Tyndall, Mark W; Krajden, Mel
2016-01-01
The British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals. The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992) of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals. Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54%) were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90-100%). Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV.
NASA Technical Reports Server (NTRS)
Parker, J. F., Jr.; Duffy, J. W.
1982-01-01
Key problems in single pilot instrument flight operations are in the management of flight data and the processing of cockpit information during conditions of heavy workload. A flight data console was developed to allow simulation of a digital data link to replace the current voice communications stem used in air traffic control. This is a human factors evaluation of a data link communications system to determine how such a system might reduce cockpit workload, improve flight proficiency, and be accepted by general aviation pilots. The need for a voice channel as backup to a digital link is examined. The evaluations cover both airport terminal area operations and full mission instrument flight. Results show that general aviation pilots operate well with a digital data link communications system. The findings indicate that a data link system for pilot/ATC communications, with a backup voice channel, is well accepted by general aviation pilots and is considered to be safer, more efficient, and result in less workload than the current voice system.
Clewe, Oskar; Karlsson, Mats O; Simonsson, Ulrika S H
2015-12-01
Bronchoalveolar lavage (BAL) is a pulmonary sampling technique for characterization of drug concentrations in epithelial lining fluid and alveolar cells. Two hypothetical drugs with different pulmonary distribution rates (fast and slow) were considered. An optimized BAL sampling design was generated assuming no previous information regarding the pulmonary distribution (rate and extent) and with a maximum of two samples per subject. Simulations were performed to evaluate the impact of the number of samples per subject (1 or 2) and the sample size on the relative bias and relative root mean square error of the parameter estimates (rate and extent of pulmonary distribution). The optimized BAL sampling design depends on a characterized plasma concentration time profile, a population plasma pharmacokinetic model, the limit of quantification (LOQ) of the BAL method and involves only two BAL sample time points, one early and one late. The early sample should be taken as early as possible, where concentrations in the BAL fluid ≥ LOQ. The second sample should be taken at a time point in the declining part of the plasma curve, where the plasma concentration is equivalent to the plasma concentration in the early sample. Using a previously described general pulmonary distribution model linked to a plasma population pharmacokinetic model, simulated data using the final BAL sampling design enabled characterization of both the rate and extent of pulmonary distribution. The optimized BAL sampling design enables characterization of both the rate and extent of the pulmonary distribution for both fast and slowly equilibrating drugs.
Lopes, M C A; Araújo, V F P; Vasconcellos, A
2015-08-01
Litterfall has a strong influence on biodiversity and on the chemical and physical characteristics of the soil. Its production can be quite variable over time and space, and can be influenced by both natural and anthropogenic factors. We evaluated litterfall production and its relationship with rainfall, species richness, and the densities of the arboreal vegetation. Thirty litter traps were constructed with 1.0 m2 nylon mesh (1.0 mm) and randomly installed within a 2000 m × 500 m area of arboreal/shrub Caatinga (dryland) vegetation. Litter samples were collected monthly from November/2010 to June/2012, and the collected material was classified, dried, and weighted. Species richness and tree densities were determined by conducting phytosociological surveys in 20 m × 20 m plots surrounding each of the litter traps. The litterfall accumulation rate was 3.673 Mgha-1yr-1, similar to values from other seasonally dry tropical forests. Litterfall production was continuous, and principally accompanied the rainfall rate, but with a time interval of 2 to 3 months, with the greatest accumulation at the beginning of the dry season and the least during the rainy season. The different fractions of materials demonstrated distinct accumulation rates, with leaves being the principal category. Litterfall production was found to be related to tree density, but no link was found to species richness. The observed temporal heterogeneity of litterfall production demonstrated a strong link between rainfall and the dynamics of nutrient cycling in the semiarid region of Brazil.
Refugee Resettlement Patterns and State-Level Health Care Insurance Access in the United States.
Agrawal, Pooja; Venkatesh, Arjun Krishna
2016-04-01
We sought to evaluate the relationship between state-level implementation of the Patient Protection and Affordable Care Act (ACA) and resettlement patterns among refugees. We linked federal refugee resettlement data to ACA expansion data and found that refugee resettlement rates are not significantly different according to state-level insurance expansion or cost. Forty percent of refugees have resettled to states without Medicaid expansion. The wide state-level variability in implementation of the ACA should be considered by federal agencies seeking to optimize access to health insurance coverage among refugees who have resettled to the United States.
Case studies of energy efficiency financing in the original five pilot states, 1993-1996
DOE Office of Scientific and Technical Information (OSTI.GOV)
Farhar, B C; Collins, N E; Walsh, R W
1997-05-01
The purpose of this report is to document progress in state-level programs in energy efficiency financing programs that are linked with home energy rating systems. Case studies are presented of programs in five states using a federal pilot program to amortize the costs of home energy improvements. The case studies present background information, describe the states` program, list preliminary evaluation data and findings, and discuss problems and solution encountered in the programs. A comparison of experiences in pilot states will be used to provide guidelines for program implementers, federal agencies, and Congress. 5 refs.
Communications processor for C3 analysis and wargaming
NASA Astrophysics Data System (ADS)
Clark, L. N.; Pless, L. D.; Rapp, R. L.
1982-03-01
This thesis developed the software capability to allow the investigation of c3 problems, procedures and methodologies. The resultant communications model, that while independent of a specific wargame, is currently implemented in conjunction with the McClintic Theater Model. It provides a computerized message handling system (C3 Model) which allows simulation of communication links (circuits) with user-definable delays; garble and loss rates; and multiple circuit types, addresses, and levels of command. It is designed to be used for test and evaluation of command and control problems in the areas of organizational relationships, communication networks and procedures, and combat doctrine or tactics.
Evaluating the Controls on Magma Ascent Rates Through Numerical Modelling
NASA Astrophysics Data System (ADS)
Thomas, M. E.; Neuberg, J. W.
2015-12-01
The estimation of the magma ascent rate is a key factor in predicting styles of volcanic activity and relies on the understanding of how strongly the ascent rate is controlled by different magmatic parameters. The ability to link potential changes in such parameters to monitoring data is an essential step to be able to use these data as a predictive tool. We present the results of a suite of conduit flow models that assess the influence of individual model parameters such as the magmatic water content, temperature or bulk magma composition on the magma flow in the conduit during an extrusive dome eruption. By systematically varying these parameters we assess their relative importance to changes in ascent rate. The results indicate that potential changes to conduit geometry and excess pressure in the magma chamber are amongst the dominant controlling variables that effect ascent rate, but the single most important parameter is the volatile content (assumed in this case as only water). Modelling this parameter across a range of reported values causes changes in the calculated ascent velocities of up to 800%, triggering fluctuations in ascent rates that span the potential threshold between effusive and explosive eruptions.
Adaptive data rate capacity of meteor-burst communications
NASA Astrophysics Data System (ADS)
Larsen, J. D.; Melville, S. W.; Mawrey, R. S.
The use of adaptive data rates in the meteor-burst communications environment is investigated. Measured results obtained from a number of meteor links are presented and compared with previous theoretical predictions. The contribution of various meteor trail families to throughput capacity are also investigated. The results show that the use of adaptive data rates can significantly increase the throughput capacity of meteor-burst communication systems. The greatest rate of increase in throughput with increase in operating rate is found at low operating rates. This finding has been confirmed for a variety of links and days. Reasonable correspondence is obtained between the predicted modified overdense model and the observed results. Overdense trails, in particular two trail types within the overdense family, are shown to dominate adaptive data throughput.
Owen, J; Carroll, C; Cooke, J; Formby, E; Hayter, M; Hirst, J; Lloyd Jones, M; Stapleton, H; Stevenson, M; Sutton, A
2010-06-01
Report based on a service-mapping study and a systematic review concerning sexual health services for young people, either based in or closely linked to schools. To identify current forms of school-based sexual health services (SBSHS) and school-linked sexual health services (SLSHS) in the UK, review and synthesise existing evidence from qualitative and quantitative studies concerning the effectiveness, acceptability and cost-effectiveness of these types of service and to identify potential areas for further research. Electronic databases were searched from 1985 onwards. For published material: the Cochrane Library (1991-), MEDLINE, PREMEDLINE (2007-), CINAHL, EMBASE, AMED, ASSIA (1987-), IBSS, ERIC, PsycINFO, Science Citation Index (SCI) and Social Sciences Citation Index. For unpublished material and grey literature: the Social Care Institute of Excellence Research Register; the National Research Register (1997-), ReFeR; Index to Theses, and HMIC. A service-mapping questionnaire was circulated to school nurses in all parts of the UK, and semistructured telephone interviews with service coordinators in NHS and local authority (LA) roles were conducted. An evidence synthesis was performed based on a systematic review of the quantitative evidence about service effectiveness, qualitative evidence about user and professional views and a mixed-methods synthesis. A proof-of-concept model for assessing cost-effectiveness was drawn up. Three broad types of UK sexual health service provision were identified. Firstly, SBSHS staffed by school nurses, offering 'minimal' or 'basic' levels of service. Secondly, SBSHS and SLSHS staffed by a multiprofessional team, but not medical practitioners, offering 'basic' or 'intermediate' levels of service. Thirdly, SBSHS and SLSHS staffed by a multiprofessional team, including medical practitioners offering 'intermediate' or 'comprehensive' levels of service. The systematic review showed that SBSHS are not associated with higher rates of sexual activity among young people, nor with an earlier age of first intercourse. There was evidence to show positive effects in terms of reductions in births to teenage mothers, and in chlamydial infection rates among young men, although this evidence coming primarily from the USA. Therefore, the findings need to be tested in relation to UK-based services. Also evidence to suggest that broad-based, holistic service models, not restricted to sexual health, offer the strongest basis for protecting young people's privacy and confidentiality, countering perceived stigmatisation, offering the most comprehensive range of products and services, and maximising service uptake. Findings from the mapping study also indicate that broad-based services, which include medical practitioner input within a multiprofessional team, meet the stated preferences of staff and of young people most clearly. Partnership-based developments of this kind also conform to the broad policy principles embodied in the Every Child Matters framework in the UK and allied policy initiatives. However, neither these service models nor narrower ones have been rigorously evaluated in terms of their impact on the key outcomes of conception rates and sexually transmitted infection (STI) rates, in the UK or in other countries. Therefore, appropriate data were not found to support cost-effectiveness modelling. Low response rate to the questionnaire. Scotland, Wales and Northern Ireland were under-represented. Also, the distinction made in the questionnaire between 'general health' and 'sexual health' services did not prove robust. There is no single, dominant service model in the UK. The systematic review demonstrated that the evidence base for these services remains limited and uneven, and draws largely on US studies. Qualitative research is needed to develop robust process and outcome indicators for the evaluation of SLSHS/SBSHS in the UK. These indicators could then be used both in local evaluations, and in large, longitudinal studies of service effectiveness and cost-effectiveness. Future research should examine the impact of the differing types of services currently evolving in the UK, encompassing school-based and school-linked models, as well as models with and without medical practitioner involvement.
Choice and conditioned reinforcement.
Fantino, E; Freed, D; Preston, R A; Williams, W A
1991-01-01
A potential weakness of one formulation of delay-reduction theory is its failure to include a term for rate of conditioned reinforcement, that is, the rate at which the terminal-link stimuli occur in concurrent-chains schedules. The present studies assessed whether or not rate of conditioned reinforcement has an independent effect upon choice. Pigeons responded on either modified concurrent-chains schedules or on comparable concurrent-tandem schedules. The initial link was shortened on only one of two concurrent-chains schedules and on only one of two corresponding concurrent-tandem schedules. This manipulation increased rate of conditioned reinforcement sharply in the chain but not in the tandem schedule. According to a formulation of delay-reduction theory, when the outcomes chosen (the terminal links) are equal, as in Experiment 1, choice should depend only on rate of primary reinforcement; thus, choice should be equivalent for the tandem and chain schedules despite a large difference in rate of conditioned reinforcement. When the outcomes chosen are unequal, however, as in Experiment 2, choice should depend upon both rate of primary reinforcement and relative signaled delay reduction; thus, larger preferences should occur in the chain than in the tandem schedules. These predictions were confirmed, suggesting that increasing the rate of conditioned reinforcement on concurrent-chains schedules may have no independent effect on choice. PMID:2037826
Performance analysis of rain attenuation on earth-to-satellite microwave links design in Libya
NASA Astrophysics Data System (ADS)
Rafiqul Islam, Md; Hussein Budalal, Asma Ali; Habaebi, Mohamed H.; Badron, Khairayu; Fadzil Ismail, Ahmad
2017-11-01
Performances of earth-to-satellite microwave links operating in Ku, Ka, and V-bands are degraded by the environment and strongly attenuated by rain. Rain attenuation is the most significant consideration and challenge to design a reliable earth-to-satellite microwave links for these frequency bands. Hence, it is essential for satellite link designer to take into account rain fade margin accurately before system implementation. Rain rate is the main measured parameter to predict of rain attenuation. Rainfall statistical data measured and recorded in Libya for the period of 30 years are collected from 5 locations. The prediction methods require one minute integration time rain intensity. Therefore, collected data were analyzed and processed to convert into one-minute rain rate cumulative distribution in Libya. The model proposed by ITU-R is used to predict and investigate rain fade based on converted 1-minute rain rate data. Rain fade predicted at two locations are used for performance analysis in terms of link spectral efficiency and throughput. V-band downlink shows that 99.99% availability is possible in all the Southern part stations in Libya at 0.29 bps/Hz spectral efficiency and 20.74 Mbps throughput when 72 MHz transponder band width is used which is not feasible in Northern part. Results of this paper will be a very useful resource to design highly reliable earth-to-satellite communication links in Libya.
Chiu, Maria; Lebenbaum, Michael; Lam, Kelvin; Chong, Nelson; Azimaee, Mahmoud; Iron, Karey; Manuel, Doug; Guttmann, Astrid
2016-10-21
Ontario, the most populous province in Canada, has a universal healthcare system that routinely collects health administrative data on its 13 million legal residents that is used for health research. Record linkage has become a vital tool for this research by enriching this data with the Immigration, Refugees and Citizenship Canada Permanent Resident (IRCC-PR) database and the Office of the Registrar General's Vital Statistics-Death (ORG-VSD) registry. Our objectives were to estimate linkage rates and compare characteristics of individuals in the linked versus unlinked files. We used both deterministic and probabilistic linkage methods to link the IRCC-PR database (1985-2012) and ORG-VSD registry (1990-2012) to the Ontario's Registered Persons Database. Linkage rates were estimated and standardized differences were used to assess differences in socio-demographic and other characteristics between the linked and unlinked records. The overall linkage rates for the IRCC-PR database and ORG-VSD registry were 86.4 and 96.2 %, respectively. The majority (68.2 %) of the record linkages in IRCC-PR were achieved after three deterministic passes, 18.2 % were linked probabilistically, and 13.6 % were unlinked. Similarly the majority (79.8 %) of the record linkages in the ORG-VSD were linked using deterministic record linkage, 16.3 % were linked after probabilistic and manual review, and 3.9 % were unlinked. Unlinked and linked files were similar for most characteristics, such as age and marital status for IRCC-PR and sex and most causes of death for ORG-VSD. However, lower linkage rates were observed among people born in East Asia (78 %) in the IRCC-PR database and certain causes of death in the ORG-VSD registry, namely perinatal conditions (61.3 %) and congenital anomalies (81.3 %). The linkages of immigration and vital statistics data to existing population-based healthcare data in Ontario, Canada will enable many novel cross-sectional and longitudinal studies to be conducted. Analytic techniques to account for sub-optimal linkage rates may be required in studies of certain ethnic groups or certain causes of death among children and infants.
Harmsen, T; Jongerius, M C; van der Zwan, C W; Plantinga, A D; Kraaijeveld, C A; Berbers, G A
1992-01-01
A 50% neutralization enzyme immunoassay (N50-EIA) was compared with an indirect enzyme-linked immunosorbent assay (ELISA) for determining mumps virus antibodies in three consecutive serum samples from 138 children vaccinated with a live mumps vaccine at the age (in years) of 1.5. By the N50-EIA, most (132 of 138) preserum samples did not show neutralizing activity. Eight to 12 weeks after vaccination, 17 of the children were still negative, but only 7 remained so after 2.5 years, resulting in a seroconversion rate of 125 of 132 (95%). Over the same period, the neutralization geometric mean titer rose from 3.6 to 9.9. By an indirect ELISA, 128 of 138 preserum samples were found negative. The early and late postvaccination sera of 8 children were ELISA negative, resulting in a seroconversion rate of 120 of 128 (94%). Only two children remained seronegative by both methods. Seven of the late postvaccination serum samples yielded noncorresponding results, reflecting 95% correlation between both methods. Due to cross-reactivity with parainfluenza viruses, the ELISA proved to be less specific, but on the other hand, it showed a greater sensitivity than the N50-EIA. PMID:1500523
Strain rate effects on fracture behavior of Austempered Ductile Irons
NASA Astrophysics Data System (ADS)
Ruggiero, Andrew; Bonora, Nicola; Gentile, Domenico; Iannitti, Gianluca; Testa, Gabriel; Hörnqvist Colliander, Magnus; Masaggia, Stefano; Vettore, Federico
2017-06-01
Austempered Ductile Irons (ADIs), combining high strength, good ductility and low density, are candidates to be a suitable alternative to high-strength steels. Nevertheless, the concern about a low ductility under dynamic loads often leads designers to exclude cast irons for structural applications. However, results from dynamic tensile tests contradict this perception showing larger failure strain with respect to quasistatic data. The fracture behaviour of ADIs depends on damage mechanisms occurring in the spheroids of graphite, in the matrix and at their interface, with the matrix (ausferrite) consisting of acicular ferrite in carbon-enriched austenite. Here, a detailed microstructural analysis was performed on the ADI 1050-6 deformed under different conditions of strain rates, temperatures, and states of stress. Beside the smooth specimens used for uniaxial tensile tests, round notched bars to evaluate the ductility reduction with increasing stress triaxiality and tophat geometries to evaluate the propensity to shear localization and the associated microstructural alterations were tested. The aim of the work is to link the mechanical and fracture behavior of ADIs to the load condition through the microstructural modifications that occur for the corresponding deformation path.
Radhakrishnan, Srihari; Valenzuela, Nicole
2017-10-30
Sex chromosomes evolve differently from autosomes because natural selection acts distinctly on them given their reduced recombination and smaller population size. Various studies of sex-linked genes compared with different autosomal genes within species support these predictions. Here, we take a novel alternative approach by comparing the rate of evolution between subsets of genes that are sex-linked in selected reptiles/vertebrates and the same genes located in autosomes in other amniotes. We report for the first time the faster evolution of Z-linked genes in a turtle (the Chinese softshell turtle Pelodiscus sinensis) relative to autosomal orthologs in other taxa, including turtles with temperature-dependent sex determination (TSD). This faster rate was absent in its close relative, the spiny softshell turtle (Apalone spinifera), thus revealing important lineage effects, and was only surpassed by mammalian-X linked genes. In contrast, we found slower evolution of X-linked genes in the musk turtle Staurotypus triporcatus (XX/XY) and homologous Z-linked chicken genes. TSD lineages displayed overall faster sequence evolution than taxa with genotypic sex determination (GSD), ruling out global effects of GSD on molecular evolution beyond those by sex-linkage. Notably, results revealed a putative selective sweep around two turtle genes involved in vertebrate gonadogenesis (Pelodiscus-Z-linked Nf2 and Chrysemys-autosomal Tspan7). Our observations reveal important evolutionary changes at the gene level mediated by chromosomal context in turtles despite their low overall evolutionary rate and illuminate sex chromosome evolution by empirically testing expectations from theoretical models. Genome-wide analyses are warranted to test the generality and prevalence of the observed patterns. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
NASA Astrophysics Data System (ADS)
Gendron, Faustine; Bollori, Lucas; Villeneuve, Felix
2017-04-01
In France, at the end of the last year in high school, students of the scientific terminal class have written exams in all subjects they are studying, and in "Life and Earth's Sciences", they also have an Experimental Skills Testing in order to rate them in scientific approach. This one-hour evaluation is made of four steps: - During the first evaluation, students have to show that they are able to propose a scientific strategy connected to a scientific problem. - During the second evaluation, they have to experiment. - During the third evaluation, they have to introduce their results. - During the last evaluation, they have to deduce and conclude. The final testing take place at the end of May, but during all the school year, teachers have to train their students, and it's impossible to make them work on real subjects. Therefore, it's necessary to produce new subjects every year. Linked to a fall school in Sicily last October, my colleagues and I have decided to create a new Experimental Skills Test to use new examples and illustrate subduction in the Mediterranean Sea with Aeolian Islands. We would like to make our pupils understand what the Aeolian volcanism is due to, by using information, equipment and software, etc. we have in our classrooms in our high school. Since we have found several ways for our students to prove that the Aeolian Islands are linked to a subduction zone, we have decided, following our research, to divide the new experimental skills testing in three different tests, in order to make students train on most of the equipment and then to share their results to produce a collaborative final work.
Controller evaluation of initial terminal data link ATC services : mini study 3 : final report
DOT National Transportation Integrated Search
1992-12-01
This report documents the third Federal Aviation Administration (FAA) controller : evaluation of an initial group of four terminal air traffic control (ATC) : services and functions which are under development for implementation on a Data : Link air-...
Evaluation of Hierarchical Clustering Algorithms for Document Datasets
2002-06-03
link, complete-link, and group average ( UPGMA )) and a new set of merging criteria derived from the six partitional criterion functions. Overall, we...used the single-link, complete-link, and UPGMA schemes, as well as, the various partitional criterion functions described in Section 3.1. The single-link...other (complete-link approach). The UPGMA scheme [16] (also known as group average) overcomes these problems by measuring the similarity of two clusters
Photodynamic therapy with 3-(1'-hexyloxyethyl) pyropheophorbide a for cancer of the oral cavity.
