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1

Observational Studies  

NSDL National Science Digital Library

This lesson on observational studies discusses the nature of such studies, the relationships between various data sets, and regression. Graphs illustrate the relationships, and exercises at the end test the user's comprehension and understanding. It is taken from the online textbook for Western Michigan University online introductory stats course.

Abebe, Asheber; Daniels, John E.; Kapenga, J. A.; Mckean, Joe W.

2008-12-25

2

The generalizability study as a method of assessing intra- and interobserver reliability in observational research  

Microsoft Academic Search

Most researchers use interobserver agreement percentages to express the quality of their observational data. A better method\\u000a is the generalizability study, which allows the variance in a set of scores to be partitioned among several sources, such\\u000a as observers, occasions, subjects, and error. In this paper the practical application of generalizability theory is described\\u000a and illustrated, using the frequency and

Cathryn L. Booth; Sandra K. Mitchell; Frances K. Solin

1979-01-01

3

Reporting quality of statistical methods in surgical observational studies: protocol for systematic review  

PubMed Central

Background Observational studies dominate the surgical literature. Statistical adjustment is an important strategy to account for confounders in observational studies. Research has shown that published articles are often poor in statistical quality, which may jeopardize their conclusions. The Statistical Analyses and Methods in the Published Literature (SAMPL) guidelines have been published to help establish standards for statistical reporting. This study will seek to determine whether the quality of statistical adjustment and the reporting of these methods are adequate in surgical observational studies. We hypothesize that incomplete reporting will be found in all surgical observational studies, and that the quality and reporting of these methods will be of lower quality in surgical journals when compared with medical journals. Finally, this work will seek to identify predictors of high-quality reporting. Methods/Design This work will examine the top five general surgical and medical journals, based on a 5-year impact factor (2007–2012). All observational studies investigating an intervention related to an essential component area of general surgery (defined by the American Board of Surgery), with an exposure, outcome, and comparator, will be included in this systematic review. Essential elements related to statistical reporting and quality were extracted from the SAMPL guidelines and include domains such as intent of analysis, primary analysis, multiple comparisons, numbers and descriptive statistics, association and correlation analyses, linear regression, logistic regression, Cox proportional hazard analysis, analysis of variance, survival analysis, propensity analysis, and independent and correlated analyses. Each article will be scored as a proportion based on fulfilling criteria in relevant analyses used in the study. A logistic regression model will be built to identify variables associated with high-quality reporting. A comparison will be made between the scores of surgical observational studies published in medical versus surgical journals. Secondary outcomes will pertain to individual domains of analysis. Sensitivity analyses will be conducted. Discussion This study will explore the reporting and quality of statistical analyses in surgical observational studies published in the most referenced surgical and medical journals in 2013 and examine whether variables (including the type of journal) can predict high-quality reporting. PMID:24972453

2014-01-01

4

Generalizing Observational Study Results Applying Propensity Score Methods to Complex Surveys  

PubMed Central

Objective To provide a tutorial for using propensity score methods with complex survey data. Data Sources Simulated data and the 2008 Medical Expenditure Panel Survey (MEPS). Study Design Using simulation, we compared the following methods for estimating the treatment effect: a naïve estimate (ignoring both survey weights and propensity scores), survey weighting, propensity score methods (nearest neighbor matching, weighting, and subclassification), and propensity score methods in combination with survey weighting. Methods are compared in terms of bias and 95% confidence interval coverage. In Example 2, we used these methods to estimate the effect on health care spending of having a generalist versus a specialist as a usual source of care. Principal Findings In general, combining a propensity score method and survey weighting is necessary to achieve unbiased treatment effect estimates that are generalizable to the original survey target population. Conclusions Propensity score methods are an essential tool for addressing confounding in observational studies. Ignoring survey weights may lead to results that are not generalizable to the survey target population. This paper clarifies the appropriate inferences for different propensity score methods and suggests guidelines for selecting an appropriate propensity score method based on a researcher’s goal. PMID:23855598

DuGoff, Eva H.; Schuler, Megan; Stuart, Elizabeth A.

2013-01-01

5

Validation of the Work Observation Method By Activity Timing (WOMBAT) method of conducting time-motion observations in critical care settings: an observational study  

Microsoft Academic Search

Background  Electronic documentation handling may facilitate information flows in health care settings to support better coordination\\u000a of care among Health Care Providers (HCPs), but evidence is limited. Methods that accurately depict changes to the workflows\\u000a of HCPs are needed to assess whether the introduction of a Critical Care clinical Information System (CCIS) to two Intensive\\u000a Care Units (ICUs) represents a positive

Mark A Ballermann; Nicola T Shaw; Damon C Mayes; RT Noel Gibney; Johanna I Westbrook

2011-01-01

6

Adaptive list sequential sampling method for population-based observational studies  

PubMed Central

Background In population-based observational studies, non-participation and delayed response to the invitation to participate are complications that often arise during the recruitment of a sample. When both are not properly dealt with, the composition of the sample can be different from the desired composition. Inviting too many individuals or too few individuals from a particular subgroup could lead to unnecessary costs or decreased precision. Another problem is that there is frequently no or only partial information available about the willingness to participate. In this situation, we cannot adjust the recruitment procedure for non-participation before the recruitment period starts. Methods We have developed an adaptive list sequential sampling method that can deal with unknown participation probabilities and delayed responses to the invitation to participate in the study. In a sequential way, we evaluate whether we should invite a person from the population or not. During this evaluation, we correct for the fact that this person could decline to participate using an estimated participation probability. We use the information from all previously invited persons to estimate the participation probabilities for the non-evaluated individuals. Results The simulations showed that the adaptive list sequential sampling method can be used to estimate the participation probability during the recruitment period, and that it can successfully recruit a sample with a specific composition. Conclusions The adaptive list sequential sampling method can successfully recruit a sample with a specific desired composition when we have partial or no information about the willingness to participate before we start the recruitment period and when individuals may have a delayed response to the invitation. PMID:24965316

2014-01-01

7

An Introduction to Propensity Score Methods for Reducing the Effects of Confounding in Observational Studies  

ERIC Educational Resources Information Center

The propensity score is the probability of treatment assignment conditional on observed baseline characteristics. The propensity score allows one to design and analyze an observational (nonrandomized) study so that it mimics some of the particular characteristics of a randomized controlled trial. In particular, the propensity score is a balancing…

Austin, Peter C.

2011-01-01

8

Studies of Trace Gas Chemical Cycles Using Observations, Inverse Methods and Global Chemical Transport Models  

NASA Technical Reports Server (NTRS)

For interpreting observational data, and in particular for use in inverse methods, accurate and realistic chemical transport models are essential. Toward this end we have, in recent years, helped develop and utilize a number of three-dimensional models including the Model for Atmospheric Transport and Chemistry (MATCH).

Prinn, Ronald G.

2001-01-01

9

An observational study of the nightside ionospheres of Mars and Venus with radio occultation methods  

SciTech Connect

An analysis of Mars and Venus nightside electron density profiles obtained with radio occultation methods shows how the nightside ionospheres of both planets vary with solar zenith angle. From previous studies it is known that the dayside peak electron densities at Mars and Venus show a basic similarity in that they both exhibit Chapman layer-like behavior. In contrast, the peak altitudes at mars behave like an ideal Chapman layer on the dayside, whereas the altitude of the peak at Venus is fairly constant up to the terminator. The effect of major dust storms can also be seen in the peak altitudes at Mars. All Venus nightside electron density profiles show a distinct main peak for both solar minimum and maximum, whereas many profiles from the nightside of Mars do not show any peak at all. This suggests that the electron density in the Mars nightside ionosphere is frequently too low to be detected by radio occultation. On the Pioneer Venus orbiter, disappearing ionospheres were observed near solar maximum in the in-situ data when the solar wind dynamic pressure was exceptionally high. This condition occurs because the high solar wind dynamic pressure decreases the altitude of the ionopause near the terminator below {approximately}250 km, thus reducing the normal nightward transport of dayside ionospheric plasma. On the basis of the Venus observations, one might predict that if a positive correlation of nightside peak density with dynamic pressure was found, it could mean that transport from the dayside is the only significant source for the nightside ionosphere of Mars. The lack of a correlation would imply that the precipitation source at Mars is quite variable.

Zhang, M.H.G. (Austrian Academy of Sciences, Graz (Austria)); Luhmann, J.G. (Univ. of California, Los Angeles (United States)); Kliore, A.J. (Jet Propulsion Lab., Pasadena, CA (United States))

1990-10-01

10

Accuracy of dietary recall using the USDA five-step multiple-pass method in men: An observational validation study  

Microsoft Academic Search

ObjectiveThis observational validation study was conducted under controlled conditions to test the accuracy of dietary recall in normal weight, overweight, and obese men using the USDA five-step multiple-pass method for dietary recall.

Joan M. Conway; Linda A. Ingwersen; Alanna J. Moshfegh

2004-01-01

11

An observational study of the nightside ionospheres of Mars and Venus with radio occultation methods  

Microsoft Academic Search

An analysis of Mars and Venus nightside electron density profiles obtained with radio occultation methods shows how the nightside ionospheres of both planets vary with solar zenith angle. From previous studies it is known that the dayside peak electron densities at Mars and Venus show a basic similarity in that they both exhibit Chapman layer-like behavior. In contrast, the peak

M. H. G. Zhang; J. G. Luhmann; A. J. Kliore

1990-01-01

12

Volcanic emissions from AIRS observations: detection methods, case study, and statistical analysis  

NASA Astrophysics Data System (ADS)

Monitoring volcanic emissions is important for many reasons, most notably for impacts on climate and possible hazards for human health or aviation safety. Satellite instruments allow for long-term monitoring of volcanic emissions on a global scale. In this paper we introduce new detection indices for volcanic ash and sulfur dioxide (SO2) that are optimized for radiance measurements of the Atmospheric InfraRed Sounder (AIRS). Radiative transfer calculations are used to determine the sensitivity of the ash index (AI) on the aerosol optical depth and the SO2 index (SI) on the SO2 column density. A case study on AIRS observations after the eruption of the Puyehue Cordon-Caulle, Chile, in June 2011 demonstrates that the new indices work in practice. A statistical analysis of a ten-year record (2002 to 2013) of AIRS data provides AI thresholds that help to better discriminate volcanic emissions from regular events such as dust storms. We compared our new SI with the AIRS operational product and found that it is more sensitive and better suppresses interfering background signals. Our new volcanic emission data products have been successfully applied in other scientific studies.

Hoffmann, Lars; Griessbach, Sabine; Meyer, Catrin I.

2014-10-01

13

An observational study of the nightside ionospheres of Mars and Venus with radio occultation methods  

NASA Technical Reports Server (NTRS)

Using nightside electron density profiles obtained with radio occultation data from the Viking orbiters, the nightside ionospheres of Mars and Venus are investigated. It is shown that the Mars nightside ionosphere is generally weaker than the Venus nightside ionosphere, and, when it is present, the peak altitude is higher. Otherwise, there is considerable similarity. In particular, the dependence of peak density on solar zenith angle in the range of the Viking nightside observations (90-130 deg) is found to be similar for both planets.

Zhang, M. H. G.; Luhmann, J. G.; Kliore, A. J.

1990-01-01

14

Overview of the Epidemiology Methods and Applications: Strengths and Limitations of Observational Study Designs  

Microsoft Academic Search

The impact of study design on the results of medical research has long been an area of both substantial debate and a smaller body of empirical research. Examples come from many disciplines within clinical and public health research. Among the early major contributions in the 1970s was work by Mosteller and colleagues (Gilbert et al., 1997), who noted that innovations

Graham A. Colditz

2010-01-01

15

Smile: First Observational Prospective Cohort Study of Migraine in Primary Care in France. Description of Methods and Study Population  

Microsoft Academic Search

The SMILE study was conducted among migraine patients consulting in primary care in France. The first phase aimed to describe the study sample of patients at entry to the study, especially emotional dimension (Hospital Anxiety and Depression scale), functional impact (abridged Migraine Specific Questionnaire), stress (Perceived Stress Scale) and coping behaviours (brief COPE inventory avoidance subscale, Coping Strategies Questionnaire catastrophizing

G Géraud; D Valade; M Lantéri-Minet; F Radat; C Lucas; E Vives; JM Joubert; C Mekies

2008-01-01

16

A rapid method to assess grape rust mites on leaves and observations from case studies in western Oregon vineyards  

Technology Transfer Automated Retrieval System (TEKTRAN)

A rapid method for extracting eriophyoid mites was adapted from previous studies to provide growers and IPM consultants with a practical, efficient, and reliable tool to monitor for rust mites in vineyards. The rinse in bag (RIB) method allows quick extraction of mites from collected plant parts (sh...

17

A mixed observational survey method  

Microsoft Academic Search

For several years, geodesists have debated the proper role of electronic distances in modern geodetic surveys. The role must be defined on an individual basis as a function of the desired accuracy and ultimate purpose of the survey. This paper proposes a mixed mode of observations for the types of surveys currently being observed following conventional first-order triangulation techniques. The

Gary M. Young

1974-01-01

18

A mixed observational survey method  

Microsoft Academic Search

For several years, geodesists have debated the proper role of electronic distances in modern geodetic surveys. The role must\\u000a be defined on an individual basis as a function of the desired accuracy and ultimate purpose of the survey. This paper proposes\\u000a a mixed mode of observations for the types of surveys currently being observed following conventional first-order triangulation\\u000a techniques. The

Gary M. Young

1974-01-01

19

Studies That Observe Humans  

MedlinePLUS

... information can be a good place to start. Case control studies: These studies look at people who already have ... got cancer and the other didn’t. Most case-control studies are retrospective (meaning that they look back at ...

20

PM2.5 Characterization for Time Series Studies: Organic Molecular Marker Speciation Methods and Observations from Daily Measurements in Denver  

PubMed Central

Particulate matter less than 2.5 microns in diameter (PM2.5) has been shown to have a wide range of adverse health effects and consequently is regulated in accordance with the US-EPA’s National Ambient Air Quality Standards. PM2.5 originates from multiple primary sources and is also formed through secondary processes in the atmosphere. It is plausible that some sources form PM2.5 that is more toxic than PM2.5 from other sources. Identifying the responsible sources could provide insight into the biological mechanisms causing the observed health effects and provide a more efficient approach to regulation. This is the goal of the Denver Aerosol Sources and Health (DASH) study, a multi-year PM2.5 source apportionment and health study. The first step in apportioning the PM2.5 to different sources is to determine the chemical make-up of the PM2.5. This paper presents the methodology used during the DASH study for organic speciation of PM2.5. Specifically, methods are covered for solvent extraction of non-polar and semi-polar organic molecular markers using gas chromatography-mass spectrometry (GC-MS). Vast reductions in detection limits were obtained through the use of a programmable temperature vaporization (PTV) inlet along with other method improvements. Results are presented for the first 1.5 years of the DASH study revealing seasonal and source-related patterns in the molecular markers and their long-term correlation structure. Preliminary analysis suggests that point sources are not a significant contributor to the organic molecular markers measured at our receptor site. Several motor vehicle emission markers help identify a gasoline/diesel split in the ambient data. Findings show both similarities and differences when compared with other cities where similar measurements and assessments have been made. PMID:20161318

Dutton, Steven J.; Williams, Daniel E.; Garcia, Jessica K.; Vedal, Sverre; Hannigan, Michael P.

2009-01-01

21

A global analysis method for astrolabe observations  

NASA Astrophysics Data System (ADS)

In a previous paper (Chollet & Najid 1992), we gave the general principles of a new global method to analyze the astrolabe observations. The fundamental equation was obtained from the classical one in which the corrections to the star positions at the observational epoch are replaced by developments that contain the corrections to the star positions for the epoch of the catalogue, the proper motions, as well as the corrections to the precession and nutation constants. This computation gives us a new equation in which the coefficients contain only two variable parameters the azimuth and the sidereal time. The method proposed here consists in regarding the whole programme of star observations as only one group. All the possible values of the azimuth and also of the sidereal time are obtained and, in this case the column vectors of the coefficients are quite orthogonal, and the matirx of the normal equations is practically diagonal. The only problem which remains, is due to the variations of the apparent position of the station. These effects are removed by using the parameters of the Earth rotation given by the Bureau International de l'Huere (BIH) and connected to the International Earth Rotation Service (IERS) system by the Central Bureau of the IERS. Now, the new corrected unknowns are related to the mean position of the astrolabe, in the IERS system. The method to obtain absolute declinations follows the form of the preceding relations. The same error multiplied by different but known constants, affects the declination of each star, but also the latitude and zenith distance determinations. From this results, it is possible to find the well known result (Krejnin 1968) concerning the determinations of absolute declinations. But the comparison between the direct measurement and the result obtained from stellar observations will also give the systematic error in declination and latitude. The last important result is that the corrections to the precession and nutation constants appear in the equations without any perturbation due to the catalogue errors. This fact was seen in the past (Guinot 1970) but not used. The method given here does not use sophisticated methods to analyse the observational data obtained by astrolabes. Our purpose was preferably to combine and to correct the data. This method was elaborated to analyze the observations of the future automatic astrolabes. It has been tested on the series of observations obtained at Paris Observatory. observations are visual ones, the results are satisfying. &The coordinates of stars of the FK 4 catalogue are obtained with errors near 0.01 arcsec, as well as the proper motions for which the errors are about 0.005 arcsec/year. The observational data will be re-reduced in the FK 5 system in a near future before doing the same analysis using the future Hipparcos catalogue.

Chollet, F.

1993-12-01

22

Observational Study of Travelers' Diarrhea.  

PubMed

Background: European air travelers returning from Algeria, Egypt, Mexico, Morocco, and Tunisia were interviewed about their experience of travelers' diseases upon arrival in Brussels. Diarrhea was mentioned by 37% of the adults and 27% of the children. These subjects were questioned about the types of measures taken, type and duration of drug treatment (if any), and about duration of diarrhea and side effects experienced. Methods: Final analysis was performed based on 2160 interviews. The largest proportion of diarrhea was reported in the age group 15-24 years (46%). Results: The majority of the 2160 subjects had opted for drug treatment (81%): 927 subjects for loperamide alone, 235 for loperamide in combination with nifuroxazide, and 178 for nifuroxazide alone. Other drugs had been used less frequently. The median time to recovery was 2.4 days with loperamide compared to 3.2 days with nifuroxazide and to 3.4 days for the no-treatment group. Conclusions: A stratification of the results by severity of the diarrhea suggests a rank of antidiarrheal potency as follows: loperamide > nifuroxazide > no-drug treatment. The side effect with the highest incidence was constipation (2.4% with loperamide). (J Travel Med 2:11-15, 1995) Travelers' diarrhea is usually defined as the passage of at least three unformed stools per day or any number of such stools when accompanied by fever, abdominal cramping, or vomiting. The definition may be broadened to include more trivial bowel disturbance.1,2 The duration of this self-limited disease generally is 3 to 5 days. Medical intervention aims at shortening the duration of disease, thus allowing the sufferer to resume his or her usual activities at an early stage. A shortened period of recovery to physical well-being has obvious favorable economic implications if the traveler is on business and may help the maintenance of a desired level of quality of life while a traveler is on holiday. An observational study of various medical complaints made by European travelers about their stay in areas outside Europe (Algeria, Egypt, Mexico, Morocco, and Tunisia) was conducted. Air travelers returning from these areas between July 15 and August 16, 1992, were interviewed upon arrival at Brussels airport by means of a standardized questionnaire written up in lay language. As shown in Table 1, the total number of complaints in the adult group (>= 15 years of age, n = 5373) was 4919 and 446 in the pediatric group (n = 818). With fever as an exception, there were fewer complaints in children. Only approximately 50% of the travelers did not suffer PMID:9815353

Meuris

1995-03-01

23

ACCURACY OF DIETARY RECALL USING THE USDA 5-STEP MULTIPLE PASS METHOD IN A MULTI-ETHNIC POPULATION: AN OBSERVATIONAL VALIDATION STUDY.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Because of the need to test methods of dietary assessment for accuracy, we tested the ability of an ethnically diverse population to recall food intake. We observed food intake for one day in African-American (AA) and Caucasian-American (CA) male (M) and female (F) subjects. They selected all meals ...

24

Classical method of coherence estimation based on mutual wavelet-spectra of time variations of studied processes observed in the Earth atmosphere  

NASA Astrophysics Data System (ADS)

In the present article the authors offer to conduct a research into influence exerted by solar effects (Wolf number) on time variations of average monthly values of the zonal wind, obtained in Kazan Federal University with the help of a meteoric radar complex KGU-M5 within the mesosphere - lower thermosphere during the period from 1978 to 2007. There exists a wide variety of signal processing methods that can be used to identify connection between two processes. A classical method of coherence calculation based on a mutual wavelet-spectrum has become widely used. Due to limited duration of the studied time series of dynamic parameters we have found coherent structures of time variations in solar activity (Wolf number) and zonal wind within the mesosphere-lower thermosphere for the scales of about 0.5, 1, 1.5, 2, 3, and 4-5 years. SCM values have been calculated for the most pronounced periodicities observed for scales of about 3 years during the period from 1986 to 1997. The average SCM value was equal to 0.75. Confidence interval of obtained SCM values was in the range of [0.54, 0.88] for the significance level As the atmosphere is a non-linear medium, this can lead to shifting and broadening of spectral components. In addition to the above mentioned periodicities (0.5 - 5 years), a wavelet spectrum calculated in the zonal wind field indicates possible presence of time periodicities in the range of 11-20 years.

Fahrutdinova, Antonina; Rizhov, Dmitriy; Magdeev, Konstantin

25

Observational study of terrestrial eigenvibrations  

NASA Astrophysics Data System (ADS)

A comprehensive analysis has been made of analog and digital recordings of eigenvibration ground motion obtained following four great earthquakes; August 1976 (Philippines), August 1977 (Indonesia), September 1979 (West Irian), and December 1979 (Colombia). The time series (ranging in length from ˜28 to ˜140 h) are assumed to be linear combinations of damped harmonics in the presence of noise. Tables are calculated from values of the four parameters: ?, used in describing eigenvibrations, period of oscillation, amplitude, damping factor Q, and phase together with their statistical uncertainties (53 spheroidal modes, 0S 4to0S 48, and 13 torsional modes, 0T 8to0T 45). The estimation procedures are by the methods of complex demodulation and non-linear regression that specifically incorporate into the basic model the decaying aspect of the oscillations. These methods, extended to simultaneous estimations of groups of modes, help to eliminate measurement error and measurement bias from estimations of ?. The result is that overtone modes very near in frequency to fundamental modes can, under certain conditions, be resolved through a non-linear regression technique, although parameter uncertainties are underestimated in general. Of the time series analyzed, 17 were from a northern California regional network of ultra-long period seismographs at Berkeley (three components), Jamestown (vertical component), and Whiskeytown (vertical component) following the four listed earthquakes. The other 7 time series were recorded digitally by the worldwide IDA network following the 1977 Indonesian earthquake. Weighted regional and worldwide averages were made for period and Q of each eigenvibration mode. From the theoretical viewpoint, comparisons of measured period, Q, amplitude, and phase for all modes analyzed led to five conclusions. First, there are no detectable systematic shifts in period, Q, or phase of eigenvibrations within a region whose dimensions are less than a wavelength. Second, though not conclusive, there may be slight systematic shifts in period (<0.65 s) and relative amplitudes within the California regional network due to different source positions and mechanisms. Differences in Q values are not statistically significant. Third, even though differences in period obtained worldwide were as great as 1.33 s (?0.33%), differences between Q values (as great as 20%) for the same mode were not significant. The conclusion is that the damping characteristics of singlet eigenfunctions are not observed to be significantly different. Fourth, the assumption that a multiplet nS l behaves as a single oscillation is valid from at least 0S 7 through 0S 30. Fifth, no systematic pattern emerged for the shift of eigenperiod as a function of order / or posit on the Earth.

Hansen, Roger A.

1982-03-01

26

An observational study found that authors of randomized controlled trials frequently use concealment of randomization and blinding, despite the failure to report these methods  

Microsoft Academic Search

Background and objectiveReaders of randomized controlled trials (RCTs) commonly assume that what was not reported did not occur. We undertook an observational study to determine whether concealment of randomization or blinding was used in RCTs that failed to report these bias-reducing strategies.

P. J. Devereaux; Peter T.-L. Choi; Samer El-Dika; Mohit Bhandari; Victor M. Montori; Holger J. Schünemann; Amit X. Garg; Jason W. Busse; Diane Heels-Ansdell; William A. Ghali; Braden J. Manns; Gordon H. Guyatt

2004-01-01

27

Methods of Studying Persons.  

ERIC Educational Resources Information Center

Describes a method that permits answering research questions of general importance by examining individuals in a comprehensive, whole-person manner. Discusses their use in two studies of persons with spinal cord injuries. (LLL)

Heinemann, Allen W.; Shontz, Franklin C.

1985-01-01

28

Evaluation of internal noise methods for Hotelling observer models  

SciTech Connect

The inclusion of internal noise in model observers is a common method to allow for quantitative comparisons between human and model observer performance in visual detection tasks. In this article, we studied two different strategies for inserting internal noise into Hotelling model observers. In the first strategy, internal noise was added to the output of individual channels: (a) Independent nonuniform channel noise, (b) independent uniform channel noise. In the second strategy, internal noise was added to the decision variable arising from the combination of channel responses. The standard deviation of the zero mean internal noise was either constant or proportional to: (a) the decision variable's standard deviation due to the external noise, (b) the decision variable's variance caused by the external noise, (c) the decision variable magnitude on a trial to trial basis. We tested three model observers: square window Hotelling observer (HO), channelized Hotelling observer (CHO), and Laguerre-Gauss Hotelling observer (LGHO) using a four alternative forced choice (4AFC) signal known exactly but variable task with a simulated signal embedded in real x-ray coronary angiogram backgrounds. The results showed that the internal noise method that led to the best prediction of human performance differed across the studied model observers. The CHO model best predicted human observer performance with the channel internal noise. The HO and LGHO best predicted human observer performance with the decision variable internal noise. The present results might guide researchers with the choice of methods to include internal noise into Hotelling model observers when evaluating and optimizing medical image quality.

Zhang Yani; Pham, Binh T.; Eckstein, Miguel P. [Vision and Image Understanding Laboratory, Department of Psychology, University of California, Santa Barbara California, 93106 (United States)

2007-08-15

29

Card Studies for Observational Research in Practice  

PubMed Central

PURPOSE Observational studies that collect patient-level survey data at the point-of-care are often called card studies. Card studies have been used to describe clinical problems, management, and outcomes in primary care for more than 30 years. In this article we describe 2 types of card studies and the methods for conducting them. METHODS We undertook a descriptive review of card studies conducted in 3 Colorado practice-based research networks and several other networks throughout the United States. We summarized experiences of the State Networks of Colorado Ambulatory Practices and Partners (SNOCAP). RESULTS Card studies can be designed to study specific conditions or care (clinicians complete a card when they encounter patients who meet inclusion criteria) and to determine trends and prevalence of conditions (clinicians complete a card on all patients seen during a period). Data can be collected from clinicians and patients and can be linked. CONCLUSIONS Card studies provide cross-sectional descriptive data about clinical care, knowledge and behavior, perception of care, and prevalence of conditions. Card studies remain a robust method for describing primary care. PMID:21242563

Westfall, John M.; Zittleman, Linda; Staton, Elizabeth W.; Parnes, Bennett; Smith, Peter C.; Niebauer, Linda J.; Fernald, Douglas H.; Quintela, Javan; Van Vorst, Rebecca F.; Dickinson, L. Miriam; Pace, Wilson D.

2011-01-01

30

Basic Caenorhabditis elegans methods: synchronization and observation.  

PubMed

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has since been used extensively as a model organism. C. elegans possesses key attributes such as simplicity, transparency and short life cycle that have made it a suitable experimental system for fundamental biological studies for many years. Discoveries in this nematode have broad implications because many cellular and molecular processes that control animal development are evolutionary conserved. C. elegans life cycle goes through an embryonic stage and four larval stages before animals reach adulthood. Development can take 2 to 4 days depending on the temperature. In each of the stages several characteristic traits can be observed. The knowledge of its complete cell lineage together with the deep annotation of its genome turn this nematode into a great model in fields as diverse as the neurobiology, aging, stem cell biology and germ line biology. An additional feature that makes C. elegans an attractive model to work with is the possibility of obtaining populations of worms synchronized at a specific stage through a relatively easy protocol. The ease of maintaining and propagating this nematode added to the possibility of synchronization provide a powerful tool to obtain large amounts of worms, which can be used for a wide variety of small or high-throughput experiments such as RNAi screens, microarrays, massive sequencing, immunoblot or in situ hybridization, among others. Because of its transparency, C. elegans structures can be distinguished under the microscope using Differential Interference Contrast microscopy, also known as Nomarski microscopy. The use of a fluorescent DNA binder, DAPI (4',6-diamidino-2-phenylindole), for instance, can lead to the specific identification and localization of individual cells, as well as subcellular structures/defects associated to them. PMID:22710399

Porta-de-la-Riva, Montserrat; Fontrodona, Laura; Villanueva, Alberto; Cerón, Julián

2012-01-01

31

Novel sample preparation method of polymer emulsion for SEM observation.  

PubMed

The aim of this study was to design a simple and reliable method for obtaining the detailed information about the average size, size distribution, and the surface morphology of particles with variation of the sample preparation of a polymer emulsion. In this work, the characteristic features of the particles of rosin size with high viscosity were first described by scanning electron microscopy (SEM). The morphologies of polymer emulsion of solid lipid nanoparticles and of the microspheres were observed. The advantage of the method is that not only the true size and shape of emulsion particles can be shown, but the problem of high-viscosity emulsion that prevents there study with SEM is solved. Using this new method, the micromorphology and size distribution of the emulsion particles with different viscosities have been clearly observed. PMID:17576124

Xu, Jing; Hou, Zhaosheng; Li, Tianduo

2007-10-01

32

Estimation of the aerosol radiative forcing at ground level, over land, and in cloudless atmosphere, from METEOSAT-7 observation: method and case study  

NASA Astrophysics Data System (ADS)

A new method is proposed to estimate the spatial and temporal variability of the solar radiative flux reaching the surface over land (DSSF), as well as the Aerosol Radiative Forcing (ARF), in cloud-free atmosphere. The objective of regional applications of the method is attainable by using the visible broadband of METEOSAT-7 satellite instrument which scans Europe and Africa on a half-hourly basis. The method relies on a selection of best correspondence between METEOSAT-7 radiance and radiative transfer computations. The validation of DSSF is performed comparing retrievals with ground-based measurements acquired in two contrasted environments: an urban site near Paris and a continental background site located South East of France. The study is concentrated on aerosol episodes occurring around the 2003 summer heat wave, providing 42 cases of comparison for variable solar zenith angle (from 59° to 69°), variable aerosol type (biomass burning emissions and urban pollution), and variable aerosol optical thickness (a factor 6 in magnitude). The method reproduces measurements of DSSF within an accuracy assessment of 20 W m-2 (5% in relative) in 70% of the situations, and within 40 W m-2 in 90% of the situations, for the two case studies considered here. Considering aerosol is the main contributor in changing the measured radiance at the top of the atmosphere, DSSF temporal variability is assumed to be caused only by aerosols, and consequently ARF at ground level and over land is also retrieved: ARF is computed as the difference between DSSF and a parameterised aerosol-free reference level. Retrievals are linearly correlated with the ground-based measurements of the aerosol optical thickness (AOT): sensitivity is included between 120 and 160 W m-2 per unity of AOT at 440 nm. AOT being an instantaneous measure indicative of the aerosol columnar amount, we prove the feasibility to infer instantaneous aerosol radiative impact at the ground level over land with METEOSAT-7 visible channel.

Elias, T.; Roujean, J.-L.

2008-02-01

33

UFOs: Observations, Studies and Extrapolations  

E-print Network

UFOs (“ Unidentified Falling Objects”) could be one of the major performance limitations for nominal LHC operation. Therefore, in 2011, the diagnostics for UFO events were significantly improved, dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. The state of knowledge is summarized and extrapolations for LHC operation in 2012 and beyond are presented. Mitigation strategies are proposed and related tests and measures for 2012 are specified.

Baer, T; Barnes, M J; Bartmann, W; Bracco, C; Carlier, E; Cerutti, F; Dehning, B; Ducimetière, L; Ferrari, A; Ferro-Luzzi, M; Garrel, N; Gerardin, A; Goddard, B; Holzer, E B; Jackson, S; Jimenez, J M; Kain, V; Zimmermann, F; Lechner, A; Mertens, V; Misiowiec, M; Nebot Del Busto, E; Morón Ballester, R; Norderhaug Drosdal, L; Nordt, A; Papotti, G; Redaelli, S; Uythoven, J; Velghe, B; Vlachoudis, V; Wenninger, J; Zamantzas, C; Zerlauth, M; Fuster Martinez, N

2012-01-01

34

Comparing hormone therapy effects in two RCTs and two large observational studies that used similar methods for comprehensive data collection and outcome assessment  

PubMed Central

Objectives Prospective observational studies (OSs) that collect adequate information about confounders can validly assess treatment consequences. However, what constitutes adequate information is unknown. This study investigated whether the extensive information collected by the Women's Health Initiative (WHI) in two OSs and two randomised controlled trials (RCTs) was adequate. Design Secondary analysis of WHI data. Cox regression was used to select from all baseline risk factors those that best predicted outcome. Cox regression that included these risk factors was used for two types of analyses: (1) comparing RCT and OS assessments of the effects of hormone therapy on outcome for participants with specific characteristics and (2) evaluating whether adjustment for measured confounders could eliminate outcome differences among datasets. Setting The WHI included more than 800 baseline risk factors and outcomes during a median follow-up of 8?years. Participants 151?870 postmenopausal women ages 50–79. Primary and secondary outcome measures Myocardial infarction and stroke. Results RCT and OS results differed for the association of hormone therapy with outcome after adjusting for confounding factors and stratifying on factors that were hypothesised to modulate the effects of hormone therapy (eg, age and time since menopause) or that empirically modulated the effects of hormone therapy in this dataset (eg, blood pressure, previous coronary revascularisation and private medical insurance). Some of the four WHI datasets had significantly worse outcomes than others even after adjusting for risk and stratifying by type of hormone therapy, for example, the risk-adjusted HR for myocardial infarction was 1.37 (p<0.0001) in an RCT placebo group compared with an OS group not taking hormone therapy. Conclusions Apparently the WHI did not collect sufficient information to give reliable assessments of treatment effects. If the WHI did not collect sufficient data, it is likely that few OSs collect sufficient information. PMID:23861441

Hartz, Arthur; He, Tao; Wallace, Robert; Powers, John

2013-01-01

35

Clinical Utility of an Observation and Response Chart With Human Factors Design Characteristics and a Track and Trigger System: Study Protocol for a Two-Phase Multisite Multiple-Methods Design  

PubMed Central

Background Clinical deterioration of adult patients in acute medical-surgical wards continues to occur, despite a range of systems and processes designed to minimize this risk. In Australia, a standardized template for adult observation charts using human factors design principles and decision-support characteristics was developed to improve the detection of and response to abnormal vital signs. Objective To describe the study protocol for the clinical testing of these observation and response charts (ORCs). Methods We propose a two-phase multisite multiple-methods design to test the initial clinical utility of the charts in 10 hospitals of differing types and sizes across state jurisdictions in Australia. Data collection in the first phase includes user surveys, observations and field notes by project officers, handover de-briefs (short interviews with small groups of staff), and an audit of ORC documentation completion compared to the site’s existing observation chart. For the second phase, data will be collected using a retrospective audit of observation documentation from the previous hospital observation chart, prospective audit of observation documentation following implementation of the selected ORC, user focus groups, observational field notes, and patient outcome data from routinely collected organizational data sources. Results Site selection and preparation, project officer training, chart selection and implementation, participant recruitment, and data collection has been completed and the analysis of these results are in progress. Conclusions This detailed description of these study methods and data collection approaches will enable a comprehensive assessment of the clinical utility of these newly developed track and trigger charts and will be useful for clinicians and researchers when planning and implementing similar studies. Potential methodological limitations are also noted. PMID:25116446

McKinley, Sharon; Perry, Lin; Duffield, Christine; Iedema, Rick; Gallagher, Robyn; Fry, Margaret; Roche, Michael; Allen, Emily

2014-01-01

36

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for reporting observational studies.  