Rigual, Nestor; Shafirstein, Gal; Cooper, Michele T; Baumann, Heinz; Bellnier, David A; Sunar, Ulas; Tracy, Erin C; Rohrbach, Daniel J; Wilding, Gregory; Tan, Wei; Sullivan, Maureen; Merzianu, Mihai; Henderson, Barbara W
2013-12-01
The primary objective was to evaluate safety of 3-(1'-hexyloxyethyl)pyropheophorbide-a (HPPH) photodynamic therapy (HPPH-PDT) for dysplasia and early squamous cell carcinoma of the head and neck (HNSCC). Secondary objectives were the assessment of treatment response and reporters for an effective PDT reaction. Patients with histologically proven oral dysplasia, carcinoma in situ, or early-stage HNSCC were enrolled in two sequentially conducted dose escalation studies with an expanded cohort at the highest dose level. These studies used an HPPH dose of 4 mg/m(2) and light doses from 50 to 140 J/cm(2). Pathologic tumor responses were assessed at 3 months. Clinical follow up range was 5 to 40 months. PDT induced cross-linking of STAT3 were assessed as potential indicators of PDT effective reaction. Forty patients received HPPH-PDT. Common adverse events were pain and treatment site edema. Biopsy proven complete response rates were 46% for dysplasia and carcinoma in situ and 82% for squamous cell carcinomas (SCC) lesions at 140 J/cm(2). The responses in the carcinoma in situ/dysplasia cohort are not durable. The PDT-induced STAT3 cross-links is significantly higher (P = 0.0033) in SCC than in carcinoma in situ/dysplasia for all light doses. HPPH-PDT is safe for the treatment of carcinoma in situ/dysplasia and early-stage cancer of the oral cavity. Early-stage oral HNSCC seems to respond better to HPPH-PDT in comparison with premalignant lesions. The degree of STAT3 cross-linking is a significant reporter to evaluate HPPH-PDT-mediated photoreaction. ©2013 AACR.
Ido, Moges Seyoum; Bayakly, Rana; Frankel, Michael; Lyn, Rodney; Okosun, Ike S
2015-01-15
Tracking the vital status of stroke patients through death data is one approach to assessing the impact of quality improvement in stroke care. We assessed the feasibility of linking Georgia hospital discharge data with mortality data to evaluate the effect of participation in the Georgia Coverdell Acute Stroke Registry on survival rates among acute ischemic stroke patients. Multistage probabilistic matching, using a fine-grained record integration and linkage software program and combinations of key variables, was used to link Georgia hospital discharge data for 2005 through 2009 with mortality data for 2006 through 2010. Data from patients admitted with principal diagnoses of acute ischemic stroke were analyzed by using the extended Cox proportional hazard model. The survival times of patients cared for by hospitals participating in the stroke registry and of those treated at nonparticipating hospitals were compared. Average age of the 50,579 patients analyzed was 69 years, and 56% of patients were treated in Georgia Coverdell Acute Stroke Registry hospitals. Thirty-day and 365-day mortality after first admission for stroke were 8.1% and 18.5%, respectively. Patients treated at nonparticipating facilities had a hazard ratio for death of 1.14 (95% confidence interval, 1.03-1.26; P = .01) after the first week of admission compared with patients cared for by hospitals participating in the registry. Hospital discharge data can be linked with death data to assess the impact of clinical-level or community-level chronic disease control initiatives. Hospitals need to undertake quality improvement activities for a better patient outcome.
Heywood, Wendy; Lyons, Anthony
2017-07-01
This study investigates the impact of HIV diagnosis on subjective social status and if changes are linked to health outcomes. Two measures of subjective social status, socio-economic and standing in the community were examined in 342 Australian HIV-positive gay men in 2014. Participants recalled ratings at diagnosis were compared with current ratings. Self-reported mental (psychological distress, self-esteem, positive mental health and satisfaction with life) and physical health (self-rated health, CD4 count, viral load). Half of the participants reported improvements in subjective socio-economic status (59%) or standing in the community (52%) since diagnosis, yet one quarter reported socio-economic status (25%) or standing in the community had decreased (23%). Increases in either measure of subjective social status were linked to higher self-esteem, positive mental health, satisfaction with life and better self-rated health. Decreases in subjective social status, however, were strongly linked to poorer outcomes on all mental health measures. Decreases in standing in the community were also associated with poorer physical self-rated health. Most participants reported their subjective social status were the same or better since diagnosis. Changes in subjective social status following diagnosis were strongly linked to mental health outcomes. Those who reported a decrease in subjective social status were particularly vulnerable to mental health problems.
Battaile, Brian C; Trites, Andrew W
2013-01-01
We propose a method to model the physiological link between somatic survival and reproductive output that reduces the number of parameters that need to be estimated by models designed to determine combinations of birth and death rates that produce historic counts of animal populations. We applied our Reproduction and Somatic Survival Linked (RSSL) method to the population counts of three species of North Pacific pinnipeds (harbor seals, Phoca vitulina richardii (Gray, 1864); northern fur seals, Callorhinus ursinus (L., 1758); and Steller sea lions, Eumetopias jubatus (Schreber, 1776))--and found our model outperformed traditional models when fitting vital rates to common types of limited datasets, such as those from counts of pups and adults. However, our model did not perform as well when these basic counts of animals were augmented with additional observations of ratios of juveniles to total non-pups. In this case, the failure of the ratios to improve model performance may indicate that the relationship between survival and reproduction is redefined or disassociated as populations change over time or that the ratio of juveniles to total non-pups is not a meaningful index of vital rates. Overall, our RSSL models show advantages to linking survival and reproduction within models to estimate the vital rates of pinnipeds and other species that have limited time-series of counts.
ERIC Educational Resources Information Center
Agbaria, Qutaiba Ali
2013-01-01
The purpose of this study is to examine the link between learning motivation among teaching trainees and self-efficacy and the rate of participation in choosing the profession of teaching. The main assumptions: There will be a clear positive link between the rate of self-efficacy of students and academic motivation, with its various elements.…
Association Between NCAP Ratings and Real-World Rear Seat Occupant Risk of Injury.
Metzger, Kristina B; Gruschow, Siobhan; Durbin, Dennis R; Curry, Allison E
2015-01-01
Several studies have evaluated the correlation between U.S. or Euro New Car Assessment Program (NCAP) ratings and injury risk to front seat occupants, in particular driver injuries. Conversely, little is known about whether NCAP 5-star ratings predict real-world risk of injury to restrained rear seat occupants. The NHTSA has identified rear seat occupant protection as a specific area under consideration for improvements to its NCAP. In order to inform NHTSA's efforts, we examined how NCAP's current 5-star rating system predicts risk of moderate or greater injury among restrained rear seat occupants in real-world crashes. We identified crash-involved vehicles, model year 2004-2013, in NASS-CDS (2003-2012) with known make and model and nonmissing occupant information. We manually matched these vehicles to their NCAP star ratings using data on make, model, model year, body type, and other identifying information. The resultant linked NASS-CDS and NCAP database was analyzed to examine associations between vehicle ratings and rear seat occupant injury risk; risk to front seat occupants was also estimated for comparison. Data were limited to restrained occupants and occupant injuries were defined as any injury with a maximum Abbreviated Injury Scale (AIS) score of 2 or greater. We linked 95% of vehicles in NASS-CDS to a specific vehicle in NCAP. The 18,218 vehicles represented an estimated 6 million vehicles with over 9 million occupants. Rear seat passengers accounted for 12.4% of restrained occupants. The risk of injury in all crashes for restrained rear seat occupants was lower in vehicles with a 5-star driver rating in frontal impact tests (1.4%) than with 4 or fewer stars (2.6%, P =.015); results were similar for the frontal impact passenger rating (1.3% vs. 2.4%, P =.024). Conversely, side impact driver and passenger crash tests were not associated with rear seat occupant injury risk (driver test: 1.7% for 5-star vs. 1.8% for 1-4 stars; passenger test: 1.6% for 5 stars vs 1.8% for 1-4 stars). Current frontal impact test procedures provide some degree of discrimination in real-world rear seat injury risk among vehicles with 5 compared to fewer than 5 stars. However, there is no evidence that vehicles with a 5-star side impact passenger rating, which is the only crash test procedure to include an anthropomorphic test dummy (ATD) in the rear, demonstrate lower risks of injury in the rear than vehicles with fewer than 5 stars. These results support prioritizing modifications to the NCAP program that specifically evaluate rear seat injury risk to restrained occupants of all ages.
High rate data acquisition from Spacelab/Shuttle
NASA Technical Reports Server (NTRS)
Coffey, R.
1978-01-01
The need for high data rates from a variety of experiments on Spacelab/Shuttle produced the requirement for the Spacelab High Rate Multiplexer/Demultiplexer system. This system acquires serial digital data at asynchronous bit rates from up to sixteen experiments, two data buses, three voice links, two tape recorders, and a universal time channel. Experiment data rates may vary from 200 bps to 16 Mbps while recorded data rates range from 250 Kbps to 32 Mbps. The High Rate Multiplexer (HRM) accepts these data inputs and forms a serial PCM output at flexible rates up to 48 Mbps. This PCM output is transmitted to ground by a Ku-Band RF link via the Tracking and Data Relay Satellite System (TDRSS) or recorded on board for delayed transmission. A complementary ground based High Rate Demultiplexer (HRDM) accepts and demultiplexes the composite PCM data at ground processing locations.
Development and evaluation of polyvinyl-alcohol blend polymer films as battery separators
NASA Technical Reports Server (NTRS)
Manzo, M. A.
1982-01-01
Several dialdehydes and epoxies were evaluated for their suitability as cross-linkers. Optium concentrations of several cross-linking reagents were determined. A two-step method of cross-linking, which involves treatment of the film in an acid or acid periodate bath, was investigated and dropped in favor of a one-step method in which the acid catalyst, which initiates cross-linking, is added to the PVA - cross-linker solution before casting. The cross-linking was thus achieved during the drying step. This one-step method was much more adaptable to commercial processing. Cross-linked films were characterized as alkaline battery separators. Films were prepared in the lab and tested in cells in order to evaluate the effect of film composition and a number of processing parameters on cell performance. These tests were conducted in order to provide a broader data base from which to select optimum processing parameters. Results of the separator screening tests and the cell tests are discussed.
Evaluation of Dynamic Channel and Power Assignment for Cognitive Networks
DOE Office of Scientific and Technical Information (OSTI.GOV)
Syed A. Ahmad; Umesh Shukla; Ryan E. Irwin
2011-03-01
In this paper, we develop a unifying optimization formulation to describe the Dynamic Channel and Power Assignment (DCPA) problem and evaluation method for comparing DCPA algorithms. DCPA refers to the allocation of transmit power and frequency channels to links in a cognitive network so as to maximize the total number of feasible links while minimizing the aggregate transmit power. We apply our evaluation method to five algorithms representative of DCPA used in literature. This comparison illustrates the tradeoffs between control modes (centralized versus distributed) and channel/power assignment techniques. We estimate the complexity of each algorithm. Through simulations, we evaluate themore » effectiveness of the algorithms in achieving feasible link allocations in the network, as well as their power efficiency. Our results indicate that, when few channels are available, the effectiveness of all algorithms is comparable and thus the one with smallest complexity should be selected. The Least Interfering Channel and Iterative Power Assignment (LICIPA) algorithm does not require cross-link gain information, has the overall lowest run time, and highest feasibility ratio of all the distributed algorithms; however, this comes at a cost of higher average power per link.« less
Collagen telopeptides (cross-linking sites) play a role in collagen gel lattice contraction
NASA Technical Reports Server (NTRS)
Woodley, D. T.; Yamauchi, M.; Wynn, K. C.; Mechanic, G.; Briggaman, R. A.
1991-01-01
Solubilized interstitial collagens will form a fibrillar, gel-like lattice when brought to physiologic conditions. In the presence of human dermal fibroblasts the collagen lattice will contract. The rate of contraction can be determined by computer-assisted planemetry. The mechanisms involved in contraction are as yet unknown. Using this system it was found that the rate of contraction was markedly decreased when collagen lacking telopeptides was substituted for native collagen. Histidinohydroxylysinonorleucine (HHL) is a major stable trifunctional collagen cross-link in mature skin that involves a carboxyl terminal, telopeptide site 16c, the sixteenth amino acid residue from the carboxy terminal of the telopeptide region of alpha 1 (I) in type I collagen. Little, if any, HHL was present in native, purified, reconstituted, soluble collagen fibrils from 1% acetic acid-extracted 2-year-old bovine skin. In contrast, HHL cross-links were present (0.22 moles of cross-link per mole of collagen) in lattices of the same collagen contracted by fibroblasts. However, rat tail tendon does not contain HHL cross-links, and collagen lattices made of rat tail tendon collagen are capable of contraction. This suggests that telopeptide sites, and not mature HHL cross-links per se, are essential for fibroblasts to contract collagen lattices. Beta-aminopropionitrile fumarate (BAPN), a potent lathyrogen that perturbs collagen cross-linking by inhibition of lysyl oxidase, also inhibited the rate of lattice cell contraction in lattices composed of native collagen. However, the concentrations of BAPN that were necessary to inhibit the contraction of collagen lattices also inhibited fibroblast growth suggestive of cellular toxicity. In accordance with other studies, we found no inhibition of the rate of lattice contraction when fibronectin-depleted serum was used. Electron microscopy of contracted gels revealed typical collagen fibers with a characteristic axial periodicity. The data provide evidence that collagen telopeptide sites play a role in collagen gel lattice contraction.
Concordance of vitamin D peripheral levels in infertile couples' partners.
Paffoni, Alessio; Ferrari, Stefania; Mangiarini, Alice; Noli, Stefania; Bulfoni, Alessandro; Vigano, Paola; Parazzini, Fabio; Somigliana, Edgardo
2017-08-01
A large number of evidence supports the role of vitamin D insufficiency in both women and men infertility. However, no studies have evaluated the rate of concordance of vitamin D status between the partners. This finding might open new scenarios in the interpretation of the available data linking vitamin D insufficiency and infertility. In the present cross-sectional study, 103 consecutive infertile couples were recruited between April and May 2014. Both partners concomitantly provided a serum sample for the assessment of 25-hydroxy-vitamin D [25-(OH)-D]. Vitamin D insufficiency was defined as serum 25-(OH)-D <20 ng/ml. One hundred-fifty subjects (73 women and 77 males) were 25-(OH)-D insufficient, corresponding to a rate of 73%. Overall, concordance was observed in 73 couples (71%), thus higher than the expected 61% (0.732 + 0.272) based on chance (p = 0.007). The Pearson coefficient of correlation R2 between the partners of the couples was 0.52 (p < 0.001). No statistically significant differences emerged when evaluating the rate of 25-(OH)-D insufficiency according to the causes of infertility. Serum 25-(OH)-D correlates within the partners of infertile couples. Further evidence is warranted to determine the clinical relevance and possible clinical applications of this finding.
Porting Initiation and Failure into Linked CHEETAH
NASA Astrophysics Data System (ADS)
Souers, Clark; Vitello, Peter
2007-06-01
Linked CHEETAH is a thermo-chemical code coupled to a 2-D hydrocode. Initially, a quadratic-pressure dependent kinetic rate was used, which worked well in modeling prompt detonation of explosives of large size, but does not work on other aspects of explosive behavior. The variable-pressure Tarantula reactive flow rate model was developed with JWL++ in order to also describe failure and initiation, and we have moved this model into Linked CHEETAH. The model works by turning on only above a pressure threshold, where a slow turn-on creates initiation. At a higher pressure, the rate suddenly leaps to a large value over a small pressure range. A slowly failing cylinder will see a rapidly declining rate, which pushes it quickly into failure. At a high pressure, the detonation rate is constant. A sequential validation procedure is used, which includes metal-confined cylinders, rate-sticks, corner-turning, initiation and threshold, gap tests and air gaps. The size (diameter) effect is central to the calibration. This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.
Comparative study of signalling methods for high-speed backplane transceiver
NASA Astrophysics Data System (ADS)
Wu, Kejun
2017-11-01
A combined analysis of transient simulation and statistical method is proposed for comparative study of signalling methods applied to high-speed backplane transceivers. This method enables fast and accurate signal-to-noise ratio and symbol error rate estimation of a serial link based on a four-dimension design space, including channel characteristics, noise scenarios, equalisation schemes, and signalling methods. The proposed combined analysis method chooses an efficient sampling size for performance evaluation. A comparative study of non-return-to-zero (NRZ), PAM-4, and four-phase shifted sinusoid symbol (PSS-4) using parameterised behaviour-level simulation shows PAM-4 and PSS-4 has substantial advantages over conventional NRZ in most of the cases. A comparison between PAM-4 and PSS-4 shows PAM-4 gets significant bit error rate degradation when noise level is enhanced.
Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk
Ramirez-Villegas, Juan F.; Lam-Espinosa, Eric; Ramirez-Moreno, David F.; Calvo-Echeverry, Paulo C.; Agredo-Rodriguez, Wilfredo
2011-01-01
Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis. PMID:21386966
Fabian, M Patricia; Stout, Natasha K; Adamkiewicz, Gary; Geggel, Amelia; Ren, Cizao; Sandel, Megan; Levy, Jonathan I
2012-09-18
In the United States, asthma is the most common chronic disease of childhood across all socioeconomic classes and is the most frequent cause of hospitalization among children. Asthma exacerbations have been associated with exposure to residential indoor environmental stressors such as allergens and air pollutants as well as numerous additional factors. Simulation modeling is a valuable tool that can be used to evaluate interventions for complex multifactorial diseases such as asthma but in spite of its flexibility and applicability, modeling applications in either environmental exposures or asthma have been limited to date. We designed a discrete event simulation model to study the effect of environmental factors on asthma exacerbations in school-age children living in low-income multi-family housing. Model outcomes include asthma symptoms, medication use, hospitalizations, and emergency room visits. Environmental factors were linked to percent predicted forced expiratory volume in 1 second (FEV1%), which in turn was linked to risk equations for each outcome. Exposures affecting FEV1% included indoor and outdoor sources of NO2 and PM2.5, cockroach allergen, and dampness as a proxy for mold. Model design parameters and equations are described in detail. We evaluated the model by simulating 50,000 children over 10 years and showed that pollutant concentrations and health outcome rates are comparable to values reported in the literature. In an application example, we simulated what would happen if the kitchen and bathroom exhaust fans were improved for the entire cohort, and showed reductions in pollutant concentrations and healthcare utilization rates. We describe the design and evaluation of a discrete event simulation model of pediatric asthma for children living in low-income multi-family housing. Our model simulates the effect of environmental factors (combustion pollutants and allergens), medication compliance, seasonality, and medical history on asthma outcomes (symptom-days, medication use, hospitalizations, and emergency room visits). The model can be used to evaluate building interventions and green building construction practices on pollutant concentrations, energy savings, and asthma healthcare utilization costs, and demonstrates the value of a simulation approach for studying complex diseases such as asthma.
The effects of indoor environmental exposures on pediatric asthma: a discrete event simulation model
2012-01-01
Background In the United States, asthma is the most common chronic disease of childhood across all socioeconomic classes and is the most frequent cause of hospitalization among children. Asthma exacerbations have been associated with exposure to residential indoor environmental stressors such as allergens and air pollutants as well as numerous additional factors. Simulation modeling is a valuable tool that can be used to evaluate interventions for complex multifactorial diseases such as asthma but in spite of its flexibility and applicability, modeling applications in either environmental exposures or asthma have been limited to date. Methods We designed a discrete event simulation model to study the effect of environmental factors on asthma exacerbations in school-age children living in low-income multi-family housing. Model outcomes include asthma symptoms, medication use, hospitalizations, and emergency room visits. Environmental factors were linked to percent predicted forced expiratory volume in 1 second (FEV1%), which in turn was linked to risk equations for each outcome. Exposures affecting FEV1% included indoor and outdoor sources of NO2 and PM2.5, cockroach allergen, and dampness as a proxy for mold. Results Model design parameters and equations are described in detail. We evaluated the model by simulating 50,000 children over 10 years and showed that pollutant concentrations and health outcome rates are comparable to values reported in the literature. In an application example, we simulated what would happen if the kitchen and bathroom exhaust fans were improved for the entire cohort, and showed reductions in pollutant concentrations and healthcare utilization rates. Conclusions We describe the design and evaluation of a discrete event simulation model of pediatric asthma for children living in low-income multi-family housing. Our model simulates the effect of environmental factors (combustion pollutants and allergens), medication compliance, seasonality, and medical history on asthma outcomes (symptom-days, medication use, hospitalizations, and emergency room visits). The model can be used to evaluate building interventions and green building construction practices on pollutant concentrations, energy savings, and asthma healthcare utilization costs, and demonstrates the value of a simulation approach for studying complex diseases such as asthma. PMID:22989068
High rate of translocation-based gene birth on the Drosophila Y chromosome.
Tobler, Ray; Nolte, Viola; Schlötterer, Christian
2017-10-31
The Y chromosome is a unique genetic environment defined by a lack of recombination and male-limited inheritance. The Drosophila Y chromosome has been gradually acquiring genes from the rest of the genome, with only seven Y-linked genes being gained over the past 63 million years (0.12 gene gains per million years). Using a next-generation sequencing (NGS)-powered genomic scan, we show that gene transfers to the Y chromosome are much more common than previously suspected: at least 25 have arisen across three Drosophila species over the past 5.4 million years (1.67 per million years for each lineage). The gene transfer rate is significantly lower in Drosophila melanogaster than in the Drosophila simulans clade, primarily due to Y-linked retrotranspositions being significantly more common in the latter. Despite all Y-linked gene transfers being evolutionarily recent (<1 million years old), only three showed evidence for purifying selection ( ω ≤ 0.14). Thus, although the resulting Y-linked functional gene acquisition rate (0.25 new genes per million years) is double the longer-term estimate, the fate of most new Y-linked genes is defined by rapid degeneration and pseudogenization. Our results show that Y-linked gene traffic, and the molecular mechanisms governing these transfers, can diverge rapidly between species, revealing the Drosophila Y chromosome to be more dynamic than previously appreciated. Our analytical method provides a powerful means to identify Y-linked gene transfers and will help illuminate the evolutionary dynamics of the Y chromosome in Drosophila and other species. Copyright © 2017 the Author(s). Published by PNAS.