PubMed

Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study's generalisability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover three main study designs: cohort, case-control, and cross-sectional studies. We convened a 2-day workshop in September 2004, with methodologists, researchers, and journal editors to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results, and discussion sections of articles. 18 items are common to all three study designs and four are specific for cohort, case-control, or cross-sectional studies. A detailed Explanation and Elaboration document is published separately and is freely available on the Web sites of PLoS Medicine, Annals of Internal Medicine, and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies. PMID:25046131

von Elm, Erik; Altman, Douglas G; Egger, Matthias; Pocock, Stuart J; Gøtzsche, Peter C; Vandenbroucke, Jan P

2014-12-01

37

ON THINNING METHODS FOR DATA ASSIMILATION OF SATELLITE OBSERVATIONS  

E-print Network

2B.3 ON THINNING METHODS FOR DATA ASSIMILATION OF SATELLITE OBSERVATIONS T. Ochotta1 C. Gebhardt2 V ABSTRACT Thinning of observational data sets is an essen- tial task in assimilation of satellite data error analysis (EEA). EEA is an adaptive thinning method that iteratively removes observations from

Reiterer, Harald

38

3D reconstruction methods of coronal structures by radio observations  

NASA Technical Reports Server (NTRS)

The ability to carry out the three dimensional (3D) reconstruction of structures in the solar corona would represent a major advance in the study of the physical properties in active regions and in flares. Methods which allow a geometric reconstruction of quasistationary coronal structures (for example active region loops) or dynamic structures (for example flaring loops) are described: stereoscopy of multi-day imaging observations by the VLA (Very Large Array); tomography of optically thin emission (in radio or soft x-rays); multifrequency band imaging by the VLA; and tracing of magnetic field lines by propagating electron beams.

Aschwanden, Markus J.; Bastian, T. S.; White, Stephen M.

1992-01-01

39

The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 23 tumours of the head and neck.  

PubMed

In 23 cases of carcinoma of the head and neck, the combined use of Somatostatin and/or its analogue Octreotide, prolactin inhibitors, Melatonin, Retinoids, Vitamin E, Vitamin D3, Vitamin C, Calcium, chondroitin-sulphate, and minimal oral doses of cyclophosphamide (50-100 mg/day) led to a decided increase in survival with respect to the median values reported in the literature for the same tumours and stages, together with an evident improvement in the quality of life, partial or complete objective responses and, in some cases, complete and stable cure with functional recovery. The rationale and the mechanisms of molecular biology of the treatment are discussed, showing that the treatment has a differentiating, apoptotic, antiproliferative, antiangiogenic and antimetastatic effect, and, unlike chemo- and/or radiotherapy, preserves and enhances the trophism and functionality of organs, tissues and immunitary and antitumoral homeostasis. This result, achieved without toxicity, demonstrates the efficacy of this biological multitherapy (Prof. Luigi Di Bella's method or DBM) and is in agreement with the positive results already published on the use of the DBM in various neoplastic diseases. We believe it is of use to report these cases to invite greater interest in the possibilities opened up by this biological multitherapy. PMID:22635078

Di Bella, Giuseppe; Colori, Biagio

2012-01-01

40

Methods of Studying Persons.  

ERIC Educational Resources Information Center

Conventional research strategies typically emphasize behavior-determining tendencies so strongly that the person as a whole is ignored. Research strategies for studying whole persons focus on symbolic structures, formulate specific questions in advance, study persons one at a time, use individualized measures, and regard participants as expert…

Heinemann, Allen W.; Shontz, Franklin C.

41

Teaching Social Studies Methods  

NSDL National Science Digital Library

Teaching Social Studies to K-8 students is an engaging and creative process. Children learn best when they are interested and engaged in local and personal history. Connecting historical events to children\\'s lives is a powerful way to develop historical and cultural awareness. In this exercise you will be able to find some national and local resources to help you design and implement Social Studies in your K-8 classrooms. So let\\'s get started! First let\\'s see what kinds of resources are available on the web and other virtual places that are engaging and interesting ...

Kalvaitis, Darius

2006-02-17

42

CROWDSOURCING THE ACQUISITION OF NATURAL LANGUAGE CORPORA: METHODS AND OBSERVATIONS  

E-print Network

to acquire language corpora for use in natural language processing systems. Specifically, we empirically and directions in applying these methods to acquire corpora for natural language processing applications. IndexCROWDSOURCING THE ACQUISITION OF NATURAL LANGUAGE CORPORA: METHODS AND OBSERVATIONS William Yang

Horvitz, Eric

43

NASA's Satellite Observations for Atmospheric Composition Studies  

Microsoft Academic Search

Satellite studies of the Earth system constitute the primary emphasis of NASA's Earth Science Enterprise (ESE). Atmospheric composition is one of the six interdisciplinary focus areas around which NASA's ESE implements its research program, and together with its domestic and international partners, NASA is making significant steps to improve our knowledge of global atmospheric composition through use of satellite observations.

J. Kaye; P. Decola

2004-01-01

44

Observational studies of roAp stars  

NASA Astrophysics Data System (ADS)

Rapidly oscillating Ap (roAp) stars are high-overtone, low-degree p-mode pulsators that are also chemically peculiar magnetic A stars. Until recently the classical asteroseismic analysis i.e. frequency analysis, of these stars was based on ground and space photometric observations. Significant progress was achieved through access to uninterrupted, ultra-high-precision data from MOST, COROT and Kepler satellites. Over the last ten years the study of roAp stars has been altered drastically from an observational point of view through studies of time-resolved, high-resolution spectra. Their unusual pulsational characteristics, caused by an interplay between the short vertical lengths of the pulsation waves and strong stratification of chemical elements, allow us to examine the upper roAp atmosphere in more detail than is possible for any star except the Sun. In this paper I review the results of recent studies of the pulsations of roAp stars.

Sachkov, M.

2014-11-01

45

Observational and interventional study design types; an overview  

PubMed Central

The appropriate choice in study design is essential for the successful execution of biomedical and public health research. There are many study designs to choose from within two broad categories of observational and interventional studies. Each design has its own strengths and weaknesses, and the need to understand these limitations is necessary to arrive at correct study conclusions. Observational study designs, also called epidemiologic study designs, are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods. Observational study designs include ecological designs, cross sectional, case-control, case-crossover, retrospective and prospective cohorts. An important subset of observational studies is diagnostic study designs, which evaluate the accuracy of diagnostic procedures and tests as compared to other diagnostic measures. These include diagnostic accuracy designs, diagnostic cohort designs, and diagnostic randomized controlled trials. Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease. Each study design has specific outcome measures that rely on the type and quality of data utilized. Additionally, each study design has potential limitations that are more severe and need to be addressed in the design phase of the study. This manuscript is meant to provide an overview of study design types, strengths and weaknesses of common observational and interventional study designs. PMID:24969913

Thiese, Matthew S.

2014-01-01

46

The Behavior Observation Instrument: a method of direct observation for program evaluation.  

PubMed Central

The background and development of a multicategory direct observation system, the Behavior Observation Instrument (BOI), is described. This time-sampling procedure for recording the behavior of persons is demonstrated in several treatment settings and the results applied to issues of program evaluation. Elements that have prevented direct observation from being widely adopted, such as costs, manpower, and training requirements, are systematically analyzed. A basic psychometric analysis of the instrument is used to determine optimum frequency and duration of observation intervals as well as observer agreement. The results imply that direct observation methods, once assumed by some to belong to the special province of the single-subject design, can be used to assess the effects of programs on groups of psychiatric clients in an efficient and economic manner. PMID:97258

Alevizos, P; DeRisi, W; Liberman, R; Eckman, T; Callahan, E

1978-01-01

47

Issues and pitfalls in method comparison studies.  

PubMed

Method comparison studies are needed for validation of new methods of measurements, for example, non-invasive blood pressure measurements against standard reference methods. After a brief introduction into method comparison studies, this paper is organized in three sections. The first section deals with the widely, though not always appropriately, used classical Bland-Altman plot with the limits of agreement and its extensions with non-constant bias and multiple observations. The second section comments on other statistical approaches including correlation coefficients, linear regressions and sensitivities and specificities which are sometimes seen in method comparison studies. The third section proposes the usage of linear mixed effects models as a flexible way to deal with questions associated with method comparison studies. PMID:24575778

Hartnack, Sonja

2014-05-01

48

Testing Fractal Methods on Observed and Simulated Solar Magnetograms  

NASA Technical Reports Server (NTRS)

The term "magnetic complexity" has not been sufficiently quantified. To accomplish this, we must understand the relationship between the observed magnetic field of solar active regions and fractal dimension measurements. Using data from the Marshall Space Flight Center's vector magnetograph ranging from December 1991 to July 2001, we compare the results of several methods of calculating a fractal dimension, e.g., Hurst coefficient, the Higuchi method, power spectrum, and 2-D Wavelet Packet Analysis. In addition, we apply these methods to synthetic data, beginning with representations of very simple dipole regions, ending with regions that are magnetically complex.

Adams, M.; Falconer, D. A.; Lee, J. K.; Jones, C.

2003-01-01

49

The methods and techniques of solar 2D spectral observations  

Microsoft Academic Search

This paper is chiefly devoted to the principles, instrumentation, technology and methods of data analysis of the 2D solar spectroscopy, and a few examples of the observational results with instruments of various kinds are described. Moreover, the deficiencies of the work at the present stage and the prospect of future developments are also pointed out.

Shihui Ye

1997-01-01

50

An observational study of quiescent novae  

NASA Astrophysics Data System (ADS)

Quiescent novae are close binary stars which are characterised by the presence of Balmer and HeII emission lines in their optical spectra. In high-inclination systems, standard theory predicts that one should observe double-peaked emission line profiles which are eclipsed once every orbital period. However, the emission lines of eclipsing quiescent novae are single-peaked and uneclipsed, in obvious conflict with currently held beliefs on the nature of these systems. It is the purpose of this thesis to solve this long-standing problem and so arrive at a theoretical model for quiescent novae which is consistent with the observational evidence. The first part of the thesis sets the scene to the problem by presenting an overview of the conflicting observational and theoretical results. The second part then reports on a number of new observations obtained during the course of this work which have shed new light on the problem. The results of these new observations are presented in Part III of the thesis, where one chapter is devoted to each of the three objects studied (V1315 Aquilae, SW Sextantis and DW Ursae Majoris). The final part of the thesis is a discussion and comparison of the various results presented in Part III. Using these results, a series of observational constraints are defined which are then applied to a number of existing theoretical models. In the case of V1315 Aql and SW Sex, the very stringent set of constraints results in there being no single model capable of explaining the observed phenomena. DW UMa is even more enigmatic, appearing in a previously unseen low-state during which the mass transfer rate appears to have reduced dramatically and the optical spectra are dominated by Balmer emission from the inner face of the secondary star. The implications of these new observations for the wider field of cataclysmic variables are discussed, followed by a short summary of future work necessary to validate the origin, evolution and behaviour of the quiescent novae.

Dhillon, V. S.

1990-01-01

51

Mobile vehicle road and weather observation quality check methods  

NASA Astrophysics Data System (ADS)

Today State Departments of Transportation rely more and more on road weather data to make maintenance decisions. Inaccurate data can result in wrong treatment applications or inadequate staffing levels to maintain the roadway at the desired level of service. Previous methods of road condition data reporting have been limited to static in situ sensor stations. These road weather information systems (RWIS) provide varied data about precipitation, winds, temperature, and more, but their siting does not always provide an accurate representation of weather and road conditions along the roadway. The use of mobile data collection from vehicles travelling the highway corridors may assist in the locations where RWIS sitings are sparse or non-existent. The United States Department of Transporation's "Connected Vehicle" (formally IntelliDrive) research project is designed to create a fully connected transportation system providing road and weather data collection from an extensive array of vehicles. While the implementation of Connected Vehicle is in the future, some of the theories and technologies are already in place today. Several states, as a part of the Pooled Fund Study Maintenance Decision Support System (MDSS), have equipped their winter maintenance vehicles with Mobile Data Collection Automated / Vehicle Location (MDC/AVL) systems. In addition, since 1996, automobiles sold in the United States are required to be equipped with an Onboard Diagnostic Version 2 (OBDII) port that streams live data from sensors located in and around the vehicle. While these sensors were designed for vehicle diagnostics, some of the data can be used to determine weather characteristics around the vehicle. The OBDII data can be collected by a smartphone and sent to a server in real time to be processed. These mobile systems may fill the information gap along the roads that stationary environmental sensor stations are not able to collect. Particular concern and care needs to be focused on data quality and accuracy, requiring the development of quality checks for mobile data collection. Using OBDII-equipped automobiles and mobile collection methods, we can begin to address issues of data quality by understanding, characterizing, and demonstrating the quality of mobile system observations from operational and research environments. Several forms of quality checking can be used, including range checks, Barnes spatial checks, comparing vehicle data to road weather models, and applying Clarus quality check methodologies and algorithms to mobile observations. Development of these quality checks can lead to the future integration of mobile data into the Clarus system, data implementation for improved forecasting, maintenance decision support, and traveler safety. This paper will discuss the benefits and challenges in mobile data collection, along with how the development and implementation of a system of quality checks will improve the quality and accuracy of mobile data collection.

Koller, Daniel Raymond

52

STRengthening Analytical Thinking for Observational Studies: the STRATOS initiative  

PubMed Central

The validity and practical utility of observational medical research depends critically on good study design, excellent data quality, appropriate statistical methods and accurate interpretation of results. Statistical methodology has seen substantial development in recent times. Unfortunately, many of these methodological developments are ignored in practice. Consequently, design and analysis of observational studies often exhibit serious weaknesses. The lack of guidance on vital practical issues discourages many applied researchers from using more sophisticated and possibly more appropriate methods when analyzing observational studies. Furthermore, many analyses are conducted by researchers with a relatively weak statistical background and limited experience in using statistical methodology and software. Consequently, even ‘standard’ analyses reported in the medical literature are often flawed, casting doubt on their results and conclusions. An efficient way to help researchers to keep up with recent methodological developments is to develop guidance documents that are spread to the research community at large. These observations led to the initiation of the strengthening analytical thinking for observational studies (STRATOS) initiative, a large collaboration of experts in many different areas of biostatistical research. The objective of STRATOS is to provide accessible and accurate guidance in the design and analysis of observational studies. The guidance is intended for applied statisticians and other data analysts with varying levels of statistical education, experience and interests. In this article, we introduce the STRATOS initiative and its main aims, present the need for guidance documents and outline the planned approach and progress so far. We encourage other biostatisticians to become involved. PMID:25074480

Sauerbrei, Willi; Abrahamowicz, Michal; Altman, Douglas G; le Cessie, Saskia; Carpenter, James

2014-01-01

53

An observational assessment method for aging laboratory rats  

EPA Science Inventory

The growth of the aging population highlights the need for laboratory animal models to study the basic biological processes ofaging and susceptibility to toxic chemicals and disease. Methods to evaluate health ofaging animals over time are needed, especially efficient methods for...

54

An Observational Study of Cataclysmic Variable Evolution  

NASA Astrophysics Data System (ADS)

In this thesis I present an observational study of the evolution of Cataclysmic Variables (CVs). Disrupted magnetic braking has been the standard paradigm of CV evolution for the past twenty years. Unfortunately, some of its predictions are in strong disagreement with the observations. In recent years, a number of additions/alternatives to the standard model have been proposed. Yet, none have been able to explain all of the features observed in the currently known CV population. The work presented in this thesis is based mainly on a large-scale search for CVs. The primary aim of this project is to resolve the disagreement between theory and observations by eliminating the observational biases of the present CV sample. Here, I use two complementary approaches to search for CVs: (1) from the spectroscopic appearance in the Hamburg Quasar Survey (HQS), and (2) by using a combination of ROSAT and 2MASS archival data. So far, we have discovered 52 new CVs in the HQS and 11 new CVs (the majority of them magnetic) and 1 pre-CV in the ROSAT/2MASS. Follow-up observations of two newly discovered HQS CVs, 1RXS J062518.2+733433 and HS 2331+3905, resulted in the classification of the first as an Intermediate Polar, with P_orb = 283.0 min and P_spin = 19.8 min, and the second as a short orbital period system, P_orb = 81.0 min, harbouring a white dwarf pulsator. In addition, we found that the dominant ~3.5 h radial velocity variation of HS 2331+3905 does not correspond to the orbital period of the system, contrary to all other CVs. Despite its novel selection criterion, the HQS does not provide many short-period CVs -- even though tests with the known CVs included in the survey have shown that it is very sensitive to those objects. The biggest surprise in the new HQS sample is the discovery of many new SW Sex stars. The clustering of SW Sex stars in the 3-4 h period range is probably an important feature in the evolution of CVs that we currently do not understand at all. To improve our chances of understanding what is going on in that period range, we need accurate system parameters for these stars, which is difficult mainly because of their defining characteristics. I have used HST data of one of the sporadic low states of the SW Sex star DW UMa to derive its system parameters. The success of this study is the first step towards the otherwise impossible task of compiling reliable system parameters for the SW Sex stars.

Araujo-Betancor, Sofia

2004-03-01

55

Globally Gridded Satellite observations for climate studies  

USGS Publications Warehouse

Geostationary satellites have provided routine, high temporal resolution Earth observations since the 1970s. Despite the long period of record, use of these data in climate studies has been limited for numerous reasons, among them that no central archive of geostationary data for all international satellites exists, full temporal and spatial resolution data are voluminous, and diverse calibration and navigation formats encumber the uniform processing needed for multisatellite climate studies. The International Satellite Cloud Climatology Project (ISCCP) set the stage for overcoming these issues by archiving a subset of the full-resolution geostationary data at ~10-km resolution at 3-hourly intervals since 1983. Recent efforts at NOAA's National Climatic Data Center to provide convenient access to these data include remapping the data to a standard map projection, recalibrating the data to optimize temporal homogeneity, extending the record of observations back to 1980, and reformatting the data for broad public distribution. The Gridded Satellite (GridSat) dataset includes observations from the visible, infrared window, and infrared water vapor channels. Data are stored in Network Common Data Format (netCDF) using standards that permit a wide variety of tools and libraries to process the data quickly and easily. A novel data layering approach, together with appropriate satellite and file metadata, allows users to access GridSat data at varying levels of complexity based on their needs. The result is a climate data record already in use by the meteorological community. Examples include reanalysis of tropical cyclones, studies of global precipitation, and detection and tracking of the intertropical convergence zone.

Knapp, K.R.; Ansari, S.; Bain, C.L.; Bourassa, M.A.; Dickinson, M.J.; Funk, C.; Helms, C.N.; Hennon, C.C.; Holmes, C.D.; Huffman, G.J.; Kossin, J.P.; Lee, H.-T.; Loew, A.; Magnusdottir, G.

2011-01-01

56

A method for observing gas evolution during plastic laminate cure  

NASA Technical Reports Server (NTRS)

Polyimide, phenolic, and other resins which develop volatiles during laminating or molding cure are studied using optimum cure cycles. The specimen is placed on a platen and sealed in a plastic bag, then heated and observed for gas evolution using a binocular microscope. A cover plate is added to sumulate an autoclave.

Nicholls, A. H.

1969-01-01

57

Reported Significant Observation (RSO) studies. Revision 1  

SciTech Connect

The Reported Significant Observation (RSO) study used in the field of safety is an information-gathering technique where employee-participants describe situations they have personally witnessed involving good and bad practices and safe and unsafe conditions. This information is useful in the risk assessment process because it focuses on hazards and thereby facilitates their elimination. However, RSO cannot be the only component in a risk assessment program. Used by the Air Force in their aviation psychology program and further developed by John C. Flanagan, RSO is more commonly known as the ``Critical Incident Technique.`` However, the words ``Critical`` and ``Incident`` had other connotations in nuclear safety, prompting early users within the Aerojet Nuclear Company to coin the more fitting title of ``Reported Significant Observations.`` The technique spread slowly in the safety field primarily because the majority of users were researchers interested in after-the-fact data, with application to everyday problems and behavioral factors. RSO was formally recognized as a significant hazard reduction tool during the development of the Management Oversight and Risk Tree (MORT) program for the US Atomic Energy Commission. The Department of Energy (DOE) has, in turn, adopted MORT for its system safety program, and this has resulted in RSO being a modern and viable technique for DOE contractor safety programs.

Eicher, R.W.

1992-12-01

58

Development of acoustic observation method for seafloor hydrothermal flows  

NASA Astrophysics Data System (ADS)

In October 2009, we conducted seafloor reconnaissance using a manned deep-sea submersible Shinkai6500 in Central Indian Ridge 18-20deg.S, where hydrothermal plume signatures were previously perceived. Acoustic video camera "DIDSON" was equipped on the top of Shinkai6500 in order to get acoustic video images of hydrothermal plumes. The acoustic video images of the hydrothermal plumes had been captured in three of seven dives. We could identify shadings inside the acoustic video images of the hydrothermal plumes. Silhouettes of the hydrothermal plumes varied from second to second, and the shadings inside them also varied. These variations corresponded to internal structures and flows of the plumes. DIDSON (Dual-Frequency IDentification SONar) is acoustic lens-based sonar. It has sufficiently high resolution and rapid refresh rate that it can substitute for optical system in turbid or dark water where optical systems fail. Ins. of Industrial Science, University of Tokyo has understood DIDSON's superior performance and tried to develop a new observation method based on DIDSON for hydrothermal discharging from seafloor vent. We expected DIDSON to reveal whole image of hydrothermal plume as well as detail inside the plume. The proposed method to observe and measure hydrothermal flow is the one to utilize a sheet-like acoustic beam. Scanning with concentrated acoustic beam gives distances to the edges of the hydrothermal flows. And then, the shapes of the flows can be identified even in low and zero visibility conditions. Tank experiment was conducted. The purposes of this experiment were to make an attempt at proposed method to delineate underwater hydrothermal flows and to understand relationships among acoustic video image, flow rate and water temperature. Water was heated in the hot tub and pumped to the water tank through the silicon tube. We observed water flows discharging from the tip of the tube with DIDSON. Flow rate had been controlled and temperatures of the discharging water and background water had been measured. 3D images of flows in the tank could be reconstructed with the proposed method. We will report the overview of the tank experiments, and discuss possibility of DIDSON as an observation tool for seafloor hydrothermal activity.

Mochizuki, M.; Tamura, H.; Asada, A.; Kinoshita, M.; Tamaki, K.

2012-12-01

59

Five Methods to Score the Teacher Observation of Classroom Adaptation Checklist and to Examine Group Differences  

ERIC Educational Resources Information Center

This study compared 5 scoring methods in terms of their statistical assumptions. They were then used to score the Teacher Observation of Classroom Adaptation Checklist, a measure consisting of 3 subscales and 21 Likert-type items. The 5 methods used were (a) sum/average scores of items, (b) latent factor scores with continuous indicators, (c)…

Wang, Ze; Rohrer, David; Chuang, Chi-ching; Fujiki, Mayo; Herman, Keith; Reinke, Wendy

2015-01-01

60

STRengthening Analytical Thinking for Observational Studies: the STRATOS initiative.  

PubMed

The validity and practical utility of observational medical research depends critically on good study design, excellent data quality, appropriate statistical methods and accurate interpretation of results. Statistical methodology has seen substantial development in recent times. Unfortunately, many of these methodological developments are ignored in practice. Consequently, design and analysis of observational studies often exhibit serious weaknesses. The lack of guidance on vital practical issues discourages many applied researchers from using more sophisticated and possibly more appropriate methods when analyzing observational studies. Furthermore, many analyses are conducted by researchers with a relatively weak statistical background and limited experience in using statistical methodology and software. Consequently, even 'standard' analyses reported in the medical literature are often flawed, casting doubt on their results and conclusions. An efficient way to help researchers to keep up with recent methodological developments is to develop guidance documents that are spread to the research community at large. These observations led to the initiation of the strengthening analytical thinking for observational studies (STRATOS) initiative, a large collaboration of experts in many different areas of biostatistical research. The objective of STRATOS is to provide accessible and accurate guidance in the design and analysis of observational studies. The guidance is intended for applied statisticians and other data analysts with varying levels of statistical education, experience and interests. In this article, we introduce the STRATOS initiative and its main aims, present the need for guidance documents and outline the planned approach and progress so far. We encourage other biostatisticians to become involved. © 2014 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd. PMID:25074480

Sauerbrei, Willi; Abrahamowicz, Michal; Altman, Douglas G; le Cessie, Saskia; Carpenter, James

2014-12-30

61

Determination of Reference Catalogs for Meridian Observations Using Statistical Method  

NASA Astrophysics Data System (ADS)

The meridian observational data are useful for developing high-precision planetary ephemerides of the solar system. These historical data are provided by the jet propulsion laboratory (JPL) or the Institut De Mecanique Celeste Et De Calcul Des Ephemerides (IMCCE). However, we find that the reference systems (realized by the fundamental catalogs FK3 (Third Fundamental Catalogue), FK4 (Fourth Fundamental Catalogue), and FK5 (Fifth Fundamental Catalogue), or Hipparcos), to which the observations are referred, are not given explicitly for some sets of data. The incompleteness of information prevents us from eliminating the systematic effects due to the different fundamental catalogs. The purpose of this paper is to specify clearly the reference catalogs of these observations with the problems in their records by using the JPL DE421 ephemeris. The data for the corresponding planets in the geocentric celestial reference system (GCRS) obtained from the DE421 are transformed to the apparent places with different hypothesis regarding the reference catalogs. Then the validations of the hypothesis are tested by two kinds of statistical quantities which are used to indicate the significance of difference between the original and transformed data series. As a result, this method is proved to be effective for specifying the reference catalogs, and the missed information is determined unambiguously. Finally these meridian data are transformed to the GCRS for further applications in the development of planetary ephemerides.

Li, Z. Y.

2014-09-01

62

Observer rated sleepiness and real road driving: an explorative study.  

PubMed

The aim of the present study was to explore if observer rated sleepiness (ORS) is a feasible method for quantification of driver sleepiness in field studies. Two measures of ORS were used: (1) one for behavioural signs based on facial expression, body gestures and body movements labelled B-ORS, and (2) one based on driving performance e.g. if swerving and other indicators of impaired driving occurs, labelled D-ORS. A limited number of observers sitting in the back of an experimental vehicle on a motorway about 2 hours repeatedly 3 times per day (before lunch, after lunch, at night) observed 24 participant's sleepiness level with help of the two observer scales. At the same time the participant reported subjective sleepiness (KSS), EOG was recorded (for calculation of blink duration) and several driving measure were taken and synchronized with the reporting. Based on mixed model Anova and correlation analysis the result showed that observer ratings of sleepiness based on drivers' impaired performance and behavioural signs are sensitive to extend the general pattern of time awake, circadian phase and time of driving. The detailed analysis of the subjective sleepiness and ORS showed weak correspondence on an individual level. Only 16% of the changes in KSS were predicted by the observer. The correlation between the observer ratings based on performance (D-ORS) and behavioural signs (B-ORS) are high (r?=?.588), and the B-ORS shows a moderately strong association (r?=?.360) with blink duration. Both ORS measures show an association (r>0.45) with KSS, whereas the association with driving performance is weak. The results show that the ORS-method detects the expected general variations in sleepy driving in field studies, however, sudden changes in driver sleepiness on a detailed level as 5 minutes is usually not detected; this holds true both when taking into account driving behaviour or driver behavioural signs. PMID:23724094

Anund, Anna; Fors, Carina; Hallvig, David; Åkerstedt, Torbjörn; Kecklund, Göran

2013-01-01

63

The Observation and Study of Shallow-contact Binary Systems  

NASA Astrophysics Data System (ADS)

The shallow-contact binary is a system with low degree of contact, short orbital period and late spectral type. It is a bridge to connect detached binary system, semi-detached binary system with contact binary system. The study of the common convective envelope (CCE) of shallow-contact binary system is important to know how the CCE comes into being because the CCE of shallow-contact binary system is very thin. We have observed several systems (e.g. RV Psc, AW Vir, II CMa, AD Cnc). And we study their basic parameters using W-D method. The period studies will help us to understand their structure and evolution.

He, J.-J.; Qian, S.-B.

2009-08-01

64

Performance study of supertree methods  

E-print Network

. Figures 9 and 10. These two figures show how changes in SPR affect the number of false positives and false negatives. Each dot represents an increase in SPR for a total of 80 input trees over an average of 10 simulations. Summer 2013 – Spring 2014...Summer 2013 – Spring 2014 | 41 Performance study of supertree methods Patrick Niehaus INTRODUCTION Phylogenetic trees depict the relationships among varying species [1]. A simple example of this is a family tree. When referring to Figure 1...

Niehaus, Patrick

2014-04-01

65

BAYESIAN SHRINKAGE METHODS FOR PARTIALLY OBSERVED DATA WITH MANY PREDICTORS*  

PubMed Central

Motivated by the increasing use of and rapid changes in array technologies, we consider the prediction problem of fitting a linear regression relating a continuous outcome Y to a large number of covariates X, eg measurements from current, state-of-the-art technology. For most of the samples, only the outcome Y and surrogate covariates, W, are available. These surrogates may be data from prior studies using older technologies. Owing to the dimension of the problem and the large fraction of missing information, a critical issue is appropriate shrinkage of model parameters for an optimal bias-variance tradeoff. We discuss a variety of fully Bayesian and Empirical Bayes algorithms which account for uncertainty in the missing data and adaptively shrink parameter estimates for superior prediction. These methods are evaluated via a comprehensive simulation study. In addition, we apply our methods to a lung cancer dataset, predicting survival time (Y) using qRT-PCR (X) and microarray (W) measurements. PMID:24436727

Boonstra, Philip S.; Mukherjee, Bhramar; Taylor, Jeremy MG

2013-01-01

66

Age Estimation in Forensic Anthropology: Quantification of Observer Error in Phase Versus Component-Based Methods.  

PubMed

The purpose of this study was to assess observer error in phase versus component-based scoring systems used to develop age estimation methods in forensic anthropology. A method preferred by forensic anthropologists in the AAFS was selected for this evaluation (the Suchey-Brooks method for the pubic symphysis). The Suchey-Brooks descriptions were used to develop a corresponding component-based scoring system for comparison. Several commonly used reliability statistics (kappa, weighted kappa, and the intraclass correlation coefficient) were calculated to assess observer agreement between two observers and to evaluate the efficacy of each of these statistics for this study. The linear weighted kappa was determined to be the most suitable measure of observer agreement. The results show that a component-based system offers the possibility for more objective scoring than a phase system as long as the coding possibilities for each trait do not exceed three states of expression, each with as little overlap as possible. PMID:25389078

Shirley, Natalie R; Ramirez Montes, Paula Andrea

2014-11-12

67

Observability studies of inertial navigation systems  

NASA Technical Reports Server (NTRS)

The present work deals with an undamped three-channel inertial-navigation-system error model. It is shown that it is possible to fully observe, and thus estimate, all the states of the system. This is in contrast to a previous two-channel system, in which it was impossible to fully observe and estimate all the states of the system. The conclusions of the analysis are verified through covariance simulation, which yields identical results.

Bar-Itzhack, I. Y.; Goshen-Meskin, D.

1989-01-01

68

A double-observer method to estimate detection rate during aerial waterfowl surveys  

USGS Publications Warehouse

We evaluated double-observer methods for aerial surveys as a means to adjust counts of waterfowl for incomplete detection. We conducted our study in eastern Canada and the northeast United States utilizing 3 aerial-survey crews flying 3 different types of fixed-wing aircraft. We reconciled counts of front- and rear-seat observers immediately following an observation by the rear-seat observer (i.e., on-the-fly reconciliation). We evaluated 6 a priori models containing a combination of several factors thought to influence detection probability including observer, seat position, aircraft type, and group size. We analyzed data for American black ducks (Anas rubripes) and mallards (A. platyrhynchos), which are among the most abundant duck species in this region. The best-supported model for both black ducks and mallards included observer effects. Sample sizes of black ducks were sufficient to estimate observer-specific detection rates for each crew. Estimated detection rates for black ducks were 0.62 (SE = 0.10), 0.63 (SE = 0.06), and 0.74 (SE = 0.07) for pilot-observers, 0.61 (SE = 0.08), 0.62 (SE = 0.06), and 0.81 (SE = 0.07) for other front-seat observers, and 0.43 (SE = 0.05), 0.58 (SE = 0.06), and 0.73 (SE = 0.04) for rear-seat observers. For mallards, sample sizes were adequate to generate stable maximum-likelihood estimates of observer-specific detection rates for only one aerial crew. Estimated observer-specific detection rates for that crew were 0.84 (SE = 0.04) for the pilot-observer, 0.74 (SE = 0.05) for the other front-seat observer, and 0.47 (SE = 0.03) for the rear-seat observer. Estimated observer detection rates were confounded by the position of the seat occupied by an observer, because observers did not switch seats, and by land-cover because vegetation and landform varied among crew areas. Double-observer methods with on-the-fly reconciliation, although not without challenges, offer one viable option to account for detection bias in aerial waterfowl surveys where birds are distributed at low density in remote areas that are inaccessible by ground crews. Double-observer methods, however, estimate only detection rate of animals that are potentially observable given the survey method applied. Auxiliary data and methods must be considered to estimate overall detection rate.

Koneff, M.D.; Royle, J.A.; Otto, M.C.; Wortham, J.S.; Bidwell, J.K.

2008-01-01

69

A processing method and results of meteor shower radar observations  

NASA Technical Reports Server (NTRS)

Studies of meteor showers permit the solving of some principal problems of meteor astronomy: to obtain the structure of a stream in cross section and along its orbits; to retrace the evolution of particle orbits of the stream taking into account gravitational and nongravitational forces and to discover the orbital elements of its parent body; to find out the total mass of solid particles ejected from the parent body taking into account physical and chemical evolution of meteor bodies; and to use meteor streams as natural probes for investigation of the average characteristics of the meteor complex in the solar system. A simple and effective method of determining the flux density and mass exponent parameter was worked out. This method and its results are discussed.

Belkovich, O. I.; Suleimanov, N. I.; Tokhtasjev, V. S.