ImNet: a fiber optic network with multistar topology for high-speed data transmission
NASA Astrophysics Data System (ADS)
Vossebuerger, F.; Keizers, Andreas; Soederman, N.; Meyer-Ebrecht, Dietrich
1993-10-01
ImNet is a fiber-optic local area network, which has been developed for high speed image communication in Picture Archiving and Communication Systems (PACS). A comprehensive analysis of image communication requirements in hospitals led to the conclusion that there is a need for networks which are optimized for the transmission of large datafiles. ImNet is optimized for this application in contrast to current-state LANs. ImNet consists of two elements: a link module and a switch module. The point-to-point link module can be up to 4 km by using fiber optic cable. For short distances up to 100 m a cheaper module using shielded twisted pair cable is available. The link module works bi-directionally and handles all protocols up to OSI-Level 3. The data rate per link is up to 140 MBit/s (clock rate 175 MHz). The switch module consists of the control unit and the cross-point-switch array. The array has up to fourteen interfaces for link modules. Up to fourteen data transfers each with a maximal transfer rate of 400 MBit/s can be handled at the same time. Thereby the maximal throughput of a switch module is 5.6 GBit/s. Out of these modules a multi-star network can be built i.e., an arbitrary tree structure of stars. This topology allows multiple transmissions at the same time as long as they do not require identical links. Therefore the overall throughput of ImNet can be a multiple of the datarate per link.
Levine, Stephen Z; Leucht, Stefan
2013-04-01
The treatment and measurement of negative symptoms are currently at issue in schizophrenia, but the clinical meaning of symptom severity and change is unclear. To offer a clinically meaningful interpretation of severity and change scores on the Scale for the Assessment of Negative Symptoms (SANS). Patients were intention-to-treat participants (n=383) in two double-blind randomized placebo-controlled clinical trials that compared amisulpride with placebo for the treatment of predominant negative symptoms. Equipercentile linking was used to examine extrapolation from (a) CGI-S to SANS severity ratings, and (b) CGI-I to SANS percentage change (n=383). Linking was conducted at baseline, 8-14 days, 28-30 days, and 56-60 days of the trials. Across visits, CGI-S ratings of 'not ill' linked to SANS scores of 0-13, and ranged to 'extreme' ratings that linked to SANS scores of 102-105. The relationship between the CGI-S and the SANS severity scores assumed a linear trend (1=0-13, 2=15-56, 3=37-61, 4=49-66, 5=63-75, 6=79-89, 7=102-105). Similarly the relationship between CGI-I ratings and SANS percentage change followed a linear trend. For instance, CGI-I ratings of 'very much improved' were linked to SANS percent changes of -90 to -67, 'much improved' to -50 to -42, and 'minimally improved' to -21 to -13. The current results uniquely contribute to the debate surrounding negative symptoms by providing clinical meaning to SANS severity and change scores and so offer direction regarding clinically meaningful response cut-off scores to guide treatment targets of predominant negative symptoms. Copyright © 2013 Elsevier B.V. All rights reserved.
Pasco, Paul Matthew D; Jamora, Roland Dominic G; Rosales, Raymond L; Diesta, Cid Czarina E; Ng, Arlene R; Teleg, Rosalia A; Go, Criscely L; Lee, Lillian; Fernandez, Hubert H
2017-01-01
X-linked dystonia-parkinsonism(XDP) is a neurodegenerative disorder endemic to the Philippines. A rating scale was developed by the authors under the guidance of the Movement Disorder Society of the Philippines (MDSP) to assess XDP severity and progression, functional impact, and response to treatment in future clinical trials. Our main objective was to validate our new scale, the XDP-MDSP scale. The initial validation process included pragmatic testing to XDP patients followed by a modified Delphi procedure with an international advisory panel of dystonia, parkinsonism and scale development experts. Pearson correlation was used to assess construct validity of our new scale versus the assess construct validity of our new scale versus standard dystonia, parkinsonism, non-motor and functional scales; and also to assess divergent validity against behavioral and cognitive scales. The 37-item XDP-MDSP scale has five parts: I-dystonia, II-parkinsonism, III-non-motor features, IV-ADL, and V-global impression. After initial validation, the scale was administered to 204 XDP patients. Inter-domain correlation for the first four parts was acceptable. The correlation between these domains and the global rating was slightly lower. Correlations between Parts I, II, III, and IV versus standard dystonia, parkinsonism, non-motor and functional scales were acceptable with values ranging from 0.323 to 0.428. For divergent validity, a significant correlation was seen with behavioral scales. No significant correlation was noted with the cognitive scale. The proposed XDP-MDSP scale is internally valid but the global rating subscale may need to be modified or eliminated. While there is convergent validity, divergent validation was successful only on cognitive and not behavioral scales. The frequent co-occurrence of anxiety and depression, and its effect on the motor and functional state, may explain this finding.
45 Km Horizontal Path Optical Link Experiment
NASA Technical Reports Server (NTRS)
Biswas, A.; Ceniceros, J.; Novak, M.; Jeganathan, M.; Portillo, A.; Erickson, D.; Depew, J.; Sanii, B.; Lesh, J. R.
2000-01-01
Mountain-top to mountain-top optical link experiments have been initiated at JPL, in order to perform a systems level evaluation of optical communications. Progress made so far is reported. ne NASA, JPL developed optical communications demonstrator (OCD) is used to transmit a laser signal from Strawberry Peak (SP), located in the San Bernadino mountains of California. This laser beam is received by a 0.6 m aperture telescope at JPL's Table Mountain Facility (TMF), located in Wrightwood, California. The optical link is bi-directional with the TMF telescope transmitting a continuous 4-wave (cw) 780 run beacon and the OCD sending back a 840 nm, 100 - 500 Mbps pseudo noise (PN) modulated, laser beam. The optical link path is at an average altitude of 2 km above sea level, covers a range of 46.8 km and provides an atmospheric channel equivalent to approx. 4 air masses. Average received power measured at either end fall well within the uncertainties predicted by link analysis. The reduction in normalized intensity variance (sigma(sup 2, sub I)) for the 4-beam beacon, compared to each individual beam, at SP, was from approx. 0.68 to 0.22. With some allowance for intra-beam mis-alignment, this is consistent with incoherent averaging. The sigma(sup2, sub I) measured at TMF approx. 0.43 +/- 0.22 exceeded the expected aperture averaged value of less than 0.1, probably because of beam wander. The focused spot sizes of approx. 162 +/- 6 microns at the TMF Coude and approx. 64 +/- 3 microns on the OCD compare to the predicted size range of 52 - 172 microns and 57 - 93 microns, respectively. This is consistent with 4 - 5 arcsec of atmospheric "seeing". The preliminary evaluation of OCD's fine tracking indicates that the uncompensated tracking error is approx. 3.3 micro rad compared to approx. 1.7 micro rad observed in the laboratory. Fine tracking performance was intermittent, primarily due to beacon fades on the OCD tracking sensor. The best bit error rates observed while tracking worked were 1E-5 to 1E-6.
Low validity of Google Trends for behavioral forecasting of national suicide rates
Niederkrotenthaler, Thomas; Till, Benedikt; Ajdacic-Gross, Vladeta; Voracek, Martin
2017-01-01
Recent research suggests that search volumes of the most popular search engine worldwide, Google, provided via Google Trends, could be associated with national suicide rates in the USA, UK, and some Asian countries. However, search volumes have mostly been studied in an ad hoc fashion, without controls for spurious associations. This study evaluated the validity and utility of Google Trends search volumes for behavioral forecasting of suicide rates in the USA, Germany, Austria, and Switzerland. Suicide-related search terms were systematically collected and respective Google Trends search volumes evaluated for availability. Time spans covered 2004 to 2010 (USA, Switzerland) and 2004 to 2012 (Germany, Austria). Temporal associations of search volumes and suicide rates were investigated with time-series analyses that rigorously controlled for spurious associations. The number and reliability of analyzable search volume data increased with country size. Search volumes showed various temporal associations with suicide rates. However, associations differed both across and within countries and mostly followed no discernable patterns. The total number of significant associations roughly matched the number of expected Type I errors. These results suggest that the validity of Google Trends search volumes for behavioral forecasting of national suicide rates is low. The utility and validity of search volumes for the forecasting of suicide rates depend on two key assumptions (“the population that conducts searches consists mostly of individuals with suicidal ideation”, “suicide-related search behavior is strongly linked with suicidal behavior”). We discuss strands of evidence that these two assumptions are likely not met. Implications for future research with Google Trends in the context of suicide research are also discussed. PMID:28813490
Local Equation of State for Protons, and Implications for Proton Heating in the Solar Wind.
NASA Astrophysics Data System (ADS)
Zaslavsky, A.; Maksimovic, M.; Kasper, J. C.
2017-12-01
The solar wind protons temperature is observed to decrease with distance to the Sun at a slower rate than expected from an adiabatic expansion law: the protons are therefore said to be heated. This observation raises the question of the evaluation of the heating rate, and the question of the heat source.These questions have been investigated by previous authors by gathering proton data on various distances to the Sun, using spacecraft as Helios or Ulysses, and then computing the radial derivative of the proton temperature in order to obtain a heating rate from the internal energy equation. The problem of such an approach is the computation of the radial derivative of the temperature profile, for which uncertainties are very large, given the dispersion of the temperatures measured at a given distance.An alternative approach, that we develop in this paper, consists in looking for an equation of state that links locally the pressure (or temperature) to the mass density. If such a relation exists then one can evaluate the proton heating rate on a local basis, without having any space derivative to compute.Here we use several years of STEREO and WIND proton data to search for polytropic equation of state. We show that such relationships are indeed a good approximation in given solar wind's velocity intervals and deduce the associated protons heating rates as a function of solar wind's speed. The obtained heating rates are shown to scale from around 1 kW/kg in the slow wind to around 10 kW/kg in the fast wind, in remarkable agreement with the rate of energy observed by previous authors to cascade in solar wind's MHD turbulence at 1 AU. These results therefore support the idea of proton turbulent heating in the solar wind.
A Glider-Assisted Link Disruption Restoration Mechanism in Underwater Acoustic Sensor Networks.
Jin, Zhigang; Wang, Ning; Su, Yishan; Yang, Qiuling
2018-02-07
Underwater acoustic sensor networks (UASNs) have become a hot research topic. In UASNs, nodes can be affected by ocean currents and external forces, which could result in sudden link disruption. Therefore, designing a flexible and efficient link disruption restoration mechanism to ensure the network connectivity is a challenge. In the paper, we propose a glider-assisted restoration mechanism which includes link disruption recognition and related link restoring mechanism. In the link disruption recognition mechanism, the cluster heads collect the link disruption information and then schedule gliders acting as relay nodes to restore the disrupted link. Considering the glider's sawtooth motion, we design a relay location optimization algorithm with a consideration of both the glider's trajectory and acoustic channel attenuation model. The utility function is established by minimizing the channel attenuation and the optimal location of glider is solved by a multiplier method. The glider-assisted restoration mechanism can greatly improve the packet delivery rate and reduce the communication energy consumption and it is more general for the restoration of different link disruption scenarios. The simulation results show that glider-assisted restoration mechanism can improve the delivery rate of data packets by 15-33% compared with cooperative opportunistic routing (OVAR), the hop-by-hop vector-based forwarding (HH-VBF) and the vector based forward (VBF) methods, and reduce communication energy consumption by 20-58% for a typical network's setting.
A Glider-Assisted Link Disruption Restoration Mechanism in Underwater Acoustic Sensor Networks
Wang, Ning; Su, Yishan; Yang, Qiuling
2018-01-01
Underwater acoustic sensor networks (UASNs) have become a hot research topic. In UASNs, nodes can be affected by ocean currents and external forces, which could result in sudden link disruption. Therefore, designing a flexible and efficient link disruption restoration mechanism to ensure the network connectivity is a challenge. In the paper, we propose a glider-assisted restoration mechanism which includes link disruption recognition and related link restoring mechanism. In the link disruption recognition mechanism, the cluster heads collect the link disruption information and then schedule gliders acting as relay nodes to restore the disrupted link. Considering the glider’s sawtooth motion, we design a relay location optimization algorithm with a consideration of both the glider’s trajectory and acoustic channel attenuation model. The utility function is established by minimizing the channel attenuation and the optimal location of glider is solved by a multiplier method. The glider-assisted restoration mechanism can greatly improve the packet delivery rate and reduce the communication energy consumption and it is more general for the restoration of different link disruption scenarios. The simulation results show that glider-assisted restoration mechanism can improve the delivery rate of data packets by 15–33% compared with cooperative opportunistic routing (OVAR), the hop-by-hop vector-based forwarding (HH-VBF) and the vector based forward (VBF) methods, and reduce communication energy consumption by 20–58% for a typical network’s setting. PMID:29414898
The contribution of preterm birth to the Black-White infant mortality gap, 1990 and 2000.
Schempf, Ashley H; Branum, Amy M; Lukacs, Susan L; Schoendorf, Kenneth C
2007-07-01
We evaluated whether the decline of the racial disparity in preterm birth during the last decade was commensurate with a decline in the contribution of preterm birth to the infant mortality gap. We used linked files of 1990 and 2000 data on US infant births and deaths to partition the gap between Black and White infant mortality rates into differences in the (1) distribution of gestational age and (2) gestational age-specific mortality rates. Between 1990 and 2000, the Black-White infant mortality rate ratio did not change significantly (2.3 vs 2.4). Excess deaths among preterm Black infants accounted for nearly 80% of the Black-White infant mortality gap in both 1990 and 2000. The narrowing racial disparity in the preterm birth rate was counterbalanced by greater mortality reductions in White than in Black preterm infants. Extremely preterm birth (<28 weeks) was 4 times higher in Black infants and accounted for more than half of the infant mortality gap. Substantial reductions in the Black-White infant mortality gap will require improved prevention of extremely preterm birth among Black infants.
Daniel, David G; Revicki, Dennis A; Canuso, Carla M; Turkoz, Ibrahim; Fu, Dong-Jing; Alphs, Larry; Ishak, K. Jack; Bartko, John J; Lindenmayer, Jean-Pierre
2012-01-01
Objective: The Clinical Global Impression for Schizoaffective Disorder scale is a new rating scale adapted from the Clinical Global Impression scale for use in patients with schizoaffective disorder. The psychometric characteristics of the Clinical Global Impression for Schizoaffective Disorder are described. Design: Content validity was assessed using an investigator questionnaire. Inter-rater reliability was determined with 12 sets of videotaped interviews rated independently by two trained individuals. Test-retest reliability was assessed using 30 randomly selected raters from clinical trials who evaluated the same videos on separate occasions two weeks apart. Convergent and divergent validity and effect size were evaluated by comparing scores between the Clinical Global Impression for Schizoaffective Disorder and the Positive and Negative Syndrome Scale, 21-item Hamilton Rating Scale for Depression, and Young Mania Rating Scale scales using pooled patient data from two clinical trials. Clinical Global Impression for Schizoaffective Disorder scores were then linked to corresponding Positive and Negative Syndrome Scale scores. Results: Content validity was strong. Inter-rater agreement was good to excellent for most scales and subscales (intra-class correlation coefficient ≥0.50). Test-retest showed good reproducibility, with intraclass correlation coefficients ranging from 0.444 to 0.898. Spearman correlations between Clinical Global Impression for Schizoaffective Disorder domains and corresponding symptom scales were 0.60 or greater, and effect sizes for Clinical Global Impression for Schizoaffective Disorder overall and domain scores were similar to Positive and Negative Syndrome Scale Young Mania Rating Scale, and 21-item Hamilton Rating Scale for Depression scores. Raters anticipated that the scale might be less effective in distinguishing negative from depressive symptoms, and, in fact, the results here may reflect that clinical reality. Conclusion: Multiple lines of evidence support the reliability and validity of the Clinical Global Impression for Schizoaffective Disorder for studies in schizoaffective disorder. PMID:22347687
Kinetics of copper ion absorption by cross-linked calcium polyacrylate membranes
NASA Technical Reports Server (NTRS)
Philipp, W. H.; May, C. E.
1983-01-01
The absorption of copper ions from aqueous copper acetate solutions by cross-linked calcium acrylate membranes was found to obey parabolic kinetics similar to that found for oxidation of metals that form protective oxide layers. For pure calcium polyacrylate membranes the rate constant was essentially independent of copper acetate concentration and film thickness. For a cross-linked copolymer film of polyvinyl alcohol and calcium polyacrylate, the rate constant was much greater and dependent on the concentration of copper acetate. The proposed mechanism in each case involves the formation of a copper polyacrylate phase on the surface of the membrane. The diffusion of the copper ion through this phase appears to be the rate controlling step for the copolymer film. The diffusion of the calcium ion is apparently the rate controlling step for the calcium polyacrylate. At low pH, the copper polyacrylate phase consists of the normal copper salt; at higher pH, the phase appears to be the basic copper salt.
Hybrid attacks on model-based social recommender systems
NASA Astrophysics Data System (ADS)
Yu, Junliang; Gao, Min; Rong, Wenge; Li, Wentao; Xiong, Qingyu; Wen, Junhao
2017-10-01
With the growing popularity of the online social platform, the social network based approaches to recommendation emerged. However, because of the open nature of rating systems and social networks, the social recommender systems are susceptible to malicious attacks. In this paper, we present a certain novel attack, which inherits characteristics of the rating attack and the relation attack, and term it hybrid attack. Furtherly, we explore the impact of the hybrid attack on model-based social recommender systems in multiple aspects. The experimental results show that, the hybrid attack is more destructive than the rating attack in most cases. In addition, users and items with fewer ratings will be influenced more when attacked. Last but not the least, the findings suggest that spammers do not depend on the feedback links from normal users to become more powerful, the unilateral links can make the hybrid attack effective enough. Since unilateral links are much cheaper, the hybrid attack will be a great threat to model-based social recommender systems.
Preparation and evaluation of polysaccharide sulfates for inhibiting Helicobacter pylori adhesion.
Song, Weijuan; Wang, Yalong; Zhang, Liyan; Fu, Shengnan; Zeng, Ying; Hu, Haiyan
2014-03-15
In treatments of Helicobacter pylori infections, recrudescences were common because of an unfavorable bacterial eradication rate due to the ever increasing resistance to antibiotics. In this study, we chose pectin, guar gum and chitosan to synthesize their sulfates to inhibit adhesions of H. pylori and thus enhance the eradication rate. The introduction of sulfates was characterized using FT-IR and elemental analysis. Data from zeta-potential, hydrodynamic diameter, hydrolysis and rheological property demonstrated the sulfates were physicochemically stable. Inhibition assay of hemagglutination and adhesion indicated sulfates prevented H. pylori from adhering to erythrocytes and AGS cells. In binding assay, affinities of sulfates to H. pylori suggested sulfates could compete with target cells for bacteria and moderated the bacterial adhesion to hosts. A higher content of galactoses and 2,3-O-linked sulfates benefited this action. Thus polysaccharide sulfates can serve as potential adjuvants to raise the bacterial eradication rate by inhibiting adhesions of H. pylori. Copyright © 2013 Elsevier Ltd. All rights reserved.
Aryl sulfonate based anticancer alkylating agents.
Sheikh, Hamdullah Khadim; Arshad, Tanzila; Kanwal, Ghazala
2018-05-01
This research work revolves around synthesis of antineoplastic alkylating sulfonate esters with dual alkylating sites for crosslinking of the DNA strands. These molecules were evaluated as potential antineoplastic cross linking alkylating agents by reaction with the nucleoside of Guanine DNA nucleobase at both ends of the synthesized molecule. Synthesis of the alkylating molecules and the crosslinking with the guanosine nucleoside was monitored by MALDITOF mass spectroscopy. The synthesized molecule's crosslinking or adduct forming rate with the nucleoside was compared with that of 1,4 butane disulfonate (busulfan), in form of time taken for the appearance of [M+H] + . It was found that aryl sulfonate leaving group was causing higher rate of nucleophilic attack by the Lewis basic site of the nucleobase. Furthermore, the rate was also found to be a function of electron withdrawing or donating nature of the substituent on the aryl ring. Compound with strong electron withdrawing substituent on the para position of the ring reacted fastest. Hence, new alkylating agents were synthesized with optimized or desired reactivity.
Holohan, Brody; De Meyer, Tim; Batten, Kimberly; Mangino, Massimo; Hunt, Steven C; Bekaert, Sofie; De Buyzere, Marc L; Rietzschel, Ernst R; Spector, Tim D; Wright, Woodring E; Shay, Jerry W
2015-01-01
Telomere length shortens with aging, and short telomeres have been linked to a wide variety of pathologies. Previous studies suggested a discrepancy in age-associated telomere shortening rate estimated by cross-sectional studies versus the rate measured in longitudinal studies, indicating a potential bias in cross-sectional estimates. Intergenerational changes in initial telomere length, such as that predicted by the previously described effect of a father’s age at birth of his offspring (FAB), could explain the discrepancy in shortening rate measurements. We evaluated whether changes occur in initial telomere length over multiple generations in three large datasets and identified paternal birth year (PBY) as a variable that reconciles the difference between longitudinal and cross-sectional measurements. We also clarify the association between FAB and offspring telomere length, demonstrating that this effect is substantially larger than reported in the past. These results indicate the presence of a downward secular trend in telomere length at birth over generational time with potential public health implications. PMID:25952108
Sward structure and nutritive value of Alexandergrass fertilized with nitrogen.
Salvador, Paulo R; Pötter, Luciana; Rocha, Marta G; Hundertmarck, Anelise P; Sichonany, Maria José O; Amaral Neto, Luiz G; Negrini, Mateus; Moterle, Paulo H
2016-03-01
This experiment evaluated forage production, sward structure, stocking rate, weight gain per area and nutritive value of forage as grazed by beef heifers on Alexandergrass (Urochloa plantaginea (Link) Hitch) pasture fertilized with nitrogen (N): 0; 100; 200 or 300 kg of N/ha. The experiment was a completely randomized design following a repeated measurement arrangement. The experimental animals were Angus heifers with initial age and weight of 15 months and 241.5±5 kg, respectively. The grazing method was continuous, with put-and-take stocking. N utilization, regardless of the level, increase by 25% the daily forage accumulation rate and the weight gain per area by 23%. The level of 97.2 kg N/ha leads to a higher leaf blade mass and increases by 20% the leaf:stem ratio. Alterations in sward structure changes the nutritive value of forage as grazed. The utilization of 112.7 kg of N/ha allows the highest stocking rate (2049.8 kg of BW/ha), equivalent to 7.5 heifers per hectare.