1987-01-01

70

Evaluation of Inversion Methods Applied to Ionospheric ro Observations  

NASA Astrophysics Data System (ADS)

The new technique of radio-occultation can be used to study the Earth's ionosphere. The retrieval processes of ionospheric profiling from radio occultation observations usually assume spherical symmetry of electron density distribution at the locality of occultation and use the Abel integral transform to invert the measured total electron content (TEC) values. This pa-per presents a set of ionospheric profiles obtained from SAC-C satellite with the Abel inversion technique. The effects of the ionosphere on the GPS signal during occultation, such as bending and scintillation, are examined. Electron density profiles are obtained using the Abel inversion technique. Ionospheric radio occultations are validated using vertical profiles of electron con-centration from inverted ionograms , obtained from ionosonde sounding in the vicinity of the occultation. Results indicate that the Abel transform works well in the mid-latitudes during the daytime, but is less accurate during the night-time.

Rios Caceres, Arq. Estela Alejandra; Rios, Victor Hugo; Guyot, Elia

71

Field Science Ethnography: Methods For Systematic Observation on an Expedition  

NASA Technical Reports Server (NTRS)

The Haughton-Mars expedition is a multidisciplinary project, exploring an impact crater in an extreme environment to determine how people might live and work on Mars. The expedition seeks to understand and field test Mars facilities, crew roles, operations, and computer tools. I combine an ethnographic approach to establish a baseline understanding of how scientists prefer to live and work when relatively unemcumbered, with a participatory design approach of experimenting with procedures and tools in the context of use. This paper focuses on field methods for systematically recording and analyzing the expedition's activities. Systematic photography and time-lapse video are combined with concept mapping to organize and present information. This hybrid approach is generally applicable to the study of modern field expeditions having a dozen or more multidisciplinary participants, spread over a large terrain during multiple field seasons.

Clancey, William J.; Clancy, Daniel (Technical Monitor)

2001-01-01

72

Folic Acid Supplementation and Preterm Birth: Results from Observational Studies  

PubMed Central

Introduction. Folic acid (FA) supplementation is recommended worldwide in the periconceptional period for the prevention of neural tube defects. Due to its involvement in a number of cellular processes, its role in other pregnancy outcomes such as miscarriage, recurrent miscarriage, low birth weight, preterm birth (PTB), preeclampsia, abruptio placentae, and stillbirth has been investigated. PTB is a leading cause of perinatal mortality and morbidity; therefore its association with FA supplementation is of major interest. The analysis of a small number of randomized clinical trials (RCTs) has not found a beneficial role of FA in reducing the rate of PTBs. Aim of the Study. The aim of this review was to examine the results from recent observational studies about the effect of FA supplementation on PTB. Materials and Methods. We carried out a search on Medline and by manual search of the observational studies from 2009 onwards that analyzed the rate of PTB in patients who received supplementation with FA before and/or throughout pregnancy. Results. The results from recent observational studies suggest a slight reduction of PTBs that is not consistent with the results from RCTs. Further research is needed to better understand the role of FA supplementation before and during pregnancy in PTB. PMID:24724083

Franchi, Massimo

2014-01-01

73

Advanced Earth Observation System Instrumentation Study (AEOSIS)  

NASA Technical Reports Server (NTRS)

The feasibility, practicality, and cost are investigated for establishing a national system or grid of artificial landmarks suitable for automated (near real time) recognition in the multispectral scanner imagery data from an earth observation satellite (EOS). The intended use of such landmarks, for orbit determination and improved mapping accuracy is reviewed. The desirability of using xenon searchlight landmarks for this purpose is explored theoretically and by means of experimental results obtained with LANDSAT 1 and LANDSAT 2. These results are used, in conjunction with the demonstrated efficiency of an automated detection scheme, to determine the size and cost of a xenon searchlight that would be suitable for an EOS Searchlight Landmark Station (SLS), and to facilitate the development of a conceptual design for an automated and environmentally protected EOS SLS.

Var, R. E.

1976-01-01

74

Effects of the observation method (direct v. from video) and of the presence of an observer on behavioural results in veal calves.  

PubMed

This study aimed at assessing the effect of the observation method (direct or from video) and the effect of the presence of an observer on the behavioural results in veal calves kept on a commercial farm. To evaluate the effect of the observation method, 20 pens (four to five calves per pen) were observed by an observer for 60 min (two observation sessions of 30 min) and video-recorded at the same time. To evaluate the effect of the presence of the observer in front of the pen, 24 pens were video-recorded on 4 consecutive days and an observer was present in front of each pen for 60 min (two observation sessions of 30 min) on the third day. Behaviour was recorded using instantaneous scan sampling. For the study of the observer's effect, the analysis was limited to the posture, abnormal oral behaviour and manipulation of substrates. The two observation methods gave similar results for the time spent standing, but different results for all other behaviours. The presence of an observer did not affect the behaviour of calves at day level; however, their behaviour was affected when the observer was actually present in front of the pens. A higher percentage of calves were standing and were manipulating substrate in the presence of the observer, but there was no effect on abnormal oral behaviour. In conclusion, direct observations are a more suitable observation method than observations from video recordings for detailed behaviours in veal calves. The presence of an observer has a short-term effect on certain behaviours of calves that will have to be taken into consideration when monitoring these behaviours. PMID:23916373

Leruste, H; Bokkers, E A M; Sergent, O; Wolthuis-Fillerup, M; van Reenen, C G; Lensink, B J

2013-11-01

75

Alternating Renewal Process Models for Behavioral Observation: Simulation Methods, Software, and Validity Illustrations  

ERIC Educational Resources Information Center

Direct observation recording procedures produce reductive summary measurements of an underlying stream of behavior. Previous methodological studies of these recording procedures have employed simulation methods for generating random behavior streams, many of which amount to special cases of a statistical model known as the alternating renewal…

Pustejovsky, James E.; Runyon, Christopher

2014-01-01

76

Structural equation modeling for observational studies  

USGS Publications Warehouse

Structural equation modeling (SEM) represents a framework for developing and evaluating complex hypotheses about systems. This method of data analysis differs from conventional univariate and multivariate approaches familiar to most biologists in several ways. First, SEMs are multiequational and capable of representing a wide array of complex hypotheses about how system components interrelate. Second, models are typically developed based on theoretical knowledge and designed to represent competing hypotheses about the processes responsible for data structure. Third, SEM is conceptually based on the analysis of covariance relations. Most commonly, solutions are obtained using maximum-likelihood solution procedures, although a variety of solution procedures are used, including Bayesian estimation. Numerous extensions give SEM a very high degree of flexibility in dealing with nonnormal data, categorical responses, latent variables, hierarchical structure, multigroup comparisons, nonlinearities, and other complicating factors. Structural equation modeling allows researchers to address a variety of questions about systems, such as how different processes work in concert, how the influences of perturbations cascade through systems, and about the relative importance of different influences. I present 2 example applications of SEM, one involving interactions among lynx (Lynx pardinus), mongooses (Herpestes ichneumon), and rabbits (Oryctolagus cuniculus), and the second involving anuran species richness. Many wildlife ecologists may find SEM useful for understanding how populations function within their environments. Along with the capability of the methodology comes a need for care in the proper application of SEM.

Grace, J.B.

2008-01-01

77

Linking Indigenous Knowledge and Observed Climate Change Studies  

NASA Technical Reports Server (NTRS)

We present indigenous knowledge narratives and explore their connections to documented temperature and other climate changes and observed climate change impact studies. We then propose a framework for enhancing integration of these indigenous narratives of observed climate change with global assessments. Our aim is to contribute to the thoughtful and respectful integration of indigenous knowledge with scientific data and analysis, so that this rich body of knowledge can inform science, and so that indigenous and traditional peoples can use the tools and methods of science for the benefit of their communities if they choose to do so. Enhancing ways of understanding such connections are critical as the Intergovernmental Panel on Climate Change Fifth Assessment process gets underway.

Alexander, Chief Clarence; Bynum, Nora; Johnson, Liz; King, Ursula; Mustonen, Tero; Neofotis, Peter; Oettle, Noel; Rosenzweig, Cynthia; Sakakibara, Chie; Shadrin, Chief Vyacheslav; Vicarelli, Marta; Waterhouse, Jon; Weeks, Brian

2010-01-01

78

A video-based observation method to assess musculoskeletal load in kitchen work.  

PubMed

This paper describes a new video-based observation method aimed to assess musculoskeletal load in kitchen work, aspects of its repeatability and validity, and problems confronted by the observers. Two pairs of researchers observed individually 117 video clips recorded in kitchens. Interobserver repeatability was assessed by computing the proportion of agreement and weighted kappa values (kappa(w)). Validity was analyzed by studying the distribution of the assessments over the rating scales and the ratings before and after the interventions, which were compared with expert assessments made from the same intervention targets. The proportion of agreement ranged from 57 to 88%. Interobserver repeatability based on weighted kappa values was mainly good to moderate. The method detected the changes in physical load due to the interventions. Direction of the changes corresponded with the expert assessments. Further development of the method is needed to assess the load on the hands and wrists. PMID:19272242

Pehkonen, Irmeli; Ketola, Ritva; Ranta, Riikka; Takala, Esa-Pekka

2009-01-01

79

Solution of nonlinear finite difference ocean models by optimization methods with sensitivity and observational strategy analysis  

NASA Technical Reports Server (NTRS)

The paper studies with finite difference nonlinear circulation models the uncertainties in interesting flow properties, such as western boundary current transport, potential and kinetic energy, owing to the uncertainty in the driving surface boundary condition. The procedure is based upon nonlinear optimization methods. The same calculations permit quantitative study of the importance of new information as a function of type, region of measurement and accuracy, providing a method to study various observing strategies. Uncertainty in a model parameter, the bottom friction coefficient, is studied in conjunction with uncertain measurements. The model is free to adjust the bottom friction coefficient such that an objective function is minimized while fitting a set of data to within prescribed bounds. The relative importance of the accuracy of the knowledge about the friction coefficient with respect to various kinds of observations is then quantified, and the possible range of the friction coefficients is calculated.

Schroeter, Jens; Wunsch, Carl

1986-01-01

80

Unsteady aerodynamic modeling based on POD-observer method  

Microsoft Academic Search

A new hybrid approach to constructing reduced-order models (ROM) of unsteady aerodynamics applicable to aeroelastic analysis\\u000a is presented by using proper orthogonal decomposition (POD) in combination with observer techniques. Fluid modes are generated\\u000a through POD by sampling observations of solutions derived from the full-order model. The response in the POD training is projected\\u000a onto the fluid modes to determine the

Chao Yang; XiaoYan Liu; ZhiGang Wu

2010-01-01

81

CNODES: the Canadian Network for Observational Drug Effect Studies  

PubMed Central

Abstract Although administrative health care databases have long been used to evaluate adverse drug effects, responses to drug safety signals have been slow and uncoordinated. We describe the establishment of the Canadian Network for Observational Drug Effect Studies (CNODES), a collaborating centre of the Drug Safety and Effectiveness Network (DSEN). CNODES is a distributed network of investigators and linked databases in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec and Nova Scotia. Principles of operation are as follows: (1) research questions are prioritized by the coordinating office of DSEN; (2) the linked data stay within the provinces; (3)?for each question, a study team formulates a detailed protocol enabling consistent analyses in each province; (4) analyses are “blind” to results obtained elsewhere; (5) protocol deviations are permitted for technical reasons only; (6)?analyses using multivariable methods are lodged centrally with a methods team, which is responsible for combining the results to provide a summary estimate of effect. These procedures are designed to achieve high internal validity of risk estimates and to eliminate the possibility of selective reporting of analyses or outcomes. The value of a coordinated multi-provincial approach is illustrated by projects studying acute renal injury with high-potency statins, community-acquired pneumonia with proton pump inhibitors, and hyperglycemic emergencies with antipsychotic drugs. CNODES is an academically based distributed network of Canadian researchers and data centres with a commitment to rapid and sophisticated analysis of emerging drug safety signals in study populations totalling over 40 million. PMID:23687528

Suissa, Samy; Henry, David; Caetano, Patricia; Dormuth, Colin R; Ernst, Pierre; Hemmelgarn, Brenda; LeLorier, Jacques; Levy, Adrian; Martens, Patricia J; Paterson, J Michael; Platt, Robert W; Sketris, Ingrid; Teare, Gary

2012-01-01

82

COMPARATIVE STUDY OF PLUME OPACITY MEASUREMENT METHODS  

EPA Science Inventory

The opacity of smoke-stack emissions was measured by three methods at thirteen different plants and the results compared. The three opacity measurement methods are trained observer, in-stack transmissometer, and laser radar (lidar). The instrumental methods, lidar and in-stack tr...

83

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 21, METHOD 611--HALOETHERS  

EPA Science Inventory

Described herein are the experimental design and the results of an interlaboratory study of an analytical method to detect haloethers in water. The method, EPA Method 611 - Haloethers, consisted of a liquid/liquid extraction using methylene chloride, an evaporation step using Kud...

84

A stroboscopic method for phase resolved pulsar observations  

E-print Network

We present a stroboscopic system developed for optical observations of pulsars and its application in the CLYPOS survey. The stroboscopic device is connected to a GPS clock and provides absolute timing to the stroboscopic shutter relative to the pulsar's radio ephemerides. By changing the phase we can examine the pulsar's light curve. The precisely timed stroboscope in front of the CCD camera can perform highly accurate time resolved pulsar photometry and offers the advantages of CCD cameras, which are high quantum efficiency as well as relatively large field of view, which is important for flux calibrations. CLYPOS (Cananea Ljubljana Young Pulsar Optical Survey) is an extensive search for optical counterparts of about 30 northern hemisphere radio pulsars. It is a collaboration between the INAOE, Mexico and the Faculty of Mathematics and Physics of the University of Ljubljana. Stroboscopic observations were done between December 1998 and November 2000 at the 2.12 m telescope of the Observatory Guillermo Haro ...

Vidrih, S; Carramiñana, A; Vidrih, Simon; Cadez, Andrej; Carraminana, Alberto

2004-01-01

85

Methods for Composing Tradeoff Studies under Uncertainty  

E-print Network

METHODS FOR COMPOSING TRADEOFF STUDIES UNDER UNCERTAINTY A Thesis by CHRISTOPHER STEPHEN BILY Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 2012 Major Subject: Mechanical Engineering Methods for Composing Tradeoff Studies under Uncertainty Copyright 2012 Christopher Stephen Bily METHODS FOR COMPOSING...

Bily, Christopher

2012-10-19

86

A stroboscopic method for phase resolved pulsar observations  

E-print Network

We present a stroboscopic system developed for optical observations of pulsars and its application in the CLYPOS survey. The stroboscopic device is connected to a GPS clock and provides absolute timing to the stroboscopic shutter relative to the pulsar's radio ephemerides. By changing the phase we can examine the pulsar's light curve. The precisely timed stroboscope in front of the CCD camera can perform highly accurate time resolved pulsar photometry and offers the advantages of CCD cameras, which are high quantum efficiency as well as relatively large field of view, which is important for flux calibrations. CLYPOS (Cananea Ljubljana Young Pulsar Optical Survey) is an extensive search for optical counterparts of about 30 northern hemisphere radio pulsars. It is a collaboration between the INAOE, Mexico and the Faculty of Mathematics and Physics of the University of Ljubljana. Stroboscopic observations were done between December 1998 and November 2000 at the 2.12 m telescope of the Observatory Guillermo Haro in Cananea, Sonora. The first results of the survey are presented. Analyzed data indicate that there is no optical counterpart brighter than ~22.

Simon Vidrih; Andrej Cadez; Alberto Carraminana

2004-02-02

87

Cementation as a method of observing defects in PVD coatings  

Microsoft Academic Search

The cementation test as previously used to investigate defects in single metal nitride PVD coatings has been extended to the study of the new generation of mixed nitride coatings by its application to the study of defects in TiAlN coatings. Copper cementation tests carried out in a solution containing 0.1 g 1?1 of copper at pH 1.1 showed that the

P. Ernst; A. Earnshaw; I. P. Wadsworth; G. W. Marshall

1997-01-01

88

Warfarin and fibrinolysis - a challenging combination: an observational cohort study  

PubMed Central

Background Patients presenting with ST-segment elevation myocardial infarction (STEMI) frequently use warfarin. Fibrinolytic agents and warfarin both increase bleeding risk, but only a few studies have been published concerning the bleeding risk of warfarin-prescribed patients receiving fibrinolysis. The objective of this study was to define the prevalence for intracranial haemorrhage (ICH) or major bleeding in patients on warfarin treatment receiving pre-hospital fibrinolysis. Methods This was an observational cohort study. Data for this retrospective case series were collected in Helsinki Emergency Medical Service catchment area from 1.1.1997 to 30.6.2010. All warfarin patients with suspected ST-segment elevation myocardial infarction (STEMI), who received pre-hospital fibrinolysis, were included. Bleeding complications were detected from Medical Records and classified as ICH, major or minor bleeding. Results Thirty-six warfarin patients received fibrinolysis during the study period. Fourteen patients had bleeding complications. One (3%, 95% CI 0-15%) patient had ICH, six (17%, 95% CI 7-32%) had major and seven (19%, 95% CI 9-35%) had minor bleeding. The only fatal bleeding occurred in a patient with ICH. Patients' age, fibrinolytic agent used or aspirin use did not predispose to bleeding complications. High International Normalized Ratio (INR) seemed to predispose to bleedings with values over 3, but no statistically significant difference was found. Conclusions Bleedings occur frequently in warfarin patients treated with fibrinolysis in the real world setting, but they are rarely fatal. PMID:21466702

2011-01-01

89

A facile method to observe graphene growth on copper foil  

NASA Astrophysics Data System (ADS)

A novel scanning electron microscope (SEM) method is presented for high contrast identification of each layer of pyramidal graphene domains grown on copper. We obtained SEM images by combining the advantages of the high resolution property of the secondary electron signal and the elemental sensitivity of the backscattering electron signal. Through this method, we investigated the difference in the growth mechanisms of mono-layer and few-layer graphene. Due to different lattice mismatches, both the surface adsorption process and the epitaxial growth process existed under the atmospheric growth conditions. Moreover, the copper oxidation process can be easily discovered. It is obvious from the SEM images that the graphene greatly delayed the oxidation process of the copper surface. Finally, the nucleation and growth speed of graphene domains was found to depend on the linear array distribution of surface ledges and terraces of annealed rolled copper foil. This result explains the linear rows of graphene during the growth process and accords with theoretical results.

Yang, Fan; Liu, Yangqiao; Wu, Wei; Chen, Wei; Gao, Lian; Sun, Jing

2012-11-01

90

A Proxy Outcome Approach for Causal Effect in Observational Studies: A Simulation Study  

PubMed Central

Background. Known and unknown/unmeasured risk factors are the main sources of confounding effects in observational studies and can lead to false observations of elevated protective or hazardous effects. In this study, we investigate an alternative approach of analysis that is operated on field-specific knowledge rather than pure statistical assumptions. Method. The proposed approach introduces a proxy outcome into the estimation system. A proxy outcome possesses the following characteristics: (i) the exposure of interest is not a cause for the proxy outcome; (ii) causes of the proxy outcome and the study outcome are subsets of a collection of correlated variables. Based on these two conditions, the confounding-effect-driven association between the exposure and proxy outcome can then be measured and used as a proxy estimate for the effects of unknown/unmeasured confounders on the outcome of interest. Performance of this approach is tested by a simulation study, whereby 500 different scenarios are generated, with the causal factors of a proxy outcome and a study outcome being partly overlapped under low-to-moderate correlations. Results. The simulation results demonstrate that the conventional approach only led to a correct conclusion in 21% of the 500 scenarios, as compared to 72.2% for the alternative approach. Conclusion. The proposed method can be applied in observational studies in social science and health research that evaluates the health impact of behaviour and mental health problems. PMID:24695548

Liang, Wenbin; Zhao, Yuejen; Lee, Andy H.

2014-01-01

91

In-Hospital Recruitment to Observational Studies of Stroke  

ERIC Educational Resources Information Center

The objective of this study was to examine recruitment in three observational follow-up studies of patients with stroke, focusing on reasons for nonparticipation and the role of potential factors in explaining recruitment rates. It comprised secondary analysis of the three studies. Recruitment rates varied between the studies. Between 10 and 50%…

Pickering, Ruth M.; Kunkel, Dorit; Fitton, Carolyn; Ashburn, Ann; Jenkinson, Damian

2010-01-01

92

Case Study: Protein Folding using Homotopy Methods  

E-print Network

Case Study: Protein Folding using Homotopy Methods james robert white Since the late 1990s. In this case study, we will use the Homotopy Optimization Method (HOM) to predict how chains of particles fold at the University of Maryland, and this case study parallels the experiments in his thesis. See pointer

O'Leary, Dianne P.

93

COMPARISON OF METHODS FOR THE ANALYSIS OF PANEL STUDIES  

EPA Science Inventory

Three different methods of analysis of panels were compared using asthma panel data from a 1970-1971 study done by EPA in Riverhead, New York. The methods were (1) regression analysis using raw attack rates; (2) regression analysis using the ratio of observed attacks to expected ...

94

Quantifying Kelvin-Helmholtz instability dynamics observed in noctilucent clouds: 1. Methods and observations  

NASA Astrophysics Data System (ADS)

clouds (NLCs) have been imaged during two nights in summer 2009 from northern Germany (Kühlungsborn, 54°N) and middle Norway (Trondheim, 64°N). For the first time a horizontal resolution of 10 to 20 m at the altitude of the clouds (about 83 km) and a temporal resolution of about 1 s was achieved. Additional imaging using a coarser resolution provided monitoring of the larger-scale (~100 km) structures observed in the clouds. Two series of NLC images are described that reveal apparent Kelvin-Helmholtz (KH) billow structures having very different morphologies and apparent transitions to turbulence and mixing. One series exhibits deep KH billows and apparent secondary instabilities in the billow exteriors having streamwise alignment (and spanwise wave number), suggesting a small initial Richardson number (Ri). A second series of images suggests a larger and less unstable Ri, a slower KH billow evolution, shallower billows, and turbulence and mixing confined to the billow cores. We suggest that systematic exploration of these dynamics employing NLC imaging may enable characterization and quantification of KH instability occurrence statistics and of their contributions to turbulence and mixing in the summer mesopause environment with unique sensitivity to their small-scale dynamics.

Baumgarten, Gerd; Fritts, David C.

2014-08-01

95

Evaluation of methods to derive green-up dates based on daily NDVI satellite observations  

NASA Astrophysics Data System (ADS)

Bridging the gap between satellite derived green-up dates and in situ phenological observations has been the purpose of many studies over the last decades. Despite substantial advancements in satellite technology and data quality checks there is as yet no universally accepted method for extracting phenological metrics based on satellite derived vegetation indices. Dependent on the respective method derived green-up dates can vary up to serveral weeks using identical data sets. Consequently, it is difficult to compare various studies and to accurately determine an increased vegetation length due to changing temperature patterns as observed by ground phenological networks. Here, I compared how the characteristic NDVI increase over temperate deciduous forests in Germany in spring relates to respective budburst events observed on the ground. MODIS Terra daily surface reflectances with a 250 m resolution (2000-2008) were gathered to compute daily NDVI values. As ground truth, observations of the extensive phenological network of the German Weather Service were used. About 1500 observations per year and species (Beech, Oak and Birch) were available evenly distributed all over Germany. Two filtering methods were tested to reduce the noisy raw data. The first method only keeps NDVI values which are classified as ‚ideal global quality' and applies on those a temporal moving window where values are removed which differ more than 20% of the mean. The second method uses an adaptation of the BISE (Best Index Slope Extraction) algorithm. Subsequently, three functions were fitted to the selected observations: a simple linear interpolation, a sigmoidal function and a double logistic sigmoidal function allowing to approximate two temporally separated green-up signals. The green-up date was then determined at halfway between minimum and maximum (linear interpolation) or at the inflexion point of the sigmoidal curve. A number of global threshold values (NDVI 0.4,0.5,0.6) and varying definitions of the NDVI baseline during dormancy were also tested. In contrast to most past studies, I did not attempt to identify matched pairs of geographically coincident ground and satellite observations. Rather than comparing on an individual grid-cell basis I analysed and compared the statistical properties of distributions generated from ground and satellite observations. It has been noticed that remote sensing provides a statistical distribution of a random variable, not an exact representation of the state of the land surface or atmosphere at a particular pixel. The same holds true for ground observations as they sample from biological variability and landscapes with heterogeneous microclimates. First results reveal substantial differences between the applied methods. Based on the assumption that the satellite captures predominantly the greening-up of the canopy - which occurs about 2 weeks later than observed budburst dates - the double sigmoidal function combined with the BISE filtering procedure performed best.

Doktor, Daniel

2010-05-01

96

An Observational Study of Skilled Memory in Waitresses.  

ERIC Educational Resources Information Center

A two-phase study about skilled memory as it is used by waitresses included a participant-observer phase and an observational phase. Participants were three experienced waitresses who had worked at a midtown Manhattan restaurant for 14, 7, and 3 years respectively and a team of 5 confederate customers. Waitresses and customers wore microphones.…

Stevens, Joy

97

An Observational Study of Print Literacy in Canadian Preschool Classrooms  

ERIC Educational Resources Information Center

The purpose of this study was to examine the role of print literacy in preschool classrooms. There were seven preschool teachers working in central Canada who were observed over three sessions. The process of analytic induction was used to formulate categories based on interviews, classroom observations and documents. The following categories were…

Lynch, Jacqueline

2011-01-01

98

TUTORIAL IN BIOSTATISTICS SURVIVAL ANALYSIS IN OBSERVATIONAL STUDIES  

Microsoft Academic Search

SUMMARY Multi-centre databases are making an increasing contribution to medical understanding. While the statist- ical handling of randomized experimental studies is well documented in the medical literature, the analysis of observational studies requires the addressing of additional important issues relating to the timing of entry to the study and the e?ect of potential explanatory variables not introduced until after that

KATE BULL; DAVID J. SPIEGELHALTER

1997-01-01

99

Mathematical methods of studying physical phenomena  

NASA Astrophysics Data System (ADS)

In recent decades, substantial theoretical and experimental progress was achieved in understanding the quantum nature of physical phenomena that serves as the foundation of present and future quantum technologies. Quantum correlations like the entanglement of the states of composite systems, the phenomenon of quantum discord, which captures other aspects of quantum correlations, quantum contextuality and, connected with these phenomena, uncertainty relations for conjugate variables and entropies, like Shannon and Rényi entropies, and the inequalities for spin states, like Bell inequalities, reflect the recently understood quantum properties of micro and macro systems. The mathematical methods needed to describe all quantum phenomena mentioned above were also the subject of intense studies in the end of the last, and beginning of the new, century. In this section of CAMOP 'Mathematical Methods of Studying Physical Phenomena' new results and new trends in the rapidly developing domain of quantum (and classical) physics are presented. Among the particular topics under discussion there are some reviews on the problems of dynamical invariants and their relations with symmetries of the physical systems. In fact, this is a very old problem of both classical and quantum systems, e.g. the systems of parametric oscillators with time-dependent parameters, like Ermakov systems, which have specific constants of motion depending linearly or quadratically on the oscillator positions and momenta. Such dynamical invariants play an important role in studying the dynamical Casimir effect, the essence of the effect being the creation of photons from the vacuum in a cavity with moving boundaries due to the presence of purely quantum fluctuations of the electromagnetic field in the vacuum. It is remarkable that this effect was recently observed experimentally. The other new direction in developing the mathematical approach in physics is quantum tomography that provides a new vision of quantum states. In the tomographic picture of quantum mechanics, the states are identified with fair conditional probability distributions, which contain the same information on the states as the wave function or the density matrix. The mathematical methods of the tomographic approach are based on studying the star-product (associative product) quantization scheme. The tomographic star-product technique provides an additional understanding of the associative product, which is connected with the existence of specific pairs of operators called quantizers and dequantizers. These operators code information on the kernels of all the star-product schemes, including the traditional phase-space Weyl-Wigner-Moyal picture describing the quantum-system evolution. The new equation to find quantizers, if the kernel of the star product of functions is given, is presented in this CAMOP section. For studying classical systems, the mathematical methods developed in quantum mechanics can also be used. The case of paraxial-radiation beams propagating in waveguides is a known example of describing a purely classical phenomenon by means of quantum-like equations. Thus, some quantum phenomenon like the entanglement can be mimicked by the properties of classical beams, for example, Gaussian modes. The mathematical structures and relations to the symplectic symmetry group are analogous for both classical and quantum phenomena. Such analogies of the mathematical classical and quantum methods used in research on quantum-like communication channels provide new tools for constructing a theoretical basis of the new information-transmission technologies. The conventional quantum mechanics and its relation to classical mechanics contain mathematical recipes of the correspondence principle and quantization rules. Attempts to find rules for deriving the quantum-mechanical formalism starting from the classical field theory, taking into account the influence of classical fluctuations of the field, is considered in these papers. The methods to solve quantum equations and formulate the boundary co

Man'ko, Margarita A.

2013-03-01

100

A double-observer method for reducing bias in faecal pellet surveys of forest ungulates  

USGS Publications Warehouse

1. Faecal surveys are used widely to study variations in abundance and distribution of forest-dwelling mammals when direct enumeration is not feasible. The utility of faecal indices of abundance is limited, however, by observational bias and variation in faecal disappearance rates that obscure their relationship to population size. We developed methods to reduce variability in faecal surveys and improve reliability of faecal indices. 2. We used double-observer transect sampling to estimate observational bias of faecal surveys of Roosevelt elk Cervus elaphus roosevelti and Columbian black-tailed deer Odocoileus hemionus columbianus in Olympic National Park, Washington, USA. We also modelled differences in counts of faecal groups obtained from paired cleared and uncleared transect segments as a means to adjust standing crop faecal counts for a standard accumulation interval and to reduce bias resulting from variable decay rates. 3. Estimated detection probabilities of faecal groups ranged from < 0.2-1.0 depending upon the observer, whether the faecal group was from elk or deer, faecal group size, distance of the faecal group from the sampling transect, ground vegetation cover, and the interaction between faecal group size and distance from the transect. 4. Models of plot-clearing effects indicated that standing crop counts of deer faecal groups required 34% reduction on flat terrain and 53% reduction on sloping terrain to represent faeces accumulated over a standard 100-day interval, whereas counts of elk faecal groups required 0% and 46% reductions on flat and sloping terrain, respectively. 5. Synthesis and applications. Double-observer transect sampling provides a cost-effective means of reducing observational bias and variation in faecal decay rates that obscure the interpretation of faecal indices of large mammal abundance. Given the variation we observed in observational bias of faecal surveys and persistence of faeces, we emphasize the need for future researchers to account for these comparatively manageable sources of bias before comparing faecal indices spatially or temporally. Double-observer sampling methods are readily adaptable to study variations in faecal indices of large mammals at the scale of the large forest reserve, natural area, or other forested regions when direct estimation of populations is problematic. ?? 2008 The Authors.

Jenkins, K.J.; Manly, B.F.J.

2008-01-01

101

Application of the time-delay integration method: Survey observations of geosynchronous orbit objects and short-term variability observations  

NASA Astrophysics Data System (ADS)

"Time-Delay Integration (TDI)" readout technique has been adopted to a mosaic CCD camera equipped with four fully-depleted CCDs. Optical distortion and image deformation due to the TDI operation are discussed. The manner and advantages of the TDI method in survey observations of geosynchronous orbit objects are summarized. We propose a new TDI application method of getting short-term light curves of artificial space objects. This method of detecting a short-term variability can be applied for a variety of objects, ranging from satellites to stars. It can also be used for the light-curve observations of transient objects which might show short-term variability and of which the precise time information is needed.

Okumura, Shin-ichiro; Yanagisawa, Toshifumi; Nakaya, Hidehiko; Tanaka, Wataru; Nishiyama, Kota; Takahashi, Noritsugu; Yoshikawa, Makoto

2014-12-01

102

Case study research: design and methods  

Microsoft Academic Search

Providing a complete portal to the world of case study research, the Fourth Edition of Robert K. Yin's bestselling text Case Study Research offers comprehensive coverage of the design and use of the case study method as a valid research tool. This thoroughly revised text now covers more than 50 case studies (approximately 25\\\\% new), gives fresh attention to quantitative

Robert K. Yin; M S Sridhar

2009-01-01

103

Observational study of prehospital delays in patients with chest pain  

PubMed Central

Method: A prospective observational study of prehospital times and events was undertaken on a target population of patients presenting with acute chest pain attributable to an acute coronary syndrome over a three month period. Results: Patients who decided to call the ambulance service were compared with patients who contacted any other service. Most patients who contact non-ambulance services are seen by general practitioners. The prehospital system time for 121 patients who chose to call the ambulance service first was significantly shorter than for 96 patients who chose to call another service (median 57 min v 107 min; p<0.001). Of the 42 patients thrombolysed in the emergency department, those who chose to call the ambulance service had significantly shorter prehospital system times (number 21 v 21; median 44 v 69 min; p<0.001). Overall time from pain onset to initiation of thrombolysis was significantly longer in the group of patients who called a non-ambulance service first (median 130 min v 248 min; p=0.005). Conclusions: Patient with acute ischaemic chest pain who call their general practice instead of the ambulance service are likely to have delayed thrombolysis. This is likely to result in increased mortality. The most beneficial current approach is for general practices to divert all patients with possible ischaemic chest pain onset within 12 hours direct to the ambulance service. PMID:12748152

Hitchcock, T; Rossouw, F; McCoubrie, D; Meek, S

2003-01-01

104

A method of initial orbit determination from three or more observations on a short arc. (Russian Title: ????? ??????????? ?????????????? ?????? ?? ???? ? ????? ??????????? ?? ???????? ????)  

NASA Astrophysics Data System (ADS)

A new method is suggested for computing the initial orbit of a small celestial body from its three or more pairs of angular measurements at three times. The method is based on using the approach that we previously developed for constructing the intermediate orbit from minimal number of observations. This intermediate orbit allows for most of the perturbations in the motion of the body under study. The method proposed uses the Herget's algorithmic scheme that makes it possible to involve additional observations as well. The methodical error of orbit computation by the proposed method is two orders smaller than the corresponding error of the Herget's approach based on the construction of the unperturbed Keplerian orbit. The new method is especially efficient if applied to high-accuracy observational data covering short orbital arcs.

Shefer, V. A.

2010-12-01

105

A new method of preliminary orbit determination from three or more observations on a short arc. (Russian Title: ????? ????? ??????????? ??????????????? ?????? ?? ???? ? ????? ??????????? ?? ???????? ????)  

NASA Astrophysics Data System (ADS)

A new method is suggested for finding the preliminary orbit of a small celestial body from its three or more pairs of angular measurements at three times. The method is based on using the approach that we previously developed for constructing the intermediate orbit from minimal number of observations. This intermediate orbit allows for most of the perturbations in the motion of the body under study. The method proposed uses the Herget's algorithmic scheme that makes it possible to involve additional observations as well. The methodical error of orbit computation by the proposed method is two orders smaller than the corresponding error of the commonly used approach based on the construction of the unperturbed Keplerian orbit. The new method is especially efficient if applied to high-accuracy observational data covering short orbital arcs.

Shefer, V. A.

2011-07-01

106

Ions, isotopes, and metal cyanides: Observational and laboratory studies  

NASA Astrophysics Data System (ADS)

Chemistry in the interstellar medium is very different from the processes which take place in terrestrial settings. Environments such as circumstellar envelopes, molecular clouds, and comets contain diverse and complex chemical networks. The low temperatures (10 50 K) and densities (1 10 6 cm-3) allow normally unstable molecules to exist in significant quantities. At these temperatures, the rotational energy levels of molecules are populated, and thus these species can be detected by millimeter-wave radio astronomy. The detection and quantification of interstellar molecules, including metal cyanides and molecular ions, is the basis of this dissertation work. While conducting observations of CN and 13CN to determine the 12C/13C ratio throughout the Galaxy, it was found that the ratios in photon- dominated regions (PDRs) were much higher than those in nearby molecular clouds. This can be explained by isotope-selective photodissociation, in which the 12CN molecules are self-shielded. However, the chemistry in these regions is poorly understood, and other processes may be occurring. In order to understand one of the chemical networks present in PDRs, observations of HCO+, HOC +, and CO+ were made toward several of these sources. Previous studies indicated that the HCO+/HOC+ ratio was much lower in PDRs, due to the presence of CO+. The new observations indicate that there is a strong correlation between CO + and HOC+ abundances, which suggests that other molecular ions which have not been detected in molecular clouds may be present in PDRs. There is a significant obstacle to the detection of new interstellar molecular ions, however. The laboratory spectra are virtually unknown for many of these species, due to their inherent instability. Thus, techniques which can selectively detect ionic spectra must be utilized. One such method is velocity modulation, which incorporates an AC electrical discharge to produce and detect ions. Previously, velocity modulation spectroscopy was employed only at infrared wavelengths. The final phase of this dissertation work was to design, build and test a velocity modulation spectrometer which functions at millimeter/sub-mm wavelengths. This system was then used to measure the previously unknown pure rotational spectrum of SH+ (X3E- ).

Savage, Chandra Shannon

2004-11-01

107

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 14, METHOD 604-PHENOLS  

EPA Science Inventory

An interlaboratory study in which 20 laboratories participated was conducted to provide precision and accuracy statements for the proposed EPA Method 604-Phenols for measuring concentrations of the Category 8 chemicals phenol, 2,4-dimethylphenol, 2-chlorophenol, 4-chloro-3-methyl...

108

Randomized trials versus observational studies in adolescent pregnancy prevention  

Microsoft Academic Search

The objective of this study is to compare the results of randomized trials and observational studies of interventions to prevent adolescent pregnancy. We identified published and unpublished reports through computerized searches of CATLINE, CINAHL, CONFERENCE PAPERS INDEX, DISSERTATION ABSTRACTS ONLINE, EMBASE, ERIC, MEDLINE, NTIS, POPLINE, PsycINFO, and SOCIOLOGICAL ABSTRACTS; manual searches of eight relevant journals; reference lists from primary articles;

Gordon H. Guyatt; Alba DiCenso; Vern Farewell; Andrew Willan; Lauren Griffith

2000-01-01

109

Observational study of potential risk factors of medication administration errors  

Microsoft Academic Search

Objective: Medication administration errors (MAEs) are the second most frequent type of medication errors, as has been shown in different studies in the literature. The aims of this observational study were to assess the rate and the potential clinical significance of MAEs and to determine the associated risk factors. Design: In two departments, Geriatric Unit (GU) and Cardiovascular-Thoracic Surgery Unit

Edgar Tissot; Christian Cornette; Samuel Limat; Jean-Louis Mourand; Michèle Becker; Joseph-Philippe Etievent; Jean-Louis Dupond; Micheline Jacquet; Marie-Christine Woronoff-Lemsi

2003-01-01

110

Survival after postoperative morbidity: a longitudinal observational cohort study  

PubMed Central

Background Previous studies have suggested that there may be long-term harm associated with postoperative complications. Uncertainty exists however, because of the need for risk adjustment and inconsistent definitions of postoperative morbidity. Methods We did a longitudinal observational cohort study of patients undergoing major surgery. Case-mix adjustment was applied and morbidity was recorded using a validated outcome measure. Cox proportional hazards modelling using time-dependent covariates was used to measure the independent relationship between prolonged postoperative morbidity and longer term survival. Results Data were analysed for 1362 patients. The median length of stay was 9 days and the median follow-up time was 6.5 yr. Independent of perioperative risk, postoperative neurological morbidity (prevalence 2.9%) was associated with a relative hazard for long-term mortality of 2.00 [P=0.001; 95% confidence interval (CI) 1.32–3.04]. Prolonged postoperative morbidity (prevalence 15.6%) conferred a relative hazard for death in the first 12 months after surgery of 3.51 (P<0.001; 95% CI 2.28–5.42) and for the next 2 yr of 2.44 (P<0.001; 95% CI 1.62–3.65), returning to baseline thereafter. Conclusions Prolonged morbidity after surgery is associated with a risk of premature death for a longer duration than perhaps is commonly thought; however, this risk falls with time. We suggest that prolonged postoperative morbidity measured in this way may be a valid indicator of the quality of surgical healthcare. Our findings reinforce the importance of research and quality improvement initiatives aimed at reducing the duration and severity of postoperative complications. PMID:25012586

Moonesinghe, S. R.; Harris, S.; Mythen, M. G.; Rowan, K. M.; Haddad, F. S.; Emberton, M.; Grocott, M. P. W.

2014-01-01

111

Using the Nordic Geodetic Observing System for land uplift studies  

NASA Astrophysics Data System (ADS)

Geodetic observing systems have been planned and developed during the last decade. An ideal observing system consists of a network of geodetic observing stations with several techniques at the same site, publicly accessible databases, and as a product delivers data time series, combination of techniques or some other results obtained from the data sets. Globally, there is the International Association of Geodesy (IAG) Global Geodetic Observing System (GGOS), and there are ongoing attempts to create also regional observing systems. In this paper we introduce one regional system, the Nordic Geodetic Observing System (NGOS) hosted by the Nordic Geodetic Commission (NKG). Data availability and accessibility are one of the major issues today. We discuss in general data-related topics, and introduce a pilot database project of NGOS. As a demonstration of the use of such a database, we apply it for postglacial rebound studies in the Fennoscandian area. We compare land uplift values from three techniques, GNSS, tide gauges and absolute gravity, with the Nordic Geodetic Commission NKG2005LU land uplift model for Fennoscandia. The purpose is to evaluate the data obtained from different techniques and different sources and get the most reliable values for the uplift using publicly available data. The primary aim of observing systems will be to produce data and other products needed by multidisciplinary projects, such as Upper Mantle Dynamics and Quaternary Climate in Cratonic Areas (DynaQlim) or the European Plate Observing System (EPOS), but their needs may currently exceed the scope of an existing observing system. We discuss what requirements the projects pose to observing systems and their development. To make comparisons between different studies possible and reliable, the researcher should document what they have in detail, either in appendixes, supplementary material or some other available format.

Nordman, M.; Poutanen, M.; Kairus, A.; Virtanen, J.

2014-07-01

112

Evaluation of flow direction methods against field observations of overland flow dispersion  

NASA Astrophysics Data System (ADS)

Despite the broad effort made in grid-based distributed catchment modeling to account for planar overland flow dispersion, actual dispersion experienced by overland flow along a natural slope has not been measured so far, and the ability of terrain analysis methods to reproduce this dispersion has not been evaluated. In the present study, the D8, D8-LTD, D? -LTD, D? , MD? , and MD8 flow direction methods are evaluated against field observations of overland flow dispersion obtained from novel experimental methods. Thin flows of cold (2--10oC) water were released at selected points on a warmer (15--30oC) slope and individual overland flow patterns originating from each of these points were observed using a terrestrial laser scanner and a thermal imaging camera. Prior to each experimental water release, a ScanStation C10 terrestrial laser scanner by Leica Geosystems was used to acquire a point cloud having average density of 25~points/cm2. This point cloud was used to generate alternative grid-based digital elevation models having resolution h ranging from 1~cm to 2~m. During the experiments, an Avio Advanced Thermo TVS-500EX camera by Nippon Avionics was used to monitor land surface temperature with resolution better than 0.05oC. The overland flow patterns were also found to be discernible in terrestrial laser scanner reflectance signal acquired immediately following the flow experiments. Overland flow patterns were determined by considering contrasted temperature and reflectance of the dry and wetted land surface portions. Predicted propagation patterns and observed flow patterns were compared by considering the fractions of flow released at the point source that propagates through the grid cells. Predictions of these quantities were directly provided by flow direction methods and by related flow accumulation algorithms. Suitable data for the comparison were derived from observed overland flow patterns by assuming a uniform distribution of flow along each cross section. Planar overland flow dispersion is found to play an important role in the region lying immediately downslope of the point source, but attenuates rapidly as flow propagates downslope displaying a nearly constant width of about 50~cm. In contrast, existing dispersive flow direction methods are found to provide a continued dispersion with distance downslope. Predicted propagation patterns, for all methods considered here, depend critically on h. All methods are found to be poorly sensitive in extremely fine grids (h ? 2~cm), and to be poorly specific in coarse grids (h = 2~m). Satisfactory results are, however, obtained when h approaches the average flow width, with the best performances in terms of Pearson correlation coefficient displayed by the MD8 method in the finest grids (5~cm ? h ? 20~cm), and by the MD? , D? , and D? -LTD methods in the coarsest grids (20~cm < h ? 1~m). The results obtained in this study suggest further testing of terrain analysis methods with longer flow patterns and coarser grids. Scale issues affecting the relation between land surface microtopography, dispersion, and size of grid cells involved need then to be addressed to provide a hydrologic model of flow partitioning along the slope directions identified by terrain analysis methods.

Orlandini, S.; Moretti, G.; Corticelli, M. A.; Santangelo, P. E.; Capra, A.; Rivola, R.; Albertson, J. D.

2012-12-01

113

Capturing intraoperative process deviations using a direct observational approach: the glitch method  

PubMed Central

Objectives To develop a sensitive, reliable tool for enumerating and evaluating technical process imperfections during surgical operations. Design Prospective cohort study with direct observation. Setting Operating theatres on five sites in three National Health Service Trusts. Participants Staff taking part in elective and emergency surgical procedures in orthopaedics, trauma, vascular and plastic surgery; including anaesthetists, surgeons, nurses and operating department practitioners. Outcome measures Reliability and validity of the glitch count method; frequency, type, temporal pattern and rate of glitches in relation to site and surgical specialty. Results The glitch count has construct and face validity, and category agreement between observers is good (?=0.7). Redundancy between pairs of observers significantly improves the sensitivity over a single observation. In total, 429 operations were observed and 5742 glitches were recorded (mean 14 per operation, range 0–83). Specialty-specific glitch rates varied from 6.9 to 8.3/h of operating (ns). The distribution of glitch categories was strikingly similar across specialties, with distractions the commonest type in all cases. The difference in glitch rate between specialty teams operating at different sites was larger than that between specialties (range 6.3–10.5/h, p<0.001). Forty per cent of glitches occurred in the first quarter of an operation, and only 10% occurred in the final quarter. Conclusions The glitch method allows collection of a rich dataset suitable for analysing the changes following interventions to improve process safety, and appears reliable and sensitive. Glitches occur more frequently in the early stages of an operation. Hospital environment, culture and work systems may influence the operative process more strongly than the specialty. PMID:24282244

Morgan, Lauren; Robertson, Eleanor; Hadi, Mohammed; Catchpole, Ken; Pickering, Sharon; New, Steve; Collins, Gary; McCulloch, Peter

2013-01-01

114

Food intake patterns and body mass index in observational studies  

Microsoft Academic Search

OBJECTIVE: To review studies of patterns of food intake, as assessed by diet index, factor analysis or cluster analysis, and their associations with body mass index or obesity (BMI\\/Ob).DESIGN: Systematic literature review MEDLINE search with crosscheck of references.STUDIES: Thirty observational studies relating food intake patterns to anthropometric information were identified and reviewed. Food intake patterns were defined using a diet

P Togo; M Osler; TIA Sørensen; BL Heitmann

2001-01-01

115

Home Videophones Improve Direct Observation in Tuberculosis Treatment: A Mixed Methods Evaluation  

PubMed Central

Background The use of direct observation to monitor tuberculosis treatment is controversial: cost, practical difficulties, and lack of patient acceptability limit effectiveness. Telehealth is a promising alternative delivery method for improving implementation. This study aimed to evaluate the clinical and cost-effectiveness of a telehealth service delivering direct observation, compared to an in-person drive-around service. Methodology/Principal Findings The study was conducted within a community nursing service in South Australia. Telehealth patients received daily video calls at home on a desktop videophone provided by the nursing call center. A retrospective cohort study assessed the effectiveness of the telehealth and traditional forms of observation, defined by the proportion of missed observations recorded in case notes. This data was inputted to a model, estimating the incremental cost-effectiveness ratio (ICER) of telehealth. Semi-structured interviews were conducted with current patients, community nursing and Chest Clinic staff, concerning service acceptability, usability and sustainability. The percentage of missed observations for the telehealth service was 12.1 (n?=?58), compared to 31.1 for the in-person service (n?=?70). Most of the difference of 18.9% (95% CI: 12.2 – 25.4) was due to fewer pre-arranged absences. The economic analysis calculated the ICER to be AUD$1.32 (95% CI: $0.51 – $2.26) per extra day of successful observation. The video service used less staff time, and became dominant if implemented on a larger scale and/or with decreased technology costs. Qualitative analysis found enabling factors of flexible timing, high patient acceptance, staff efficiency, and Chest Clinic support. Substantial technical problems were manageable, and improved liaison between the nursing service and Chest Clinic was an unexpected side-benefit. Conclusions/Significance Home video observation is a patient-centered, resource efficient way of delivering direct observation for TB, and is cost-effective when compared with a drive-around service. Future research is recommended to determine applicability and effectiveness in other settings. PMID:23226243

Wade, Victoria A.; Karnon, Jonathan; Eliott, Jaklin A.; Hiller, Janet E.

2012-01-01

116

Carbon nanotubes : a study on assembly methods  

E-print Network

The urgent stipulation is to manufacture CNTs of desired properties and dimensions. The heart of this yearning lies in understanding the growth and assembly methods of CNTs, which are not yet clear. In this study, hence, ...

Quiñones, Lisandro E. (Quiñones Ortiz)

2008-01-01

117

Methods of studying soil microbial diversity  

Microsoft Academic Search

Soil microorganisms, such as bacteria and fungi, play central roles in soil fertility and promoting plant health. This review examines and compares the various methods used to study microbial diversity in soil.

Jennifer L. Kirk; Lee A. Beaudette; Miranda Hart; Peter Moutoglis; John N. Klironomos; Hung Lee; Jack T. Trevors

2004-01-01

118

Lifetime Socioeconomic Position and Mortality: Prospective Observational Study  

Microsoft Academic Search

Objectives: To assess the influence of socioeconomic position over a lifetime on risk factors for cardiovascular disease, on morbidity, and on mortality from various causes. Design: Prospective observational study with 21 years of follow up. Social class was determined as manual or non-manual at three stages of participants' lives: from the social class of their father's job, the social class

George Davey Smith; Carole Hart; David Blane; Charles Gillis; Victor Hawthorne

1997-01-01

119

Scientific and Ethical Approaches for Observational Exposure Studies  

EPA Science Inventory

Researchers conduct observational human exposure studies to understand how and the extent to which people come into contact with chemicals and environmental stressors in their everyday lives, through the air they breathe, the food and liquids they consume, and the things they tou...

120

The effects of CPOE on ICU workflow: an observational study  

Microsoft Academic Search

Computerized physician order entry (CPOE) has had demonstrated benefits in error reduction and guideline adherence, but its implementation has often been complicated by disruptions in established workflow processes. We conducted an observational study of the healthcare team in an intensive care unit after the implementation of mandatory CPOE. We found that policies designed to increase flexibility and safety led to

MK Goldstein; E Geller

121

Observational Studies Randomized Controlled Experiments Principles of Experimental Design Random Samples Case Study Producing Data  

E-print Network

Samples Case Study Topic 4 Producing Data Formal Statistical Procedures 1 / 16 #12;Observational Studies Randomized Controlled Experiments Principles of Experimental Design Random Samples Case Study Outline Setting a Design Random Samples Case Study 2 / 16 #12;Observational Studies Randomized Controlled

Watkins, Joseph C.

122

A Conceptual Study of Visual Training Methods.  

ERIC Educational Resources Information Center

Proposes a research study to investigate the effects of two visual training methods on the productivity of new workers on an assembly line at a wood products plant in Indonesia. Suggests that such a study would be useful to the managers in deciding what types of training would be most appropriate. (Contains 23 references.) (CAK)

Aik, Chong-Tek

2003-01-01

123

Inverse Method for Estimating the Spatial Variability of Soil Particle Size Distribution from Observed Soil Moisture  

SciTech Connect

Soil particle size distribution (PSD) (i.e., clay, silt, sand, and rock contents) information is one of critical factors for understanding water cycle since it affects almost all of water cycle processes, e.g., drainage, runoff, soil moisture, evaporation, and evapotranspiration. With information about soil PSD, we can estimate almost all soil hydraulic properties (e.g., saturated soil moisture, field capacity, wilting point, residual soil moisture, saturated hydraulic conductivity, pore-size distribution index, and bubbling capillary pressure) based on published empirical relationships. Therefore, a regional or global soil PSD database is essential for studying water cycle regionally or globally. At the present stage, three soil geographic databases are commonly used, i.e., the Soil Survey Geographic database, the State Soil Geographic database, and the National Soil Geographic database. Those soil data are map unit based and associated with great uncertainty. Ground soil surveys are a way to reduce this uncertainty. However, ground surveys are time consuming and labor intensive. In this study, an inverse method for estimating mean and standard deviation of soil PSD from observed soil moisture is proposed and applied to Throughfall Displacement Experiment sites in Walker Branch Watershed in eastern Tennessee. This method is based on the relationship between spatial mean and standard deviation of soil moisture. The results indicate that the suggested method is feasible and has potential for retrieving soil PSD information globally from remotely sensed soil moisture data.

Pan, Feifei [University of Texas; Peters-lidard, Christa D. [NASA Goddard Space Flight Center; King, Anthony Wayne [ORNL

2010-11-01

124

The Aging, Demographics, and Memory Study: Study Design and Methods  

Microsoft Academic Search

Objective: We describe the design and methods of the Aging, Demographics, and Memory Study (ADAMS), a new national study that will provide data on the antecedents, prevalence, outcomes, and costs of dementia and ‘cognitive impairment, not demented’ (CIND) using a unique study design based on the nationally representative Health and Retirement Study (HRS). We also illustrate potential uses of the

Kenneth M. Langa; Brenda L. Plassman; Robert B. Wallace; A. Regula Herzog; Steven G. Heeringa; Mary Beth Ofstedal; James R. Burke; Gwenith G. Fisher; Nancy H. Fultz; Michael D. Hurd; Guy G. Potter; Willard L. Rodgers; David C. Steffens; David R. Weir; Robert J. Willis

2005-01-01

125

Research of the orbit fitting method using rectangular coordinates as observations. (Russian Title: ???????????? ??????? ????????? ?????, ????????????? ????????????? ?????????? ? ???????? ??????????)  

NASA Astrophysics Data System (ADS)

The theoretical and experimental research of the least-square orbit fitting method using rectangular coordinates as observations has been completed in the case of just angular observations used. In this case missing celestial object distances are replaced by their calculated values in the orbit fitting iterative process. It has been indicated that considered fitting method is equivalent to the standard one the weight coefficients are proportional to squared inverse distances of the observed object. Besides, it has been shown that the considered method has usually greater convergence region to compare with a region of the standard one.

Baturin, A. P.

2009-10-01

126

Study of coronal loops observed by GOES-SXI  

NASA Astrophysics Data System (ADS)

We study the temporal evolution of coronal loops using data from the Solar X-ray Imager SXI on board the Geosynchronous Operational Environmental Satellite 12 GOES-12 This instrument has the advantage of providing continuous soft X-ray observations of the solar corona at a high temporal cadence which allows us to follow the full lifetime of a set of coronal loops from their brightening to their decay From the observed light curves we can divide the evolution of the loops in three phases rise main and decay For each of these phases we compute the corresponding evolutionary timescales and since we have full time coverage the real loop lifetime Using data in different filters we derive temperature and density averages The values found place SXI loops halfway between the typical ranges of physical parameters for loops observed by the Soft X-ray Telescope Yohkoh SXT and those for loops observed by the Transition Region and Coronal Explorer TRACE We compute radiative and conductive cooling times which turn out to be much shorter than the evolutionary timescales of the loops These results confirm previous findings Porter and Klimchuk 1995 based on observations covering partially the loop temporal evolution Our results can be interpreted in terms of two alternative coronal heating scenarios quasi-static heating of monolithic uniform loop structures or impulsive heating nanoflaring of multiple-stranded loops We present arguments based on recent observations and loop modelling that support the idea

Lopez-Fuentes, M. C.; Mandrini, C. H.; Klimchuk, J. A.

127

Studies of non-ideal superconductors using DC magnetic methods  

Microsoft Academic Search

Among the most informative and facile methods for investigations of a superconductor are measurements of its static magnetization. The objective of this paper is to analyze some experimental features frequently observed in static (dc) magnetization studies of conventional and high-(Tc) superconductors. We shall discuss investigations employing measurement protocols in which the sample is cooled through the superconductive transition temperature in

J. R. Thompson; D. K. Christen; H. R. D. K. Kerchner; L. A. Boatner; B. C. Sales; B. C. Chakoumakos; H. Hsu; J. Brynestad; D. M. Kroeger; R. K. Williams; R. Feenstra; Yang Ren Sun; Y. C. Kim; J. G. Ossandon; A. P. Malozemoff; Civa

1991-01-01

128

Method for Determining the Radius Vector for a Planet from Two Observations of Position  

ERIC Educational Resources Information Center

Presents a method for determining the approximate radius vector of a planet or asteroid from two closely separated observation positions, using mathematics suitable for lower division college students. (MLH)

Gainer, Michael Kizinski

1977-01-01

129

Results of Observational Studies: Analysis of Findings from the Nurses’ Health Study  

PubMed Central

Background The role of observational studies in informing clinical practice is debated, and high profile examples of discrepancies between the results of observational studies and randomised controlled trials (RCTs) have intensified that debate. We systematically reviewed findings from the Nurses’ Health Study (NHS), one of the longest and largest observational studies, to assess the number and strength of the associations reported and to determine if they have been confirmed in RCTs. Methods We reviewed NHS publication abstracts from 1978–2012, extracted information on associations tested, and graded the strength of the reported effect sizes. We searched PubMed for RCTs or systematic reviews for 3 health outcomes commonly reported in NHS publications: breast cancer, ischaemic heart disease (IHD) and osteoporosis. NHS results were compared with RCT results and deemed concordant when the difference in effect sizes between studies was ?0.15. Findings 2007 associations between health outcomes and independent variables were reported in 1053 abstracts. 58.0% (1165/2007) were statistically significant, and 22.2% (445/2007) were neutral (no association). Among the statistically significant results that reported a numeric odds ratio (OR) or relative risk (RR), 70.5% (706/1002) reported a weak association (OR/RR 0.5–2.0), 24.5% (246/1002) a moderate association (OR/RR 0.25–0.5 or 2.0–4.0) and 5.0% (50/1002) a strong association (OR/RR ?0.25 or ?4.0). 19 associations reported in NHS publications for breast cancer, IHD and osteoporosis have been tested in RCTs, and the concordance between NHS and RCT results was low (?25%). Conclusions NHS publications contain a large number of analyses, the majority of which reported statistically significant but weak associations. Few of these associations have been tested in RCTs, and where they have, the agreement between NHS results and RCTs is poor. PMID:25330007

Tai, Vicky; Grey, Andrew; Bolland, Mark J.

2014-01-01

130

Rationale and design of the multinational observational study assessing insulin use: the MOSAIc study  

PubMed Central

Background Although consensus guidelines recommend insulin progression among patients with type 2 diabetes (T2DM) who fail to meet glycemic targets over time, many fewer patients are progressed than may benefit. We describe the rationale and design of the MOSAIc (Multinational Observational Study Assessing Insulin use) study, a multinational observational cohort study to identify patient-, physician, and health care environment-based factors associated with insulin progression for patients with T2DM in real-world practice. Methods/design We will enroll 4,500 patients with T2DM taking initial insulin therapy for ?3?months across 175 physician practice sites in 18 countries. Extensive demographic, clinical, and psychosocial data at the patient and physician level and practice site characteristics will be collected at baseline and regular intervals during a 24-month follow-up period. We will use a multivariable logistic regression model to identify predictors of insulin progression and highlight potential opportunities for health behavior intervention to improve insulin progression rates. Secondary outcomes include evaluating factors associated with glycemic control, hypoglycemia, and treatment adherence among patients who do and do not progress beyond their initial insulin therapy and exploring geographic heterogeneity in treatment. Discussion Practice site and patient recruitment began in 2011 and baseline data will be available in late 2012. The MOSAIC study’s longitudinal observational design as well as the breadth and depth of data will be used to explore and quantify predictors of insulin progression and to identify potential opportunities for health behavior intervention in order to improve T2DM treatment and clinical outcomes. PMID:22999494

2012-01-01

131

Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): Explanation and Elaboration  

PubMed Central

Much medical research is observational. The reporting of observational studies is often of insufficient quality. Poor reporting hampers the assessment of the strengths and weaknesses of a study and the generalisability of its results. Taking into account empirical evidence and theoretical considerations, a group of methodologists, researchers, and editors developed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) recommendations to improve the quality of reporting of observational studies. The STROBE Statement consists of a checklist of 22 items, which relate to the title, abstract, introduction, methods, results and discussion sections of articles. Eighteen items are common to cohort studies, case-control studies and cross-sectional studies and four are specific to each of the three study designs. The STROBE Statement provides guidance to authors about how to improve the reporting of observational studies and facilitates critical appraisal and interpretation of studies by reviewers, journal editors and readers. This explanatory and elaboration document is intended to enhance the use, understanding, and dissemination of the STROBE Statement. The meaning and rationale for each checklist item are presented. For each item, one or several published examples and, where possible, references to relevant empirical studies and methodological literature are provided. Examples of useful flow diagrams are also included. The STROBE Statement, this document, and the associated Web site (http://www.strobe-statement.org/) should be helpful resources to improve reporting of observational research. PMID:17941715

Vandenbroucke, Jan P; von Elm, Erik; Altman, Douglas G; Gøtzsche, Peter C; Mulrow, Cynthia D; Pocock, Stuart J; Poole, Charles; Schlesselman, James J; Egger, Matthias

2007-01-01

132

Rapid alignment method based on local observability analysis for strapdown inertial navigation system  

NASA Astrophysics Data System (ADS)

This paper presents a new method for rapid transfer alignment of strapdown inertial navigation system (SINS) by combining the local observability concept with robust adaptive filtering. The system state and observation models are simplified to analyze the observability of the SINS attitude error. Based on the simplified models, the observability matrix and its condition number are constructed to determine the observability degree of SINS during the process of rapid transfer alignment. On the basis of the local obsersability analysis, a robust adaptive filter is developed to estimate the attitude angle error for SINS rapid transfer alignment. Simulation experiments and comparison analysis have been conducted, demonstrating that the proposed method cannot only effectively measure the local observability of SINS, but it can also enhance the performance of SINS rapid transfer alignment and reduce the alignment time.

Gao, Shesheng; Wei, Wenhui; Zhong, Yongmin; Feng, Zhihua

2014-02-01

133

Power of Observation Students will sharpen one of the key skills in scientific study, observation, by using a variety of tools,  

E-print Network

-8 Benchmark I: Use scientific methods to develop questions, design and conduct experiments using appropriatePower of Observation Students will sharpen one of the key skills in scientific study, observation and nano and explore how scientists "see" the invisible world. Strand I: Scientific Thinking and Practice

134

Determining best method for estimating observed level of maximum convective detrainment based on radar reflectivity  

NASA Astrophysics Data System (ADS)

Convective mass transport is the transport of mass from near the surface up to the upper troposphere and lower stratosphere (UTLS) by a deep convective updraft. This transport can alter the chemical makeup and water vapor balance of the UTLS, which can affect cloud formation and the radiative properties of the atmosphere. It is therefore important to understand the exact altitudes at which mass is detrained from convection. The purpose of this study is to improve upon previously published methodologies for estimating the level of maximum detrainment (LMD) within convection using data from individual radars. Three methods were used to identify the LMD and validated against dual-Doppler derived vertical mass divergence fields. The best method for locating the LMD was determined to be the method that uses a horizontal reflectivity texture-based technique to determine convective cores and a multi-layer echo identification to determine anvil locations. The methodology was found to work in many but not all cases. The methodology works best when applied to convective systems with mature updrafts, and is most accurate with convective lines and isolated cells. A time lag is present in the reflectivity based LMD compared to the vertical mass divergence based LMD because the reflectivity method is dependent on anvil growth. This methodology was then applied to archived NEXRAD 3D mosaic radar data. The regions of analysis were chosen to coincide with the observation regions for the Deep Convective Clouds and Chemistry Experiment (DC3): the Colorado Foothills, Southern Plains (OK/TX), and Southeast US (AL). These three regions provide a wide variety of convection. The dates analyzed were from May and June of 2012 so the results can be compared to future DC3 studies

Carletta, Nicholas Daniel

135

An Observational Method in the Foreign Language Classroom: A Closer Look at Interaction Analysis  

ERIC Educational Resources Information Center

This paper analyzes both Flanders' and the Foreign Language Interaction (FLint) methods of classroom observation and concludes that both systems are deficient in accuracy, reliability and practicality. Observing, recording and decision-making difficulties are inherent, and system complexities and teacher biases add to the problems. (CHK)

Bailey, Leona G.

1975-01-01

136

Motivation Observations and methods Results & Discussion Minor compounds in Saturn's stratosphere  

E-print Network

Motivation Observations and methods Results & Discussion Minor compounds in Saturn's stratosphere - 7 October 2009 Sandrine Guerlet Minor compounds in Saturn's stratosphere #12;Motivation Observations of hydrocarbons in Saturn's stratosphere Origin: by-products of CH4 photolysis by solar UV ; Production rates

Demoulin, Pascal

137

Methods for Observed-Cluster Inference When Cluster Size Is Informative: A Review and Clarifications  

PubMed Central

Clustered data commonly arise in epidemiology. We assume each cluster member has an outcome Y and covariates . When there are missing data in Y, the distribution of Y given in all cluster members (“complete clusters”) may be different from the distribution just in members with observed Y (“observed clusters”). Often the former is of interest, but when data are missing because in a fundamental sense Y does not exist (e.g., quality of life for a person who has died), the latter may be more meaningful (quality of life conditional on being alive). Weighted and doubly weighted generalized estimating equations and shared random-effects models have been proposed for observed-cluster inference when cluster size is informative, that is, the distribution of Y given in observed clusters depends on observed cluster size. We show these methods can be seen as actually giving inference for complete clusters and may not also give observed-cluster inference. This is true even if observed clusters are complete in themselves rather than being the observed part of larger complete clusters: here methods may describe imaginary complete clusters rather than the observed clusters. We show under which conditions shared random-effects models proposed for observed-cluster inference do actually describe members with observed Y. A psoriatic arthritis dataset is used to illustrate the danger of misinterpreting estimates from shared random-effects models. PMID:24479899

Seaman, Shaun R; Pavlou, Menelaos; Copas, Andrew J

2014-01-01

138

Inter-Observer Reliability Assessments in Time Motion Studies: The Foundation for Meaningful Clinical Workflow Analysis  

PubMed Central

Understanding clinical workflow is critical for researchers and healthcare decision makers. Current workflow studies tend to oversimplify and underrepresent the complexity of clinical workflow. Continuous observation time motion studies (TMS) could enhance clinical workflow studies by providing rich quantitative data required for in-depth workflow analyses. However, methodological inconsistencies have been reported in continuous observation TMS, potentially reducing the validity of TMS’ data and limiting their contribution to the general state of knowledge. We believe that a cornerstone in standardizing TMS is to ensure the reliability of the human observers. In this manuscript we review the approaches for inter-observer reliability assessment (IORA) in a representative sample of TMS focusing on clinical workflow. We found that IORA is an uncommon practice, inconsistently reported, and often uses methods that provide partial and overestimated measures of agreement. Since a comprehensive approach to IORA is yet to be proposed and validated, we provide initial recommendations for IORA reporting in continuous observation TMS. PMID:24551381

Lopetegui, Marcelo A.; Bai, Shasha; Yen, Po-Yin; Lai, Albert; Embi, Peter; Payne, Philip R.O.

2013-01-01

139

Fog forecasting: ``old fashioned'' semi-empirical methods from radio sounding observations versus ``modern'' numerical models  

NASA Astrophysics Data System (ADS)

Fog forecasting is a very challenging task due to the local and small-scale nature of the relevant physical processes and land surface heterogeneities. Despite the many research efforts, numerical models remain to have difficulties with fog forecasting, and forecast skill from direct model output is relatively poor. In order to put the progress of fog forecasting in the last decades into a historical perspective, we compare the fog forecasting skill of a semi-empirical method based on radio sounding observations (developed in the 60s and 70s) with the forecasting skill of a state-of-the-art numerical weather prediction model (MM5) for The Netherlands. The semi-empirical method under investigation, the Fog Stability Index, depends solely on the temperature difference between the surface and 850 hPa, the surface dew point depression and the wind speed at 850 hPa, and a threshold value to indicate the probability of fog in the coming hours. Using the critical success index (CSI) as a criterion for forecast quality, we find that the Fog Stability Index is a rather successful predictor for fog, with similar performance as MM5. The FSI could even been optimized for different observational stations in the Netherlands. Also, it appears that adding the 10 m wind as a predictor did not increase the CSI score for all stations. The results of the current study clearly indicate that the current state of knowledge requires improvement of the physical insight in different physical processes in order to beat simple semi-empirical methods.

Holtslag, M. C.; Steeneveld, G. J.; Holtslag, A. A. M.

2010-07-01

140

Continuing Studies in Support of Ultraviolet Observations of Planetary Atmospheres  

NASA Technical Reports Server (NTRS)

This program was a one-year extension of an earlier Planetary Atmospheres program grant, covering the period 1 August 1996 through 30 September 1997. The grant was for supporting work to complement an active program observing planetary atmospheres with Earth-orbital telescopes, principally the Hubble Space Telescope (HST). The recent concentration of this work has been on HST observations of Jupiter's upper atmosphere and aurora, but it has also included observations of Io, serendipitous observations of asteroids, and observations of the velocity structure in the interplanetary medium. The observations of Jupiter have been at vacuum ultraviolet wavelengths, including imaging and spectroscopy of the auroral and airglow emissions. The most recent HST observations have been at the same time as in situ measurements made by the Galileo orbiter instruments, as reflected in the meeting presentations listed below. Concentrated efforts have been applied in this year to the following projects: The analysis of HST WFPC 2 images of Jupiter's aurora, including the Io footprint emissions. We have performed a comparative analysis of the lo footprint locations with two magnetic field models, studied the statistical properties of the apparent dawn auroral storms on Jupiter, and found various other repeated patterns in Jupiter's aurora. Analysis and modeling of airglow and auroral Ly alpha emission line profiles from Jupiter. This has included modeling the aurora] line profiles, including the energy degradation of precipitating charged particles and radiative transfer of the emerging emissions. Jupiter's auroral emission line profile is self-absorbed, since it is produced by an internal source, and the resulting emission with a deep central absorption from the overlying atmosphere permits modeling of the depth of the emissions, plus the motion of the emitting layer with respect to the overlying atmospheric column from the observed Doppler shift of the central absorption. By contrast the airglow emission line, which is dominated by resonant scattering of solar emission, has no central absorption, but displays rapid time variations and broad wings, indicative of a superthermal component (or corona) in Jupiter's upper atmosphere. Modeling of the observed motions of the plumes produced after the impacts of the fragments of Comet S/L-9 with Jupiter in July 1994, from the HST WFPC 2 imaging series.