20-meter underwater wireless optical communication link with 1.5 Gbps data rate.
Shen, Chao; Guo, Yujian; Oubei, Hassan M; Ng, Tien Khee; Liu, Guangyu; Park, Ki-Hong; Ho, Kang-Ting; Alouini, Mohamed-Slim; Ooi, Boon S
2016-10-31
The video streaming, data transmission, and remote control in underwater call for high speed (Gbps) communication link with a long channel length (~10 meters). We present a compact and low power consumption underwater wireless optical communication (UWOC) system utilizing a 450-nm laser diode (LD) and a Si avalanche photodetector. With the LD operating at a driving current of 80 mA with an optical power of 51.3 mW, we demonstrated a high-speed UWOC link offering a data rate up to 2 Gbps over a 12-meter-long, and 1.5 Gbps over a record 20-meter-long underwater channel. The measured bit-error rate (BER) are 2.8 × 10-5, and 3.0 × 10-3, respectively, which pass well the forward error correction (FEC) criterion.
Space Link Extension Protocol Emulation for High-Throughput, High-Latency Network Connections
NASA Technical Reports Server (NTRS)
Tchorowski, Nicole; Murawski, Robert
2014-01-01
New space missions require higher data rates and new protocols to meet these requirements. These high data rate space communication links push the limitations of not only the space communication links, but of the ground communication networks and protocols which forward user data to remote ground stations (GS) for transmission. The Consultative Committee for Space Data Systems, (CCSDS) Space Link Extension (SLE) standard protocol is one protocol that has been proposed for use by the NASA Space Network (SN) Ground Segment Sustainment (SGSS) program. New protocol implementations must be carefully tested to ensure that they provide the required functionality, especially because of the remote nature of spacecraft. The SLE protocol standard has been tested in the NASA Glenn Research Center's SCENIC Emulation Lab in order to observe its operation under realistic network delay conditions. More specifically, the delay between then NASA Integrated Services Network (NISN) and spacecraft has been emulated. The round trip time (RTT) delay for the continental NISN network has been shown to be up to 120ms; as such the SLE protocol was tested with network delays ranging from 0ms to 200ms. Both a base network condition and an SLE connection were tested with these RTT delays, and the reaction of both network tests to the delay conditions were recorded. Throughput for both of these links was set at 1.2Gbps. The results will show that, in the presence of realistic network delay, the SLE link throughput is significantly reduced while the base network throughput however remained at the 1.2Gbps specification. The decrease in SLE throughput has been attributed to the implementation's use of blocking calls. The decrease in throughput is not acceptable for high data rate links, as the link requires constant data a flow in order for spacecraft and ground radios to stay synchronized, unless significant data is queued a the ground station. In cases where queuing the data is not an option, such as during real time transmissions, the SLE implementation cannot support high data rate communication.
Zhu, Zhikai; Su, Xiaomeng; Go, Eden P; Desaire, Heather
2014-09-16
Glycoproteins are biologically significant large molecules that participate in numerous cellular activities. In order to obtain site-specific protein glycosylation information, intact glycopeptides, with the glycan attached to the peptide sequence, are characterized by tandem mass spectrometry (MS/MS) methods such as collision-induced dissociation (CID) and electron transfer dissociation (ETD). While several emerging automated tools are developed, no consensus is present in the field about the best way to determine the reliability of the tools and/or provide the false discovery rate (FDR). A common approach to calculate FDRs for glycopeptide analysis, adopted from the target-decoy strategy in proteomics, employs a decoy database that is created based on the target protein sequence database. Nonetheless, this approach is not optimal in measuring the confidence of N-linked glycopeptide matches, because the glycopeptide data set is considerably smaller compared to that of peptides, and the requirement of a consensus sequence for N-glycosylation further limits the number of possible decoy glycopeptides tested in a database search. To address the need to accurately determine FDRs for automated glycopeptide assignments, we developed GlycoPep Evaluator (GPE), a tool that helps to measure FDRs in identifying glycopeptides without using a decoy database. GPE generates decoy glycopeptides de novo for every target glycopeptide, in a 1:20 target-to-decoy ratio. The decoys, along with target glycopeptides, are scored against the ETD data, from which FDRs can be calculated accurately based on the number of decoy matches and the ratio of the number of targets to decoys, for small data sets. GPE is freely accessible for download and can work with any search engine that interprets ETD data of N-linked glycopeptides. The software is provided at https://desairegroup.ku.edu/research.
NASA Technical Reports Server (NTRS)
Reinhart, Richard C.
1993-01-01
The Power Control and Rain Fade Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Power Control and Rain Fade Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Power Control and Rain Fade Software automatically controls the LET uplink power to compensate for signal fades. Besides power augmentation, the C&PM Software system is also responsible for instrument control during HBR-LET experiments, control of the Intermediate Frequency Switch Matrix on board the ACTS to yield a desired path through the spacecraft payload, and data display. The Power Control and Rain Fade Software User's Guide, Version 1.0 outlines the commands and procedures to install and operate the Power Control and Rain Fade Software. The Power Control and Rain Fade Software Maintenance Manual, Version 1.0 is a programmer's guide to the Power Control and Rain Fade Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Power Control and Rain Fade Software, computer algorithms, format representations, and computer hardware configuration. The Power Control and Rain Fade Test Plan provides a step-by-step procedure to verify the operation of the software using a predetermined signal fade event. The Test Plan also provides a means to demonstrate the capability of the software.
Sin, Nancy L.; Sloan, Richard P.; McKinley, Paula S.; Almeida, David M.
2015-01-01
Objective This study evaluates the associations between people’s trait-like patterns of stress in daily life (stressor frequency, perceived stressor severity, affective reactivity to stressors, and negative affect) and laboratory-assessed heart rate variability (HRV). Methods Data were collected from 909 participants ages 35-85 in the Midlife in the United States Study. Participants reported negative affect and minor stressful events during telephone interviews on eight consecutive evenings. On a separate occasion, HRV was measured from electrocardiograph recordings taken at rest during a laboratory-based psychophysiology protocol. Regression models were used to evaluate the associations between daily stress processes and 3 log-transformed HRV indices: standard deviation of RR intervals (SDRR), root mean square of successive differences (RMSSD), and high-frequency power (HF-HRV). Analyses were adjusted for demographics, body mass index, comorbid conditions, medications, physical activity, and smoking. Results Stressor frequency was unrelated to HRV (r-values ranging from −0.04 to −0.01, p’s > 0.20). However, people with greater perceived stressor severity had lower resting SDRR (fully-adjusted B [SE] = −0.05 [0.02]), RMSSD (−0.08 [0.03]), and HF-HRV (−0.16 [0.07]). Individuals with more pronounced affective reactivity to stressors also had lower levels of all 3 HRV indices (SDRR: B [SE] = −0.28 [0.14]; RMSSD: −0.44 [0.19]; HF-HRV: −0.96 [0.37]). Furthermore, aggregated daily negative affect was linked to reduced RMSSD (B [SE] = −0.16 [0.08]) and HF-HRV (−0.35 [0.15]). Conclusions In a national sample, individual differences in daily negative affect and responses to daily stressors were more strongly related to cardiovascular autonomic regulation than the frequency of such stressors. PMID:26867082
NASA Technical Reports Server (NTRS)
Reinhart, Richard C.
1993-01-01
The Communication Protocol Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Communication Protocol Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Communication Protocol Software allows users to control and configure the Intermediate Frequency Switch Matrix (IFSM) on board the ACTS to yield a desired path through the spacecraft payload. Besides IFSM control, the C&PM Software System is also responsible for instrument control during HBR-LET experiments, uplink power control of the HBR-LET to demonstrate power augmentation during signal fade events, and data display. The Communication Protocol Software User's Guide, Version 1.0 (NASA CR-189162) outlines the commands and procedures to install and operate the Communication Protocol Software. Configuration files used to control the IFSM, operator commands, and error recovery procedures are discussed. The Communication Protocol Software Maintenance Manual, Version 1.0 (NASA CR-189163, to be published) is a programmer's guide to the Communication Protocol Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Communication Protocol Software, computer algorithms, format representations, and computer hardware configuration. The Communication Protocol Software Test Plan (NASA CR-189164, to be published) provides a step-by-step procedure to verify the operation of the software. Included in the Test Plan is command transmission, telemetry reception, error detection, and error recovery procedures.
Conditions for the optical wireless links bit error ratio determination
NASA Astrophysics Data System (ADS)
Kvíčala, Radek
2017-11-01
To determine the quality of the Optical Wireless Links (OWL), there is necessary to establish the availability and the probability of interruption. This quality can be defined by the optical beam bit error rate (BER). Bit error rate BER presents the percentage of successfully transmitted bits. In practice, BER runs into the problem with the integration time (measuring time) determination. For measuring and recording of BER at OWL the bit error ratio tester (BERT) has been developed. The 1 second integration time for the 64 kbps radio links is mentioned in the accessible literature. However, it is impossible to use this integration time for singularity of coherent beam propagation.
SCAILET: An intelligent assistant for satellite ground terminal operations
NASA Technical Reports Server (NTRS)
Shahidi, A. K.; Crapo, J. A.; Schlegelmilch, R. F.; Reinhart, R. C.; Petrik, E. J.; Walters, J. L.; Jones, R. E.
1993-01-01
NASA Lewis Research Center has applied artificial intelligence to an advanced ground terminal. This software application is being deployed as an experimenter interface to the link evaluation terminal (LET) and was named Space Communication Artificial Intelligence for the Link Evaluation Terminal (SCAILET). The high-burst-rate (HBR) LET provides 30-GHz-transmitting and 20-GHz-receiving, 220-Mbps capability for wide band communications technology experiments with the Advanced Communication Technology Satellite (ACTS). The HBR-LET terminal consists of seven major subsystems. A minicomputer controls and monitors these subsystems through an IEEE-488 or RS-232 protocol interface. Programming scripts (test procedures defined by design engineers) configure the HBR-LET and permit data acquisition. However, the scripts are difficult to use, require a steep learning curve, are cryptic, and are hard to maintain. This discourages experimenters from utilizing the full capabilities of the HBR-LET system. An intelligent assistant module was developed as part of the SCAILET software. The intelligent assistant addresses critical experimenter needs by solving and resolving problems that are encountered during the configuring of the HBR-LET system. The intelligent assistant is a graphical user interface with an expert system running in the background. In order to further assist and familiarize an experimenter, an on-line hypertext documentation module was developed and included in the SCAILET software.
NASA Astrophysics Data System (ADS)
Sharan, Lucky; Agrawal, Vaibhav M.; Chaubey, V. K.
2017-08-01
Higher spectral efficiency and greater data rate per channel are the most cost-effective strategies to meet the exponential demand of data traffic in the optical core network. Multilevel modulation formats being spectrally efficient enhance the transmission capacity by coding information in the amplitude, phase, polarization or a combination of all. This paper presents the design architecture of a 32-channel dense wavelength division multiplexed (DWDM) system, where each channel operates with multi-level phase modulation formats at 40 Gbps. The proposed design has been simulated for 50 GHz channel spacing to numerically compute the performance of both differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK) modulation formats in such high-speed DWDM system. The transmission link is analyzed with perfect dispersion compensation and also with under-compensation scheme. The link performance in terms of quality factor (Q) for varying input powers with different dispersion compensation schemes has been evaluated. The simulation study shows significant nonlinear mitigation for both DPSK- and DQPSK-based DWDM systems up to 1,000 km and beyond. It is concluded that at higher power levels DQPSK format having a narrower spectrum shows better tolerance to dispersion and nonlinearities than DPSK format.
Houghton, Adele; Castillo-Salgado, Carlos
2017-12-06
Climate change is increasingly exacerbating existing population health hazards, as well as resulting in new negative health effects. Flooding is one particularly deadly example of its amplifying and expanding effect on public health. This systematic review considered evidence linking green building strategies in the Leadership in Energy and Environmental Design ® (LEED) Rating System with the potential to reduce negative health outcomes following exposure to urban flooding events. Queries evaluated links between LEED credit requirements and risk of exposure to urban flooding, environmental determinants of health, co-benefits to public health outcomes, and co-benefits to built environment outcomes. Public health co-benefits to leveraging green building design to enhance flooding resilience included: improving the interface between humans and wildlife and reducing the risk of waterborne disease, flood-related morbidity and mortality, and psychological harm. We conclude that collaborations among the public health, climate change, civil society, and green building sectors to enhance community resilience to urban flooding could benefit population health.
Li, Keqiang; Ma, Yunpeng; Dai, Aiquan; Wang, Xiulin
2017-11-30
Dissolved organic nitrogen (DON) is the major nitrogen form in the Bohai Sea. Land-based DON is released into the nitrogen pool and degraded by planktonic microbiota in coastal ocean. In this study, we evaluated the degradation of land-based DON, particularly its dynamics and bioavailability, in coastal water by linking experiment and modeling. Results showed that the degradation rate constant of DON from sewage treatment plant was significantly faster than those of other land-based sources (P<0.05). DON was classified into three categories based on dynamics and bioavailability. The supply of dissolved inorganic nitrogen (DIN) pool from the DON pool of Liao River, Hai River, and Yellow River was explored using a 3D hydrodynamic multi-DON biogeochemical model in the Bohai Sea. In the model, large amounts of DIN were supplied from DON of Liao River than the other rivers because of prolonged flushing time in Liaodong Bay. Copyright © 2017 Elsevier Ltd. All rights reserved.
Gelam (Melaleuca spp.) Honey-Based Hydrogel as Burn Wound Dressing
Mohd Zohdi, Rozaini; Abu Bakar Zakaria, Zuki; Yusof, Norimah; Mohamed Mustapha, Noordin; Abdullah, Muhammad Nazrul Hakim
2012-01-01
A novel cross-linked honey hydrogel dressing was developed by incorporating Malaysian honey into hydrogel dressing formulation, cross-linked and sterilized using electron beam irradiation (25 kGy). In this study, the physical properties of the prepared honey hydrogel and its wound healing efficacy on deep partial thickness burn wounds in rats were assessed. Skin samples were taken at 7, 14, 21, and 28 days after burn for histopathological and molecular evaluations. Application of honey hydrogel dressings significantly enhanced (P < 0.05) wound closure and accelerated the rate of re-epithelialization as compared to control hydrogel and OpSite film dressing. A significant decrease in inflammatory response was observed in honey hydrogel treated wounds as early as 7 days after burn (P < 0.05). Semiquantitative analysis using RT-PCR revealed that treatment with honey hydrogel significantly (P < 0.05) suppressed the expression of proinflammatory cytokines (IL-1α, IL-1β, and IL-6). The present study substantiates the potential efficacy of honey hydrogel dressings in accelerating burn wound healing. PMID:21941590
Wavelength assignment algorithm considering the state of neighborhood links for OBS networks
NASA Astrophysics Data System (ADS)
Tanaka, Yu; Hirota, Yusuke; Tode, Hideki; Murakami, Koso
2005-10-01
Recently, Optical WDM technology is introduced into backbone networks. On the other hand, as the future optical switching scheme, Optical Burst Switching (OBS) systems become a realistic solution. OBS systems do not consider buffering in intermediate nodes. Thus, it is an important issue to avoid overlapping wavelength reservation between partially interfered paths. To solve this problem, so far, the wavelength assignment scheme which has priority management tables has been proposed. This method achieves the reduction of burst blocking probability. However, this priority management table requires huge memory space. In this paper, we propose a wavelength assignment algorithm that reduces both the number of priority management tables and burst blocking probability. To reduce priority management tables, we allocate and manage them for each link. To reduce burst blocking probability, our method announces information about the change of their priorities to intermediate nodes. We evaluate its performance in terms of the burst blocking probability and the reduction rate of priority management tables.
Kaltschmidt, Jens; Schmitt, Simon P W; Pruszydlo, Markus G; Haefeli, Walter E
2008-01-01
Electronic mailing systems (e-mail) are an important means to disseminate information within electronic networks. However, in large business communities including the hectic environment of hospitals it may be difficult to induce account holders to read the e-mail. In two mailings disseminated in a large university hospital we evaluated the impact of e-mail layout (three e-mail text versions, two e-mails with graphics) on the willingness of its approximately 6500 recipients to seek additional electronic information and open an integrated link. Overall access rates after 90 days were 21.1 and 23.5% with more than 70% of the respondents opening the link within 3 days. Differences between different layouts were large and artwork text, HTML text, animated GIF, and static image prompted 1.2, 1.7, 1.8, and 2.3 times more often access than the courier plain text message (p
Kaltschmidt, Jens; Schmitt, Simon P.W.; Pruszydlo, Markus G.; Haefeli, Walter E.
2008-01-01
Electronic mailing systems (e-mail) are an important means to disseminate information within electronic networks. However, in large business communities including the hectic environment of hospitals it may be difficult to induce account holders to read the e-mail. In two mailings disseminated in a large university hospital we evaluated the impact of e-mail layout (three e-mail text versions, two e-mails with graphics) on the willingness of its ∼6500 recipients to seek additional electronic information and open an integrated link. Overall access rates after 90 days were 21.1 and 23.5% with more than 70% of the respondents opening the link within 3 days. Differences between different layouts were large and artwork text, HTML text, animated GIF, and static image prompted 1.2, 1.7, 1.8, and 2.3 times more often access than the courier plain text message (p ≤ 0.001). This study revealed that layout is a major determinant of the success of an information campaign. PMID:18096910
Personal responsibility, regret, and medical stigma among individuals living with lung cancer.
Criswell, Kevin R; Owen, Jason E; Thornton, Andrea A; Stanton, Annette L
2016-04-01
Understanding the degree to which adults with lung cancer perceive personal responsibility for their disease, personal regret for actions that may have contributed to lung cancer, and potential stigmatization from others is important, because these perceptions and experiences may be linked with treatment nonadherence, feelings of isolation, avoidance of healthcare providers, and poor quality of life. The purpose of this study was to evaluate rates and intensity of these types of experiences and to characterize the extent to which they are linked with smoking status and psychological adjustment in those living with lung cancer. Adults with lung cancer (N = 213) were recruited from two major cancer centers to complete a mail survey. Perceived responsibility was frequent in those who had ever smoked (74-80%), whereas regret and feelings of stigmatization were less frequent. When present, however, personal regret and stigmatization were associated with adverse psychological outcomes, particularly for never smokers. These results are consistent with the theory of stereotype threat and have clinical implications for management of people with lung cancer.
Fiber-Coupled Wide Field of View Optical Receiver for High Speed Space Communication
NASA Astrophysics Data System (ADS)
Suddath, Shannon N.
Research groups at NASA Glenn Research Center are interested in improving data rates on the International Space Station (ISS) using a free-space optical (FSO) link. However, known flexure of the ISS structure is expected to cause misalignment of the FSO link. Passive-control designs for mitigating misalignment are under investigation, including using a fiber-bundle for improved field of view. The designs must overcome the obstacle of coupling directly to fiber, rather than a photodetector, as NASA will maintain the use of small form-factor pluggable optical transceivers (SFPs) in the ISS network. In this thesis, a bundle-based receiver capable of coupling directly to fiber is designed, simulated, and tested in lab. Two 3-lens systems were evaluated for power performance in the lab, one with a 20 mm focal length aspheric lens and the other with a 50 mm focal length aspheric lens. The maximum output power achieved was 8 muW.
Gast, Anne; Rothermund, Klaus
2011-10-01
Evaluative conditioning (EC) effects are often assumed to be based on a learned mental link between the CS (conditioned stimulus) and the US (unconditioned stimulus). We demonstrate that this link is not the only one that can underlie EC effects, but that if evaluative responses are actually given during the learning phase also a direct link between the CS and an evaluative response-a CS-ER link-can be learned and lead to EC effects. In Experiment 1, CSs were paired with USs and participants were asked to evaluate the pairs during the conditioning phase. Resulting EC effects were unaffected by a later revaluation of the USs, suggesting that these EC effects can be attributed to CS-ER learning rather than to CS-US learning. Experiment 2 replicated Experiment 1 with the difference that no evaluative responses were given during the learning phase. EC effects in this study were influenced by US revaluation, suggesting that these EC effects are mainly based on CS-US learning. In Experiment 3, it was shown that EC effects can be found even if the USs are entirely removed from the procedure and the CSs are only paired with enforced evaluative responses. Together the experiments show that the valence of a stimulus can change because of a contingency with an evaluative response. (PsycINFO Database Record (c) 2011 APA, all rights reserved).
Living fast, dying when? The link between aging and energetics.
Speakman, John R; Selman, Colin; McLaren, Jane S; Harper, E Jean
2002-06-01
The idea that aging should be linked to energy expenditure has a long history that can be traced to the late 1800s and the industrial revolution. Machines that are run fast wear out more quickly, so the notion was born that humans and animals might experience similar fates: the faster they live (expressed as greater energy expenditure), the sooner they die. Evidence supporting the "rate-of-living" theory was gleaned from the scaling of resting metabolism and life span as functions of body mass. The product of these factors yields a mass-invariant term, equivalent to the "amount of living." There are at least four problems with this evidence, which are summarized and reviewed in this communication: 1) life span is a poor measure of aging, 2) resting metabolism is a poor measure of energy expenditure, 3) the effects are confounded by body mass and 4) the comparisons made are not phylogenetically independent. We demonstrate that there is a poor association between resting metabolic rate (RMR) and daily energy expenditure (DEE) measured using the doubly labeled water (DLW) method at the level of species. Nevertheless, the scaling relation between DEE and body mass still has the same scaling exponent as the RMR and body mass relationship. Thus, if we use DEE rather than RMR in the analysis, the rate-of-living ideas are still supported. Data for 13 species of small mammal were obtained, where energy demands by DLW and longevity were reliably known. In these species, there was a strong negative relationship between residual longevity and residual DEE, both with the effects of body mass removed (r(2) = 0.763, F = 32.1, P < 0.001). Hence, the association of energy demands and life span is not attributed to the confounding effects of body size. We subjected these latter data to an analysis that extracts phylogenetically independent contrasts, and the relationship remained significant (r(2) = 0.815, F = 39.74, P < 0.001). Small mammals that live fast really do die young. However, there are very large differences between species in the amounts of living that each enjoy and these disparities are even greater when other taxa are included in the comparisons. Such differences are incompatible with the "rate-of-living" theory. However, the link between energetics and aging across species is reconcilable within the framework of the "free-radical damage hypothesis" and the "disposable soma hypothesis." Within species one might anticipate the rate-of-living model would be more appropriate. We reviewed data generated from three different sources to evaluate whether this were so, studies in which metabolic rate is experimentally increased and impacts on life span followed, studies of caloric restriction and studies where links between natural variation in metabolism and life span are sought. This review reveals that there might be contrasting effects of resting and nonresting energy expenditure on aging, with increases in the former being protective and increases in the latter being harmful.
NASA Astrophysics Data System (ADS)
Weng, Yi; He, Xuan; Wang, Junyi; Pan, Zhongqi
2017-01-01
Spatial-division multiplexing (SDM) techniques have been purposed to increase the capacity of optical fiber transmission links by utilizing multicore fibers or few-mode fibers (FMF). The most challenging impairments of SDMbased long-haul optical links mainly include modal dispersion and mode-dependent loss (MDL), whereas MDL arises from inline component imperfections, and breaks modal orthogonality thus degrading the capacity of multiple-inputmultiple- output (MIMO) receivers. To reduce MDL, optical approaches include mode scramblers and specialty fiber designs, yet these methods were burdened with high cost, yet cannot completely remove the accumulated MDL in the link. Besides, space-time trellis codes (STTC) were purposed to lessen MDL, but suffered from high complexity. In this work, we investigated the performance of space-time block-coding (STBC) scheme to mitigate MDL in SDM-based optical communication by exploiting space and delay diversity, whereas weight matrices of frequency-domain equalization (FDE) were updated heuristically using decision-directed recursive-least-squares (RLS) algorithm for convergence and channel estimation. The STBC was evaluated in a six-mode multiplexed system over 30-km FMF via 6×6 MIMO FDE, with modal gain offset 3 dB, core refractive index 1.49, numerical aperture 0.5. Results show that optical-signal-to-noise ratio (OSNR) tolerance can be improved via STBC by approximately 3.1, 4.9, 7.8 dB for QPSK, 16- and 64-QAM with respective bit-error-rates (BER) and minimum-mean-square-error (MMSE). Besides, we also evaluate the complexity optimization of STBC decoding scheme with zero-forcing decision feedback (ZFDF) equalizer by shortening the coding slot length, which is robust to frequency-selective fading channels, and can be scaled up for SDM systems with more dynamic channels.
The role of race and poverty on steps to kidney transplantation in the Southeastern United States.
Patzer, R E; Perryman, J P; Schrager, J D; Pastan, S; Amaral, S; Gazmararian, J A; Klein, M; Kutner, N; McClellan, W M
2012-02-01
Racial disparities in access to renal transplantation exist, but the effects of race and socioeconomic status (SES) on early steps of renal transplantation have not been well explored. Adult patients referred for renal transplant evaluation at a single transplant center in the Southeastern United States from 2005 to 2007, followed through May 2010, were examined. Demographic and clinical data were obtained from patient's medical records and then linked with United States Renal Data System and American Community Survey Census data. Cox models examined the effect of race on referral, evaluation, waitlisting and organ receipt. Of 2291 patients, 64.9% were black, the mean age was 49.4 years and 33.6% lived in poor neighborhoods. Racial disparities were observed in access to referral, transplant evaluation, waitlisting and organ receipt. SES explained almost one-third of the lower rate of transplant among black versus white patients, but even after adjustment for demographic, clinical and SES factors, blacks had a 59% lower rate of transplant than whites (hazard ratio = 0.41; 95% confidence interval: 0.28-0.58). Results suggest that improving access to healthcare may reduce some, but not all, of the racial disparities in access to kidney transplantation. © 2011 The American Society of Transplantation and the American Society of Transplant Surgeons.
NASA Astrophysics Data System (ADS)
Liu, Xiaoyu; Mason, Mark A.; Guo, Zhishi; Krebs, Kenneth A.; Roache, Nancy F.
2015-12-01
This paper describes the measurement and model evaluation of formaldehyde source emissions from composite and solid wood furniture in a full-scale chamber at different ventilation rates for up to 4000 h using ASTM D 6670-01 (2007). Tests were performed on four types of furniture constructed of different materials and from different manufacturers. The data were used to evaluate two empirical emission models, i.e., a first-order and power-law decay model. The experimental results showed that some furniture tested in this study, made only of solid wood and with less surface area, had low formaldehyde source emissions. The effect of ventilation rate on formaldehyde emissions was also examined. Model simulation results indicated that the power-law decay model showed better agreement than the first-order decay model for the data collected from the tests, especially for long-term emissions. This research was limited to a laboratory study with only four types of furniture products tested. It was not intended to comprehensively test or compare the large number of furniture products available in the market place. Therefore, care should be taken when applying the test results to real-world scenarios. Also, it was beyond the scope of this study to link the emissions to human exposure and potential health risks.
Controller evaluation of initial data link en route air traffic control services : mini study 3
DOT National Transportation Integrated Search
1991-06-01
This report documents a Federal Aviation Administration controller evaluation of air traffic control (ATC) Data Link services planned for implementation in the en route ATC system. The main body of the report includes a detailed description of the ob...
Experimental evaluation of open-loop UpLink Power Control using ACTS
NASA Technical Reports Server (NTRS)
Dissanayake, Asoka
1995-01-01
The present investigation deals with the implementation of open-loop up-link power control using a beacon signal in the down-link frequency band as the control parameter. A power control system was developed and tested using the ACTS satellite. ACTS carries beacon signals in both up- and down-link bands with which the relationship between the up- and down-link fading can be established. A power controlled carrier was transmitted to the ACTS satellite from a NASA operated ground station and the transponded signal was received at COMSAT Laboratories using a terminal that was routinely used to monitor the two ACTS beacon signals. The experiment ran for a period of approximately six months and the collected data were used to evaluate the performance of the power control system. A brief review of propagation factors involved in estimating the up-link fade using a beacon signal in the down-link band are presented. The power controller design and the experiment configuration are discussed. Results of the experiment are discussed.
Analysis of link performance for the FOENEX laser communications system
NASA Astrophysics Data System (ADS)
Juarez, Juan C.; Young, David W.; Venkat, Radha A.; Brown, David M.; Brown, Andrea M.; Oberc, Rachel L.; Sluz, Joseph E.; Pike, H. Alan; Stotts, Larry B.
2012-06-01
A series of experiments were conducted to validate the performance of the free-space optical communications (FSOC) subsystem under DARPA's FOENEX program. Over six days, bidirectional links at ranges of 10 and 17 km were characterized during different periods of the day to evaluate link performance. This paper will present the test configuration, evaluate performance of the FSOC subsystem against a variety of characterization approaches, and discuss the impact of the results, particularly with regards to the optical terminals. Finally, this paper will summarize the impact of turbulence conditions on the FSOC subsystem and present methods for estimating performance under different link distances and turbulence conditions.
Evaluation of Aqua-Ammonia Chiller Technologies and Field Site Installation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zaltash, Abdolreza
2007-09-01
The Naval Facilities Engineering Service Center (NFESC) has sponsored Oak Ridge National Laboratory (ORNL) to review, select, and evaluate advanced, gas-fired, 5-ton, aqua-ammonia, chiller technologies. The selection criteria was that units have COP values of 0.67 or better at Air-conditioning and Refrigeration Institute (ARI) 95 F outdoor rating conditions, an active refrigerant flow control, and a variable-speed condenser fan. These features are expected to allow these units to operate at higher ambient temperatures (up to the maximum operating temperature of 110 F) with minimal degradation in performance. ORNL evaluated three potential manufacturers of advanced, gas-fired, 5-ton, aqua-ammonia chillers-Robur, Ambian, andmore » Cooling Technologies. Unfortunately, Robur did not meet the COP requirements and Cooling Technologies could not deliver a unit to be tested at the U.S. Department of Energy (DOE)-ORNL environmental chamber testing facility for thermally activated heat pumps. This eliminated these two technologies from further consideration, leaving only the Ambian chillers for evaluation. Two Ambian chillers were evaluated at the DOE-ORNL test facility. Overall these chillers operated well over a wide range of ambient conditions with minimal degradation in performance due to several control strategies used such as a variable speed condenser fan, a modulating burner, and active refrigerant flow control. These Ambian pre-commercial units were selected for installation and field testing at three federal facilities. NFESC worked with ORNL to assist with the site selection for installation and evaluation of these chillers. Two sites (ORNL and Naval Surface Warfare Center [NSWC] Corona) had a single chiller unit installed; and at one site (Naval Amphibious Base [NAB] Little Creek), two 5-ton chillers linked together were installed to provide 10 tons of cooling. A chiller link controller developed under this project was evaluated in the field test at Little Creek.« less
Contreras, Carmen C; Millones, Ana K; Santa Cruz, Janeth; Aguilar, Margot; Clendenes, Martin; Toranzo, Miguel; Llaro, Karim; Lecca, Leonid; Becerra, Mercedes C; Yuen, Courtney M
2017-04-01
For a cohort of patients with tuberculosis in Carabayllo, Peru, we describe the prevalence of medical comorbidities and socio-economic needs, the efforts required by a comprehensive support programme ('TB Cero') to address them and the success of this programme in linking patients to care. Patients diagnosed with tuberculosis in Carabayllo underwent evaluations for HIV, diabetes, mental health and unmet basic needs. For patients initiating treatment during 14 September, 2015-15 May, 2016, we abstracted data from evaluation forms and a support request system. We calculated the prevalence of medical comorbidities and the need for socio-economic support at the time of tuberculosis diagnosis, as well as the proportion of patients successfully linked to care or support. Of 192 patients, 83 (43%) had at least one medical comorbidity other than tuberculosis. These included eight (4%) patients with HIV, 12 (6%) with diabetes and 62 (32%) deemed at risk for a mental health condition. Of patients who required follow-up for a comorbidity, 100% initiated antiretroviral therapy, 71% attended endocrinology consultations and 66% attended psychology consultations. Of 126 (65%) patients who completed the socio-economic evaluation, 58 (46%) reported already receiving food baskets from the municipality, and 79 (63%) were given additional support, most commonly food vouchers and assistance in accessing health care. Carabayllo tuberculosis patients face many challenges in addition to tuberculosis. A collaborative, comprehensive treatment support programme can achieve high rates of linkage to care for these needs. © 2017 John Wiley & Sons Ltd.
Deciding to Change OpenURL Link Resolvers
ERIC Educational Resources Information Center
Johnson, Megan; Leonard, Andrea; Wiswell, John
2015-01-01
This article will be of interest to librarians, particularly those in consortia that are evaluating OpenURL link resolvers. This case study contrasts WebBridge (an Innovative Interface product) and LinkSource (EBSCO's product). This study assisted us in the decision-making process of choosing an OpenURL link resolver that was sustainable to…
Bandyopadhyay, Pradipta; Kuntz, Irwin D
2009-01-01
The determination of protein structure using distance constraints is a new and promising field of study. One implementation involves attaching residues of a protein using a cross-linking agent, followed by protease digestion, analysis of the resulting peptides by mass spectroscopy, and finally sequence threading to detect the protein folds. In the present work, we carry out computational modeling of the kinetics of cross-linking reactions in proteins using the master equation approach. The rate constants of the cross-linking reactions are estimated using the pKas and the solvent-accessible surface areas of the residues involved. This model is tested with fibroblast growth factor (FGF) and cytochrome C. It is consistent with the initial experimental rate data for individual lysine residues for cytochrome C. Our model captures all observed cross-links for FGF and almost 90% of the observed cross-links for cytochrome C, although it also predicts cross-links that were not observed experimentally (false positives). However, the analysis of the false positive results is complicated by the fact that experimental detection of cross-links can be difficult and may depend on specific experimental conditions such as pH, ionic strength. Receiver operator characteristic plots showed that our model does a good job in predicting the observed cross-links. Molecular dynamics simulations showed that for cytochrome C, in general, the two lysines come closer for the observed cross-links as compared to the false positive ones. For FGF, no such clear pattern exists. The kinetic model and MD simulation can be used to study proposed cross-linking protocols.
1982-02-01
control unit will detect and classify submerged submarins transiting within PJ The EnCAPsulated pedo augments air, surface and submarine anti...vidicon (date link video enhancement). Conduct Operational Test and Evaluation. Complete Large Scale Integration Receiver-Decoder improvement. Continue...analysis, and data link video enhancement focusing on application of a new silicon vidicon was continued; data link improvements such as adaptive null
Simultaneous oxidation of ammonium and p-cresol linked to nitrite reduction by denitrifying sludge.
González-Blanco, G; Beristain-Cardoso, R; Cuervo-López, F; Cervantes, F J; Gómez, J
2012-01-01
The metabolic capability of denitrifying sludge to oxidize ammonium and p-cresol was evaluated in batch cultures. Ammonium oxidation was studied in presence of nitrite and/or p-cresol by 55 h. At 50 mg/L NH4+-N and 76 mg/L NO2--N, the substrates were consumed at 100% and 95%, respectively, being N2 the product. At 50 mg/L NH4+-N and 133 mg/L NO2--N, the consumption efficiencies decreased to 96% and 70%, respectively. The increase in nitrite concentration affected the ammonium oxidation rate. Nonetheless, the N2 production rate did not change. In organotrophic denitrification, the p-cresol oxidation rate was slower than ammonium oxidation. In litho-organotrophic cultures, the p-cresol and ammonium oxidation rates were affected at 133 mg/L NO2--N. Nonetheless, at 76 mg/L NO2--N the denitrifying sludge oxidized ammonium and p-cresol, but at different rate. Finally, this is the first work reporting the simultaneous oxidation of ammonium and p-cresol with the production of N2 from denitrifying sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.
Goldman, L Elizabeth; Walker, Rod; Hubbard, Rebecca; Kerlikowske, Karla
2013-04-01
Whether timeliness of follow-up after abnormal mammography differs at facilities serving vulnerable populations, such as women with limited education or income, in rural areas, and racial/ethnic minorities is unknown. We examined receipt of diagnostic evaluation after abnormal mammography using 1998-2006 Breast Cancer Surveillance Consortium-linked Medicare claims. We compared whether time to recommended breast imaging or biopsy depended on whether women attended facilities serving vulnerable populations. We characterized a facility by the proportion of mammograms performed on women with limited education or income, in rural areas, or racial/ethnic minorities. We analyzed 30,874 abnormal screening examinations recommended for follow-up imaging across 142 facilities and 10,049 abnormal diagnostic examinations recommended for biopsy across 114 facilities. Women at facilities serving populations with less education or more racial/ethnic minorities had lower rates of follow-up imaging (4%-5% difference, P<0.05), and women at facilities serving more rural and low-income populations had lower rates of biopsy (4%-5% difference, P<0.05). Women undergoing biopsy at facilities serving vulnerable populations had longer times until biopsy than those at facilities serving nonvulnerable populations (21.6 vs. 15.6 d; 95% confidence interval for mean difference 4.1-7.7). The proportion of women receiving recommended imaging within 11 months and biopsy within 3 months varied across facilities (interquartile range, 85.5%-96.5% for imaging and 79.4%-87.3% for biopsy). Among Medicare recipients, follow-up rates were slightly lower at facilities serving vulnerable populations, and among those women who returned for diagnostic evaluation, time to follow-up was slightly longer at facilities that served vulnerable population. Interventions should target variability in follow-up rates across facilities, and evaluate effectiveness particularly at facilities serving vulnerable populations.
Controller evaluation of initial data link terminal air traffic control services : final report
DOT National Transportation Integrated Search
1991-01-01
This document details the results the first Federal Aviation Administration : Technical Center investigation of the initial terminal air traffic control : services developed for transmission using Data Link technology. Initial Data : Link services we...
Vandeputte, Doris; Falony, Gwen; Vieira-Silva, Sara; Tito, Raul Y; Joossens, Marie; Raes, Jeroen
2016-01-01
The assessment of potentially confounding factors affecting colon microbiota composition is essential to the identification of robust microbiome based disease markers. Here, we investigate the link between gut microbiota variation and stool consistency using Bristol Stool Scale classification, which reflects faecal water content and activity, and is considered a proxy for intestinal colon transit time. Through 16S rDNA Illumina profiling of faecal samples of 53 healthy women, we evaluated associations between microbiome richness, Bacteroidetes:Firmicutes ratio, enterotypes, and genus abundance with self-reported, Bristol Stool Scale-based stool consistency. Each sample's microbiota growth potential was calculated to test whether transit time acts as a selective force on gut bacterial growth rates. Stool consistency strongly correlates with all known major microbiome markers. It is negatively correlated with species richness, positively associated to the Bacteroidetes:Firmicutes ratio, and linked to Akkermansia and Methanobrevibacter abundance. Enterotypes are distinctly distributed over the BSS-scores. Based on the correlations between microbiota growth potential and stool consistency scores within both enterotypes, we hypothesise that accelerated transit contributes to colon ecosystem differentiation. While shorter transit times can be linked to increased abundance of fast growing species in Ruminococcaceae-Bacteroides samples, hinting to a washout avoidance strategy of faster replication, this trend is absent in Prevotella-enterotyped individuals. Within this enterotype adherence to host tissue therefore appears to be a more likely bacterial strategy to cope with washout. The strength of the associations between stool consistency and species richness, enterotypes and community composition emphasises the crucial importance of stool consistency assessment in gut metagenome-wide association studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Yousefi, Masoud; Kashani, Fatemeh Dabbagh; Golmohammady, Shole; Mashal, Ahmad
2017-12-01
In this paper, the performance of underwater wireless optical communication (UWOC) links, which is made up of the partially coherent flat-topped (PCFT) array laser beam, has been investigated in detail. Providing high power, array laser beams are employed to increase the range of UWOC links. For characterization of the effects of oceanic turbulence on the propagation behavior of the considered beam, using the extended Huygens-Fresnel principle, an analytical expression for cross-spectral density matrix elements and a semi-analytical one for fourth-order statistical moment have been derived. Then, based on these expressions, the on-axis scintillation index of the mentioned beam propagating through weak oceanic turbulence has been calculated. Furthermore, in order to quantify the performance of the UWOC link, the average bit error rate (BER) has also been evaluated. The effects of some source factors and turbulent ocean parameters on the propagation behavior of the scintillation index and the BER have been studied in detail. The results of this investigation indicate that in comparison with the Gaussian array beam, when the source size of beamlets is larger than the first Fresnel zone, the PCFT array laser beam with the higher flatness order is found to have a lower scintillation index and hence lower BER. Specifically, in the sense of scintillation index reduction, using the PCFT array laser beams has a considerable benefit in comparison with the single PCFT or Gaussian laser beams and also Gaussian array beams. All the simulation results of this paper have been shown by graphs and they have been analyzed in detail.
Williams, Rachael; van Staa, Tjeerd-Pieter; Gallagher, Arlene M; Hammad, Tarek; Leufkens, Hubert G M; de Vries, Frank
2018-05-26
Conflicting results from studies using electronic health records to evaluate the associations between type 2 diabetes and cancer fuel concerns regarding potential biases. This study aimed to describe completeness of cancer recording in UK primary care data linked to hospital admissions records. Patients aged 40+ years with insulin or oral antidiabetic prescriptions in Clinical Practice Research Datalink (CPRD) primary care without type 1 diabetes were matched by age, sex and general practitioner practice to non-diabetics. Those eligible for linkage to Hospital Episode Statistics Admitted Patient Care (HES APC), and with follow-up during April 1997-December 2006 were included. Cancer recording and date of first record of cancer were compared. Characteristics of patients with cancer most likely to have the diagnosis recorded only in a single data source were assessed. Relative rates of cancer estimated from the two datasets were compared. 53 585 patients with type 2 diabetes matched to 47 435 patients without diabetes were included. Of all cancers (excluding non-melanoma skin cancer) recorded in CPRD, 83% were recorded in HES APC. 94% of cases in HES APC were recorded in CPRD. Concordance was lower when restricted to same-site cancer records, and was negatively associated with increasing age. Relative rates for cancer were similar in both datasets. Good concordance in cancer recording was found between CPRD and HES APC among type 2 diabetics and matched controls. Linked data may reduce misclassification and increase case ascertainment when analysis focuses on site-specific cancers. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Muryn, J; Wilkinson, D
Purpose: The purpose of this work is to evaluate a method for confirming source strength of I-125 seeds in a bulk assay while maintaining sterility and time efficiency. Methods: The I-125 seeds used in this study (STM 1251, Bard Brachytherapy, Inc.) were available as loose seeds or linked in 3, 4, or 5 seed configurations. A third party 10% assay (NIST traceable) is provided. Source strengths ranging from 0.395 to 0.504 U were available for this study. A stand was built out of aluminum to hold an exposure meter (Inovision (Fluke) 451P) at 25 cm above the I-125 sources tomore » measure the exposure rate. Three different seed configurations were measured: loose, linked, and loaded needles (Bard FastFil Seed Implant Needle). The measurements were made in an operating room, and a sterile sheet was used under the non-sterile aluminum stand. Seeds and needles were placed in a sterile tray. Results: One hundred forty-two loose seeds in 5 batches (0.395, 0.395, 0.409, 0.444, 0.444 U/seed) and 902 seeds in 7 batches containing various strands (0.444, 0.444,.0444, 0.466, 0.466, 0.504, 0.504 U/seed) were measured. The average exposure rate per unit activity was measured to be 0.593 mR per hr per U with a standard deviation of 0.016. The Result for loaded needles was 0.261 mR per hr per U with a standard deviation of 0.014. Once the apparatus is set up, measurements of 180 linked sources as supplied in the Bard package requires only a few minutes. Conclusion: The proposed method can confirm the activity of a batch of loose or stranded I-125 seeds within a range of 5%.« less
Chen, Lin; Huang, Zhennan; Shahbazian-Yassar, Reza; Libera, Joseph A; Klavetter, Kyle C; Zavadil, Kevin R; Elam, Jeffrey W
2018-02-28
Lithium metal is considered the "holy grail" of next-generation battery anodes. However, severe parasitic reactions at the lithium-electrolyte interface deplete the liquid electrolyte and the uncontrolled formation of high surface area and dendritic lithium during cycling causes rapid capacity fading and battery failure. Engineering a dendrite-free lithium metal anode is therefore critical for the development of long-life batteries using lithium anodes. In this study, we deposit a conformal, organic/inorganic hybrid coating, for the first time, directly on lithium metal using molecular layer deposition (MLD) to alleviate these problems. This hybrid organic/inorganic film with high cross-linking structure can stabilize lithium against dendrite growth and minimize side reactions, as indicated by scanning electron microscopy. We discovered that the alucone coating yielded several times longer cycle life at high current rates compared to the uncoated lithium and achieved a steady Coulombic efficiency of 99.5%, demonstrating that the highly cross-linking structured material with great mechanical properties and good flexibility can effectively suppress dendrite formation. The protected Li was further evaluated in lithium-sulfur (Li-S) batteries with a high sulfur mass loading of ∼5 mg/cm 2 . After 140 cycles at a high current rate of ∼1 mA/cm 2 , alucone-coated Li-S batteries delivered a capacity of 657.7 mAh/g, 39.5% better than that of a bare lithium-sulfur battery. These findings suggest that flexible coating with high cross-linking structure by MLD is effective to enable lithium protection and offers a very promising avenue for improved performance in the real applications of Li-S batteries.