Clark, John

1997-01-01

141

Applications of neural network methods to the processing of earth observation satellite data.  

PubMed

The new generation of earth observation satellites carries advanced sensors that will gather very precise data for studying the Earth system and global climate. This paper shows that neural network methods can be successfully used for solving forward and inverse remote sensing problems, providing both accurate and fast solutions. Two examples of multi-neural network systems for the determination of cloud properties and for the retrieval of total columns of ozone using satellite data are presented. The developed algorithms based on multi-neural network are currently being used for the operational processing of European atmospheric satellite sensors and will play a key role in related satellite missions planed for the near future. PMID:16530385

Loyola, Diego G

2006-03-01

142

Development of a standard method to observe the surface friction of high-strength gels  

NASA Astrophysics Data System (ADS)

In 2003, the most effective but simple way was proposed to synthesize double network gels, whose compression fracture stress reached about 30MPa, while that of common gels were several tens kPa. Our group has focused on PAMPSPDMAAm DN gel, because it possibly has both biocompatibility and permeability, which are good for developing artificial articular cartilage and artificial blood vessel. It is also possibly used for rapid additive manufacturing with 3D gel printer. Here, we develop a novel apparatus of the ball on disk method to observe the surface friction of the DN gels. We hope to apply this apparatus for various studies about the tribological behavior of the gels, especially about the effect of external electric field on the gel friction.

Yamada, Kouhei; Watanabe, Yosuke; Yamada, Naoya; Wada, Masato; Gong, Jin; Makino, Masato; Kabir, M. Hasnat; Furukawa, Hidemitsu

2014-03-01

143

An observational study of the initial management of hypothyroidism in France: the ORCHIDÉE study  

PubMed Central

Objective To document the initial management of hypothyroidism in France with respect to diagnostic setting, investigations, and therapeutic approach. Design Observational study of the management by primary care practitioners (PCPs) and endocrinologists of patients diagnosed with, and treated for, hypothyroidism during the enrollment period or the previous 6 months. Methods A representative sample of PCPs and endocrinologists enrolled up to five consecutive patients and reported sociodemographic, clinical, therapeutic, and laboratory data. Data were submitted at baseline and at the first measurement of TSH after starting the treatment. Results The analysis population comprised 1255 patients (mean (s.d.) age 52.8 (16.3) years; 84% female). Hypothyroidism was suspected on clinical grounds in 77% of patients, with goiter in 16%. Autoimmune thyroiditis, supported by positive anti-thyroid antibodies, was the most frequent diagnosis (59%), followed by iatrogenic causes (28%), of which thyroidectomy was the most common. The median baseline TSH was 8.6?mIU/l, suggesting a high incidence of subclinical hypothyroidism. Imaging studies were requested in over 75% of patients, with ultrasound performed in 98% and scintigraphy performed in 19% of these patients. Both groups of physicians treated their patients almost exclusively with levothyroxine. Endocrinologists were more likely than PCPs to provide counseling on how to take medication correctly. Conclusions This observational study of a large cohort of patients with newly diagnosed hypothyroidism in France illustrates current practice and indicates some areas where physician education may be required to optimize adherence to guidelines and cost-effectiveness. PMID:23034782

Delemer, Brigitte; Aubert, Jean-Pierre; Nys, Pierre; Landron, Frédéric; Bouée, Stéphane

2012-01-01

144

Observational studies of reconnection in the solar corona  

SciTech Connect

In recent years, observational studies of the corona have shifted focus. Where they were once purely qualitative morphological explorations seeking to support the presence of reconnection, more investigations are providing empirical estimates of the physical conditions in the reconnecting corona. These studies are enabled and enhanced by orbiting telescopes with high angular and temporal resolution. In this article, some recent findings about the empirical quantities are reviewed, including recent estimates of the flux transferred in individual patchy reconnection episodes, the size distribution of post-reconnection flux tubes, and the energy released by the flux tubes as they shrink.

McKenzie, David E. [Department of Physics, Montana State University, P.O. Box 173840, Bozeman, Montana 59717-3840 (United States)

2011-11-15

145

An Observational Method to Prevent Cross-Talk and Calibrate Mof-Based Instruments  

Microsoft Academic Search

We present a method for calibrating every instrument working with magneto-optical filter (MOF) technology, in order to take into account the effect in the observations due to the aging of the vapour cells. The method allows the evaluation of some characteristics of the transmission profile by modelling the blue and\\/or the red line intensity images acquired with the MOF system.

Maria Magrì; Maurizio Oliviero; Giuseppe Severino

2005-01-01

146

Preequating with Empirical Item Characteristic Curves: An Observed-Score Preequating Method  

ERIC Educational Resources Information Center

Preequating is in demand because it reduces score reporting time. In this article, we evaluated an observed-score preequating method: the empirical item characteristic curve (EICC) method, which makes preequating without item response theory (IRT) possible. EICC preequating results were compared with a criterion equating and with IRT true-score…

Zu, Jiyun; Puhan, Gautam

2014-01-01

147

Study of underground power cable installation methods  

Microsoft Academic Search

Detailed examination of the various installation steps was made and a range of costs was presented for each. After analyzing those higher cost steps for each cable type studied, various technologies were identified that could reduce these costs if utilities adopted these methods for use in other areas of construction. The result of these analyses was to recommend research and

J. Nicol

1977-01-01

148

Automated Parameter Studies Using a Cartesian Method  

Microsoft Academic Search

A modular process for performing general parametric studies about an aerodynamic configuration using a Cartesian method is described. A novel part of this process is the automatic handling of general control surfaces deflections based upon simple, user- specified inputs. The article focuses on the use of aerodynamic databases in the design process. Database fly-through is used to develop and analyze

Scott M. Murman; Michael J. Aftosmis; Marian Nemec

149

Some observations on a new numerical method for solving Navier-Stokes equations  

NASA Technical Reports Server (NTRS)

An explicit-implicit technique for solving Navier-Stokes equations is described which, is much less complex than other implicit methods. It is used to solve a complex, two-dimensional, steady-state, supersonic-flow problem. The computational efficiency of the method and the quality of the solution obtained from it at high Courant-Friedrich-Lewy (CFL) numbers are discussed. Modifications are discussed and certain observations are made about the method which may be helpful in using it successfully.

Kumar, A.

1981-01-01

150

An observational study of medication administration errors in old-age psychiatric inpatients  

Microsoft Academic Search

Background. Relatively little is known about medication administration errors in mental health settings. Objective. To investigate the frequency and nature of medication administration errors in old-age psychiatry. To assess the acceptability of the observational technique to nurse participants. Method. Cross-sectional study technique using (i) direct observation, (ii) medication chart review and (iii) incident reports. Setting. Two elderly long-stay wards in

CAMILLA HAW; JEAN STUBBS; GEOFF DICKENS

2007-01-01

151

Formal Methods Case Studies for DO-333  

NASA Technical Reports Server (NTRS)

RTCA DO-333, Formal Methods Supplement to DO-178C and DO-278A provides guidance for software developers wishing to use formal methods in the certification of airborne systems and air traffic management systems. The supplement identifies the modifications and additions to DO-178C and DO-278A objectives, activities, and software life cycle data that should be addressed when formal methods are used as part of the software development process. This report presents three case studies describing the use of different classes of formal methods to satisfy certification objectives for a common avionics example - a dual-channel Flight Guidance System. The three case studies illustrate the use of theorem proving, model checking, and abstract interpretation. The material presented is not intended to represent a complete certification effort. Rather, the purpose is to illustrate how formal methods can be used in a realistic avionics software development project, with a focus on the evidence produced that could be used to satisfy the verification objectives found in Section 6 of DO-178C.

Cofer, Darren; Miller, Steven P.

2014-01-01

152

A study of GPS ionospheric scintillations observed at Shenzhen  

NASA Astrophysics Data System (ADS)

Ionospheric scintillation variations are studied using GPS measurements at the low latitude station of Shenzhen (22.59°N, 113.97°E), situated under the northern crest of the equatorial anomaly region, from the Chinese Meridian Project. The results are presented for data collected during the current phase of rising solar activity (low to high solar activity) from December 2010 to April 2014. The results show that GPS scintillation events were largely a nighttime phenomenon during the whole observation period. Scintillation events mainly occurred along the inner edge of the northern crest of the equatorial anomaly in China. The occurrence of scintillations in different sectors of the sky was also investigated, and the results revealed that it is more likely for the scintillations to be observed in the west sector of the sky above Shenzhen. During the present period of study, a total number of 512 total electron content (TEC) depletions and 460 lock loss events were observed. In addition, both of these events are likely to increase during periods of high solar activity, especially because the strong scintillations are often simultaneously accompanied by TEC depletions and lock losses by GPS receivers.

Huang, Linfeng; Wang, Jinsong; Jiang, Yong; Chen, Zhou; Zhao, Kai

2014-12-01

153

Microbiota and healthy ageing: observational and nutritional intervention studies  

PubMed Central

Summary Hundred years ago Metchnikoff associated human health and particularly healthy ageing with a specific type of gut microbiota. Classical culture methods associated a decrease in bifidobacteria and an increase in enterobacteria with ageing. Modern molecular methods blurred this simple picture and documented a substantial inter-individual variability for the gut microbiome even when stratifying the elderly subjects according to health status. Nutritional interventions with resistant starch showed consistent gut microbiota changes across studies from different geographical areas and prebiotic supplementation induced a 10-fold increase in gut bifidobacteria. However, in the ELDERMET study, microbiota changes do not precede, but follow the changes in health status of elderly subjects possibly as a consequence of diet changes. PMID:23527905

Brüssow, Harald

2013-01-01

154

Studies of Tropical/Mid-Latitude Exchange Using UARS Observations  

NASA Technical Reports Server (NTRS)

At the time this proposal was submitted, recent publications had suggested an important role for transport of midlatitude air into the tropical lower stratosphere. Most of these studies had employed data that gave only a time-averaged picture, making it difficult to determine the nature of the transport processes responsible for the observed behavior. We proposed to analyze observations of long-lived trace gases, such as nitric acid, methane, nitrous oxide, and chlorofluorocarbons, made from the Upper Atmosphere Research Satellite, to investigate the seasonal behavior of mixing between the midlatitudes and tropics. We planned to construct probability distributions of the concentrations of these species over small altitude ranges and to compare them to expectations based on modeled mean concentrations and knowledge of instrument precision. Differences from expectation were to be analyzed with respect to meteorological parameters to determine whether wave activity may have induced apparent mixing.

Avallone, Linnea

2001-01-01

155

A generic method to constrain the dark matter model parameters from Fermi observations of dwarf spheroids  

SciTech Connect

Observation of ?-rays from dwarf galaxies is an effective way to search for particle dark matter. Using 4-year data of Fermi-LAT observations on a series of Milky Way satellites, we develop a general way to search for the signals from dark matter annihilation in such objects. Instead of giving prior information about the energy spectrum of dark matter annihilation, we bin the Fermi-LAT data into several energy bins and build a likelihood map in the ''energy bin - flux'' plane. The final likelihood of any spectrum can be easily derived through combining the likelihood of all the energy bins. It gives consistent result with that directly calculated using the Fermi Scientific Tool. This method is very efficient for the study of any specific dark matter models with ?-rays. We use the new likelihood map with Fermi-LAT 4 year data to fit the parameter space in three representative dark matter models: i) toy dark matter model, ii) effective dark matter operators, and iii) supersymmetric neutralino dark matter.

Tsai, Yue-Lin Sming [National Center for Nuclear Research, Hoza 69, 00-681 Warsaw (Poland); Yuan, Qiang [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R.China (China); Huang, Xiaoyuan, E-mail: Sming.Tsai@fuw.edu.pl, E-mail: yuanq@ihep.ac.cn, E-mail: x_huang@bao.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, P.R.China (China)

2013-03-01

156

Evaluating causal relationships between urban built environment characteristics and obesity: a methodological review of observational studies.  

PubMed

BackgroundExisting reviews identify numerous studies of the relationship between urban built environment characteristics and obesity. These reviews do not generally distinguish between cross-sectional observational studies using single equation analytical techniques and other studies that may support more robust causal inferences. More advanced analytical techniques, including the use of instrumental variables and regression discontinuity designs, can help mitigate biases that arise from differences in observable and unobservable characteristics between intervention and control groups, and may represent a realistic alternative to scarcely-used randomised experiments. This review sought first to identify, and second to compare the results of analyses from, studies using more advanced analytical techniques or study designs.MethodsIn March 2013, studies of the relationship between urban built environment characteristics and obesity were identified that incorporated (i) more advanced analytical techniques specified in recent UK Medical Research Council guidance on evaluating natural experiments, or (ii) other relevant methodological approaches including randomised experiments, structural equation modelling or fixed effects panel data analysis.ResultsTwo randomised experimental studies and twelve observational studies were identified. Within-study comparisons of results, where authors had undertaken at least two analyses using different techniques, indicated that effect sizes were often critically affected by the method employed, and did not support the commonly held view that cross-sectional, single equation analyses systematically overestimate the strength of association.ConclusionsOverall, the use of more advanced methods of analysis does not appear necessarily to undermine the observed strength of association between urban built environment characteristics and obesity when compared to more commonly-used cross-sectional, single equation analyses. Given observed differences in the results of studies using different techniques, further consideration should be given to how evidence gathered from studies using different analytical approaches is appraised, compared and aggregated in evidence synthesis. PMID:25406733

Martin, Adam; Ogilvie, David; Suhrcke, Marc

2014-11-18

157

Success and Failure in Helping SMEs. A Three-Year Observational Study.  

ERIC Educational Resources Information Center

A 3-year observational study of a project to help small and medium-sized enterprises (SMEs) conducted by a British university highlighted initial contacts and working methods that were effective. Results identified why some SMEs do not make full use of facilities offered and reasons for overall success. (Contains 13 references.) (JOW)

Stewardson, Dave; Coleman, Shirley

2003-01-01

158

Power calculations for generalized linear models in observational longitudinal studies: A simulation approach in SAS  

Microsoft Academic Search

Repeated measurements arising from longitudinal studies occur frequently in applied research. Methods to calculate power in the context of repeated measures are available for experimental settings where the covariate of interest is a discrete treatment indicator. However, no closed form expression exists to calculate power for generalized linear models with non-zero within-cluster correlation that are common in epidemiological and observational

Victor M. Gastañaga; Christine E. Mclaren; Ralph J. Delfino

2006-01-01

159

Studies on Training Ground Observers to Estimate Range to Aerial Targets.  

ERIC Educational Resources Information Center

Six pilot studies were conducted to determine the effects of training on range estimation performance for aerial targets, and to identify some of the relevant variables. Observers were trained to estimate ranges of 350, 400, 800, 1,500, or 2,500 meters. Several variations of range estimation training methods were used, including immediate…

McCluskey, Michael R.; And Others

160

ADAPTIVE MATCHING IN RANDOMIZED TRIALS AND OBSERVATIONAL STUDIES  

PubMed Central

SUMMARY In many randomized and observational studies the allocation of treatment among a sample of n independent and identically distributed units is a function of the covariates of all sampled units. As a result, the treatment labels among the units are possibly dependent, complicating estimation and posing challenges for statistical inference. For example, cluster randomized trials frequently sample communities from some target population, construct matched pairs of communities from those included in the sample based on some metric of similarity in baseline community characteristics, and then randomly allocate a treatment and a control intervention within each matched pair. In this case, the observed data can neither be represented as the realization of n independent random variables, nor, contrary to current practice, as the realization of n/2 independent random variables (treating the matched pair as the independent sampling unit). In this paper we study estimation of the average causal effect of a treatment under experimental designs in which treatment allocation potentially depends on the pre-intervention covariates of all units included in the sample. We define efficient targeted minimum loss based estimators for this general design, present a theorem that establishes the desired asymptotic normality of these estimators and allows for asymptotically valid statistical inference, and discuss implementation of these estimators. We further investigate the relative asymptotic efficiency of this design compared with a design in which unit-specific treatment assignment depends only on the units’ covariates. Our findings have practical implications for the optimal design and analysis of pair matched cluster randomized trials, as well as for observational studies in which treatment decisions may depend on characteristics of the entire sample. PMID:25097298

van der Laan, Mark J.; Balzer, Laura B.; Petersen, Maya L.

2014-01-01

161

Globally Gridded Satellite (GridSat) Observations for Climate Studies  

NASA Technical Reports Server (NTRS)

Geostationary satellites have provided routine, high temporal resolution Earth observations since the 1970s. Despite the long period of record, use of these data in climate studies has been limited for numerous reasons, among them: there is no central archive of geostationary data for all international satellites, full temporal and spatial resolution data are voluminous, and diverse calibration and navigation formats encumber the uniform processing needed for multi-satellite climate studies. The International Satellite Cloud Climatology Project set the stage for overcoming these issues by archiving a subset of the full resolution geostationary data at approx.10 km resolution at 3 hourly intervals since 1983. Recent efforts at NOAA s National Climatic Data Center to provide convenient access to these data include remapping the data to a standard map projection, recalibrating the data to optimize temporal homogeneity, extending the record of observations back to 1980, and reformatting the data for broad public distribution. The Gridded Satellite (GridSat) dataset includes observations from the visible, infrared window, and infrared water vapor channels. Data are stored in the netCDF format using standards that permit a wide variety of tools and libraries to quickly and easily process the data. A novel data layering approach, together with appropriate satellite and file metadata, allows users to access GridSat data at varying levels of complexity based on their needs. The result is a climate data record already in use by the meteorological community. Examples include reanalysis of tropical cyclones, studies of global precipitation, and detection and tracking of the intertropical convergence zone.

Knapp, Kenneth R.; Ansari, Steve; Bain, Caroline L.; Bourassa, Mark A.; Dickinson, Michael J.; Funk, Chris; Helms, Chip N.; Hennon, Christopher C.; Holmes, Christopher D.; Huffman, George J.; Kossin, James P.; Lee, Hai-Tien; Loew, Alexander; Magnusdottir, Gudrun

2012-01-01

162

A statistical study of merging galaxies: Theory and observations  

NASA Technical Reports Server (NTRS)

A study of the expected frequency of merging galaxies is conducted, using the impulsive approximation. Results indicate that if we consider mergers involving galaxy pairs without halos in a single crossing time or orbital period, the expected frequency of mergers is two orders of magnitude below the observed value for the present epoch. If we consider mergers involving several orbital periods or crossing times, the expected frequency goes up by an order of magnitude. Preliminary calculation indicate that if we consider galaxy mergers between pairs with massive halos, the merger is very much hastened.

Chatterjee, Tapan K.

1990-01-01

163

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 24, METHOD 601--PURGEABLE HALOCARBONS BY THE PURGE TRAP METHOD  

EPA Science Inventory

The experimental design and results of a validations study for an analytical method to detect 29 halocarbons in water are described herein. In Method 601, the halocarbons are purged by an inert gas which is bubbled through the aqueous sample. The vapors are then trapped in a shor...

164

Guideline adaptation and implementation planning: a prospective observational study  

PubMed Central

Background Adaptation of high-quality practice guidelines for local use has been advanced as an efficient means to improve acceptability and applicability of evidence-informed care. In a pan-Canadian study, we examined how cancer care groups adapted pre-existing guidelines to their unique context and began implementation planning. Methods Using a mixed-methods, case-study design, five cases were purposefully sampled from self-identified groups and followed as they used a structured method and resources for guideline adaptation. Cases received the ADAPTE Collaboration toolkit, facilitation, methodological and logistical support, resources and assistance as required. Documentary and primary data collection methods captured individual case experience, including monthly summaries of meeting and field notes, email/telephone correspondence, and project records. Site visits, process audits, interviews, and a final evaluation forum with all cases contributed to a comprehensive account of participant experience. Results Study cases took 12 to >24 months to complete guideline adaptation. Although participants appreciated the structure, most found the ADAPTE method complex and lacking practical aspects. They needed assistance establishing individual guideline mandate and infrastructure, articulating health questions, executing search strategies, appraising evidence, and achieving consensus. Facilitation was described as a multi-faceted process, a team effort, and an essential ingredient for guideline adaptation. While front-line care providers implicitly identified implementation issues during adaptation, they identified a need to add an explicit implementation planning component. Conclusions Guideline adaptation is a positive initial step toward evidence-informed care, but adaptation (vs. ‘de novo’ development) did not meet expectations for reducing time or resource commitments. Undertaking adaptation is as much about the process (engagement and capacity building) as it is about the product (adapted guideline). To adequately address local concerns, cases found it necessary to also search and appraise primary studies, resulting in hybrid (adaptation plus de novo) guideline development strategies that required advanced methodological skills. Adaptation was found to be an action element in the knowledge translation continuum that required integration of an implementation perspective. Accordingly, the adaptation methodology and resources were reformulated and substantially augmented to provide practical assistance to groups not supported by a dedicated guideline panel and to provide more implementation planning support. The resulting framework is called CAN-IMPLEMENT. PMID:23656884

2013-01-01

165

Spacelab Science Results Study. Volume 1; External Observations  

NASA Technical Reports Server (NTRS)

Some of the 36 Spacelab missions were more or less dedicated to specific scientific disciplines, while other carried a eclectic mixture of experiments ranging from astrophysics to life sciences. However, the experiments can be logically classified into two general categories; those that make use of the Shuttle as an observing platform for external phenomena (including those which use the Shuttle in an interactive mode) and those which use the Shuttle as a microgravity laboratory. This first volume of this Spacelab Science Results study will be devoted to experiments of the first category. The disciplines included are Astrophysics, Solar Physics, Space Plasma Physics, Atmospheric Sciences, and Earth Sciences. Because of the large number of microgravity investigations, Volume 2 will be devoted to Microgravity Sciences, which includes Fluid Physics, Combustion Science, Materials Science, and Biotechnology, and Volume 3 will be devoted to Space Life Sciences, which studies the response and adaptability of living organisms to the microgravity environment.

Naumann, Robert J. (Compiler)

1999-01-01

166

DNA Fingerprinting Validates Seed Dispersal Curves from Observational Studies in the Neotropical Legume Parkia  

PubMed Central

Background Determining the distances over which seeds are dispersed is a crucial component for examining spatial patterns of seed dispersal and their consequences for plant reproductive success and population structure. However, following the fate of individual seeds after removal from the source tree till deposition at a distant place is generally extremely difficult. Here we provide a comparison of observationally and genetically determined seed dispersal distances and dispersal curves in a Neotropical animal-plant system. Methodology/Principal Findings In a field study on the dispersal of seeds of three Parkia (Fabaceae) species by two Neotropical primate species, Saguinus fuscicollis and Saguinus mystax, in Peruvian Amazonia, we observationally determined dispersal distances. These dispersal distances were then validated through DNA fingerprinting, by matching DNA from the maternally derived seed coat to DNA from potential source trees. We found that dispersal distances are strongly right-skewed, and that distributions obtained through observational and genetic methods and fitted distributions do not differ significantly from each other. Conclusions/Significance Our study showed that seed dispersal distances can be reliably estimated through observational methods when a strict criterion for inclusion of seeds is observed. Furthermore, dispersal distances produced by the two primate species indicated that these primates fulfil one of the criteria for efficient seed dispersers. Finally, our study demonstrated that DNA extraction methods so far employed for temperate plant species can be successfully used for hard-seeded tropical plants. PMID:22514748

Heymann, Eckhard W.; Lüttmann, Kathrin; Michalczyk, Inga M.; Saboya, Pedro Pablo Pinedo; Ziegenhagen, Birgit; Bialozyt, Ronald

2012-01-01

167

A Tikhonov regularization method to estimate Earth's oblateness variations from global GPS observations  

NASA Astrophysics Data System (ADS)

Earth's oblateness is varying due to the redistribution of Earth's fluid mass and the interaction of various components in the Earth system. Nowadays, continuous Global Positioning System (GPS) observations can estimate Earth's oblateness (J2) variations with the least squares method, but are subject to ill-conditioned equations with limited GPS observations and aliasing errors from truncated degrees. In this paper, a Tikhonov regularization method is used to estimate J2 variations from global continuous GPS observations. Results show that the J2 has been better estimated from GPS observations based on a Tikhonov regularization method than the usual least squares method when compared to SLR solutions. Furthermore, the amplitudes and phases of the annual and semi-annual J2 variations are closer to the SLR results with truncated degrees from 2 to 5. Higher truncated degrees will degrade the J2 estimate. Annual J2 variations are best estimated from GPS observations with truncated degree 4 and semi-annual J2 variations are best estimated with truncated degree 2.

Jin, Shuanggen; Zhang, Xinggang

2014-09-01

168

Method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein  

DOEpatents

A method is described for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein. A direct correlation between the octane rating of gasoline and the frequency of corresponding acoustic resonances therein has been experimentally observed. Therefore, the octane rating of a gasoline sample can be directly determined through speed of sound measurements instead of by the cumbersome process of quantifying the knocking quality of the gasoline. Various receptacle geometries and construction materials may be employed. Moreover, it is anticipated that the measurements can be performed on flowing samples in pipes, thereby rendering the present method useful in refineries and distilleries. 3 figs.

Sinha, D.N.; Anthony, B.W.

1997-02-25

169

An observational study of post-asymptotic-giant-branch stars  

NASA Astrophysics Data System (ADS)

In this thesis, we present an LTE model atmosphere analyses of a group of early B-type postasymptotic giant branch (pAGB) stars. With initial masses ? 9M?, post-AGB stars form an important group of evolved stars and provide a unique opportunity to study stellar evolution almost on a human time-scale. Post-AGB stars have spectral types ranging from K to B and luminosities between 103 and 104L?. These objects ended their asymptotic giant branch (AGB) evolution phase with a period of strong mass loss (10-7 - 10-4M? yr-1) and have been evolving from cooler to hotter temperatures at almost constant luminosity on a timescale of ˜ 104yr. B-type pAGB stars span a wide range in effective temperature (10 000 - 30 000K). Their expected surface gravities (log g ) and effective temperatures ( Teff ) coincide with those of B stars evolving from the main sequence. Therefore systematic observational analyses are required to distinguish these two groups. Furthermore, p! ost-AGB stars may be divided into four distinct groups based on their chemical composition. In this thesis, groups I and II represent post-AGB stars which are very metal deficient with C/O ? 1 and metal poor with C/O<1, when compared with the Sun, respectively. The question is whether hot pAGB stars belong to either of these four groups. Three further objectives included: 1. to discover whether post-AGB star have helium-normal or helium-rich photospheres. 2. the detection and measurement of s-process element abundances (e.g. Sr, Y, Ba, Hf). 3. to determine whether they show any anomaly in phosphorus abundance such as that seen in the extreme helium stars (EHes). High-resolution ´echelle spectra of several post-AGB stars were obtained at the AAT in 1999 and 2005 in order to study chemical composition, rotation velocities and other fundamental properties. Echelle spectra present many difficulties for data reduction, including the problems of order rectification and merging. To address these problems we developed an ´echelle spectrum reduction package, known as TIGER. These spectra were analyzed using model atmospheres and synthetic spectra computed with the Armagh LTE stellar atmospheres software. The semiautomated spectral fitting package SFIT was used to measure the stellar surface parameters and composition. The results show that Teff of the programme stars are in the range 15 000 - 25 000 K and log g are in the range 2.5 - 3.0. In addition to being metal-poor stars, they show mostly C/O<1. Several of our programme stars, namely HD119608, LSS4331, LSS5112, and LB3116 confirm this. The majority of hot post-AGB stars can be identified with the group II, metal-poor and C-deficient post-AGB stars. The model atmosphere parameters, LTE element abundances and estimated distance obtained here support the idea that programme stars are in true post-AGB stars. We detected helium enrichment in the post-AGB stars Hen3-1428 and LSS4331. We did not detect any evidence of s-process elements, primarily because of the high Teff of our targets. Our results do not show overabundance in phosphorus for any hot pAGB stars. Since we used the same atomic data and methods, we conclude that the enhancement of phosphorus previously found in some EHe stars is real. We studied stellar wind signatures for the post-AGB star LSIV-12 111. Emission line equivalent widths for Balmer lines show changes between two different epochs. Hen3-1428 and LSIV-12 111 show blue shifted absorption lines. A stellar wind is clearly present in both stars. We compared variability of a group of post-AGB and a group EHe stars using archival photometry. We did not detect variability in EHe stars. We detected variability in five post-AGB stars. Large variations in HR4049, HD213985, and HD52961 appear to be related to the binary period.

Sahin, T.

2008-05-01

170

Arctic Sea ice studies with passive microwave satellite observations  

NASA Technical Reports Server (NTRS)

The objectives of this research are: (1) to improve sea ice concentration determinations from passive microwave space observations; (2) to study the role of Arctic polynyas in the production of sea ice and the associated salinization of Arctic shelf water; and (3) to study large scale sea ice variability in the polar oceans. The strategy is to analyze existing data sets and data acquired from both the DMSP SSM/I and recently completed aircraft underflights. Special attention will be given the high resolution 85.5 GHz SSM/I channels for application to thin ice algorithms and processes studies. Analysis of aircraft and satellite data sets is expected to provide a basis for determining the potential of the SSM/I high frequency channels for improving sea ice algorithms and for investigating oceanic processes. Improved sea ice algorithms will aid the study of Arctic coastal polynyas which in turn will provide a better understanding of the role of these polynyas in maintaining the Arctic watermass structure. Analysis of satellite and archived meteorological data sets will provide improved estimates of annual, seasonal and shorter-term sea ice variability.

Cavalieri, D. J.

1988-01-01

171

Mucocutaneous manifestations of acquired hypoparathyroidism: An observational study.  

PubMed

Hypoparathyroidism is a disorder of calcium and phosphorus metabolism due to decreased secretion of parathyroid hormone. Hypoparathyroidism can be hereditary and acquired. Acquired hypoparathyroidism usually occurs following neck surgery (thyroid surgery or parathyroid surgery). Along with systemic manifestations, hypoparathyroidism produces some skin manifestations. Lack of study regarding mucocutaneous manifestations of acquired hypoparathyroidism prompted us to undertake this study. To evaluate the mucocutaneous manifestations of acquired hypoparathyroidism. An observational study done in a tertiary care hospital of Kolkata by comprehensive history taking, through clinical examination and relevant laboratory investigations. Twenty-one patients were included in the study. The commonest form of acquired hypoparathyroidism was neck surgery (thyroidectomy and parathyroidectomy operation). Mucocutaneous manifestations were present in 76.19% of patients. The most frequent mucocutaneous manifestation was found in the hairs like the loss of axillary hair (61.9%), loss of pubic hair (52.38%), coarsening of body hair (47.62%), and alopecia areata (9.52%). The nail changes noted were brittle and ridged nail, followed by onycholysis, onychosezia, and onychomedesis. The most common skin features were xerotic skin in 11 patients (52.38%), followed by pellagra-like skin pigmentation, pustular psoriasis and acne form eruption, bullous impetigo, etc. Mucosa was normal in all the cases excepting the one which showed oral candidiasis. PMID:23087872

Sarkar, Somenath; Mondal, Modhuchanda; Das, Kapildev; Shrimal, Arpit

2012-09-01

172

The PRIAMO study: background, methods and recruitment.  

PubMed

PRIAMO (PaRkinson And non Motor symptOms) is an epidemiology study aimed to assess the prevalence and incidence of non-motor symptoms (NMS) in patients with parkinsonism. PRIAMO consists of two phases: (1) a transversal assessment of the prevalence of NMS and (2) a longitudinal observation with two follow-up visits at 12 and 24 months to establish the incidence of NMS. A secondary aim of PRIAMO is to study the relationship between NMS and quality of life. Patients with parkinsonism have been evaluated in 59 Neurology Centres widely distributed throughout Italy. PRIAMO has analysed a total of 1307 patients (out of 1325 initially enrolled). We expect that PRIAMO will substantially help to quantify the burden of NMS in patients with parkinsonism. PMID:18483702

Antonini, Angelo; Colosimo, Carlo; Marconi, Roberto; Morgante, Letterio; Barone, Paolo

2008-04-01

173

Molecular Carbon in the Galaxy: Laboratory and Observational Studies  

NASA Technical Reports Server (NTRS)

In a collaboration with the Mats Larsson group from Stockholm, we carried out a new measurement of the rate of dissociative recombination of H(sup *, sub j), using a new pulsed supersonic beam source of rotationally cold H(sup *, sub j). This source was first designed and characterized in our lab by IR cavity ringdown spectroscopy, determining a rotationaYtranslationa1 temperature of 20-60K, depending on conditions. This new source was then taken to Stockholm for the recombination rate studies at the CRYRING storage ring. The recombination rate constant measured against temperature yields values consistent with the most recent calculations, whereas previous experimental measurements varied over a range of 10(exp 4) and were poor agreement with theory. This is a crucial achievement for understanding the ion chemistry of diffuse clouds. Moreover, this result in combination with recent observations implies a greatly enhanced (factor of 40) cosmic ray ionization rate in a diffuse cloud (zeta Persei) relative to previous studies. The implications of this are discussed in our recent Nature paper. An enhanced cosmic-ray flux towards zeta Persei inferred from a laboratory study of the H(sup *, sub j)-e(sup -) recombination rate.

Saykally, Richard James

2003-01-01

174

Bowenoid papulosis. A clinicopathologic study with ultrastructural observations.  