Min, Yul Ha; Park, Hyeoun-Ae; Lee, Joo Yun; Jo, Soo Jung; Jeon, Eunjoo; Byeon, Namsoo; Choi, Seung Yong; Chung, Eunja
2014-01-01
The aim of this study is to develop and evaluate a natural language generation system to populate nursing narratives using detailed clinical models. Semantic, contextual, and syntactical knowledges were extracted. A natural language generation system linking these knowledges was developed. The quality of generated nursing narratives was evaluated by the three nurse experts using a five-point rating scale. With 82 detailed clinical models, in total 66,888 nursing narratives in four different types of statement were generated. The mean scores for overall quality was 4.66, for content 4.60, for grammaticality 4.40, for writing style 4.13, and for correctness 4.60. The system developed in this study generated nursing narratives with different levels of granularity. The generated nursing narratives can improve semantic interoperability of nursing data documented in nursing records.
[The experience of the Mexican maternal health care program Arranque Parejo en la Vida].
Orozco-Núñez, Emanuel; González-Block, Miguel Angel; Kageyama-Escobar, Luz María; Hernández-Prado, Bernardo
2009-01-01
To evaluate the implementation of its participative strategies and the creation of support networks for poor pregnant women. A qualitative and comparative evaluation was carried on in four states. Coordination and community participation were relevant in relation with major resources allocation and availability, particularly housing and transportation. Governmental actors involvement and leadership favoured linking and coordination. Pregnant women used to valuate as the major support source the one provided by their kinship networks. To strengthen and to stimulate participative strategies is fundamental in zones with high maternal mortality rates. The wide appreciation of kinship networks, midwives and voluntaries' support to pregnant women in housing and transportation, suggests that these actors are a functional component of the support network; it is insufficient focusing the support network on health services and municipal authorities.
An Analysis of Website Accessibility in Higher Education in Indonesia Based on WCAG 2.0 Guidelines
NASA Astrophysics Data System (ADS)
Arasid, W.; Abdullah, A. G.; Wahyudin, D.; Abdullah, C. U.; Widiaty, I.; Zakaria, D.; Amelia, N.; Juhana, A.
2018-02-01
Website accessibility is a simple way to access a website by everyone so that information on the website can be easily understood. This study aims to improve the accessibility of universities’ website to analyze website accessibility problems based on WCAG 2.0 guidelines. This study analyzed 13 universities’ websites in West Java, Indonesia by using TAW as an evaluation tool. The evaluation results were presented in a graph showing the error rate of each university’s website. The same errors that occurred in almost all websites were: non-text content, info and relationships, page title, link purpose, language of page, on input, labels and instructions, parsing, and name, role, value criteria. This study was expected to provide information to the university and to perform as guidelines for website accessibility improvements.
Wideband 1.064 micrometer detector evaluation
NASA Technical Reports Server (NTRS)
Green, S. I.
1975-01-01
The performance of several candidate detectors for use as communications detectors in a 400 Mbps 1.064 micrometers laser communication system was evaluated. The results of communication system Bit Error Rate (BER) testing for the best detector of each type are summarized. Complete testing data of each type detector is presented. The 400 Mbps 1.064 micrometers communication system receiver test bed is described. The best communication system results for each detector type are included. Performance comparisons are made at 0.000001 BER, the specification level chosen for satellite laser communication links. The data is presented in two groups. The first indicates the best performance levels that can be expected on normal space laser communication system operation. The second cites the best performance levels which can be achieved by focusing the signal to diffraction limited spots on the photosensitive area.
The Link: Connecting Juvenile Justice and Child Welfare. Volume 3, Number 2, Spring 2004
ERIC Educational Resources Information Center
Blassingame, Kelley M., Ed.
2004-01-01
This issue of "The Link" includes the following articles: (1) "Oregon Crafts Guidelines for Effective Girls Programming - By Pam Patton and Marcia Morgan" (Pam Patton and Marcia Morgan); (2) "Linking Child Placement and Juvenile Delinquency: Research Examines the Role of Placement in Increased Delinquency Rates"; and (3) "Unlocking the Future:…
Idea Generation in Student Writing: Computational Assessments and Links to Successful Writing
ERIC Educational Resources Information Center
Crossley, Scott A.; Muldner, Kasia; McNamara, Danielle S.
2016-01-01
Idea generation is an important component of most major theories of writing. However, few studies have linked idea generation in writing samples to assessments of writing quality or examined links between linguistic features in a text and idea generation. This study uses human ratings of idea generation, such as "idea fluency, idea…
A classifier neural network for rotordynamic systems
NASA Astrophysics Data System (ADS)
Ganesan, R.; Jionghua, Jin; Sankar, T. S.
1995-07-01
A feedforward backpropagation neural network is formed to identify the stability characteristic of a high speed rotordynamic system. The principal focus resides in accounting for the instability due to the bearing clearance effects. The abnormal operating condition of 'normal-loose' Coulomb rub, that arises in units supported by hydrodynamic bearings or rolling element bearings, is analysed in detail. The multiple-parameter stability problem is formulated and converted to a set of three-parameter algebraic inequality equations. These three parameters map the wider range of physical parameters of commonly-used rotordynamic systems into a narrow closed region, that is used in the supervised learning of the neural network. A binary-type state of the system is expressed through these inequalities that are deduced from the analytical simulation of the rotor system. Both the hidden layer as well as functional-link networks are formed and the superiority of the functional-link network is established. Considering the real time interpretation and control of the rotordynamic system, the network reliability and the learning time are used as the evaluation criteria to assess the superiority of the functional-link network. This functional-link network is further trained using the parameter values of selected rotor systems, and the classifier network is formed. The success rate of stability status identification is obtained to assess the potentials of this classifier network. The classifier network is shown that it can also be used, for control purposes, as an 'advisory' system that suggests the optimum way of parameter adjustment.
MMIC Phased Array Demonstrations with ACTS
NASA Technical Reports Server (NTRS)
Raquet, Charles A. (Compiler); Martzaklis, Konstantinos (Compiler); Zakrajsek, Robert J. (Compiler); Andro, Monty (Compiler); Turtle, John P.
1996-01-01
Over a one year period from May 1994 to May 1995, a number of demonstrations were conducted by the NASA Lewis Research Center (LeRC) in which voice, data, and/or video links were established via NASA's advanced communications technology satellite (ACTS) between the ACTS link evaluation terminal (LET) in Cleveland, OH, and aeronautical and mobile or fixed Earth terminals having monolithic microwave integrated circuit (MMIC) phased array antenna systems. This paper describes four of these. In one, a duplex voice link between an aeronautical terminal on the LeRC Learjet and the ACTS was achieved. Two others demonstrated duplex voice (and in one case video as well) links between the ACTS and an Army vehicle. The fourth demonstrated a high data rate downlink from ACTS to a fixed terminal. Array antenna systems used in these demonstrations were developed by LeRC and featured LeRC and Air Force experimental arrays using gallium arsenide MMIC devices at each radiating element for electronic beam steering and distributed power amplification. The single 30 GHz transmit array was developed by NASA/LeRC and Texas Instruments. The three 20 GHz receive arrays were developed in a cooperative effort with the Air Force Rome Laboratory, taking advantage of existing Air Force array development contracts with Boeing and Lockheed Martin. The paper describes the four proof-of-concept arrays and the array control system. The system configured for each of the demonstrations is described, and results are discussed.
THz and sub-THz (MMW)-over-Fiber Data Links and Radar Technology
2016-12-05
propagation loss in free-space or transmission line, and their inherent straight-line path of propagation affects connections and synchronization between the...effort is to realize photonic-network compatible wireless data link at data rate up to 100 Gbit/s, and to explore a real-time MMW radar imaging system...global village at terabit rate, hopefully wirelessly. Unfortunately, such high-volume data transmission over air consumes radio bandwidth—lots of it
THz and sub THz (MMW)-over-Fiber Data Links and Radar Technology
2016-11-30
propagation loss in free-space or transmission line, and their inherent straight-line path of propagation affects connections and synchronization between the...effort is to realize photonic-network compatible wireless data link at data rate up to 100 Gbit/s, and to explore a real-time MMW radar imaging system...global village at terabit rate, hopefully wirelessly. Unfortunately, such high-volume data transmission over air consumes radio bandwidth—lots of it
NASA Technical Reports Server (NTRS)
Vyhnalek, Brian E.; Tedder, Sarah A.; Nappier, Jennifer M.
2018-01-01
Space-to-ground photon-counting optical communication links supporting high data rates over large distances require enhanced ground receiver sensitivity in order to reduce the mass and power burden on the spacecraft transmitter. Superconducting nanowire single-photon detectors (SNSPDs) have been demonstrated to offer superior performance in detection efficiency, timing resolution, and count rates over semiconductor photodetectors, and are a suitable technology for high photon efficiency links. Recently photon detectors based on superconducting nanowires have become commercially available, and we have assessed the characteristics and performance of one such commercial system as a candidate for potential utilization in ground receiver designs. The SNSPD system features independent channels which can be added modularly, and we analyze the scalability of the system to support different data rates, as well as consider coupling concepts and issues as the number of channels increases.
Erath, Stephen A.; Bierman, Karen L.
2009-01-01
Direct associations between aggressive marital conflict and child aggressive-disruptive behavior at home and school were explored in this cross-sectional study of 360 kindergarten children. In addition, mediated pathways linking aggressive marital conflict to maternal harsh punishment to child aggressive-disruptive behavior were examined. Moderation analyses explored how the overall frequency of marital disagreement might buffer or exacerbate the impact of aggressive marital conflict on maternal harsh punishment and child aggressive-disruptive behavior. Hierarchical regressions revealed direct pathways linking aggressive marital conflict to child aggressive-disruptive behavior at home and school and a partially mediated pathway linking aggressive marital conflict to child aggressive-disruptive behavior at home. Further analyses revealed that rates of marital disagreement moderated the association between aggressive marital conflict and child aggressive-disruptive behavior at home, with an attenuated association at high rates of marital disagreement as compared with low rates of marital disagreement. PMID:16756397
Entangled quantum key distribution over two free-space optical links.
Erven, C; Couteau, C; Laflamme, R; Weihs, G
2008-10-13
We report on the first real-time implementation of a quantum key distribution (QKD) system using entangled photon pairs that are sent over two free-space optical telescope links. The entangled photon pairs are produced with a type-II spontaneous parametric down-conversion source placed in a central, potentially untrusted, location. The two free-space links cover a distance of 435 m and 1,325 m respectively, producing a total separation of 1,575 m. The system relies on passive polarization analysis units, GPS timing receivers for synchronization, and custom written software to perform the complete QKD protocol including error correction and privacy amplification. Over 6.5 hours during the night, we observed an average raw key generation rate of 565 bits/s, an average quantum bit error rate (QBER) of 4.92%, and an average secure key generation rate of 85 bits/s.
Flow, affect and visual creativity.
Cseh, Genevieve M; Phillips, Louise H; Pearson, David G
2015-01-01
Flow (being in the zone) is purported to have positive consequences in terms of affect and performance; however, there is no empirical evidence about these links in visual creativity. Positive affect often--but inconsistently--facilitates creativity, and both may be linked to experiencing flow. This study aimed to determine relationships between these variables within visual creativity. Participants performed the creative mental synthesis task to simulate the creative process. Affect change (pre- vs. post-task) and flow were measured via questionnaires. The creativity of synthesis drawings was rated objectively and subjectively by judges. Findings empirically demonstrate that flow is related to affect improvement during visual creativity. Affect change was linked to productivity and self-rated creativity, but no other objective or subjective performance measures. Flow was unrelated to all external performance measures but was highly correlated with self-rated creativity; flow may therefore motivate perseverance towards eventual excellence rather than provide direct cognitive enhancement.
Vigil, Jacob M; Coulombe, Patrick
2011-09-01
This experiment examines the impact of biological sex and audience composition on laboratory-induced ischemic pain intensity and observational coding of other people's pain behaviors. Situational context was manipulated by varying the sex and number of audience stimuli in the laboratory setting during the pain task and during observational evaluations of other people's pain suffering. The analyses revealed sex differences in felt pain intensity and observable pain behaviors, with male subjects reporting lower pain intensity and evidencing fewer pain behaviors than female subjects on average. Follow-up analyses revealed that, after controlling for social anxiety, audience composition was linked to felt pain intensity, and this relation was moderated by participant sex and audience sex, such that only male subjects showed decreased pain intensity with increasing number of female audience members. Sex differences were also found in the rating of other people's pain behaviors, with male observers rating the pain of others lower than female observers. Composition of the audience influenced observers' pain ratings such that the presence of more male subjects in the audience correlated with lower observer ratings, whereas the presence of more female subjects correlated with higher observer ratings. This is the first study to show that the sex and the composition of the social context in which pain is experienced affects the intensity of felt pain and the evaluation of other people's pain suffering. Implications of the findings for measuring and interpreting pain suffering in male and female patients by male and female treatment providers in health care settings are discussed. Published by Elsevier B.V.
Multifunction Data Link for an Advanced Air-Traffic Management System
DOT National Transportation Integrated Search
1972-11-01
This report evaluates the requirements relating to a multi-function data link for an advanced Air Traffic Management System. A two-way time ordered data link is postulated to accomplish the communication and control function. Several candidate modula...
The Potential of School-Linked Centers To Promote Adolescent Health and Development. Working Paper.
ERIC Educational Resources Information Center
Millstein, Susan G.
The future of school-linked adolescent health centers cannot be determined without further evaluation. The recent development of school-linked health centers stems from concerns about the special health needs of adolescents. Currently there are 125 school-based and school-linked centers in operation. Characteristics include the following: (1) most…
Sato, Nahoko; Nunome, Hiroyuki; Ikegami, Yasuo
2015-02-01
In hip-hop dance contests, a procedure for evaluating performances has not been clearly defined, and objective criteria for evaluation are necessary. It is assumed that most hip-hop dance techniques have common motion characteristics by which judges determine the dancer's skill level. This study aimed to extract motion characteristics that may be linked to higher evaluations by judges. Ten expert and 12 nonexpert dancers performed basic rhythmic movements at a rate of 100 beats per minute. Their movements were captured using a motion capture system, and eight judges evaluated the performances. Four kinematic parameters, including the amplitude of the body motions and the phase delay, which indicates the phase difference between two joint angles, were calculated. The two groups showed no significant differences in terms of the amplitudes of the body motions. In contrast, the phase delay between the head motion and the other body parts' motions of expert dancers who received higher scores from the judges, which was approximately a quarter cycle, produced a loop-shaped motion of the head. It is suggested that this slight phase delay was related to the judges' evaluations and that these findings may help in constructing an objective evaluation system.
Poetry in teaching pharmacology: Exploring the possibilities.
Kalra, Juhi; Singh, Satendra; Badyal, Dinesh; Barua, Purnima; Sharma, Taruna; Dhasmana, Dinesh Chandra; Singh, Tejinder
2016-10-01
To explore poetry as a tool for active learning in linking knowledge and affective domains and to find if correlating learning with imagination can be used in "assessment for learning." After taking a conventional lecture on Asthma, a creative writing assignment in the form of poetry writing was given to the students. Different triggers were given to the students to channelize their thought pattern in a given direction that was linked to specific areas of academic relevance. Students were asked to reflect on this learning experience and the faculty was asked to evaluate the student assignment on a 5-point Likert scale. Most student groups scored well in the "overall assessment" of creative assignments and were rated as good or fair by the faculty. Students reflections were very informative and revealed that more than 90% of the students liked the exercise and many were too exuberant and liberal with emotional reactions that breathed positive. Around 5% students found the exercise average and another 5% found it very childish. Poetry writing turned out to be like a simulation exercise that linked academic knowledge, creativity, and the affective domain in an assumed scenario, rehearsed in free locales of mind. The metaphorical transition embedded in its subtle creation helped assess deeper understanding of the subject and the logical sequence of thought pattern.
Foraging theory predicts predator-prey energy fluxes.
Brose, U; Ehnes, R B; Rall, B C; Vucic-Pestic, O; Berlow, E L; Scheu, S
2008-09-01
1. In natural communities, populations are linked by feeding interactions that make up complex food webs. The stability of these complex networks is critically dependent on the distribution of energy fluxes across these feeding links. 2. In laboratory experiments with predatory beetles and spiders, we studied the allometric scaling (body-mass dependence) of metabolism and per capita consumption at the level of predator individuals and per link energy fluxes at the level of feeding links. 3. Despite clear power-law scaling of the metabolic and per capita consumption rates with predator body mass, the per link predation rates on individual prey followed hump-shaped relationships with the predator-prey body mass ratios. These results contrast with the current metabolic paradigm, and find better support in foraging theory. 4. This suggests that per link energy fluxes from prey populations to predator individuals peak at intermediate body mass ratios, and total energy fluxes from prey to predator populations decrease monotonically with predator and prey mass. Surprisingly, contrary to predictions of metabolic models, this suggests that for any prey species, the per link and total energy fluxes to its largest predators are smaller than those to predators of intermediate body size. 5. An integration of metabolic and foraging theory may enable a quantitative and predictive understanding of energy flux distributions in natural food webs.
Refugee Resettlement Patterns and State-Level Health Care Insurance Access in the United States
Venkatesh, Arjun Krishna
2016-01-01
We sought to evaluate the relationship between state-level implementation of the Patient Protection and Affordable Care Act (ACA) and resettlement patterns among refugees. We linked federal refugee resettlement data to ACA expansion data and found that refugee resettlement rates are not significantly different according to state-level insurance expansion or cost. Forty percent of refugees have resettled to states without Medicaid expansion. The wide state-level variability in implementation of the ACA should be considered by federal agencies seeking to optimize access to health insurance coverage among refugees who have resettled to the United States. PMID:26890186
Self-match based on polling scheme for passive optical network monitoring
NASA Astrophysics Data System (ADS)
Zhang, Xuan; Guo, Hao; Jia, Xinhong; Liao, Qinghua
2018-06-01
We propose a self-match based on polling scheme for passive optical network monitoring. Each end-user is equipped with an optical matcher that exploits only the specific length patchcord and two different fiber Bragg gratings with 100% reflectivity. The simple and low-cost scheme can greatly simplify the final recognition processing of the network link status and reduce the sensitivity of the photodetector. We analyze the time-domain relation between reflected pulses and establish the calculation model to evaluate the false alarm rate. The feasibility of the proposed scheme and the validity of the time-domain relation analysis are experimentally demonstrated.
A Theoretical Study of Vapour Phase Nucleation of the Rocket Propellant N2O4
NASA Astrophysics Data System (ADS)
Pal, P.
2003-05-01
The residual vapour of a rocket fuel at the venting stage develops a potential aerodynamic problem which is linked with the vapour phase nucleation phenomena of the propellant. This study, based entirely on molecular treatment, addresses the problem by focusing specifically on the N2O4 propellant which is used in the ARIANE flight. The phenomenon is examined by considering the thermodynamic free energies of N2O4 clusters, leading to the evaluation of nucleation flux rates of critical nuclei at incipient nucleation. Preliminary examinations of the kinetics of flux pulses provide basic explanation from a molecular perspective.
Morita, Daigo; Seki, Taisuke; Higuchi, Yoshitoshi; Takegami, Yasuhiko; Ishiguro, Naoki
2017-12-01
This study aimed at investigating differences in femoral head penetration between highly cross-linked polyethylene (HXLPE) cemented sockets and uncemented liners during 5 years postoperatively. Ninety-six patients (106 hips) with a mean age of 64.4 (range, 35-83) years underwent total hip arthroplasty using a HXLPE cemented socket or liner and were respectively divided into cemented (35 patients [37 hips]) and uncemented (61 patients [69 hips]) groups. Femoral head penetrations were evaluated on both anteroposterior (AP)-view and Lauenstein-view radiographs, and mean polyethylene (PE) wear rates were calculated based on femoral head penetration from 2 to 5 years. Multivariate analyses were performed to assess risk factors for PE wear. At 5 years postoperatively, the cemented and uncemented groups exhibited proximal direction femoral head penetrations of 0.103 mm and 0.124 mm (P = .226) and anterior direction penetrations of 0.090 mm and 0.151 mm (P = .002), respectively. The corresponding mean PE wear rates were 0.004 mm/y and 0.009 mm/y in the AP-view (P = .286) and 0.005 mm/y and 0.012 mm/y in the Lauenstein-view (P = .168), respectively. Left-side operation and high activity were independent risk factors for PE wear on AP-view. When HXLPE was used, all mean PE wear rates were very low and those of cemented sockets and uncemented liners were very similar. PE particle theory suggests that the occurrence of osteolysis and related aseptic loosening might consequently decrease. Copyright © 2017 Elsevier Inc. All rights reserved.
Free-space high data rate communications technologies for near terrestrial space
NASA Astrophysics Data System (ADS)
Edwards, C. L.; Bruzzi, J. R.; Boone, B. G.
2008-08-01
Recent progress at the Applied Physics Laboratory in high data rate communications technology development is described in this paper. System issues for developing and implementing high data rate downlinks from geosynchronous earth orbit to the ground, either for CONUS or in-theater users is considered. Technology is described that supports a viable dual-band multi-channel system concept. Modeling and simulation of micro-electro-mechanical systems (MEMS) beamsteering mirrors has been accomplished to evaluate the potential for this technology to support multi-channel optical links with pointing accuracies approaching 10 microradians. These models were validated experimentally down to levels in which Brownian motion was detected and characterized for single mirror devices only 500 microns across. This multi-channel beamsteering technology can be designed to address environmental compromises to free-space optical links, which derive from turbulence, clouds, as well as spacecraft vibration. Another technology concept is being pursued that is designed to mitigate the adverse effects of weather. It consists of a dual-band (RF/optical) antenna that is optimally designed in both bands simultaneously (e.g., Ku-band and near infrared). This technology would enable optical communications hardware to be seamlessly integrated with existing RF communications hardware on spacecraft platforms, while saving on mass and power, and improving overall system performance. These technology initiatives have been pursued principally because of potential sponsor interest in upgrading existing systems to accommodate quick data recovery and decision support, particularly for the warfighter in future conflicts where the exchange of large data sets such as high resolution imagery would have significant tactical benefits.
Mark 6: A Next-Generation VLBI Data System
NASA Astrophysics Data System (ADS)
Whitney, A. R.; Lapsley, D. E.; Taveniku, M.
2011-07-01
A new real-time high-data-rate disk-array system based on entirely commercial-off-the-shelf hardware components is being evaluated for possible use as a next-generation VLBI data system. The system, developed by XCube Communications of Nashua, NH, USA was originally developed for the automotive industry for testing/evaluation of autonomous driving systems that require continuous capture of an array of video cameras and automotive sensors at ~8Gbps from multiple 10GigE data links and other data sources. In order to sustain the required recording data rate, the system is designed to account for slow and/or failed disks by shifting the load to other disks as necessary in order to maintain the target data rate. The system is based on a Linux OS with some modifications to memory management and drivers in order to guarantee the timely movement of data, and the hardware/software combination is highly tuned to achieve the target data rate; data are stored in standard Linux files. A kit is also being designed that will allow existing Mark 5 disk modules to be modified to be used with the XCube system (though PATA disks will need to be replaced by SATA disks). Demonstrations of the system at Haystack Observatory and NRAO Socorro have proved very encouraging; some modest software upgrades/revisions are being made by XCube in order to meet VLBI-specific requirements. The system is easily expandable, with sustained 16 Gbps likely to be supported before end CY2011.
Korst, Lisa M; Fridman, Moshe; Lu, Michael C; Mitchell, Connie; Lawton, Elizabeth; Griffin, Flojaune; Gregory, Kimberly D
2014-09-01
The purpose of this study was to evaluate the use of a childbirth composite morbidity indicator for monitoring childbirth morbidity at hospital and regional levels in California. Study data were obtained from the 2005 linked maternal and neonatal discharge dataset for California hospitals. The study population was limited to laboring women with singleton, term (≥37 weeks' gestation), inborn, and live births. Women with and without pregnancy complications were stratified into high- and low-risk groups. The composite outcome was defined as any significant morbidity of the mother or newborn infant during the childbirth admission. Submeasures for maternal and neonatal composite morbidity and for severe maternal morbidity were examined with both aggregate and hospital-level analyses. Of 377,869 eligible deliveries, 120,218 (31.8%) were categorized as high risk and 257,651 (68.2%) were categorized as low risk. High-risk women had higher morbidity rates for all comparisons. The mean childbirth composite morbidity rate was 21% overall: 28% for high-risk women and 18% for low-risk women. For high- and low-risk strata, the rates of maternal complications were 18% and 13%, and the rates of severe maternal morbidity were 1.4% and 0.5%, respectively. There was substantial variation across hospitals for all measures. The childbirth composite morbidity rate is designed to report childbirth complication rates that combine maternal and neonatal morbidity. This measure and its submeasures met the criteria for quality indicator evaluation as specified by the Agency for Healthcare Research and Quality and can be used for benchmarking or for monitoring childbirth outcomes at regional levels. Copyright © 2014. Published by Elsevier Inc.
High Prevalence of Insecure Attachment in Patients with Primary Hypertension
Balint, Elisabeth M.; Gander, Manuela; Pokorny, Dan; Funk, Alexandra; Waller, Christiane; Buchheim, Anna
2016-01-01
Hypertension is a major cardiovascular (CV) risk factor and is predicted by heightened CV reactivity to stress in healthy individuals. Patients with hypertension also show an altered stress response, while insecure attachment is linked to a heightened stress reactivity as well. This is the first study aiming to assess attachment representations in patients with primary hypertension and to investigate their CV responses when their attachment system is activated. We studied 50 patients (38 men, 12 women) with primary hypertension. The Adult Attachment Projective Picture System (AAP), a widely used and validated interview, was performed to measure the patients' attachment representations, and to activate their attachment system. Blood pressure and heart rate were measured after 10 min at rest prior to and directly after the AAP interview. Mood and state anxiety were assessed using the Multidimensional Mood State Questionnaire (MDBF) and the State Trait Anxiety Inventory-State (STAI-S) before and after the experiment. The prevalence of insecure attachment (dismissing, preoccupied, unresolved) in hypertensive patients was predominant (88%), while in non-clinical populations, only about 50% of individuals had insecure attachment patterns. Blood pressure (p < 0.001), heart rate (p = 0.016), and rate pressure product (p < 0.001) significantly increased in response to the attachment interview. Secure attached patients showed the highest rise in systolic blood pressure (p = 0.020) and the lowest heart rate compared to the other attachment groups (p = 0.043). However, attachment representation showed no significant group or interaction effects on diastolic blood pressure (DBP) and rate pressure product. Insecure attachment was highly over-represented in our sample of patients with primary hypertension. Additionally, a robust CV response to the attachment-activating stimulus was observed. Our data suggest that insecure attachment is significantly linked to primary hypertension, which implies the need for further investigations to evaluate attachment insecurity as a possible risk factor for hypertension. PMID:27536255
Woodhouse, Susan S; Lauer, Maria; Beeney, Julie R S; Cassidy, Jude
2015-03-01
The present study investigated links between the observer-rated process of psychotherapy and 2 key psychotherapy relationship constructs (i.e., working alliance and attachment to the therapist) in the context of a brief, attachment-based, home-visiting, mother-infant intervention that aimed to promote later secure infant attachment. Additionally, links between observer ratings of intervener and mother contributions to process were examined. Participants included 85 economically stressed mothers of first-born, 5.5-month-old, temperamentally irritable infants. Therapists included 2 doctoral-level and 4 master's-level home visitors. Observer-rated therapist psychotherapy process variables (i.e., warmth, exploration, and negative attitude) were not linked to maternal ratings of working alliance. Therapist warmth, however, was positively associated with maternal ratings of security of attachment to the therapist, and therapist negative attitude was positively related to maternal ratings of preoccupied-merger attachment to the therapist. As expected, both therapist warmth and exploration were positively associated with both maternal participation and exploration. Therapist negative attitude was inversely related to maternal exploration, but not to maternal participation. Results support the idea that attention to the psychotherapy process and relationship may be important in the context of a brief home-visiting parenting intervention with a nonclinical sample. (PsycINFO Database Record (c) 2015 APA, all rights reserved).
NASA Astrophysics Data System (ADS)
Carbonneau, Theresa H.; Wisely, David R.
1998-01-01
Never before has the opportunity for terrestrial optical wireless communications links been so great. The high data rates attainable, up to OC-24, make it a very attractive and cost effective alternative to traditional fiber optic and microwave links. With today's demand for interactive multimedia-based applications, such as video conferencing and telemedicine, optical wireless products are the only ones that can provide the needed bandwidth in situations when it is too costly or impossible to install fiber optic cable. Recent developments in laser and optics technologies, in addition to auto beam tracking, permit transmission units to achieve excellent performance rates in all weather conditions.
Flight Deck Data Link Displays: An Evaluation of Textual and Graphical Implementations
NASA Technical Reports Server (NTRS)
McGann, Alison; Lozito, Sandy; Corker, Kevin; Ashford, Rose (Technical Monitor)
2001-01-01
In Experiment 1, 16 pilots participated in a part-task simulation study that evaluated pilot data link communication for short and long message types and for two textual formats. No differences were found between the two textual formats when evaluating data link transaction times and pilot performance on a secondary task. Pilots initiated flight changes more quickly with the T-Scan format, where location of clearance information roughly corresponded to the cockpit instrument layout. Longer messages were less problematic than two short messages sent in close succession as pilots required more verbal clarification for closely spaced messages. 24 pilots participated in a second experiment that evaluated pilot communication performance for textual data link, two implementations of graphical data link, and a combined graphical and textual information modality. The two modalities incorporating text resulted in significantly faster transaction times and better performance on the secondary task than the two graphical-only implementations. The interval between messages was also more systematically varied in Experiment 2, and a short interval between messages significantly increased the access time for the second message. This delay in access was long enough to increase significantly the total transaction time of the second message, and this effect was exaggerated for the graphical-only implementations. Time to view the message before acknowledgement and time to initiate flight changes were not affected by the interval manipulation, This suggests that pilots adopt a sequential message handling strategy, and presenting messages closely in succession may present operational problems in a data link Air Traffic Control (ATC) environment. The results of this study also indicate that the perceived importance of message content is currently a crucial element in pilot data link communication.
Laughter and Subjective Health Among Community-Dwelling Older People in Japan
Hayashi, Kei; Kawachi, Ichiro; Ohira, Tetsuya; Kondo, Katsunori; Shirai, Kokoro; Kondo, Naoki
2015-01-01
Abstract The aim of this study was to evaluate the association of laughter with subjective health independent of socioeconomic status and social participation among older people in Japan. We used the data of 26,368 individuals (men, 12,174; women, 14,194) 65 years or older who participated in the Japan Gerontological Evaluation Study (JAGES) in 2013. Participants provided information on laughter and self-rated health, depression, socioeconomic, and psychosocial factors. We evaluated laughter from three perspectives: frequency, opportunities, and interpersonal interactions. Even after adjustment for depression, sociodemographic factors, and social participation, the prevalence ratio for poor subjective health among women who never or almost never laugh was 1.78 (95% confidence interval, 1.48–2.15) compared with those who reported laughing every day. Similar associations were observed among men. Laughter may be an important factor for the promotion of general and mental health of older adults. The mechanisms linking laughter and health warrant further study. PMID:26649930
Gittelsohn, Joel; Suratkar, Sonali; Song, Hee-Jung; Sacher, Suzanne; Rajan, Radha; Rasooly, Irit R.; Bednarek, Erin; Sharma, Sangita; Anliker, Jean A.
2011-01-01
Reduced access to affordable healthy foods is linked to higher rates of chronic diseases in low-income urban settings. The authors conduct a feasibility study of an environmental intervention (Baltimore Healthy Stores) in seven corner stores owned by Korean Americans and two supermarkets in low-income East Baltimore. The goal is to increase the availability of healthy food options and to promote them at the point of purchase. The process evaluation is conducted largely by external evaluators. Participating stores stock promoted foods, and print materials are displayed with moderate to high fidelity. Interactive consumer taste tests are implemented with high reach and dose. Materials developed specifically for Korean American corner store owners are implemented with moderate to high fidelity and dose. Results indicate that small food store–based intervention programs are feasible to implement and are a viable means of increasing healthy food availability and a good location for point-of-purchase promotions in low-income urban settings. PMID:19144859
The computation of equating errors in international surveys in education.
Monseur, Christian; Berezner, Alla
2007-01-01
Since the IEA's Third International Mathematics and Science Study, one of the major objectives of international surveys in education has been to report trends in achievement. The names of the two current IEA surveys reflect this growing interest: Trends in International Mathematics and Science Study (TIMSS) and Progress in International Reading Literacy Study (PIRLS). Similarly a central concern of the OECD's PISA is with trends in outcomes over time. To facilitate trend analyses these studies link their tests using common item equating in conjunction with item response modelling methods. IEA and PISA policies differ in terms of reporting the error associated with trends. In IEA surveys, the standard errors of the trend estimates do not include the uncertainty associated with the linking step while PISA does include a linking error component in the standard errors of trend estimates. In other words, PISA implicitly acknowledges that trend estimates partly depend on the selected common items, while the IEA's surveys do not recognise this source of error. Failing to recognise the linking error leads to an underestimation of the standard errors and thus increases the Type I error rate, thereby resulting in reporting of significant changes in achievement when in fact these are not significant. The growing interest of policy makers in trend indicators and the impact of the evaluation of educational reforms appear to be incompatible with such underestimation. However, the procedure implemented by PISA raises a few issues about the underlying assumptions for the computation of the equating error. After a brief introduction, this paper will describe the procedure PISA implemented to compute the linking error. The underlying assumptions of this procedure will then be discussed. Finally an alternative method based on replication techniques will be presented, based on a simulation study and then applied to the PISA 2000 data.
Rosenberg Goldstein, Rachel E; Cruz-Cano, Raul; Jiang, Chengsheng; Palmer, Amanda; Blythe, David; Ryan, Patricia; Hogan, Brenna; White, Benjamin; Dunn, John R; Libby, Tanya; Tobin-D'Angelo, Melissa; Huang, Jennifer Y; McGuire, Suzanne; Scherzinger, Karen; Lee, Mei-Ling Ting; Sapkota, Amy R
2016-07-22
Campylobacter is a leading cause of foodborne illness in the United States. Campylobacter infections have been associated with individual risk factors, such as the consumption of poultry and raw milk. Recently, a Maryland-based study identified community socioeconomic and environmental factors that are also associated with campylobacteriosis rates. However, no previous studies have evaluated the association between community risk factors and campylobacteriosis rates across multiple U.S. states. We obtained Campylobacter case data (2004-2010; n = 40,768) from the Foodborne Diseases Active Surveillance Network (FoodNet) and socioeconomic and environmental data from the 2010 Census of Population and Housing, the 2011 American Community Survey, and the 2007 U.S. Census of Agriculture. We linked data by zip code and derived incidence rate ratios using negative binomial regression models. Community socioeconomic and environmental factors were associated with both lower and higher campylobacteriosis rates. Zip codes with higher percentages of African Americans had lower rates of campylobacteriosis (incidence rate ratio [IRR]) = 0.972; 95 % confidence interval (CI) = 0.970,0.974). In Georgia, Maryland, and Tennessee, three leading broiler chicken producing states, zip codes with broiler operations had incidence rates that were 22 % (IRR = 1.22; 95 % CI = 1.03,1.43), 16 % (IRR = 1.16; 95 % CI = 0.99,1.37), and 35 % (IRR = 1.35; 95 % CI = 1.18,1.53) higher, respectively, than those of zip codes without broiler operations. In Minnesota and New York FoodNet counties, two top dairy producing areas, zip codes with dairy operations had significantly higher campylobacteriosis incidence rates (IRR = 1.37; 95 % CI = 1.22, 1.55; IRR = 1.19; 95 % CI = 1.04,1.36). Community socioeconomic and environmental factors are important to consider when evaluating the relationship between possible risk factors and Campylobacter infection.
Trends and Disparities in Heart Disease Mortality Among American Indians/Alaska Natives, 1990–2009
Ayala, Carma; Schieb, Linda; Dai, Shifan; Henderson, Jeffrey A.; Cho, Pyone
2014-01-01
Objectives. We evaluated heart disease death rates among American Indians and Alaska Natives (AI/ANs) and Whites after improving identification of AI/AN populations. Methods. Indian Health Service (IHS) registration data were linked to the National Death Index for 1990 to 2009 to identify deaths among AI/AN persons aged 35 years and older with heart disease listed as the underlying cause of death (UCOD) or 1 of multiple causes of death (MCOD). We restricted analyses to IHS Contract Health Service Delivery Areas and to non-Hispanic populations. Results. Heart disease death rates were higher among AI/AN persons than Whites from 1999 to 2009 (1.21 times for UCOD, 1.30 times for MCOD). Disparities were highest in younger age groups and in the Northern Plains, but lowest in the East and Southwest. In AI/AN persons, MCOD rates were 84% higher than UCOD rates. From 1990 to 2009, UCOD rates declined among Whites, but only declined significantly among AI/AN persons after 2003. Conclusions. Analysis with improved race identification indicated that AI/AN populations experienced higher heart disease death rates than Whites. Better prevention and more effective care of heart disease is needed for AI/AN populations. PMID:24754556
Loopstra, Rachel; Reeves, Aaron; Barr, Ben; Taylor-Robinson, David; McKee, Martin; Stuckler, David
2016-01-01
Background It is unclear why rates of homelessness claims in England have risen since 2010. We used variations in rates across local authorities to test the impact of economic downturns and budget cuts. Methods Using cross-area fixed effects models of data from 323 UK local authorities between 2004 and 2012, we evaluated associations of changes in statutory homelessness rates with economic activity (Gross Value Added per capita), unemployment, and local and central government expenditure. Results Each 10% fall in economic activity was associated with an increase of 0.45 homelessness claims per 1000 households (95% CI: 0.10–0.80). Increasing rates of homelessness were also strongly linked with government reductions in welfare spending. Disaggregating types of welfare expenditure, we found that strongest associations with reduced homelessness claims were spending on social care, housing services, discretionary housing payments and income support for older persons. Conclusions Recession and austerity measures are associated with significant increases in rates of homelessness assistance. These findings likely understate the full burden of homelessness as they only capture those who seek aid. Future research is needed to investigate what is happening to vulnerable groups who may not obtain assistance, including those with mental health problems and rough sleepers. PMID:26364320
Langberg, Kurt; Phillips, Matthew; Rueppell, Olav
2018-04-01
The rate of genomic recombination displays evolutionary plasticity and can even vary in response to environmental factors. The western honey bee (Apis mellifera L.) has an extremely high genomic recombination rate but the mechanistic basis for this genome-wide upregulation is not understood. Based on the hypothesis that meiotic recombination and DNA damage repair share common mechanisms in honey bees as in other organisms, we predicted that oxidative stress leads to an increase in recombination rate in honey bees. To test this prediction, we subjected honey bee queens to oxidative stress by paraquat injection and measured the rates of genomic recombination in select genome intervals of offspring produced before and after injection. The evaluation of 26 genome intervals in a total of over 1750 offspring of 11 queens by microsatellite genotyping revealed several significant effects but no overall evidence for a mechanistic link between oxidative stress and increased recombination was found. The results weaken the notion that DNA repair enzymes have a regulatory function in the high rate of meiotic recombination of honey bees, but they do not provide evidence against functional overlap between meiotic recombination and DNA damage repair in honey bees and more mechanistic studies are needed.
Controller/Computer Interface with an Air-Ground Data Link
DOT National Transportation Integrated Search
1976-06-01
This report describes the results of an experiment for evaluating the controller/computer interface in an ARTS III/M&S system modified for use with a simulated digital data link and a voice link utilizing a computer-generated voice system. A modified...
Fogel, Anna; Fries, Lisa R; McCrickerd, Keri; Goh, Ai Ting; Quah, Phaik Ling; Chan, Mei Jun; Toh, Jia Ying; Chong, Yap-Seng; Tan, Kok Hian; Yap, Fabian; Shek, Lynette P; Meaney, Michael J; Broekman, Birit F P; Lee, Yung Seng; Godfrey, Keith M; Fong Chong, Mary Foong; Forde, Ciarán G
2018-07-01
Oral processing behaviours associated with faster eating rates have been consistently linked to increased energy intakes, but little is known about their links to children's appetitive traits. This study used the Child Eating Behaviour Questionnaire (CEBQ) to explore cross-sectional and prospective associations between parent-reported appetitive traits and observed oral processing behaviours. Participants were 195 children from the Growing Up in Singapore Towards healthy Outcomes cohort, who participated in a video-recorded ad libitum lunch at 4.5 (Time 1) and 6 years (Time 2). Their mothers completed the CEBQ around the same time points. Children's bites, chews and swallows were coded, and used to calculate their eating rate, bite size, chews per bite, chew rate, oral exposure time and oral exposure per bite. At Time 1, children with higher scores in slowness in eating had lower eating and chew rates. At Time 2, higher scores for food enjoyment and lower for satiety responsiveness, slowness in eating, and food fussiness were linked with higher eating rates and greater energy intakes (r > 0.16, p < 0.05). Post-hoc analyses revealed that these associations were moderated by BMI and only present among children with higher BMI. Faster eating rates mediated the associations between greater food enjoyment, lower slowness in eating, lower food fussiness and higher intakes of energy. Children with higher slowness in eating scores had lower increases in eating rates over time, and children with higher BMI who had greater food enjoyment and food responsiveness scores had greater increases in eating rates over time. The findings suggest that oral processing behaviours linked with increased obesity risk may be underpinned by appetitive traits and may be one of the behavioural pathways through which these appetitive traits influence energy intakes. Copyright © 2018 Elsevier Ltd. All rights reserved.
William John. Mattson
1983-01-01
Spruce budworm growth was best on balsam fir, poorest on lowland black spruce, and intermediate on upland white and black spruce. Growth was consistently, positively linked to foliar N and negatively linked to Fe, K, and select terpenes. Survival rates were not strongly, nor consistently linked to any of the measured foliar chemical traits.