PubMed

One hundred eight patients were studied who had anogenital lesions showing microscopic features as seen in bowenoid papulosis (BP), a recently described condition occurring most commonly in young adults. Patients typically show multiple papules, small nodules, or plaques that clinically mimic verrucae or nevocellular nevi. Although the lesions show microscopic cytologic atypia, a distinction from Bowen's disease, erythroplasia of Queyrat, and other forms of carcinoma in situ can usually be made on the basis of histologic and clinical criteria. The disorder responds to conservative treatment, although recurrences are not uncommon. Evolution of the lesions to invasive carcinoma was not observed. Mounting evidence links the development of BP to infection with human papilloma virus, but other viruses, as well as hormonal and immunologic factors, may also play a role. PMID:3002589

Patterson, J W; Kao, G F; Graham, J H; Helwig, E B

1986-02-15

175

A Direct Method to Self-Calibrate a Surveillance Camera by Observing a Walking Pedestrian  

Microsoft Academic Search

Recent efforts show that it is possible to calibrate a surveillance camera simply from observing a walking hu- man. This procedure can be seen as a special application of the camera self-calibration technique. Several methods have been proposed along this line, but most of them have certain restrictions, such as require the human walking at a constant speed, or require

Worapan Kusakunniran; Hongdong Li; Jian Zhang

2009-01-01

176

Low Quality Evidence of Epidemiological Observational Studies on Leishmaniasis in Brazil  

PubMed Central

Background Brazil has implemented systematic control methods for leishmaniasis for the past 30 years, despite an increase in cases and continued spread of the disease to new regions. A lack high quality evidence from epidemiological observational studies impedes the development of novel control methods to prevent disease transmission among the population. Here, we have evaluated the quality of observational studies on leishmaniasis conducted in Brazil to highlight this issue. Methods/Principal Findings For this systematic review, all publications on leishmaniasis conducted in Brazil from January 1st, 2002 to December 31st, 2012 were screened via Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist to select observational studies involving human subjects. The 283 included studies, representing only 14.1% of articles screened, were then further evaluated for quality of epidemiological methods and study design based on the STROBE (Strengthening the Reporting of Observational studies in Epidemiology) checklists. Over half of these studies were descriptive or case reports (53.4%, 151), followed by cross-sectional (20.8%, n?=?59), case-control (8.5%, n?=?24), and cohort (6.0%, n?=?17). Study design was not stated in 46.6% (n?=?181) and incorrectly stated in 17.5% (n?=?24). Comparison groups were utilized in just 39.6% (n?=?112) of the publications, and only 13.4% (n?=?38) employed healthy controls. Majority of studies were performed at the city-level (62.9%, n?=?178), in contrast with two (0.7%) studies performed at the national-level. Coauthorship networks showed the number of author collaborations rapidly decreased after three collaborations, with 70.9% (n?=?659/929) of coauthors publishing only one article during the study period. Conclusions/Significance A review of epidemiological research in Brazil revealed a major lack of quality and evidence. While certain indicators suggested research methods may have improved in the last two years, an emphasis on observational research which employs comparison groups and representative samples is urgently needed. PMID:25197965

Trentini, Bruno; Steindel, Mário; Marlow, Mariel A.

2014-01-01

177

Using direct clinical observation to assess the quality of cesarean delivery in Afghanistan: an exploratory study  

PubMed Central

Background As part of a National Emergency Obstetric and Newborn Care (EmONC) Needs Assessment, a special study was undertaken in July 2010 to examine the quality of cesarean deliveries in Afghanistan and examine the utility of direct clinical observation as an assessment method in low-resource settings. Methods This cross-sectional assessment of the quality of cesareans at 14 facilities in Afghanistan included a survey of surgeons regarding their routine cesarean practices, direct observation of 29 cesarean deliveries and comparison of observations with facility records for 34 additional cesareans conducted during the 3 days prior to the observation period at each facility. For both observed cases and record reviews, we assessed time intervals between specified points of care-arrival to the ward, first evaluation, detection of a complication, decision for cesarean, incision, and birth. Results All time intervals with the exception of “decision to skin incision” were longer in the record reviews than in observed cases. Prior cesarean was the most common primary indication for all cases. All mothers in both groups observed survived through one hour postpartum. Among newborns there were two stillbirths (7%) in observed births and seven (21%) record reviews. Although our sample is too small to show statistical significance, the difference is noteworthy. In six of the reviewed cesareans resulting in stillbirth, a fetal heart rate was recorded in the operating theater, although four were recorded as macerated. For the two fresh stillbirths, the cesarean surgeries were recorded as scheduled and not urgent. Conclusions Direct observation of cesarean deliveries enabled us to assess a number of preoperative, postoperative, and intraoperative procedures that are often not described in medical records in low resource settings. Comparison of observations with findings from provider interviews and facility records allowed us to infer whether observed practices were typical of providers and facilities and detect potential Hawthorne effects. PMID:24886143

2014-01-01

178

Quality of Life after Stapled Hemorrhoidopexy: A Prospective Observational Study  

PubMed Central

Objective. The objective of the study was to assess the change in quality of life (QOL) of patients undergoing stapled hemorrhoidopexy (SH) using WHO Quality of Life-BREF (WHOQOL-BREF) questionnaire. Methods. The study sample comprised patients with symptomatic II, III, and IV degree hemorrhoids, undergoing SH. The patients were asked to complete WHOQOL-BREF questionnaire before and one month following the surgery. Result. There were 20 patients in the study group. The postoperative pain score measured by visual analogue scale at six hours postoperatively was 7.60 ± 1.23, which reduced to 0.70 ± 0.92 at 24 hours. The items in the WHOQOL-BREF had high-internal consistency or reliability as shown by high Cronbach's alpha coefficient which was 0.82 and 0.90 for pre- and postoperative questionnaires. There was significant improvement in the overall perception of QOL and health, and in physical and psychological domains. There was modest improvement in environmental domain, while no change was noted in social domain. Conclusion. SH improved the quality of life of patients treated for hemorrhoids. PMID:24058916

Garg, Pankaj Kumar; Kumar, Gopal; Jain, Bhupendra Kumar; Mohanty, Debajyoti

2013-01-01

179

CSM research: Methods and application studies  

NASA Technical Reports Server (NTRS)

Computational mechanics is that discipline of applied science and engineering devoted to the study of physical phenomena by means of computational methods based on mathematical modeling and simulation, utilizing digital computers. The discipline combines theoretical and applied mechanics, approximation theory, numerical analysis, and computer science. Computational mechanics has had a major impact on engineering analysis and design. When applied to structural mechanics, the discipline is referred to herein as computational structural mechanics. Complex structures being considered by NASA for the 1990's include composite primary aircraft structures and the space station. These structures will be much more difficult to analyze than today's structures and necessitate a major upgrade in computerized structural analysis technology. NASA has initiated a research activity in structural analysis called Computational Structural Mechanics (CSM). The broad objective of the CSM activity is to develop advanced structural analysis technology that will exploit modern and emerging computers, such as those with vector and/or parallel processing capabilities. Here, the current research directions for the Methods and Application Studies Team of the Langley CSM activity are described.

Knight, Norman F., Jr.

1989-01-01

180

Observational Study of Contracts Processing at 29 CTSA Sites  

PubMed Central

We measured contracts Final Negotiation (FN) and Full Execution (FE) times using shared definitions in a prospective observational study of management of contracts for clinical trials at 29 CTSA institutions. Median FN and FE times were reached in 39 and 91 days, respectively; mean times for FN and FE were 55 and 103 days, respectively. Individual site medians ranged from 3 to 116 days for FN and 34 to 197 days for FE. The use of Master Agreements (MAs) and Previously Negotiated Terms (PNTs) was associated with significant reduction of FN times by a mean of 33 days (p<0) and 22 days (p<0.001), respectively. PNTs, but not MAs, were associated with significantly reduced FE time (22 days, p<.007). Gap analysis revealed a gap of 22 days between contracts negotiation and Institutional Review Board (IRB) review and intervals of 33 days (contracts) and 48 days (IRB review) during which the process steps were being conducted alone, suggesting a potential benefit with parallel processing. These baseline data support a plan to investigate root causes of prolonged study startup time by examining causes of variation and outliers. PMID:23919362

Kiriakis, James; Gaich, Nicholas; Johnston, S Claiborne; Kitterman, Darlene; Rosenblum, Daniel; Salberg, Libby; Rifkind, Adam

2013-01-01

181

2D vs. 3D mammography observer study  

NASA Astrophysics Data System (ADS)

Breast cancer is the most common type of non-skin cancer in women. 2D mammography is a screening tool to aid in the early detection of breast cancer, but has diagnostic limitations of overlapping tissues, especially in dense breasts. 3D mammography has the potential to improve detection outcomes by increasing specificity, and a new 3D screening tool with a 3D display for mammography aims to improve performance and efficiency as compared to 2D mammography. An observer study using a mammography phantom was performed to compare traditional 2D mammography with this ne 3D mammography technique. In comparing 3D and 2D mammography there was no difference in calcification detection, and mass detection was better in 2D as compared to 3D. There was a significant decrease in reading time for masses, calcifications, and normals in 3D compared to 2D, however, as well as more favorable confidence levels in reading normal cases. Given the limitations of the mammography phantom used, however, a clearer picture in comparing 3D and 2D mammography may be better acquired with the incorporation of human studies in the future.

Fernandez, James Reza F.; Hovanessian-Larsen, Linda; Liu, Brent

2011-03-01

182

Singlet oxygen generated from the decomposition of peroxymonocarbonate and its observation with chemiluminescence method  

NASA Astrophysics Data System (ADS)

The decomposition of peroxymonocarbonate (HCO 4-) has been investigated by flow-injection chemiluminescence (CL) method. An ultraweak CL was observed during mixing the bicarbonate and hydrogen peroxide solution in organic cosolvent. An appropriate amount of fluorescent organic compounds, such as dichlorofluorescein (DCF), was added to the HCO 4- solution, a strong CL was recorded. Based on studies of the spectrum of fluorescence, CL and UV-vis spectra, electron spin trapping (ESR) technique, mass spectra (MS) and comparison with H 2O 2/hypochlorite (ClO -) and H 2O 2/molybdate (MoO 4-) systems, the CL mechanism was proposed. The reaction is initiated by unimolecular homolysis of the peroxo O sbnd O bond in HO sbnd OCOO - molecule. It was suggested that the bond rearrangement within radicals yield superoxide ion (O 2rad -). The interaction of superoxide ion with perhydroxyl radical produces singlet oxygen ( 1O 2). The energy transfers from singlet oxygen to DCF forming an excited energy acceptor (DCF*). Luminescence ( ?max = 509 nm) was emitted during the relaxation of the energy acceptor to the ground state.

Lin, Jin-Ming; Liu, Meilin

2009-02-01

183

The Saturn Ring Observer: In situ studies of planetary rings  

NASA Astrophysics Data System (ADS)

As part of the Planetary Science Decadal Survey recently undertaken by the NRC's Space Studies Board for the National Academy of Sciences, studies were commissioned for a number of potential missions to outer planet targets. One of these studies examined the technological feasibility of a mission to carry out in situ studies of Saturn's rings, from a spacecraft placed in a circular orbit above the ring plane: the Saturn Ring Observer. The technical findings and background are discussed in a companion poster by T. R. Spilker et al. Here we outline the science goals of such a mission. Most of the fundamental interactions in planetary rings occur on spatial scales that are unresolved by flyby or orbiter spacecraft. Typical particle sizes in the rings of Saturn are in the 1 cm - 10 m range, and average interparticle spacings are a few meters. Indirect evidence indicates that the vertical thickness of the rings is as little as 5 - 10 m, which implies a velocity dispersion of only a few mm/sec. Theories of ring structure and evolution depend on the unknown characteristics of interparticle collisions and on the size distribution of the ring particles. The SRO could provide direct measurements of both the coefficient of restitution -- by monitoring individual collisions -- and the particles’ velocity dispersion. High-resolution observations of individual ring particles should also permit estimates of their spin states. Numerical simulations of Saturn’s rings incorporating both collisions and self-gravity predict that the ring particles are not uniformly distributed, but are instead clustered into elongated structures referred to as “self-gravity wakes”, which are continually created and destroyed on an orbital timescale. Theory indicates that the average separation between wakes in the A ring is of order 30-100 m. Direct imaging of self-gravity wakes, including their formation and subsequent dissolution, would provide critical validation of these models. Other targets of observation by the SRO will include “propellers” (thought to be the signature of sub-km moonlets embedded in the rings), the “ropy” and “straw” structure seen in images of strong density waves and gap edges, and km-scale radial oscillations which may be signatures of “viscous overstabilities” in high-optical depth regions. Most of the science goals identified above could be accomplished by high-resolution nadir imaging of the rings from a platform that co-orbits with the ring particles, i.e., from a spacecraft in circular orbit a few km above the rings. The vertical displacement of the spacecraft is maintained by a continuous low-thrust ion engine, which can be tilted to provide a slow inward radial drift across the rings. Chemical thrusters permit the craft to `hop' over vertical obstacles in the rings (e.g., bending waves and inclined ringlets). In addition to an imaging system with a resolution of at least 10 cm (with 1 cm a desirable goal), other instrumentat ion might include a laser altimeter/range-finder to measure the effective thickness of the rings, as well as the vertical component of particle motions, aswell as in situ instruments to measure the density and composition of the neutral and ionized ring atmosphere, meteoritic and secondary dust fluxes, and local electric fields (especially in spoke regions).

Nicholson, P. D.; Tiscareno, M. S.; Spilker, L. J.

2010-12-01

184

Observational Study of Spinal Muscular Atrophy Type 2 and 3  

PubMed Central

Objective To characterize the short-term course of spinal muscular atrophy (SMA) in a genetically and clinically well-defined cohort of patients with SMA. Design A comprehensive multicenter, longitudinal, observational study. Setting The Pediatric Neuromuscular Clinical Research Network for SMA, a consortium of clinical investigators at 3 clinical sites. Participants Sixty-five participants with SMA types 2 and 3, aged 20 months to 45 years, were prospectively evaluated. Intervention We collected demographic and medical history information and determined the SMN2 copy number. Main Outcome Measures Clinical outcomes included measures of motor function (Gross Motor Function Measure and expanded Hammersmith Functional Motor Scale), pulmonary function (forced vital capacity), and muscle strength (myometry). Participants were evaluated every 2 months for the initial 6 months and every 3 months for the subsequent 6 months. We evaluated change over 12 months for all clinical outcomes and examined potential correlates of change over time including age, sex, SMA type, ambulatory status, SMN2 copy number, medication use, and baseline function. Results There were no significant changes over 12 months in motor function, pulmonary function, and muscle strength measures. There was evidence of motor function gain in ambulatory patients, especially in those children younger than 5 years. Scoliosis surgery during the observation period led to a subsequent decline in motor function. Conclusions Our results confirm previous clinical reports suggesting that SMA types 2 and 3 represent chronic phenotypes that have relatively stable clinical courses. We did not detect any measurable clinical disease progression in SMA types 2 and 3 over 12 months, suggesting that clinical trials will have to be designed to measure improvement rather than stabilization of disease progression. PMID:21320981

Kaufmann, Petra; McDermott, Michael P.; Darras, Basil T.; Finkel, Richard; Kang, Peter; Oskoui, Maryam; Constantinescu, Andrei; Sproule, Douglas Michael; Foley, A. Reghan; Yang, Michele; Tawil, Rabi; Chung, Wendy; Martens, Bill; Montes, Jacqueline; O'Hagen, Jessica; Dunaway, Sally; Flickinger, Jean M.; Quigley, Janet; Riley, Susan; Glanzman, Allan M.; Benton, Maryjane; Ryan, Patricia A.; Irvine, Carrie; Annis, Christine L.; Butler, Hailly; Caracciolo, Jayson; Montgomery, Megan; Marra, Jonathan; Koo, Benjamin; De Vivo, Darryl C.

2013-01-01

185

Satellite Observation Systems for Polar Climate Change Studies  

NASA Technical Reports Server (NTRS)

The key observational tools for detecting large scale changes of various parameters in the polar regions have been satellite sensors. The sensors include passive and active satellite systems in the visible, infrared and microwave frequencies. The monitoring started with Tiros and Nimbus research satellites series in the 1970s but during the period, not much data was stored digitally because of limitations and cost of the needed storage systems. Continuous global data came about starting with the launch of ocean color, passive microwave, and thermal infrared sensors on board Nimbus-7 and Synthetic Aperture Radar, Radar Altimeter and Scatterometer on board SeaSat satellite both launched in 1978. The Nimbus-7 lasted longer than expected and provided about 9 years of useful data while SeaSat quit working after 3 months but provided very useful data that became the baseline for follow-up systems with similar capabilities. Over the years, many new sensors were launched, some from Japan Aeronautics and Space Agency (JAXA), some from the European Space Agency (ESA) and more recently, from RuSSia, China, Korea, Canada and India. For polar studies, among the most useful sensors has been the passive microwave sensor which provides day/night and almost all weather observation of the surface. The sensor provide sea surface temperature, precipitation, wind, water vapor and sea ice concentration data that have been very useful in monitoring the climate of the region. More than 30 years of such data are now available, starting with the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7, the Special Scanning Microwave/Imager (SSM/I) on board a Defense Meteorological Satellite Program (DMSP) and the Advanced Microwave Scanning Radiometer on board the EOS/ Aqua satellite. The techniques that have been developed to derive geophysical parameters from data provided by these and other sensors and associated instrumental and algorithm errors and validation techniques will be discussed. An important issue is the organization and storage of hundreds of terabytes of data collected by even just a few of these satellite sensors. Advances in mass storage and computer technology have made it possible to overcome many of the collection and archival problems and the availability of comprehensive satellite data sets put together by NASA's Earth Observing System project will be discussed.

Comiso, Josefino C.

2012-01-01

186

Phonation into a Tube as a Voice Training Method: Acoustic and Physiologic Observations  

Microsoft Academic Search

Phonation into narrow glass tubes has been used as a voice training method. The present study examined phonatory and voice quality during and after tube phonation. The methods used were (a) electromyography with surface electrodes, (b) a dual-channel electroglottography from which the vertical larynx position was derived and (c) inverse filtering of the acoustic signal of vowel samples produced before

Anne-Maria Laukkanen; Päivi Lindholm; Erkki Vilkman

1995-01-01

187

Cell observation method under near-living conditions by scanning electron microscopy.  

PubMed

Most cells of multicellular organisms have "primary cilia", which are single, non-motile, and sensory cilia. They have been reported to detect mechanical stimulation and transform it into internal cell, but the mechanisms are not still well known. Dermal papilla (DP) cells, which locate in the skin and regulate hair follicle development and hair cycle, were reported to have their primary cilia by immune-fluorescent method [1], but their detailed structure and function is unclear.For observation by scanning electron microscopy (SEM), biological specimens are conventionally fixed with glutaraldehyde and dehydrated in 30%, 50%, 70%, 90% and 100% ethanol. Then specimens are dried by butyl alcohol and coated with gold. It takes several days to prepare these specimens. Using many chemical reagent and many steps in this way may lead to destroy biological specimens structure. Here we attempted a recently proposed method using ionic liquid to prepare cell samples in near- living conditions observed the structure of DP cells (2D and clumps) with primary cilia.This time, we used ionic liquid for preparing specimens. First, cultured cells were fixed in glutaraldehyde, and immersed in ionic liquid. Next, the specimens were coated with gold and observed by SEM. Thus, it takes shorter time due to fewer step than conventional method and the process has no drying step. In a conventional way, we got the micrographs of 2D cultured DP cells and observed the cilium of DP cells (200-nm in diameter and 1.5um in length) on nucleus (15-um). In addition we could observe the clumps of DP cells and the cilia-like structure (?12-um), but they do not attach to scaffoldings of the surface, probably due to drying. In observation using ionic liquid, we got the micrographs of 2D cultured DP cells and observed the cilium- like structure (200-nm in diameter and 2.1-um in length) on nucleus (30-um), as well. In this case, we could not find the cilia- like structure in the clumps of DP cells yet, but they well attached to the scaffoldings and kept the extending structure such as filopodia, too.We here observed DP cells and their cilia in near-living conditions. Unfortunately, we could not primary cilia in clumps of DP cells immersed in ionic liquid yet, but we could reduce damage receiving in the process of specimen's preparation, especially drying. In addition, we are challenging the observation using not only ionic liquid but also nano-suits by detergents [2] and the observation the cilia by SEM after identifying them by fluorescence microscopy, such as CLEM. PMID:25359834

Tanaka, Misaki; Matsushima, Kazuyuki; Kaseda, Kuniyoshi; Yasunaga, Takuo

2014-11-01

188

Analytic Perturbation Method for Estimating Ground Flash Fraction from Satellite Lightning Observations  

NASA Technical Reports Server (NTRS)

An analytic perturbation method is introduced for estimating the lightning ground flash fraction in a set of N lightning flashes observed by a satellite lightning mapper. The value of N is large, typically in the thousands, and the observations consist of the maximum optical group area produced by each flash. The method is tested using simulated observations that are based on Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) data. National Lightning Detection NetworkTM (NLDN) data is used to determine the flash-type (ground or cloud) of the satellite-observed flashes, and provides the ground flash fraction truth for the simulation runs. It is found that the mean ground flash fraction retrieval errors are below 0.04 across the full range 0-1 under certain simulation conditions. In general, it is demonstrated that the retrieval errors depend on many factors (i.e., the number, N, of satellite observations, the magnitude of random and systematic measurement errors, and the number of samples used to form certain climate distributions employed in the model).

Koshak, William; Solakiewicz, Richard

2013-01-01

189

Analytic Perturbation Method for Estimating Ground Flash Fraction from Satellite Lightning Observations  

NASA Astrophysics Data System (ADS)

An analytic perturbation method is introduced for estimating the lightning ground flash fraction in a set of N lightning flashes observed by a satellite lightning mapper. The value of N is large, typically in the thousands, and the observations consist of the maximum optical group area produced by each flash. The method is tested using simulated observations that are based on Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) data. National Lightning Detection Network (NLDN) data is used to determine the flash-type (ground or cloud) of the satellite-observed flashes, and provides the ground flash fraction truth for the simulation runs. It is found that the mean ground flash fraction retrieval errors are below 0.04 across the full range 0-1 under certain simulation conditions. In general, it is demonstrated that the retrieval errors depend on many factors (i.e., the number, N, of satellite observations, the magnitude of random and systematic measurement errors, and the number of samples used to form certain climate distributions employed in the model).

Koshak, W. J.; Solakiewicz, R.

2013-12-01

190

Validation of Satellite-Based Objective Overshooting Cloud-Top Detection Methods Using CloudSat Cloud Profiling Radar Observations  

NASA Technical Reports Server (NTRS)

Two satellite infrared-based overshooting convective cloud-top (OT) detection methods have recently been described in the literature: 1) the 11-mm infrared window channel texture (IRW texture) method, which uses IRW channel brightness temperature (BT) spatial gradients and thresholds, and 2) the water vapor minus IRW BT difference (WV-IRW BTD). While both methods show good performance in published case study examples, it is important to quantitatively validate these methods relative to overshooting top events across the globe. Unfortunately, no overshooting top database currently exists that could be used in such study. This study examines National Aeronautics and Space Administration CloudSat Cloud Profiling Radar data to develop an OT detection validation database that is used to evaluate the IRW-texture and WV-IRW BTD OT detection methods. CloudSat data were manually examined over a 1.5-yr period to identify cases in which the cloud top penetrates above the tropopause height defined by a numerical weather prediction model and the surrounding cirrus anvil cloud top, producing 111 confirmed overshooting top events. When applied to Moderate Resolution Imaging Spectroradiometer (MODIS)-based Geostationary Operational Environmental Satellite-R Series (GOES-R) Advanced Baseline Imager proxy data, the IRW-texture (WV-IRW BTD) method offered a 76% (96%) probability of OT detection (POD) and 16% (81%) false-alarm ratio. Case study examples show that WV-IRW BTD.0 K identifies much of the deep convective cloud top, while the IRW-texture method focuses only on regions with a spatial scale near that of commonly observed OTs. The POD decreases by 20% when IRW-texture is applied to current geostationary imager data, highlighting the importance of imager spatial resolution for observing and detecting OT regions.

Bedka, Kristopher M.; Dworak, Richard; Brunner, Jason; Feltz, Wayne

2012-01-01

191

Photographic zenith tube of the Zvenigorod INASAN Observatory - Processing method and observation results  

NASA Astrophysics Data System (ADS)

A method for the reduction of PZT plates which has been used at the Zvenigorod INASAN Observatory since 1986 is described. The formulas used for computing the coordinates of the stellar image in the focal plane at the midpoint of the exposure are correct to 0.0024 arcsec. Observations from February 1986 to October 1988 are compared with data of BIH and IERS, and the results of the comparison are used to compute the amplitudes of the annual terms of nonpolar variations in the observed latitudes and Delta(UTI).

Yurov, E. A.

1992-10-01

192

Practical Methods for Studying Collisional Breakup  

NASA Astrophysics Data System (ADS)

The quantum theory of three-body breakup in Coulomb systems, formulated in the early sixties, has formed the basis of a considerable body of theoretical analysis of low energy electron impact ionization. Although aspects of this theory have been incorporated into various perturbative and distorted-wave treatments, the formal theory has not provided a viable comupational approach to a first-principles treatment of ionization, due to the complicated nature of the boundary conditions for three-body breakup in Coulomb systems and the fact that they are only known in the far asymptotic region. Exterior complex scaling allows one to solve the Schrödinger equation without explicit imposition of asymptotic boundary conditions. This approach has produced the first triple differential cross sections for e-H ionization that are in complete agreement with absolute measurements[1]. In this talk, I will review the essential aspects of this approach and present new results on double differential cross sections for e-H ionization. I will also discuss some new methods for extracting dynamical information from numerically obtained wave functions that are more efficient than the flux operator approach we previously employed. These methods allow us to explore ionization in the threshold region and open the way to calculations on systems with more than two electrons, where new physical effects can be studied. [1] T. N. Rescigno, M. Baertschy, W. A. Isaacs and C. W. McCurdy, Science 286, 2474 (1999)

Rescigno, T. N.

2000-10-01

193

Temperament in young adulthood and later mortality: prospective observational study  

PubMed Central

Study objective: To determine the association between a clinician assessment of temperament in early adulthood and cause specific mortality. Design: Prospective observational study. Setting: Glasgow University. Participants: 9239 male former students aged 16–30 (mean 20.5) years who participated in an ongoing health survey from 1948–68. A physician recorded free text assessment of temperament, which seemed to capture aspects of personality (trait) and mental health (state), was coded into: stable, anxious, schizoid, hypomanic, odd, depressed, immature, hypochondriacal, unstable, and obsessive. Associations between temperament and mortality were investigated using Cox proportional hazards models. Main results: There were 878 deaths. Most students—8342 (90.3%)—were assessed as stable, the remaining 897 (9.7%) having at least one, and 103 (1.1%) having more than one, temperament type. The second most common temperament was anxiety, recorded in 520 (5.6%) students. In multivariable analyses, having at least one temperament type was associated with increased all cause and stroke mortality, hazard ratios (95% confidence intervals): 1.23 (1.01 to 1.50) and 1.95 (1.06 to 3.59) respectively, compared with stable students. Students with more than one temperament type had higher risk of death from: all causes, 2.05 (1.36 to 3.09); stroke, 3.26 (1.01 to 10.56); and cancer, 2.90 (1.62 to 5.20). Anxiety was positively associated with all cause and cancer mortality, respective hazard ratios: 1.36 (1.07 to 1.72) and 1.51 (1.04 to 2.20). Men labelled hypomanic had increased cardiovascular mortality risk, 1.90 (1.05 to 3.44). Conclusions: Markers of early adult psychological distress are associated with increased mortality. Mechanisms underlying these associations require investigation. PMID:14600116

McCarron, P; Gunnell, D; Harrison, G; Okasha, M; Davey, S

2003-01-01

194

Trigeminocardiac reflex in neurosurgical practice: An observational prospective study  

PubMed Central

Background: Considering wide variations regarding the incidence of trigeminocardiac reflex (TCR) during cranial neurosurgical procedures, and paucity of reliable data, we intended to design a prospective study to determine the incidence of TCR in patients undergoing standard general anesthesia for surgery of supra/infra-tentorial cranial and skull base lesions. Methods: A total of 190 consecutive patients candidate for elective surgery of supra-tentorial, infra-tentorial, and skull base lesions were enrolled. All the patients were operated in the neurosurgical operating room of a university-affiliated teaching hospital. All surgeries were performed using sufficient depth of anesthesia achieved by titration of propofol–alfentanil mixture, adjusted according to target Cerebral State Index (CSI) values (40-60). All episodes of bradycardia and hypotension indicating the occurrence of TCR during the surgery (sudden decrease of more than 20% from the previous level) were recorded. Results: Four patients, two female and two male, developed episodes of TCR during surgery (4/190; 2.1%). Three patients showed one episode of TCR just at the end of operation when the skin sutures were applied while CSI values were 70-77 and in the last case, when small tumor samples were taken from just beneath the lateral wall of the cavernous sinus TCR episode was seen while the CSI value was 51. Conclusion: TCR is a rare phenomenon during brain surgeries when patient is anesthetized using standard techniques. Keeping the adequate depth of anesthesia using CSI monitoring method may be an advisable strategy during whole period of a neurosurgical procedure. PMID:24083052

Etezadi, Farhad; Orandi, Amir Ali; Orandi, Amir Hosein; Najafi, Atabak; Amirjamshidi, Abbas; Pourfakhr, Pejman; Khajavi, Mohammad Reza; Abbassioun, Kazem

2013-01-01

195

Dalfampridine in patients with downbeat nystagmus--an observational study.  

PubMed

We investigated the effects of dalfampridine, the sustained-release form of 4-aminopyridine, on slow phase velocity (SPV) and visual acuity (VA) in patients with downbeat nystagmus (DBN) and the side effects of the drug. In this proof-of-principle observational study, ten patients received dalfampridine 10 mg bid for 2 weeks. Recordings were conducted at baseline, 180 min after first administration, after 2 weeks of treatment and after 4 weeks of wash-out. Mean SPV decreased from a baseline of 2.12 deg/s ± 1.72 (mean ± SD) to 0.51 deg/s ± 1.00 180 min after first administration of dalfampridine 10 mg and to 0.89 deg/s ± 0.75 after 2 weeks of treatment with dalfampridine (p < 0.05; post hoc both: p < 0.05). After a wash-out period of 1 week, mean SPV increased to 2.30 deg/s ± 1.6 (p < 0.05; post hoc both: p < 0.05). The VA significantly improved during treatment with dalfampridine. Also, 50 % of patients did not report any side effects. The most common reported side effects were abdominal discomfort and dizziness. Dalfampridine is an effective treatment for DBN in terms of SPV. It was well-tolerated in all patients. PMID:23589193

Claassen, Jens; Feil, Katharina; Bardins, Stanislav; Teufel, Julian; Spiegel, Rainer; Kalla, Roger; Schneider, Erich; Jahn, Klaus; Schniepp, Roman; Strupp, Michael

2013-08-01

196

A European Network for Atmospheric Hydrogen observations and studies: EUROHYDROS  

NASA Astrophysics Data System (ADS)

and the EuroHydros team In a future energy supply chain, molecular hydrogen is expected to play an increasingly important role as a carrier of energy for mobile applications, in particular in the automotive sector. Such an increased use of molecular hydrogen is prone to lead to additional emissions into the atmosphere, due to leakages in the supply chain. While molecular hydrogen does not influence the radiation budget of the atmosphere directly, it affects its oxidation capacity, through reaction with the OH radical. This in turn leads to an increased atmospheric lifetime of many atmospheric constituents (e.g. Methane), making H2 an indirect greenhouse gas. An increase of molecular hydrogen in the atmosphere also leads to increasing H2O in the stratosphere, influencing the radiation budget of the atmosphere and ozone chemistry. In the light of these uncertainties, a thorough understanding of hydrogen in the atmosphere is necessary, and, most notably, a good understanding of the present day global distribution and budget of atmospheric hydrogen. The EU funded project Eurohydros aims at improving the understanding of the budget of molecular hydrogen in the atmosphere through a combination of atmospheric monitoring, source-sink studies and modelling work. In this presentation we focus on the observational network, showing first results from different European and Global sites, from the calibration of the data sets and a first intercomparison experiment.

Werner, A.; Engel, A.

2008-12-01

197

Prevalence of postpartum infections: a population-based observational study.  

PubMed

We investigated the prevalence of postpartum infections among women giving birth during 1 year in a population-based observational/questionnaire study at seven hospitals in the southeast region of Sweden. Of the women >99% (n = 11,124) received a questionnaire to inquire if they had endometritis, mastitis, or wound, urinary tract or any other infection within 2 months postpartum and whether they received antibiotics for this. Prevalence rates for infections and antibiotic treatment were estimated. The response rate was 60.1%. At least one infectious episode was reported by 10.3% of the women and 7.5% had received antibiotics. The prevalence for infections with and without antibiotics were, respectively, mastitis 4.7% and 2.9%, urinary tract infection 3.0% and 2.4%, endometritis 2.0% and 1.7%, wound infection 1.8% and 1.2%. There was no inter-county difference in infection prevalence. Clinical postpartum infections in a high-resource setting are relatively common. PMID:25132521

Axelsson, Daniel; Blomberg, Marie

2014-10-01

198

Critical Illness Outcome Study: An Observational Study on Protocols and Mortality in Intensive Care Units  

PubMed Central

Introduction Many individual Intensive Care Unit (ICU) characteristics have been associated with patient outcomes, including staffing, expertise, continuity and team structure. Separately, many aspects of clinical care in ICUs have been operationalized through the development of complex treatment protocols. The United State Critical Illness and Injury Trials Group-Critical Illness Outcomes Study (USCIITG-CIOS) was designed to determine whether the extent of protocol availability and use in ICUs is associated with hospital survival in a large cohort of United States ICUs. Here, we describe the study protocol and analysis plan approved by the USCIITG-CIOS Steering Committee. Methods USCIITG-CIOS is a prospective, observational, ecological multi-centered “cohort” study of mixed ICUs in the U.S. The data collected include organizational information for the ICU (e.g., protocol availability and utilization, multi-disciplinary staffing assessment) and patient level information (e.g. demographics, acute and chronic medical conditions). The primary outcome is all-cause hospital mortality, with the objective being to determine whether there is an association between protocol number and hospital mortality for ICU patients. USCIITG-CIOS is powered to detect a 3% difference in crude hospital mortality between high and low protocol use ICUs, dichotomized according to protocol number at the median. The analysis will utilize regression modeling to adjust for outcome clustering by ICU, with secondary linear analysis of protocol number and mortality and a variety of a priori planned ancillary studies. There are presently 60 ICUs participating in USCIITG-CIOS to enroll approximately 6,000 study subjects. Conclusions USCIITG-CIOS is a large multicentric study examining the effect of ICU protocol use on patient outcomes. The primary results of this study will inform our understanding of the relationship between protocol availability, use, and patient outcomes in the ICU. Moreover, given the shortage of intensivists worldwide, the results of USCIITG-CIOS can be used to promote more effective ICU and care team design and will impact the delivery of intensive care services beyond individual practitioners. Trial Registration ClinicalTrials.gov Identifier NCT01109719 PMID:25429244

Ali, Naeem A.; Gutteridge, David; Shahul, Sajid; Checkley, William; Sevransky, Jonathan; Martin, Greg S.

2014-01-01

199

Computing observables in curved multifield models of inflation - A guide (with code) to the transport method  

E-print Network

We describe how to apply the transport method to compute inflationary observables in a broad range of multiple-field models. The method is efficient and encompasses scenarios with curved field-space metrics, violations of slow-roll conditions and turns of the trajectory in field space. It can be used for an arbitrary mass spectrum, including massive modes and models with quasi-single-field dynamics. In this note we focus on practical issues. It is accompanied by a Mathematica code which can be used to explore suitable models, or as a basis for further development.