Undersea Laser Communication with Narrow Beams
2015-09-29
Abstract Laser sources enable highly efficient optical communications links due to their ability to be focused into very directive beam profiles...Recent atmospheric and space optical links have demonstrated robust laser communications links at high rate with techniques that are applicable to the...undersea environment. These techniques contrast to the broad-angle beams utilized in most reported demonstrations of undersea optical communications
NASA Astrophysics Data System (ADS)
Singh, Mehtab
2017-05-01
Free Space Optics (FSO) technique is an advanced form of the wireless communication system capable of transmitting data at higher transmission rates with higher channel bandwidth and over longer link distances. One of the major challenges faced by FSO technology is the distortion of received signal due to atmospheric effects which degrade the performance of the communication link by increasing the bit error rate (BER). By implementing Erbium Doped Fiber Amplifier (EDFA) in the FSO link, the degradation of the information signal due to atmospheric effects can be minimized. Also, by deploying spatial diversity technique in the FSO link, where multiple copies of the information signal are transmitted to increase the redundancy of the system, the system performance can be enhanced. In this paper, the performance of an FSO communication link has been analyzed under fog weather condition using a different number of Tx/Rx pairs and EDFA amplifier using OPTISYSTEM simulation software. Performance has been analyzed on the basis of Q Factor, SNR, BER, and total power of the received signal. Results show a significant improvement in the system performance by deploying multiple transceiver techniques.
Phase-modulated radio over fiber multimode links.
Gasulla, Ivana; Capmany, José
2012-05-21
We present the first experimental demonstration of a phase-modulated MMF link implementing high-frequency digital transmission in a cost-effective solution based on direct detection. Successful subcarrier transmission of QPSK, 16-QAM and 64-QAM data channels for bit rates up to 120 Mb/s through a 5 km MMF link is achieved over the microwave region comprised between 6 and 20 GHz. The overall capacity of the proposed approach can be further increased by properly accommodating more passband channels in the operative frequency range determined by the phase-to-intensity conversion process provided by the dispersive nature of the optical fiber. In this sense, our results show the possibility of achieving an aggregate bit rate per length product of 144 Gb/s · km and confirm, in consequence, the possibility of broadband phase-modulated radio over fiber transmission through MMF links suitable for multichannel SCM signal distribution.
Sensorimotor abilities predict on-field performance in professional baseball.
Burris, Kyle; Vittetoe, Kelly; Ramger, Benjamin; Suresh, Sunith; Tokdar, Surya T; Reiter, Jerome P; Appelbaum, L Gregory
2018-01-08
Baseball players must be able to see and react in an instant, yet it is hotly debated whether superior performance is associated with superior sensorimotor abilities. In this study, we compare sensorimotor abilities, measured through 8 psychomotor tasks comprising the Nike Sensory Station assessment battery, and game statistics in a sample of 252 professional baseball players to evaluate the links between sensorimotor skills and on-field performance. For this purpose, we develop a series of Bayesian hierarchical latent variable models enabling us to compare statistics across professional baseball leagues. Within this framework, we find that sensorimotor abilities are significant predictors of on-base percentage, walk rate and strikeout rate, accounting for age, position, and league. We find no such relationship for either slugging percentage or fielder-independent pitching. The pattern of results suggests performance contributions from both visual-sensory and visual-motor abilities and indicates that sensorimotor screenings may be useful for player scouting.
Changes in forest productivity across Alaska consistent with biome shift.
Beck, Pieter S A; Juday, Glenn P; Alix, Claire; Barber, Valerie A; Winslow, Stephen E; Sousa, Emily E; Heiser, Patricia; Herriges, James D; Goetz, Scott J
2011-04-01
Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline. © 2011 Blackwell Publishing Ltd/CNRS.
Experiments applications guide: Advanced Communications Technology Satellite (ACTS)
NASA Technical Reports Server (NTRS)
1988-01-01
This applications guide first surveys the capabilities of the Advanced Communication Technology Satellite (ACTS) system (both the flight and ground segments). This overview is followed by a description of the baseband processor (BBP) and microwave switch matrix (MSM) operating modes. Terminals operating with the baseband processor are referred to as low burst rate (LBR); and those operating with the microwave switch matrix, as high burst rate (HBR). Three very small-aperture terminals (VSATs), LBR-1, LBR-2, and HBR, are described for various ACTS operating modes. Also described is the NASA Lewis link evaluation terminal. A section on ACTS experiment opportunities introduces a wide spectrum of network control, telecommunications, system, and scientific experiments. The performance of the VSATs is discussed in detail. This guide is intended as a catalyst to encourage participation by the telecommunications, business, and science communities in a broad spectrum of experiments.
Knechtle, William S; Perez, Sebastian D; Raval, Mehul V; Sullivan, Patrick S; Duwayri, Yazan M; Fernandez, Felix; Sharma, Joe; Sweeney, John F
Quality-cost diagrams have been used previously to assess interventions and their cost-effectiveness. This study explores the use of risk-adjusted quality-cost diagrams to compare the value provided by surgeons by presenting cost and outcomes simultaneously. Colectomy cases from a single institution captured in the National Surgical Quality Improvement Program database were linked to hospital cost-accounting data to determine costs per encounter. Risk adjustment models were developed and observed average cost and complication rates per surgeon were compared to expected cost and complication rates using the diagrams. Surgeons were surveyed to determine if the diagrams could provide information that would result in practice adjustment. Of 55 surgeons surveyed on the utility of the diagrams, 92% of respondents believed the diagrams were useful. The diagrams seemed intuitive to interpret, and making risk-adjusted comparisons accounted for patient differences in the evaluation.
Teachers Supporting Teachers in Urban Schools: What Iterative Research Designs Can Teach Us.
Shernoff, Elisa S; Maríñez-Lora, Ane M; Frazier, Stacy L; Jakobsons, Lara J; Atkins, Marc S; Bonner, Deborah
2011-12-01
Despite alarming rates and negative consequences associated with urban teacher attrition, mentoring programs often fail to target the strongest predictors of attrition: effectiveness around classroom management and engaging learners; and connectedness to colleagues. Using a mixed-method iterative development framework, we highlight the process of developing and evaluating the feasibility of a multi-component professional development model for urban early career teachers. The model includes linking novices with peer-nominated key opinion leader teachers and an external coach who work together to (1) provide intensive support in evidence-based practices for classroom management and engaging learners, and (2) connect new teachers with their larger network of colleagues. Fidelity measures and focus group data illustrated varying attendance rates throughout the school year and that although seminars and professional learning communities were delivered as intended, adaptations to enhance the relevance, authenticity, level, and type of instrumental support were needed. Implications for science and practice are discussed.
[THE GLOBAL AND ECONOMIC CRISIS. AND HEALTH MANAGEMENT].
del Rey Calero, Juan
2014-01-01
The Global and economic crisis and Health Management The Health care process discussed are 4 steps: assessment, planing, intervention and evaluation. The identify association between social factors linked to social vulnerability (socio economic status, unemployed, poverty) and objective health relate quality of life. The poverty rate is 24.2%, unemployed 26.26%, youth unemployed 56.13%.ratio worker/retired 2.29. Debts 100% GDP The health inequality influence on health related quality of life. The Health System efficiency index. according Bloomber rate (2,013) Spain is 5 degrees in the world, points 68.3 on 100, for the life expectancy 82.3 years, the personal cost of health care 2,271€. Health care 10% GDP (public 7%,private 3%), SS protected population 92.4%, retired person cost 9.2% GDP, p. capita GDP 23,737€. Cost of Care: Hospital/specialist 54%, P. Care 15%, Pharmaceutical 19.8%, P. Health 3.1%.
Donor cross-linking for keratoplasty: a laboratory evaluation.
Mukherjee, Achyut; Hayes, Sally; Aslanides, Ioannis; Lanchares, Elena; Meek, Keith M
2015-12-01
This laboratory-based investigation compares the topographic outcomes of conventional penetrating keratoplasty with that of a novel procedure in which donor corneas are cross-linked prior to keratoplasty. Penetrating keratoplasty procedures with continuous running sutures were carried out in a porcine whole globe model. Sixty eyes were randomly paired as 'donor' and 'host' tissue before being assigned to one of two groups. In the cross-linked group, donor corneas underwent riboflavin/UVA cross-linking prior to being trephined and sutured to untreated hosts. In the conventional keratoplasty group, both host and donor corneas remained untreated prior to keratoplasty. Topographic and corneal wavefront measurements were performed following surgery, and technical aspects of the procedure evaluated. Mean keratometric astigmatism was significantly lower in the cross-linked donor group at 3.67D (SD 1.8 D), vs. 8.43 D (SD 2.4 D) in the conventional keratoplasty group (p < 0.005). Mean wavefront astigmatism was also significantly reduced in the cross-linked donor group 4.71 D (SD 2.1) vs. 8.29D (SD 3.6) in the conventional keratoplasty group (p < 0.005). Mean RMS higher order aberration was significantly lower in the cross-linked donor group at 1.79 um (SD 0.98), vs. 3.05 um (SD 1.9) in the conventional keratoplasty group (P = 0.02). Qualitative analysis revealed less tissue distortion at the graft-host junction in the cross-linked group. Cross-linking of donor corneas prior to keratoplasty reduces intraoperative induced astigmatism and aberrations in an animal model. Further studies are indicated to evaluate the implications of this potential modification of keratoplasty surgery.
Improved Attitudes to Psychiatry: A Global Mental Health Peer-to-Peer E-Learning Partnership.
Keynejad, Roxanne; Garratt, Elisabeth; Adem, Gudon; Finlayson, Alexander; Whitwell, Susannah; Sheriff, Rebecca Syed
2016-08-01
Health links aim to strengthen healthcare systems in low and middle-income countries through mutual exchange of skills, knowledge, and experience. However, student participation remains limited despite growing educational emphasis upon global health. Medical students continue to report negative attitudes to psychiatry in high-income countries, and in Somaliland, the lack of public sector psychiatrists limits medical students' awareness of mental healthcare. The authors describe the design, implementation, and mixed-methods analysis of a peer-to-peer psychiatry e-learning partnership between UK and Somaliland students arising from a global mental health link between the two countries. Medical students at King's College London and Hargeisa and Amoud universities, Somaliland, were grouped into 24 pairs. Participants aimed to complete ten fortnightly meetings to discuss psychiatry topics via the website MedicineAfrica. Students completed initial and final evaluations including Attitudes toward Psychiatry (ATP-30) questions, a stigma questionnaire, and brief evaluations after each meeting. Quantitative findings demonstrated that enjoyment, interest, and academic helpfulness were rated highly by students in Somaliland and moderately by students in the UK. Somaliland students' attitudes to psychiatry were significantly more positive post-participation, whereas UK students' attitudes remained stable. Qualitative findings identified more gains in factual knowledge for Somaliland students, whereas UK students reported more cross-cultural learning. Reasons for non-completion and student-suggested improvements emphasized the need to ensure commitment to the program by participants. This partnership encouraged students to consider global mental health outside the standard medical education environment, through an e-learning format solely utilizing existing resources. This new approach demonstrates potential benefits to students in contrasting locations of brief, focused online peer-to-peer education partnerships, expanding the scope of health links to the medical professionals of the future.
Rigual, Nestor; Shafirstein, Gal; Cooper, Michele T.; Baumann, Heinz; Bellnier, David A.; Sunar, Ulas; Tracy, Erin C.; Rohrbach, Daniel J.; Wilding, Gregory; Tan, Wei; Sullivan, Maureen; Merzianu, Mihai; Henderson, Barbara W.
2013-01-01
Purpose The primary objective was to evaluate safety of 3-(1’-hexyloxyethyl)pyropheophorbide-a (HPPH) photodynamic therapy (HPPH-PDT) for dysplasia and early squamous cell carcinoma of the head and neck (HNSCC). Secondary objectives were the assessment of treatment response and reporters for an effective PDT reaction. Experimental Design Patients with histologically proven oral dysplasia, carcinoma in situ (CiS ) or early stage HNSCC were enrolled in two sequentially conducted dose escalation studies with an expanded cohort at the highest dose level. These studies employed an HPPH dose of 4 mg/m2 and light doses from 50 to 140 J/cm2. Pathologic tumor responses were assessed at 3 months. Clinical follow up range was 5 to 40 months. PDT induced cross-linking of signal transducer and activator of transcription 3 (STAT3) were assessed as potential indicators of PDT effective reaction. Results Forty patients received HPPH-PDT. Common adverse events were pain and treatment site edema. Biopsy proven complete response rates were 46% for dysplasia and CiS, and 82% for SCCs lesions at 140 J/cm2. The responses in the CiS/dysplasia cohort are not durable. The PDT induced STAT3 cross-links is significantly higher (P=0.0033) in SCC than in CiS/dysplasia for all light-doses. Conclusion HPPH-PDT is safe for the treatment of CiS/dysplasia and early stage cancer of the oral cavity. Early stage oral HNSCC appears to respond better to HPPH-PDT in comparison to premalignant lesions. The degree of STAT3 cross-linking is a significant reporter to evaluate HPPH-PDT mediated photoreaction. PMID:24088736
NASA Astrophysics Data System (ADS)
Gupta, Amit; Shaina, Nagpal
2017-08-01
Intersymbol interference and attenuation of signal are two major parameters affecting the quality of transmission in Free Space Optical (FSO) Communication link. In this paper, the impact of these parameters on FSO communication link is analysed for delivering high-quality data transmission. The performance of the link is investigated under the influence of amplifier in the link. The performance parameters of the link like minimum bit error rate, received signal power and Quality factor are examined by employing erbium-doped fibre amplifier in the link. The effects of amplifier are visualized with the amount of received power. Further, the link is simulated for moderate weather conditions at various attenuation levels on transmitted signal. Finally, the designed link is analysed in adverse weather conditions by using high-power laser source for optimum performance.
Self-Concept Structure and the Quality of Self-Knowledge.
Showers, Carolin J; Ditzfeld, Christopher P; Zeigler-Hill, Virgil
2015-10-01
This article explores the hidden vulnerability of individuals with compartmentalized self-concept structures by linking research on self-organization to related models of self-functioning. Across three studies, college students completed self-descriptive card sorts as a measure of self-concept structure and either the Contingencies of Self-Worth Scale, Likert ratings of perceived authenticity of self-aspects, or a response latency measure of self-esteem accessibility. In all, there were 382 participants (247 females; 77% White, 6% Hispanic, 5% Black, 5% Asian, 4% Native American, and 3% other). Consistent with their unstable self-evaluations, compartmentalized individuals report greater contingencies of self-worth and describe their experience of multiple self-aspects as less authentic than do individuals with integrative self-organization. Compartmentalized individuals also make global self-evaluations more slowly than do integrative individuals. Together with previous findings on self-clarity, these results suggest that compartmentalized individuals may experience difficulties in how they know the self, whereas individuals with integrative self-organization may display greater continuity and evaluative consistency across self-aspects, with easier access to evaluative self-knowledge. © 2014 Wiley Periodicals, Inc.
Self-Concept Structure and the Quality of Self-Knowledge
Showers, Carolin J.; Ditzfeld, Christopher P.; Zeigler-Hill, Virgil
2014-01-01
Objective Explores the hidden vulnerability of individuals with compartmentalized self-concept structures by linking research on self-organization to related models of self functioning. Method Across three studies, college students completed self-descriptive card sorts as a measure of self-concept structure and either the Contingencies of Self-Worth Scale; Likert ratings of perceived authenticity of self-aspects; or a response latency measure of self-esteem accessibility. In all, there were 382 participants (247 females; 77% White, 6% Hispanic, 5% Black, 5% Asian, 4% Native American, and 3% Other). Results Consistent with their unstable self-evaluations, compartmentalized individuals report greater contingencies of self-worth and describe their experience of multiple self-aspects as less authentic than do individuals with integrative self-organization. Compartmentalized individuals also make global self-evaluations more slowly than do integrative individuals. Conclusions Together with previous findings on self-clarity, these results suggest that compartmentalized individuals may experience difficulties in how they know the self, whereas individuals with integrative self-organization may display greater continuity and evaluative consistency across self-aspects, with easier access to evaluative self-knowledge. PMID:25180616
Error monitoring issues for common channel signaling
NASA Astrophysics Data System (ADS)
Hou, Victor T.; Kant, Krishna; Ramaswami, V.; Wang, Jonathan L.
1994-04-01
Motivated by field data which showed a large number of link changeovers and incidences of link oscillations between in-service and out-of-service states in common channel signaling (CCS) networks, a number of analyses of the link error monitoring procedures in the SS7 protocol were performed by the authors. This paper summarizes the results obtained thus far and include the following: (1) results of an exact analysis of the performance of the error monitoring procedures under both random and bursty errors; (2) a demonstration that there exists a range of error rates within which the error monitoring procedures of SS7 may induce frequent changeovers and changebacks; (3) an analysis of the performance ofthe SS7 level-2 transmission protocol to determine the tolerable error rates within which the delay requirements can be met; (4) a demonstration that the tolerable error rate depends strongly on various link and traffic characteristics, thereby implying that a single set of error monitor parameters will not work well in all situations; (5) some recommendations on a customizable/adaptable scheme of error monitoring with a discussion on their implementability. These issues may be particularly relevant in the presence of anticipated increases in SS7 traffic due to widespread deployment of Advanced Intelligent Network (AIN) and Personal Communications Service (PCS) as well as for developing procedures for high-speed SS7 links currently under consideration by standards bodies.
Modulation/demodulation techniques for satellite communications. Part 1: Background
NASA Technical Reports Server (NTRS)
Omura, J. K.; Simon, M. K.
1981-01-01
Basic characteristics of digital data transmission systems described include the physical communication links, the notion of bandwidth, FCC regulations, and performance measurements such as bit rates, bit error probabilities, throughputs, and delays. The error probability performance and spectral characteristics of various modulation/demodulation techniques commonly used or proposed for use in radio and satellite communication links are summarized. Forward error correction with block or convolutional codes is also discussed along with the important coding parameter, channel cutoff rate.
Future Mission Trends and their Implications for the Deep Space Network
NASA Technical Reports Server (NTRS)
Abraham, Douglas S.
2006-01-01
This viewgraph presentation discusses the direction of future missions and it's significance to the Deep Space Network. The topics include: 1) The Deep Space Network (DSN); 2) Past Missions Driving DSN Evolution; 3) The Changing Mission Paradigm; 4) Assessing Future Mission Needs; 5) Link Support Trends; 6) Downlink Rate Trends; 7) Uplink Rate Trends; 8) End-to-End Link Difficulty Trends; 9) Summary: Future Mission Trend Drivers; and 10) Conclusion: Implications for the DSN.
2010-01-01
recruiting needs and candidate profiles – Link the features in context of dynamic social network environments, learn from on-going market...universities, companies, etc.) • Friends list fandom (fan of) , • Endorsements (supporter of) • Navy Enlisted Rating descriptions – Hard Cards...the samples into a validation and a learning set Set aside . the validation set. Use the learning set to match the recruit ratings with the
Rainfall measurement from opportunistic use of earth-space link in Ku Band
NASA Astrophysics Data System (ADS)
Barthès, L.; Mallet, C.
2013-02-01
The present study deals with the development of a low cost microwave device devoted to measure average rain rate observed along earth - satellite links. The principle is to use rain atmospheric attenuation along Earth - space links in Ku-band to deduce the path averaged rain rate. These links are characterized by a path length of a few km through the troposphere. Ground based power measurements are carried out by receiving TV channels from different geostationary satellites in Ku-band. The major difficulty in this study is to retrieve rain characteristics among many fluctuations of the received signal which are due to atmospheric scintillations, changes in the composition of the atmosphere (water vapour concentration, cloud water content) or satellite features (variation of the emitted power, satellite motions). In order to perform a feasibility study of such a device, a measurement campaign has been performed for five months near Paris. This paper proposes an algorithm based on an artificial neural network to identify drought and rainy periods and to suppress the variability of the received signal due to no-rain effects. Taking into account the height of the rain layer, rain attenuation is then inverted to obtain path averaged rain rate. Obtained rainfall rates are compared with co-located rain gauges and radar measurements on the whole experiment period, then the most significant rainy events are analyzed.
Downer, N W; Cone, R A
1985-01-01
If a photoexcited rhodopsin molecule initiates the formation of rhodopsin oligomers during the process of visual excitation, the rate of rotational diffusion of the rhodopsin molecules involved should change markedly. Using microsecond-flash photometry, we have observed the rotational diffusion of rhodopsin throughout the time period of visual excitation and found that no detectable change occurs in its rotational diffusion rate. Partial chemical cross-linking of the retina yields oligomers of rhodopsin and causes a significant decrease in the rotational diffusion rate of rhodopsin even when as little as 20% of rhodopsin is dimeric. Moreover, the pattern of oligomers formed by cross-linking, taken together with the magnitude of decreases in rotational diffusion rate accompanying the cross-linking reaction, suggests that rhodopsin is a monomer in the dark-adapted state. The experiments reported here show that photoexcited rhodopsin molecules do not irreversibly associate with unbleached neighbors during the time course of the receptor response. Hence, it is not likely that stable oligomers of rhodopsin trigger the excitation of the photoreceptor cell. Images FIGURE 1 PMID:3919778
Young women's food preferences and taste responsiveness to 6-n-propylthiouracil (PROP).
Kaminski, L C; Henderson, S A; Drewnowski, A
2000-03-01
This study examined links between taste responsiveness to 6-n-propylthiouracil (PROP), a heritable trait, and sensory responses to six common foods. Sixty-three young women subjects were divided into PROP tasters (n = 25) and nontasters (n = 25), based on their responses to PROP-impregnated filter paper and mean bitterness intensity ratings for seven PROP solutions. Thirteen subjects were excluded as unclassifiable. The 50 subjects sampled Brussels sprouts, broccoli, spinach, black coffee, soy milk, and soybean tofu. Sensory ratings for bitter intensity; pleasantness of taste, odor, and texture, and overall food acceptability scores were obtained using nine-point category scales. All subjects completed a food-preference checklist and a modified food-frequency questionnaire. PROP tasters rated Brussels sprouts as more bitter than did nontasters (p<0.05). Subjects who perceived the foods as more bitter also rated them as less pleasant and less acceptable. Taste preferences and food preferences were linked. Self-reported food preferences and self-reported frequencies of consumption for the same foods were also linked. Taste factors and food preferences may impact dietary choices and the frequency of food consumption.