Dias, Mafalda; Seery, David

2015-01-01

200

Earth-viewing methods for on orbit assessment of ATMS observation system spatial response function  

NASA Astrophysics Data System (ADS)

As a key instrument on board the S-NPP satellite and future JPSS satellites, the Advanced Technology Microwave Sounder (ATMS), a cross-track scanner with 22 channels, provides sounding observations needed to retrieve profiles of atmospheric temperature and moisture for civilian operational weather forecasting, as well as continuity of these measurements for climate monitoring purposes. The ATMS observation system spatial response function is a fundamental important parameter since it enables an objective assessment of spatial resolution and provides basic characteristic data for instrument calibration and satellite data algorithm development. The ATMS observation system spatial response function is a combined result of the antenna pattern as well as the motion introduced by both cross track scanning and along track satellite movement during the sensor integration time. There is no on-board calibration device fully appropriate for the assessment of the observation effective system spatial response function. In this paper, an observation system spatial response retrieval algorithm based upon the earth-viewing is described. The algorithm uses a knife-edge scanning method to retrieve the line spread function (LSF) of the ATMS observation and a Filtered Back Projection algorithm based upon the Fourier slice theorem is applied to rebuild the instrument spatial response function. Preliminary retrieval results are presented.

sun, H.; Wolf, W.; Thomas, K. S.; Maddy, E. S.; Sampson, S.; Keehn, P.

2013-12-01

201

International child care practices study: methods and study population.  

PubMed

The study set out to document child care practices in as many different countries and cultures as possible with the aim of providing baseline child care data and stimulating new hypotheses to explain persisting differences in sudden infant death syndrome (SIDS) rates between countries. The protocol, piloted in four countries in 1992, was distributed to 80 potential centres in 1995. Data from 19 centres were received. This paper describes the demographic characteristics of the data from the different centres. Comparison showed significant differences for a number of variables including mean age of completion of the study, response rate, mean gestation, mean birth weight, method of delivery and incidence of admission to neonatal intensive care units. High caesarean section rates identified in the Chinese samples (44 and 40%) were unexpected and have important public health implications. This finding warrants further study but may be related to China's one child policy. We consider that international comparison of child care practice is possible using standardised data collection methods that also allow some individual variation according to local circumstances. However, in view of the heterogeneity of the samples, it will be important to avoid over-interpreting differences identified and to view any differences within the qualitative context of each individual sample. Provided there is acknowledgement of limitations, such ecological studies have potential to produce useful information especially for hypothesis generation. PMID:10390090

Nelson, E A; Taylor, B J

1999-06-01

202

Incorporating Animals in Phenological Assessments: USA National Phenology Network Methods to Observe Animal Phenology  

NASA Astrophysics Data System (ADS)

Many assessments of phenology, particularly those operating at large scales, focus on the phenology of plants, in part because of the relevance of plants in cycles of leaf greening and browning that are visible from satellite-based remote sensing, and because plants contribute significantly to global and regional biogeochemical cycles. The USA National Phenology Network (USA-NPN), a consortium of individuals, agencies, and organizations, promotes integrated assessments of both plant and animal phenology. The network is currently developing standard methods to add animal phenology to existing assessments of plant phenology. The first phase will of the standard methods will be implemented online in spring 2010. The methods for observing animals will be similar to the standard methods for making on-the-ground observations of plants—observers will be asked to monitor a fixed location regularly throughout the year. During each visit, observers will answer a series of “yes-no” questions that address the phenological state of the species of interest: Is the species present? Is it mating? Is it feeding? And so on. We are currently testing this method in several national parks in the northeastern United States, including Acadia National Park and the Appalachian Trail. By collecting new observations of this sort for a range of animals—amphibians, birds, fish, insects, mammals, and reptiles—we will greatly increase the ability of scientists and natural resource managers to understand how temporal relationships among these species and the plants on which they depend may be changing. To bolster the data available, we are collaborating with existing monitoring programs to develop common monitoring techniques, data sharing technologies, and visualizations. We are also beginning to collect legacy datasets, such as one from North American Bird Phenology Program that includes 90 years of observations of bird migration times from across the continent. We believe that increasing the amount of animal phenology data available for scientists, natural resource managers, and educators, will greatly advance our understanding of phenological changes and their causes and consequences, particularly in this time of rapid environmental change.

Miller-Rushing, A. J.; Weltzin, J. F.

2009-12-01

203

Application of new methods of interpretation of meteor observations at the Institute of Astrophysics of Tajikistan  

NASA Astrophysics Data System (ADS)

New methods of interpretation of meteor observations were developed and published in [1-9]. The interpretation of ground-based observations of meteors and bolides available today in the scientific literature all over the world suffers from serious contradictions. Observers use the so-called photometric approach for determination of extra-atmospheric masses of meteoric bodies. This approach is based on the formula proposed in 1933 [10] and very simple ideas of how to describe the interaction between the atmospheric air and the surface of a meteoric body. These ideas are provisionally suitable to describe the flow around a body in a free molecular regime. Subsequently, the photometric approach was applied to all the meteor events including bolides. The main effort aimed to elaborate the approach included a choice of new formulas for the radiative efficiency.

Gritsevich, M. I.; Popelenskaya, N. V.; Stulov, V. P.

2012-08-01

204

Improving resolution and depth of astronomical observations via modern mathematical methods for image analysis  

E-print Network

In the past years modern mathematical methods for image analysis have led to a revolution in many fields, from computer vision to scientific imaging. However, some recently developed image processing techniques successfully exploited by other sectors have been rarely, if ever, experimented on astronomical observations. We present here tests of two classes of variational image enhancement techniques: "structure-texture decomposition" and "super-resolution" showing that they are effective in improving the quality of observations. Structure-texture decomposition allows to recover faint sources previously hidden by the background noise, effectively increasing the depth of available observations. Super-resolution yields an higher-resolution and a better sampled image out of a set of low resolution frames, thus mitigating problematics in data analysis arising from the difference in resolution/sampling between different instruments, as in the case of EUCLID VIS and NIR imagers.

Castellano, Marco; Fontana, Adriano; Merlin, Emiliano; Pilo, Stefano; Falcone, Maurizio

2015-01-01

205

Transgenerational tobacco smoke exposure and childhood cancer: An observational study  

PubMed Central

Aim Although tobacco smoke is an established risk factor for adult cancer, studies of the association between parental smoking and childhood cancer have produced inconsistent results. To investigate the transgenerational relationship between pre-natal and post-natal tobacco smoke exposure from the grandmother’s pregnancies until after the post-natal period and childhood cancer. Methods Exposure to tobacco smoke was recorded for three generations. Data were collected through personal interviews using the paediatric environmental history, and were compared among 128 children with cancer and 128 matched controls. The contingency tables and a logistic multivariable regression model were used to control for possible confounding factors. Results Smoke exposure during oogenesis (maternal grandmother smokers) – odds ratio (OR) 2.2 (95% confidence interval (CI) 1.1–4.9) – and during the mother’ pregnancies – OR 1.8 (95% CI 1.1–3.3) – were significantly associated with an increased risk of childhood cancer. Conclusions Tobacco smoke exposure during the grandmother’s and mother’s pregnancies increase the risk of cancer in the descendants. The results suggest that the biological plausibility of the association between parental smoking and paediatric cancer can be explained by the large latency period of paediatric carcinogenesis. PMID:20412413

Ortega-García, Juan A; Martin, Marlene; López-Fernández, María T; Fuster-Soler, Jose L; Donat-Colomer, Joaquín; López-Ibor, Blanca; Claudio, Luz; Ferrís-Tortajada, Josep

2011-01-01

206

Identifying observational studies of surgical interventions in MEDLINE and EMBASE  

PubMed Central

Background Health technology assessments of surgical interventions frequently require the inclusion of non-randomised evidence. Literature search strategies employed to identify this evidence often exclude a methodological component because of uncertainty surrounding the use of appropriate search terms. This can result in the retrieval of a large number of irrelevant records. Methodological filters would help to minimise this, making literature searching more efficient. Methods An objective approach was employed to develop MEDLINE and EMBASE filters, using a reference standard derived from screening the results of an electronic literature search that contained only subject-related terms. Candidate terms for MEDLINE (N = 37) and EMBASE (N = 35) were derived from examination of the records of the reference standard. The filters were validated on two sets of studies that had been included in previous health technology assessments. Results The final filters were highly sensitive (MEDLINE 99.5%, EMBASE 100%, MEDLINE/EMBASE combined 100%) with precision ranging between 16.7% – 21.1%, specificity 35.3% – 43.5%, and a reduction in retrievals of over 30%. Against the validation standards, the individual filters retrieved 85.2% – 100% of records. In combination, however, the MEDLINE and EMBASE filters retrieved 100% against both validation standards with a reduction in retrieved records of 28.4% and 30.1% Conclusion The MEDLINE and EMBASE filters were highly sensitive and substantially reduced the number of records retrieved, indicating that they are useful tools for efficient literature searching. PMID:16919159

Fraser, Cynthia; Murray, Alison; Burr, Jennifer

2006-01-01

207

An Evaluation Method of the Effect of Observation Environment on Air Temperature Measurement  

NASA Astrophysics Data System (ADS)

Near-surface air temperature is the most important variable in the climatic analysis of global warming. The air temperature near the surface is affected by the artificial surface (asphalt, concrete and buildings for example) surrounding the thermometer. However, there is no quantitative method for evaluating the observational environment. Therefore, a practical evaluation method with a scientific basis is required to aid observational network managers and data users. The magnitude of the artificial surface influence on the air temperature and its characteristics are investigated using numerical experiments with various road widths and wind speeds. The results show that the temperature increase in the lee of the road depends on the distance from the road, the road width, the wind speed and the thermal stratification and that the temperature increase can be estimated using an analytical footprint model. In order to estimate the largest value of the temperature increase, a function is developed from the footprint model; it depends on the normalized distance based on the road width, and thus can be calculated easily. A practical method using this function is proposed for the evaluation of the effect of the observational environment.

Kinoshita, Nobuyuki

2014-07-01

208

Cherenkov ? shower earth-skimming method for PeV-EeV ?? observation with Ashra  

NASA Astrophysics Data System (ADS)

We describe a method of observation for PeV-EeV ? neutrinos using Cherenkov light from the air showers of decayed ?s produced by ? neutrino interactions in the Earth. Aiming for the realization of neutrino astronomy utilizing the Earth-skimming ? neutrino detection technique, highly precise determination of arrival direction is key due to the following issues: (1) clear identification of neutrinos by identifying those vertices originating within the Earth's surface and (2) identification of very high energy neutrino sources. The Ashra detector uses newly developed light collectors which realize both a 42°-diameter field-of-view and arcminute resolution. Therefore, it has superior angular resolution for imaging Cherenkov air showers. In this paper, we estimate the sensitivity of and cosmic-ray background resulting from application of the Ashra-1 Cherenkov ? shower observation method. Both data from a commissioning run and a long-term observation (with fully equipped trigger system and one light collector) are presented. Our estimates are based on a detailed Monte Carlo simulation which describes all relevant shower processes from neutrino interaction to Cherenkov photon detection produced by ? air showers. In addition, the potential to determine the arrival direction of Cherenkov showers is evaluated by using the maximum likelihood method. We conclude that the Ashra-1 detector is a unique probe into detection of very high energy neutrinos and their accelerators.

Asaoka, Yoichi; Sasaki, Makoto

2013-01-01

209

Interpolation of Superconducting Gravity Observations Using Least-Squares Collocation Method  

NASA Astrophysics Data System (ADS)

A pre-processing of the gravity data measured by superconducting gravimeter involves removing of spikes, offsets and gaps. Their presence in observations can limit the data analysis and degrades the quality of obtained results. Short data gaps are filling by theoretical signal in order to get continuous records of gravity. It requires the accurate tidal model and eventually atmospheric pressure at the observed site. The poster presents a design of algorithm for interpolation of gravity observations with a sampling rate of 1 min. Novel approach is based on least-squares collocation which combines adjustment of trend parameters, filtering of noise and prediction. It allows the interpolation of missing data up to a few hours without necessity of any other information. Appropriate parameters for covariance function are found using a Bayes' theorem by modified optimization process. Accuracy of method is improved by the rejection of outliers before interpolation. For filling of longer gaps the collocation model is combined with theoretical tidal signal for the rigid Earth. Finally, the proposed method was tested on the superconducting gravity observations at several selected stations of Global Geodynamics Project. Testing demonstrates its reliability and offers results comparable with the standard approach implemented in ETERNA software package without necessity of an accurate tidal model.

Habel, Branislav; Janak, Juraj

2014-05-01

210

Feature selection methods in QSAR studies.  

PubMed

A quantitative structure-activity relationship (QSAR) relates quantitative chemical structure attributes (molecular descriptors) to a biological activity. QSAR studies have now become attractive in drug discovery and development because their application can save substantial time and human resources. Several parameters are important in the prediction ability of a QSAR model. On the one hand, different statistical methods may be applied to check the linear or nonlinear behavior of a data set. On the other hand, feature selection techniques are applied to decrease the model complexity, to decrease the overfitting/overtraining risk, and to select the most important descriptors from the often more than 1000 calculated. The selected descriptors are then linked to a biological activity of the corresponding compound by means of a mathematical model. Different modeling techniques can be applied, some of which explicitly require a feature selection. A QSAR model can be useful in the design of new compounds with improved potency in the class under study. Only molecules with a predicted interesting activity will be synthesized. In the feature selection problem, a learning algorithm is faced with the problem of selecting a relevant subset of features upon which to focus attention, while ignoring the rest. Up to now, many feature selection techniques, such as genetic algorithms, forward selection, backward elimination, stepwise regression, and simulated annealing have been used extensively. Swarm intelligence optimizations, such as ant colony optimization and partial swarm optimization, which are feature selection techniques usually simulated based on animal and insect life behavior to find the shortest path between a food source and their nests, recently are also involved in QSAR studies. This review paper provides an overview of different feature selection techniques applied in QSAR modeling. PMID:22816254

Goodarzi, Mohammad; Dejaegher, Bieke; Vander Heyden, Yvan

2012-01-01

211

Funding sources for continuing medical education: An observational study  

PubMed Central

Aims: Medical accreditation bodies and licensing authorities are increasingly mandating continuing medical education (CME) credits for maintenance of licensure of healthcare providers. However, the costs involved in participating in these CME activities are often substantial and may be a major deterrent in obtaining these mandatory credits. It is assumed that healthcare providers often obtain sponsorship from their institutions or third party payers (i.e. pharmaceutical-industry) to attend these educational activities. Data currently does not exist exploring the funding sources for CME activities in India. In this study, we examine the relative proportion of CME activities sponsored by self, institution and the pharmaceutical-industry. We also wanted to explore the characteristics of courses that have a high proportion of self-sponsorship. Materials and Methods: This is a retrospective audit of the data during the year 2009 conducted at an autonomous clinical training academy. The details of the sponsor of each CME activity were collected from an existing database. Participants were subsequently categorized as sponsored by self, sponsored by institution or sponsored by pharmaceutical-industry. Results: In the year 2009, a total of 2235 participants attended 40 different CME activities at the training academy. Of the total participants, 881 (39.4%) were sponsored by self, 898 (40.2%) were sponsored by institution and 456 (20.3%) by pharmaceutical-industry. About 47.8% participants attended courses that carried an international accreditation. For the courses that offer international accreditation, 63.3% were sponsored by self, 34.9% were sponsored by institution and 1.6% were sponsored by pharmaceutical-industry. There were 126 participants (5.6%) who returned to the academy for another CME activity during the study period. Self-sponsored (SS) candidates were more likely to sponsor themselves again for subsequent CME activity compared with the other two groups (P < 0.001). Conclusions: In our study, majority of healthcare professionals attending CME activities were either self or institution sponsored. There was a greater inclination for self-sponsoring for activities with international accreditation. SS candidates were more likely to sponsor themselves again for subsequent CME activities. PMID:25136190

Venkataraman, Ramesh; Ranganathan, Lakshmi; Ponnish, Arun S.; Abraham, Babu K.; Ramakrishnan, Nagarajan

2014-01-01

212

Prevention of Vertical Transmission of Hepatitis B: An Observation Study  

PubMed Central

Background For mothers with chronic hepatitis B virus (HBV) infection, the US Centers for Disease Control recommend immunoprophylaxis to decrease perinatal transmission; however, its effectiveness and risk factors for failure have not been well studied in community practice. Objective To investigate the effectiveness of a contemporary immunoprophylaxis protocol. Design Observational study. Setting HBV perinatal immunoprophylaxis program within Kaiser Permanente Northern California, an integrated health services delivery organization. Patients 4,446 infants born to 3,253 HBV positive mothers, between 1997-2010. Measurements Compliance with immunoprophylaxis, follow-up testing rates, maternal risk factors for HBV transmission and transmission rates. Results The infant infection rate was 0.75 per 100 births for 1997-2010 (Poisson 95% confidence interval (CI): 0.48-1.10)]. Rates were 3.37 per 100 (95% CI 2.08-5.14) for e-antigen positive mothers; and 0.04 (95% CI 0.001-0.24) for e-antigen negative mothers. Among mothers with viral load testing, the lowest level associated with transmission was 63,200,000 IU/ml. Infection rates per 100 were 3.61 (95% CI 0.75-10.56) among the 83 births to mothers with viral loads ?50,000,000 IU/mL and 0.00 among the 831 births to mothers with viral loads <50,000,000 IU/mL, regardless of e-antigen status. Limitations Testing for HBV immunity and infection was somewhat less complete in earlier years. Viral load testing was only consistently available starting in 2007. Conclusion Pre-natal HBV screening followed by post-natal prophylaxis is highly effective in preventing vertical transmission of HBV. A negative e-antigen status or a viral load of <50,000,000 IU/mL (90.9% of women tested) identifies women at extremely low risk of transmission after immunoprophylaxis who are unlikely to benefit from further interventions. Primary Funding Source Kaiser Permanente Community Benefit Grant (CN-09LShla-01-H); National Institute of Health (K07CA166143-01A1 and KL2TR000143). PMID:24862434

Kubo, Ai; Shlager, Lyle; Marks, Amy R.; Lakritz, Dena; Beaumont, Colette; Gabellini, Kim; Corley, Douglas A.

2014-01-01

213

Contribution of amateur observations to Saturn storm studies  

E-print Network

Since 2004, Saturn Electrostatic Discharges (SEDs), which are the radio signatures of lightning in Saturn's atmosphere, have been observed by the Cassini Radio and Plasma Wave Science instrument (RPWS). Despite their important time coverage, these observations lack the resolution and positioning given by imaging around visible wavelengths. Amateur observations from Earth have been increasing in quality and coverage since a few years, bringing information on positions, drift rates and shape evolutions of large visible white spots in Saturn's atmosphere. Combining these two complementary sources has brought better analysis of Saturn's storms evolutions.

Delcroix, Marc

2010-01-01

214

Use of fuzzy method to estimate river nutrient loads from scarce observation.  

PubMed

Evaluation of data time series in order to get information about water systems is one of the routinely needed tasks. The results are always associated with uncertainties, of which one arises from data scarcity. Traditional methods, such as regression analyses etc. become rapidly useless with decreasing number of data available. A method based on fuzzy set theory was applied to get more reliable information about the system from scarce databases. Monitored daily flow and water quality data of the medium size Zala River in Hungary were considered as elements of fuzzy sets. Fuzzy rules were generated from data pairs (flow, suspended solids concentration, water temperature and phosphorus load as inputs and output, respectively) from which combined rule bases were set up. These rule bases can be considered as a tool of mapping from the input space to the output space using defuzzification procedure. The method is trainable: it can learn from observations. It is demonstrated that the method is capable to generate daily phosphorus loads and annual balance with acceptable accuracy when it is trained only by weekly, biweekly or monthly data pairs. In comparison to other approaches the tool is well suited to utilize better the information content of scarce observations. Furthermore, monitoring costs can be considerably decreased without substantial information loss since sampling of expensive and labour intensive parameters can be reduced. PMID:11385855

Buzás, K

2001-01-01

215

Dance therapy analysis: A method for observing and analyzing a dance therapy group  

Microsoft Academic Search

Several interesting ideas emerge from this study. To begin with, a large amount of information can be gleaned from quantifying\\u000a and graphing a session. From this study a developmental pattern emerged; methods for comparative leadership styles suggested\\u000a themselves; relationships between touch and movement came out; and synchronous activity and its developmental analog were\\u000a manifested.\\u000a \\u000a As studies of this nature increase,

Claire Schmais; Diana Jacoff Felber

1977-01-01

216

TECHNIQUES AND METHODS Methods for Developmental Studies of Fear  

E-print Network

air-puff conditioning among adults. Blood oxygen level­dependent (BOLD) signal was monitored in seven by pairing of a light with an air puff. Given that prior studies relate air-puff conditioning to risk an air-puff UCS to demonstrate enhanced fear conditioning in children of parents with an anxiety disor

Burgess, Neil

217

Observational Studies on Evaluating the Safety and Adverse Effects of Traditional Chinese Medicine  

PubMed Central

Background. This study aims to share our experiences when carrying out observational studies of traditional Chinese medicine (TCM). Methods. We have proactively monitored the safety profiles of Duhuo Jisheng Tang (DJT), Suan Zao Ren Tang (SZRT), and TMN-1. A list of adverse events (AEs), complete blood counts, and liver and kidney function tests were obtained from the participants during their scheduled hospital visits. Retrospective observational studies were conducted based on the reimbursement database of the National Health Insurance system, Taiwan, to explore the relationship between the use of TCM that have been adulterated by aristolochic acid and the risk from both nephrotoxins and carcinogens. Results. A total of 221, 287, and 203 AEs were detected after SZRT, DJT, and TMN-1 had been taken, respectively. Dizziness, headache, stomach ache, and diarrhea were judged to be probably related to SZRT treatment. Retrospective observational studies found an association between the consumption of aristolochic acid-containing Chinese formulae such as Mu Tong and an increased risk of CKD, ESRD, and urinary tract cancer. Conclusion. Prospective and retrospective observational studies seem to have specific advantages when investigating the safety and adverse effects of TCM therapies, as well as possibly other alternative/complementary therapies. PMID:24159351

Tang, Jin-Ling; Wang, Jung-Der

2013-01-01

218

A method of high-accuracy orbit determination from three observations of a small celestial body. (Russian Title: ????? ????????????? ??????????? ?????? ?? ???? ??????????? ?????? ????????? ????)  

NASA Astrophysics Data System (ADS)

A new method is suggested for finding the preliminary orbit of a small celestial body from its three pairs of angular measurements at three times. The method uses the intermediate orbit that we previously constructed from three position vectors and the corresponding times. This intermediate orbit allows for most of the perturbations in the motion of the body under study. The methodical error of orbit computation by the proposed method is generally three orders smaller than the corresponding error of the traditional approach based on the construction of the unperturbed Keplerian orbit. This fact allows such a reference arc to be selected that the accuracy of the intermediate orbit would always match that of the reference observations that determine this arc. The new method is a highly efficient tool, which allows reliable parameters of the perturbed motion to be obtained already at the stage of computing the preliminary orbit. It is especially efficient if applied to high-accuracy observational data covering short orbital arcs.

Shefer, V. A.

2009-11-01

219

Study report on a double isotope method of calcium absorption  

NASA Technical Reports Server (NTRS)

Some of the pros and cons of three methods to study gastrointestinal calcium absorption are briefly discussed. The methods are: (1) a balance study; (2) a single isotope method; and (3) a double isotope method. A procedure for the double isotope method is also included.

1978-01-01

220

An Observational Study for Evaluating the Effects of Interpersonal Problem-Solving Skills Training on Behavioural Dimensions  

ERIC Educational Resources Information Center

The present observational study was designed to evaluate the effectiveness of the I Can Problem Solve (ICPS) programme on behavioural change from aggression to pro-social behaviours by using the DECB rating scale. Non-participant observation method was used to collect data in pretest-training-posttest design. It was hypothesised that the ICPS…

Anliak, Sakire; Sahin, Derya

2010-01-01

221

Comparative study of brain deformation estimation methods  

Microsoft Academic Search

Shift of brain tissues during surgical procedures affects the precision of image-guided neurosurgery (IGNS). To improve the accuracy of the alignment between the patient and images, finite element model-based non-rigid registration methods have been investigated. The best prior estimate (BPE), the forced displacement method (FDM), the weighted basis solutions (WBS), and the adjoint equations method (AEM) are versions of this

Fenghong Liu; Keith D. Paulsen; Karen E. Lunn; Hai Sun; Alexander Hartov; Ziji Wu; David W. Roberts

2006-01-01

222

Lifetime socioeconomic position and mortality: prospective observational study.  

PubMed Central

OBJECTIVES: To assess the influence of socioeconomic position over a lifetime on risk factors for cardiovascular disease, on morbidity, and on mortality from various causes. DESIGN: Prospective observational study with 21 years of follow up. Social class was determined as manual or non-manual at three stages of participants' lives: from the social class of their father's job, the social class of their first job, and the social class of their job at the time of screening. A cumulative social class indicator was constructed, ranging from non-manual social class at all three stages of life to manual social class at all three stages. SETTING: 27 workplaces in the west of Scotland. PARTICIPANTS: 5766 men aged 35-64 at the time of examination. MAIN OUTCOME MEASURES: Prevalence and level of risk factors for cardiovascular disease; morbidity; and mortality from broad causes of death. RESULTS: From non-manual social class locations at all three life stages to manual at all stages there were strong positive trends for blood pressure, body mass index, current cigarette smoking, angina, and bronchitis. Inverse trends were seen for height, cholesterol concentration, lung function, and being an ex-smoker. 1580 men died during follow up. Age adjusted relative death rates in comparison with the men of non-manual social class locations at all three stages of life were 1.29 (95% confidence interval 1.08 to 1.56) in men of two non-manual and one manual social class; 1.45 (1.21 to 1.73) in men of two manual and one non-manual social class; and 1.71 (1.46 to 2.01) in men of manual social class at all three stages. Mortality from cardiovascular disease showed a similar graded association with cumulative social class. Mortality from cancer was mainly raised among men of manual social class at all three stages. Adjustment for a wide range of risk factors caused little attenuation in the association of cumulative social class with mortality from all causes and from cardiovascular disease; greater attenuation was seen in the association with mortality from non-cardiovascular, non-cancer disease. Fathers having a manual [corrected] occupation was strongly associated with mortality from cardiovascular disease: relative rate 1.41 (1.15 to 1.72). Participants' social class at the time of screening was more strongly associated than the other social class indicators with mortality from cancer and from non-cardiovascular, non-cancer causes. CONCLUSIONS: Socioeconomic factors acting over the lifetime affect health and risk of premature death. The relative importance of influences at different stages varies for the cause of death. Studies with data on socioeconomic circumstances at only one stage of life are inadequate for fully elucidating the contribution of socioeconomic factors to health and mortality risk. PMID:9055712

Smith, G. D.; Hart, C.; Blane, D.; Gillis, C.; Hawthorne, V.

1997-01-01

223

A Mixed Methods Sampling Methodology for a Multisite Case Study  

ERIC Educational Resources Information Center

The flexibility of mixed methods research strategies makes such approaches especially suitable for multisite case studies. Yet the utilization of mixed methods to select sites for these studies is rarely reported. The authors describe their pragmatic mixed methods approach to select a sample for their multisite mixed methods case study of a…

Sharp, Julia L.; Mobley, Catherine; Hammond, Cathy; Withington, Cairen; Drew, Sam; Stringfield, Sam; Stipanovic, Natalie

2012-01-01

224

The Reporting of Observational Clinical Functional Magnetic Resonance Imaging Studies: A Systematic Review  

PubMed Central

Introduction Complete reporting assists readers in confirming the methodological rigor and validity of findings and allows replication. The reporting quality of observational functional magnetic resonance imaging (fMRI) studies involving clinical participants is unclear. Objectives We sought to determine the quality of reporting in observational fMRI studies involving clinical participants. Methods We searched OVID MEDLINE for fMRI studies in six leading journals between January 2010 and December 2011.Three independent reviewers abstracted data from articles using an 83-item checklist adapted from the guidelines proposed by Poldrack et al. (Neuroimage 2008; 40: 409–14). We calculated the percentage of articles reporting each item of the checklist and the percentage of reported items per article. Results A random sample of 100 eligible articles was included in the study. Thirty-one items were reported by fewer than 50% of the articles and 13 items were reported by fewer than 20% of the articles. The median percentage of reported items per article was 51% (ranging from 30% to 78%). Although most articles reported statistical methods for within-subject modeling (92%) and for between-subject group modeling (97%), none of the articles reported observed effect sizes for any negative finding (0%). Few articles reported justifications for fixed-effect inferences used for group modeling (3%) and temporal autocorrelations used to account for within-subject variances and correlations (18%). Other under-reported areas included whether and how the task design was optimized for efficiency (22%) and distributions of inter-trial intervals (23%). Conclusions This study indicates that substantial improvement in the reporting of observational clinical fMRI studies is required. Poldrack et al.'s guidelines provide a means of improving overall reporting quality. Nonetheless, these guidelines are lengthy and may be at odds with strict word limits for publication; creation of a shortened-version of Poldrack's checklist that contains the most relevant items may be useful in this regard. PMID:24755843

Guo, Qing; Parlar, Melissa; Truong, Wanda; Hall, Geoffrey; Thabane, Lehana; McKinnon, Margaret; Goeree, Ron; Pullenayegum, Eleanor

2014-01-01

225

Large-Scale periodic solar velocities: An observational study  

NASA Technical Reports Server (NTRS)

Observations of large-scale solar velocities were made using the mean field telescope and Babcock magnetograph of the Stanford Solar Observatory. Observations were made in the magnetically insensitive ion line at 5124 A, with light from the center (limb) of the disk right (left) circularly polarized, so that the magnetograph measures the difference in wavelength between center and limb. Computer calculations are made of the wavelength difference produced by global pulsations for spherical harmonics up to second order and of the signal produced by displacing the solar image relative to polarizing optics or diffraction grating.

Dittmer, P. H.

1977-01-01

226

AN EVALUATION STUDY OF EPA METHOD 8  

EPA Science Inventory

Techniques used in EPA Method 8, the source test method for acid mist and sulfur dioxide emissions from sulfuric acid plants, have been evaluated. Evidence is shown that trace amounts of peroxides in isopropyl alcohol result in the conversion of sulfur dioxide to sulfate and caus...

227

[Indicators for quality of care. Severe problems with methods of observation].  

PubMed

Recently, there has been increasing concern about indicators for quality of care systems. Much energy has been devoted to the development of these indicators, but after a couple of years many professionals in the care organizations are complaining that the validity is extremely doubtful. In this editorial a fundamental problem is discussed, namely the reliability of the observations. In all scientific fields many precautions are necessary, for example in meteorology measuring the temperature in open air. In the manuals about the indicators of care two methods of observation are mentioned. In the first one patients are interviewed. The results seem very unreliable, because of socially desirable answers. For example, in nursing homes the patients are extremely dependent on the care-giver and it is likely they avoid complaints. The second method is used for gathering data about the frequency of falls, decubitus and so on. This is carried out by the care professionals. It goes without saying that the resulting data are vulnerable to manipulation, because of the great interests of the professionals and of the organizations involved. This problem was already described by the sociologist Blau 50 years ago. It is suggested to make a new start on a small scale with only a few indicators. It is necessary to work with unobtrusive measures-e.g. undercover observations- for observing behaviour instead of asking questions. And in the second case data should be gathered by separate organizations that are completely independent. Patients deserve that the representation of their situation should be guaranteed by scientific standards. PMID:22250366

Braam, Geert

2011-12-01

228

Eribulin Mesylate in Pretreated Breast Cancer Patients: A Multicenter Retrospective Observational Study  

PubMed Central

Background: Eribulin was recently approved in patients progressing after being treated with anthracyclines and taxanes and after two or more chemotherapy lines for advanced disease. Objectives: This multicenter observational retrospective study was performed in order to evaluate activity and tolerability of eribulin in real-world patient population. Methods: 133 advanced breast cancer patients pretreated with ? 2 chemotherapy lines for metastatic disease were retrospectively enrolled in the observational trial in 11 italian cancer centres. Results: A median of 5 cycles of eribulin (range, 1-15) were administered. Twenty-eight partial responses were observed, for an overall response rate of 21.1% (95%CI,14.1-28.0). A stable disease was recorded in 57 patients (42.8%), and a clinical benefit (response or stable disease lasting ? six months) was observed in 51 patients (38.3%, 95%CI, 30.1-46.6). The subgroup analysis showed that a significant improvement in term of partial response and clinical benefit was achieved when eribulin was administered in HER-2 negative tumors (p=0.01 and p=0.004, respectively) and when it is given as third-line (p=0.09 and p=0.02, respectively). Toxicity was manageable; fatigue is the most common side effect observed, usually of low-grade, and clearly cumulative-dose related. Conclusions: In this retrospective, observational analysis eribulin confirmed its efficacy and manageable tolerability even in real-world population and in heavily pretreated patients. PMID:24723974

Gamucci, Teresa; Michelotti, Andrea; Pizzuti, Laura; Mentuccia, Lucia; Landucci, Elisabetta; Sperduti, Isabella; Di Lauro, Luigi; Fabi, Alessandra; Tonini, Giuseppe; Sini, Valentina; Salesi, Nello; Ferrarini, Ilaria; Vaccaro, Angela; Pavese, Ida; Veltri, Enzo; Moscetti, Luca; Marchetti, Paolo; Vici, Patrizia

2014-01-01

229

LAT observation of GRBs: Simulations and Sensitivity studies  

SciTech Connect

The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high-energy gamma-ray astronomy. It employs a pair conversion technique to record photons in the energy range from 20 MeV to more than 300 GeV. The LAT will follow the steps from its predecessor EGRET (1991-2000), and will explore the high-energy gamma-ray sky with unprecedented capabilities. The observation of Gamma-Ray Bursts is one of the main science goal of the LAT: in this contribution we compute an estimation of the LAT sensitivity to GRB, adopting a phenomenological description of GRBs, where the high-energy emission in GRB is obtained extrapolating the observed BATSE spectrum up to LAT energies. The effect of the cosmological attenuation is included. We use the BATSE current catalog to build up our statistics.

Omodei, Nicola [INFN of Pisa, Polo Fibonacci Largo B. Pontecorvo 3, Pisa, 56127 (Italy); Norris, Jay [University of Denver, Denver CO 80208 (United States)

2007-07-12

230

Flashes in the Middle and Upper Atmosphere Initiated by the Lightning Discharges: Recent Results and Future Optical and Spectral Observation Methods  

NASA Astrophysics Data System (ADS)

Recent years yielded important experimental results in the field of studying the middle- and the upper-atmospheric discharges initiated by the lightning strokes. These results have been obtained using the most widespread measurement method related to the high-speed high-sensitivity visibleband cameras and the spectroscopy, which is the most rapidly developing method of observation of the upper-atmospheric flashes. Both methods are used during the ground-based, as well as the balloon- and satellite-borne observations. The above-mentioned methods are reviewed in this paper.

Kostinskiy, A. Yu.

2014-04-01

231

A wavelet-based method for extracting intermittent discontinuities observed in human motor behavior.  

PubMed

Human motor behavior often shows intermittent discontinuities even when people try to follow a continuously moving target. Although most previous studies revealed common characteristics of this "motor intermittency" using frequency analysis, this technique is not always appropriate because the nature of the intermittency is not stationary, i.e., the temporal intervals between the discontinuities may vary irregularly. In the present paper, we propose a novel method for extracting intermittent discontinuities using a continuous wavelet transform (CWT). This method is equivalent to the detection of peak of the jerk profile in principle, but it successfully and stably detects discontinuities using the amplitude and phase information of the complex wavelet transform. More specifically, the singularity point on the time-scale plane plays a key role in detecting the discontinuities. Another important feature is that the proposed method does not require parameter tuning because it is based on the nature of hand movement. In addition, this method does not contain any optimization process, which avoids explosive increase in computational cost for long time-series data. The performance of the proposed method was examined using an artificial trajectory composed of several primitive movements, and an actual hand trajectory in a continuous target-tracking task. The functional rationale of the proposed method is discussed. PMID:24866293

Inoue, Yasuyuki; Sakaguchi, Yutaka

2015-02-01

232

Body Characteristics, Dietary Protein and Body Weight Regulation. Reconciling Conflicting Results from Intervention and Observational Studies?  

PubMed Central

Background/Objectives Physiological evidence indicates that high-protein diets reduce caloric intake and increase thermogenic response, which may prevent weight gain and regain after weight loss. Clinical trials have shown such effects, whereas observational cohort studies suggest an association between greater protein intake and weight gain. In both types of studies the results are based on average weight changes, and show considerable diversity in both directions. This study investigates whether the discrepancy in the evidence could be due to recruitment of overweight and obese individuals into clinical trials. Subjects/Methods Data were available from the European Diet, Obesity and Genes (DiOGenes) post-weight-loss weight-maintenance trial and the Danish Diet, Cancer and Health (DCH) cohort. Participants of the DCH cohort were matched with participants from the DiOGenes trial on gender, diet, and body characteristics. Different subsets of the DCH-participants, comparable with the trial participants, were analyzed for weight maintenance according to the randomization status (high or low protein) of the matched trial participants. Results Trial participants were generally heavier, had larger waist circumference and larger fat mass than the participants in the entire DCH cohort. A better weight maintenance in the high-protein group compared to the low protein group was observed in the subgroups of the DCH cohort matching body characteristics of the trial participants. Conclusion This modified observational study, minimized the differences between the RCT and observational data with regard to dietary intake, participant characteristics and statistical analysis. Compared with low protein diet the high protein diet was associated with better weight maintenance when individuals with greater body mass index and waist circumference were analyzed. Selecting subsets of large-scale observational cohort studies with similar characteristics as participants in clinical trials may reconcile the otherwise conflicting results. PMID:24992329

Ankarfeldt, Mikkel Z.; Ängquist, Lars; Stocks, Tanja; Jakobsen, Marianne U.; Overvad, Kim; Halkjær, Jytte; Saris, Wim H. M.; Astrup, Arne; Sørensen, Thorkild I. A.

2014-01-01

233

Taguchi methods in electronics: A case study  

NASA Technical Reports Server (NTRS)

Total Quality Management (TQM) is becoming more important as a way to improve productivity. One of the technical aspects of TQM is a system called the Taguchi method. This is an optimization method that, with a few precautions, can reduce test effort by an order of magnitude over conventional techniques. The Taguchi method is specifically designed to minimize a product's sensitivity to uncontrollable system disturbances such as aging, temperature, voltage variations, etc., by simultaneously varying both design and disturbance parameters. The analysis produces an optimum set of design parameters. A 3-day class on the Taguchi method was held at the Marshall Space Flight Center (MSFC) in May 1991. A project was needed as a follow-up after the class was over, and the motor controller was selected at that time. Exactly how to proceed was the subject of discussion for some months. It was not clear exactly what to measure, and design kept getting mixed with optimization. There was even some discussion about why the Taguchi method should be used at all.

Kissel, R.

1992-01-01

234

Laboratory and Observational Studies of Methyl Ethyl Ketone  

NASA Astrophysics Data System (ADS)

A large fraction of the detected interstellar molecules are complex organic molecules (COMs) containing five or more atoms. Despite the prominence of these species in many types of astrophysical environments, the formation processes for these molecules are not well-understood. We have therefore undertaken a combined laboratory, modeling, and observational program in an attempt to more fully understand the effects that physical environment have on the chemical composition of astronomical sources. As part of this effort, we have conducted deep submillimeter spectral line surveys of multiple interstellar sources with varying physical conditions including hot cores, shocked regions, low-mass star forming regions, and stellar outflows. These surveys were conducted using a broadband receiver at the Caltech Submillimeter Observatory (CSO), and are forerunner observations to our upcoming Herschel OT1 program to continue these surveys at higher frequencies. In order to fully analyze these spectral line surveys, we have also collected laboratory spectra of several suspected interstellar organic molecules. One such molecular target is methyl ethyl ketone (CH_3COCH_2CH_3, MEK), which is a likely candidate for interstellar detection. The spectra for MEK were collected from 8.7 to 18.3 GHz using the chirped-pulse waveguide Fourier Transform microwave (FTMW) spectrometer at New College Florida. We have also collected spectra of MEK in selected frequency ranges from 32 to 125 GHz using the direct absorption flow cell spectrometer at Emory University. We will report on the laboratory characterization of MEK and compare these results to our observational spectral line surveys.

Kroll, J. A.; Shipman, S.; Widicus Weaver, S. L.

2011-05-01

235

A new modelling method for non-convex shapes of asteroids based on photometric observations  

NASA Astrophysics Data System (ADS)

We present the new SAGE algorithm (Shaping Asteroids with Genetic Evolution) able to derive 3-D nonconvex shapes of asteroids and solving for their spin parameters using only disk-integrated photometry. A triangular mesh of 62 vertices is used as a seed during the parameters minimization, and the Catmull-Clark method is applied to generate bodies with higher resolution. The subroutines search for the sidereal period of rotation in a given range, and the spin axis orientation on the whole celestial sphere. A step-iterative algorithm is used to make the shape evolve under the minimization constrains between the synthetic generated photometry and the real observations. In order to generate the simulated lightcurves we propose the virtual frames algorithm. The algorithm simulates the pictures visible on hypothetical CCD frames and, using only elementary vector operations or quadratic algebraic equations, it takes into account all phase angle effects. Publicly available lightcurve data has been used to obtain a new non-convex model for (9) Metis and (433) Eros. The resulting body shapes are compared with the ones obtained using other observational techniques, such as adaptive optics and stellar occultations (for Metis) or the NEAR Shoemaker observations of Eros during its rendezvous.

Bartczak, P.; Santana-Ros, T.; Marciniak, A.; Micha?owski, T.; Pr?tka-Ziomek, H.

2014-04-01

236

Thermoacoustic CT of the breast: pilot study observations  

Microsoft Academic Search

In order to assess the potential clinical utility of using thermoacoustic computer tomography (TCT) to image the breast, we conducted a retrospective pilot study of 78 patients. We recruited patients in three age groups (50 years). The study population was further segregated into normal and suspicious based on the results of the previous x-ray mammography and ultrasound. Image quality was

Robert A. Kruger; William L. Kiser; A. P. Romilly; Phyllis Scmidt

2001-01-01

237

Study of decays with first observation of and  

NASA Astrophysics Data System (ADS)

A search for charmless three-body decays of B 0 and mesons with a meson in the final state is performed using the pp collision data, corresponding to an integrated luminosity of 1.0 fb-1, collected at a centre-of-mass energy of 7 TeV recorded by the LHCb experiment. Branching fractions of the decay modes ( h (') = ?, K), relative to the well measured decay, are obtained. First observation of the decay modes and and confirmation of the decay are reported. The following relative branching fraction measurements or limits are obtained [Figure not available: see fulltext.

Aaij, R.; Adeva, B.; Adinolfi, M.; Adrover, C.; Affolder, A.; Ajaltouni, Z.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; Anderlini, L.; Anderson, J.; Andreassen, R.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Baesso, C.; Balagura, V.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Bauer, Th.; Bay, A.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Belogurov, S.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Bizzeti, A.; Bjørnstad, P. M.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brambach, T.; van den Brand, J.; Bressieux, J.; Brett, D.; Britsch, M.; Britton, T.; Brook, N. H.; Brown, H.; Burducea, I.; Bursche, A.; Busetto, G.; Buytaert, J.; Cadeddu, S.; Callot, O.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Campora Perez, D.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carranza-Mejia, H.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chen, P.; Chiapolini, N.; Chrzaszcz, M.; Ciba, K.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coca, C.; Coco, V.; Cogan, J.; Cogneras, E.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Couturier, B.; Cowan, G. A.; Cowie, E.; Craik, D. C.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; David, P.; David, P. N. Y.; Davis, A.; De Bonis, I.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Di Canto, A.; Dijkstra, H.; Dogaru, M.; Donleavy, S.; Dordei, F.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; van Eijk, D.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Falabella, A.; Färber, C.; Fardell, G.; Farinelli, C.; Farry, S.; Ferguson, D.; Fernandez Albor, V.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fitzpatrick, C.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Furcas, S.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gandelman, M.; Gandini, P.; Gao, Y.; Garofoli, J.; Garosi, P.; Garra Tico, J.; Garrido, L.; Gaspar, C.; Gauld, R.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gorbounov, P.; Gordon, H.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Hartmann, T.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Hernando Morata, J. A.; van Herwijnen, E.; Hess, M.; Hicheur, A.; Hicks, E.; Hill, D.; Hoballah, M.; Hombach, C.; Hopchev, P.; Hulsbergen, W.; Hunt, P.; Huse, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Iakovenko, V.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jans, E.; Jaton, P.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Kaballo, M.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Kenyon, I. R.; Ketel, T.; Keune, A.; Khanji, B.; Kochebina, O.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Korolev, M.; Kozlinskiy, A.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucharczyk, M.; Kudryavtsev, V.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanciotti, E.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leo, S.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Li Gioi, L.; Liles, M.; Lindner, R.; Linn, C.; Liu, B.; Liu, G.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lopez-March, N.; Lu, H.; Lucchesi, D.; Luisier, J.; Luo, H.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Malde, S.; Manca, G.; Mancinelli, G.; Maratas, J.; Marconi, U.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.

2013-10-01

238

Observation and studies of double J /? production at the Tevatron  

NASA Astrophysics Data System (ADS)

We present the observation of doubly produced J /? mesons with the D0 detector at Fermilab in p p ¯ collisions at ?{s }=1.96 TeV . The production cross section for both singly and doubly produced J /? mesons is measured using a sample with an integrated luminosity of 8.1 fb-1 . For the first time, the double J /? production cross section is separated into contributions due to single and double parton scatterings. Using these measurements, we determine the effective cross section ?eff, a parameter characterizing an effective spatial area of the parton-parton interactions and related to the parton spatial density inside the nucleon.

Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Borysova, M.; Brandt, A.; Brandt, O.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, V. N.; Fauré, A.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Gogota, O.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kaur, M.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kur?a, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Osta, J.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M.-A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Savitskyi, M.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.

2014-12-01

239

Crustal Deformations Studies in Egypt Using Gravity and Geodetic Observations  

NASA Astrophysics Data System (ADS)

The mass re-distribution and related density changes are one of the main factors affecting Earth's dynamics. Therefore, we used the observed temporal gravity variations to understand the surface tectonics and geodynamic processes. Temporal gravity variations in parallel with the geodetic technique (GPS) had been used to monitor recent crustal movements in Egypt since 1997. The geodetic networks around the High Dam, Aswan, were the first net to be measured in Egypt. More than five times of measurements were performed till Dec. 2009. The non-tidal gravity changes were constrained by the vertical component of surface movements derived from the GPS observations. The trend of gravity changes indicated a positive stress south of the Kalabsha fault in combination with expected lake water penetration into the Nubian sandstone; the lowest gravity changes along the Kalabsha fault reflect the strike component of the stress field. Also, the gravity changes were correlated with seismic activity in the areas around Cairo, Egypt (Greater Cairo and Southern part of Delta). As example, a relative considerable increase of gravity values was noticed for the network between the epochs of 2000 and 2004. Otherwise, the temporal gravity variations were reported a considerable decrease in gravity values between the two campaigns of 2004 and 2007 for the same stations. This behavior could explain by compressive deformation and strain buildup stage before the Southwest Cairo earthquake (July 31, 2005 with Mw 4.3). Then, the stress release stage were occurred after the main-shock which showed by the negative change of gravity values from the measurements of 2007. Although, the existing of this relation from gravity campaigns in 2000 - 2004 - 2007, and due to the small number of observations, we assume there is a relation rather between gravity changes and continuous deformation process, than a direct relation to earthquake occurrence. However, the limited number of campaigns has not allowed yet developing a model of such relation. The results of geodetic measurements of the network around Cairo after five campaigns showed that the average estimated horizontal velocities for most points are about 5.15 mm/year in approximately NW-SE direction. This proves the high geodynamic activity of the region and the need of further observations.

Issawy, Elsayed; Mrlina, Jan; Radwan, Anwar; Mahmoud, Salah

2010-05-01

240

Methods For Planning Repeated Measures Degradation Studies  

Microsoft Academic Search

Repeated measures degradation studies are used to assess product or component reliability when there are few or even no failures expected during a study. Such studies are often used to assess the shelf life of materials, components, and products. We show how to evaluate the properties of proposed test plans. Such evaluations are needed to identify statistically efficient tests. We

Brian P. Weaver; William Q. Meeker; Luis A. Escobar; Joanne Wendelberger

2012-01-01

241

Direct Observation, Study, and Control of Molecular Superrotors  

NASA Astrophysics Data System (ADS)

Extremely fast rotating molecules whose rotational energy is comparable with the molecular bond strength are known as "superrotors." It has been speculated that superrotors may exhibit a number of unique properties, yet only indirect evidence of these molecular objects has been reported to date. Here we demonstrate the first direct observation of molecular superrotors by detecting coherent unidirectional molecular rotation with extreme frequencies exceeding 10 THz. The technique of an "optical centrifuge" is used to control the degree of rotational excitation in an ultrabroad range of rotational quantum numbers, reaching as high as N =95 in oxygen and N=60 in nitrogen. State-resolved detection enables us to determine the shape of the excited rotational wave packet and quantify the effect of centrifugal distortion on the rotational spectrum. Femtosecond time resolution reveals coherent rotational dynamics with increasing coherence times at higher angular momentum. We demonstrate that molecular superrotors can be created and observed in dense samples under normal conditions where the effects of ultrafast rotation on many-body interactions, intermolecular collisions, and chemical reactions can be readily explored.

Korobenko, Aleksey; Milner, Alexander A.; Milner, Valery

2014-03-01

242

Direct observation, study, and control of molecular superrotors.  

PubMed

Extremely fast rotating molecules whose rotational energy is comparable with the molecular bond strength are known as "superrotors." It has been speculated that superrotors may exhibit a number of unique properties, yet only indirect evidence of these molecular objects has been reported to date. Here we demonstrate the first direct observation of molecular superrotors by detecting coherent unidirectional molecular rotation with extreme frequencies exceeding 10 THz. The technique of an "optical centrifuge" is used to control the degree of rotational excitation in an ultrabroad range of rotational quantum numbers, reaching as high as N = 95 in oxygen and N = 60 in nitrogen. State-resolved detection enables us to determine the shape of the excited rotational wave packet and quantify the effect of centrifugal distortion on the rotational spectrum. Femtosecond time resolution reveals coherent rotational dynamics with increasing coherence times at higher angular momentum. We demonstrate that molecular superrotors can be created and observed in dense samples under normal conditions where the effects of ultrafast rotation on many-body interactions, intermolecular collisions, and chemical reactions can be readily explored. PMID:24702361

Korobenko, Aleksey; Milner, Alexander A; Milner, Valery

2014-03-21

243

Plate measurement techniques and reduction methods used by the West German satellite observers, and resulting consequences for the observation  

NASA Technical Reports Server (NTRS)

The West German tracking stations are equipped with ballistic cameras. Plate measurement and plate reduction must therefore follow photogrammetric methods. Approximately 100 star positions and 200 satellite positions are measured on each plate. The mathematical model for spatial rotation of the bundle of rays is extended by including terms for distortion and internal orientation of the camera as well as by providing terms for refraction which are computed for the measured coordinates of the star positions on the plate. From the measuring accuracy of the plate coordinates it follows that the timing accuracy for the exposures has to be about one millisecond, in order to obtain a homogeneous system.

Deker, H.

1971-01-01

244

Automated method for study of drug metabolism  

NASA Technical Reports Server (NTRS)

Commercially available equipment can be modified to provide automated system for assaying drug metabolism by continuous flow-through. System includes steps and devices for mixing drug with enzyme and cofactor in the presence of pure oxygen, dialyzing resulting metabolite against buffer, and determining amount of metabolite by colorimetric method.

Furner, R. L.; Feller, D. D.

1973-01-01

245

A new method for quality control of Chinese rawinsonde wind observations  

NASA Astrophysics Data System (ADS)

In 2006, the National Meteorological Information Center (NMIC) of the China Meteorological Administration (CMA) developed its real-time quality control (QC) system of rawinsonde observations coming from the Global Telecommunications System (GTS) and established the Global Upper-air Report Dataset, which, with the NMIC B01 format, is generally referred to as the B01 dataset and updated on a daily basis. However, when the B01 dataset is applied in climate analysis, some wind errors as well as some accurate values with incorrect error marks are found. To improve the quality and usefulness of Chinese rawinsonde wind observations, a new QC method (NewQC) is proposed in this paper. Different from the QC approach used for B01 datasets, the NewQC includes two vertical-wind-shear checks to analyze the vertical consistency of winds, in which the constant height level winds are used as reference data for the QC of mandatory pressure level winds. Different threshold values are adopted in the wind shear checks for different stations and different vertical levels. Several typical examples of QC of different error types by the new algorithm are shown and its performance with respect to 1980-2008 observational data is statistically evaluated. Compared with the radiosonde QC algorithms used in both the Meteorological Assimilation Data Ingest System (MADIS, http://madis.noaa.gov/madis_raob_qc.html) of the National Oceanic and Atmospheric Administration (NOAA) and the B01 dataset, the NewQC shows higher accuracy and better reliability, particularly when used to judge successive observation errors.

Liao, Jie; Wang, Bin; Li, Qingxiang

2014-11-01

246

Atmospheric sounding by GPS radio occultation: Simulation studies and comparisons with observations  

NASA Astrophysics Data System (ADS)

Within the first two years following the activation of the GPS radio occultation experiment aboard the geoscience satellite CHAMP more than~100,000 occultation events have been observed. Between 70 and 80% of these observations were successfully processed to yield vertical profiles of atmospheric refractivity, temperature and humidity. In the upper troposphere and stratosphere the derived atmospheric refractivities agree with ECMWF meteorological analyses to better than 0.5%; in the lower troposphere, however, a negative bias exceeding several percent is observed. End-to-end simulation studies were performed to investigate possible causes for the observed refractivity bias. Using the multiple phase screen method C/A-code modulated L1 signals are propagated through a spherically symmetric refractivity field derived from a high-resolution radio sonde observation. The propagated signals are tracked by a software GPS receiver and converted to refractivity profiles using the canonical transform technique and the Abel inversion. Ignoring noise and assuming an ideal receiver tracking behaviour the true refractivity profiles are reproduced to better than 0.1% at altitude above 2~km. The non-ideal case is simulated by adding between 14 and 24~dB of Gaussian white noise to the signal and tracking the signal with receivers operating at 50 and 200~Hz sampling frequency using two different carrier phase detectors. In the upper troposphere and stratosphere the receiver models reproduce the true refractivity profile to better than 0.1%. However, in the mid-troposphere down to altitudes of about 2~km a Costas-type phase-locked loop tracking induces negative refractivity biases on the order of~-1~to~-2% at 50~Hz sampling frequency. Modifications to the receiver tracking algorithm improve the retrieved signal significantly. Based on these simulation results a heuristic procedure based on the canonical transform method and the sliding spectral technique is proposed. The procedure is applied to simulated profiles as well as observations within the existing CHAMP data set.

Beyerle, G.; Gorbunov, M. E.; Ao, C. O.; Wickert, J.; Schmidt, T.; Reigber, Ch.

2003-04-01

247

Unbiased Causal Inference from an Observational Study: Results of a Within-Study Comparison  

ERIC Educational Resources Information Center

Adjustment methods such as propensity scores and analysis of covariance are often used for estimating treatment effects in nonexperimental data. Shadish, Clark, and Steiner used a within-study comparison to test how well these adjustments work in practice. They randomly assigned participating students to a randomized or nonrandomized experiment.…

Pohl, Steffi; Steiner, Peter M.; Eisermann, Jens; Soellner, Renate; Cook, Thomas D.

2009-01-01

248

An assessment of the spontaneous activity of rats administered morphine, phencyclidine, or nicotine using automated and observational methods  

Microsoft Academic Search

The effects of morphine, phencyclidine, and nicotine on motor activity in rats were characterized using both observational and automated methods. Activity was scored observationally using a time-sampling method that tabulates discrete response categories (still, locomotion, rearing, sniffing, licking, gnawing, head down, swaying, grooming, falling). Behavior was assessed automatically using an activity monitor that records both the time and activity counts

Edgar T. Iwamoto

1984-01-01

249

Observational study of food safety practices in retail deli departments.  

PubMed

In order to improve the safety of refrigerated ready-to-eat food products prepared at retail deli departments, a better understanding of current practices in these establishments is needed. Food employees in deli departments at six chain and three independent retail establishments in Maryland and Virginia were observed, using notational analysis, as they prepared deli products for sale. The frequency of contact with objects and deli products before sale, hand washing and glove changing during preparation, and equipment, utensil, and surface cleaning and sanitizing was determined. Compliance with the U.S. Food and Drug Administration's 2005 model Food Code recommendations, which must be adopted by the individual state and local jurisdictions that are responsible for directly regulating retail establishments, was also assessed. Observations indicated there were a large number of actions for which hand washing was recommended at independent and chain stores (273 recommended of 1,098 total actions and 439 recommended of 3,073 total actions, respectively). Moreover, 67% (295 of 439) of the actions for which hand washing was recommended at the chain stores and 86% (235 of 273) of those at the independent stores resulted from employees touching non-food contact surfaces prior to handling ready-to-eat food. Compliance with hand washing recommendations was generally low and varied depending on store type with independent stores exhibiting lower compliance than chain stores (5 instances of compliance for 273 recommended actions and 73 instances of compliance for 439 recommended actions, respectively). Potential risk mitigation measures that may reduce the frequency of hand washing actions needed during ready-to-eat food preparation in retail deli departments are discussed. More research is needed to determine the impact of such measures on food safety. PMID:21067673

Lubran, M B; Pouillot, R; Bohm, S; Calvey, E M; Meng, J; Dennis, S

2010-10-01

250

Direct Observation of Molybdenum Disulfide, MoS2, Domains by Using a Liquid Crystalline Texture Method.  

PubMed

Because the properties of molybdenum disulfide (MoS2) are strongly influenced by the sizes and boundaries of its domains, the direct visualization of large-area MoS2 domains is one of the most important challenges in MoS2 research. In the current study, we developed a simple and rapid method to observe and determine the boundaries of MoS2 domains. The technique, which depends on observations of nematic liquid crystal textures on the MoS2 surface, does not damage the sample and is not limited by domain size. Thus, this approach should significantly aid not only efforts aimed at gaining an understanding of the relationships between grain boundaries and properties of MoS2 but also those focusing on how domain sizes are controlled during large-area synthesis. PMID:25494827

Kim, Dae Woo; Ok, Jong Min; Jung, Woo-Bin; Kim, Jong-Seon; Kim, Seon Joon; Choi, Hyung Ouk; Kim, Yun Ho; Jung, Hee-Tae

2015-01-14

251

Scalable Methods for Electronic Excitations and Optical Responses of Nanstructures: Mathematics to Algorithms to Observables  

SciTech Connect

This multi-investigator project was concerned with the development and application of new methods and computer codes that would allow realistic modeling of nanosystems. Carter's part in this team effort involved two method/algorithm/code development projects during the first 14 months of this grant. Carter's group has been advancing theory and applications of the orbital-free density functional theory (OF-DFT), the only DFT method that exhibits linear scaling for metals. Such a method offers the possibility of simulating large numbers of atoms with quantum mechanics, such that properties of metallic nanostructures (e.g. nanowires of realistic dimensions) could be investigated. In addition, her group has been developing and applying an embedded correlated wavefunction theory for treating localized excited states in condensed matter (including metals). The application of interest here is spin manipulation at the nanoscale, i.e., spintronics, in which local electron excitations interact with the surrounding material. Her embedded correlation method is ideal for studying such problems.

Emily A. Carter

2009-01-23

252

Optical correlation method for studying disperse media  

NASA Astrophysics Data System (ADS)

This paper presents a simple and reproducible optical correlation technique that uses the measurement of the transverse field coherence function in a particle image plane to determine the particle size distribution function of light scattering particles. The method can also be applied to nonspherical particles by using the equivalent particle approximation and the equivalent particle radius in the calculations. Experimental results from characterization of media containing Lycopodium spores, Microcystis aeroginosa cells, and erythrocytes are presented.

Angelsky, O. V.; Maksimyak, P. P.

1993-10-01

253

The ALFA (Activity Log Files Aggregation) Toolkit: A Method for Precise Observation of the Consultation  

PubMed Central

Background There is a lack of tools to evaluate and compare Electronic patient record (EPR) systems to inform a rational choice or development agenda. Objective To develop a tool kit to measure the impact of different EPR system features on the consultation. Methods We first developed a specification to overcome the limitations of existing methods. We divided this into work packages: (1) developing a method to display multichannel video of the consultation; (2) code and measure activities, including computer use and verbal interactions; (3) automate the capture of nonverbal interactions; (4) aggregate multiple observations into a single navigable output; and (5) produce an output interpretable by software developers. We piloted this method by filming live consultations (n = 22) by 4 general practitioners (GPs) using different EPR systems. We compared the time taken and variations during coded data entry, prescribing, and blood pressure (BP) recording. We used nonparametric tests to make statistical comparisons. We contrasted methods of BP recording using Unified Modeling Language (UML) sequence diagrams. Results We found that 4 channels of video were optimal. We identified an existing application for manual coding of video output. We developed in-house tools for capturing use of keyboard and mouse and to time stamp speech. The transcript is then typed within this time stamp. Although we managed to capture body language using pattern recognition software, we were unable to use this data quantitatively. We loaded these observational outputs into our aggregation tool, which allows simultaneous navigation and viewing of multiple files. This also creates a single exportable file in XML format, which we used to develop UML sequence diagrams. In our pilot, the GP using the EMIS LV (Egton Medical Information Systems Limited, Leeds, UK) system took the longest time to code data (mean 11.5 s, 95% CI 8.7-14.2). Nonparametric comparison of EMIS LV with the other systems showed a significant difference, with EMIS PCS (Egton Medical Information Systems Limited, Leeds, UK) (P = .007), iSoft Synergy (iSOFT, Banbury, UK) (P = .014), and INPS Vision (INPS, London, UK) (P = .006) facilitating faster coding. In contrast, prescribing was fastest with EMIS LV (mean 23.7 s, 95% CI 20.5-26.8), but nonparametric comparison showed no statistically significant difference. UML sequence diagrams showed that the simplest BP recording interface was not the easiest to use, as users spent longer navigating or looking up previous blood pressures separately. Complex interfaces with free-text boxes left clinicians unsure of what to add. Conclusions The ALFA method allows the precise observation of the clinical consultation. It enables rigorous comparison of core elements of EPR systems. Pilot data suggests its capacity to demonstrate differences between systems. Its outputs could provide the evidence base for making more objective choices between systems. PMID:18812313

2008-01-01

254

Cerebral Aneurysm Multicenter European Onyx (CAMEO) Trial: Results of a Prospective Observational Study in 20 European Centers  

Microsoft Academic Search

BACKGROUND AND PURPOSE: This study was designed to investigate the safety and efficacy of the Onyx liquid embolic system in treating a selected population of patients with intracranial aneurysms that presented difficulties for surgical or endovascular alternatives. METHODS: A prospective observational study was conducted in 20 European centers enroll- ing a consecutive series of 119 patients with 123 aneurysms judged

Andrew J. Molyneux; Saruhan Cekirge; Isil Saatci; Gyula Gal

255

Study Methods to Standardize Thermography NDE  

NASA Technical Reports Server (NTRS)

The purpose of this work is to develop thermographic inspection methods and standards for use in evaluating structural composites and aerospace hardware. Qualification techniques and calibration methods are investigated to standardize the thermographic method for use in the field. Along with the inspections of test standards structural hardware, support hardware is designed and fabricated to aid in the thermographic process. Also, a standard operating procedure is developed for performing inspections with the Bales Thermal Image Processor (TIP). Inspections are performed on a broad range of structural composites. These materials include various graphite/epoxies, graphite/cyanide-ester, graphite/silicon-carbide, graphite phenolic and Keviar/epoxy. Also metal honeycomb (titanium and aluminum faceplates over an aluminum honeycomb core) structures are investigated. Various structural shapes are investigated and the thickness of the structures vary from as few as 3 plies to as many as 80 plies. Special emphasis is placed on characterizing defects in attachment holes and bondlines, in addition to those resulting from impact damage and the inclusion of foreign matter. Image processing through statistical analysis and digital filtering is investigated to enhance the quality and quantify the NDE thermal images when necessary.

Walker, James L.; Workman, Gary L.

1998-01-01

256

Using a Two-Staged Propensity Score Matching Strategy and Multilevel Modeling to Estimate Treatment Effects in a Multisite Observational Study  

ERIC Educational Resources Information Center

The study is designed to demonstrate and test the utility of the proposed two-stage matching method compared to other analytic methods traditionally employed for multisite observational studies. More specifically, the study addresses the following research questions: (1) How do different specifications of the matching method influence covariate…

Rickles, Jordan H.

2012-01-01

257

Experimental and Observational Data in the Study of Interlanguage Pragmatics.  

ERIC Educational Resources Information Center

A study compared (1) data on rejections of advice by native and non-native speakers collected from natural conversation with (2) data collected from a discourse completion task (DCT). Subjects were students in an academic advising session (13 native speakers, 11 non-native speakers of English) who responded to a DCT and students (18 native…

Hartford, Beverly S.; Bardovi-Harlig, Kathleen

1992-01-01

258

Ocean observing satellite study: instrument and satellite constellation architecture options  

NASA Technical Reports Server (NTRS)

This paper provides: (1) an overview of the set of active and passive instruments identified by the IPO designed to make the ocean measurements including visible and infrared medium and high resolution imagers, radiometers, altimeters, and synthetic aperture radars and (2) the instrument and satellite constellation architecture options studied, and their ability to meet the set of measurement requirements.

Gerber, A. J.; McGuire, J.; Cunningham, J. D.; Pichel, W. G.

2002-01-01

259

Observational Study on Initiation and Acceleration of Coronal Mass Ejections  

NASA Technical Reports Server (NTRS)

During the performance period, we have successfully carried out all the tasks and fulfilled all the scientific objectives outlined in the proposal, which are about building a C1 Ch4E catalog and studying CME accelerations in both inner and outer corona.

Zhang, Jie

2005-01-01

260

Staff Reactions to Challenging Behaviour: An Observation Study  

ERIC Educational Resources Information Center

Staff reactions play an important role in the development and maintaining of clients' challenging behaviour. Because there is a paucity of research on staff reactions in naturalistic settings, this study examined sequential associations between challenging behaviour and staff reactions by means of a descriptive analysis. We analysed video…

Lambrechts, Greet; Van Den Noortgate, Wim; Eeman, Lieve; Maes, Bea

2010-01-01

261

OBSERVATIONS ON THE STATE OF MARINE DISEASE STUDIES  

EPA Science Inventory

State of marine disease studies is described. erhaps the greatest area of success in the last 20 years has been in the identification and characterization of viruses, bacteria, fungi, protozoan and metazoan disease agents. pening of new areas of investigation such as that of inte...

262

Trauma airway management in emergency departments: a multicentre, prospective, observational study in Japan  

PubMed Central

Objectives Although successful airway management is essential for emergency trauma care, comprehensive studies are limited. We sought to characterise current trauma care practice of airway management in the emergency departments (EDs) in Japan. Design Analysis of data from a prospective, observational, multicentre registry—the Japanese Emergency Airway Network (JEAN) registry. Setting 13 academic and community EDs from different geographic regions across Japan. Participants 723 trauma patients who underwent emergency intubation from March 2010 through August 2012. Outcome measures ED characteristics, patient and operator demographics, methods of airway management, intubation success or failure at each attempt and adverse events. Results A total of 723 trauma patients who underwent emergency intubation were eligible for the analysis. Traumatic cardiac arrest comprised 32.6% (95% CI 29.3% to 36.1%) of patients. Rapid sequence intubation (RSI) was the initial method chosen in 23.9% (95% CI 21.0% to 27.2%) of all trauma patients and in 35.5% (95% CI 31.4% to 39.9%) of patients without cardiac arrest. Overall, intubation was successful in ?3 attempts in 96% of patients (95% CI 94.3% to 97.2%). There was a wide variation in the initial methods of intubation; RSI as the initial method was performed in 0–50.9% of all trauma patients among 12 EDs. Similarly, there was a wide variation in success rates and adverse event rates across the EDs. Success rates varied between 35.5% and 90.5% at the first attempt, and 85.1% and 100% within three attempts across the 12 EDs. Conclusions In this multicentre prospective study in Japan, we observed a high overall success rate in airway management during trauma care. However, the methods of intubation and success rates were highly variable among hospitals. PMID:25652800

Nakao, Shunichiro; Kimura, Akio; Hagiwara, Yusuke; Hasegawa, Kohei

2015-01-01

263

A Dynamic Scheduling Method of Earth-Observing Satellites by Employing Rolling Horizon Strategy  

PubMed Central

Focused on the dynamic scheduling problem for earth-observing satellites (EOS), an integer programming model is constructed after analyzing the main constraints. The rolling horizon (RH) strategy is proposed according to the independent arriving time and deadline of the imaging tasks. This strategy is designed with a mixed triggering mode composed of periodical triggering and event triggering, and the scheduling horizon is decomposed into a series of static scheduling intervals. By optimizing the scheduling schemes in each interval, the dynamic scheduling of EOS is realized. We also propose three dynamic scheduling algorithms by the combination of the RH strategy and various heuristic algorithms. Finally, the scheduling results of different algorithms are compared and the presented methods in this paper are demonstrated to be efficient by extensive experiments. PMID:23690742

Dishan, Qiu; Chuan, He; Jin, Liu; Manhao, Ma

2013-01-01

264

Impact of peer feedback on the performance of lecturers in emergency medicine: a prospective observational study.  

PubMed

BackgroundAlthough it is often criticised, the lecture remains a fundamental part of medical training because it is an economical and efficient method for teaching both factual and experimental knowledge. However, if administered incorrectly, it can be boring and useless.Feedback from peers is increasingly recognized as an effective method of encouraging self-reflection and continuing professional development. The aim of this observational study is to analyse the impact of written peer feedback on the performance of lecturers in an emergency medicine lecture series for undergraduate students.MethodsIn this prospective study, 13 lecturers in 15 lectures on emergency medicine for undergraduate medical students were videotaped and analysed by trained peer reviewers using a 21-item assessment instrument. The lecturers received their written feedback prior to the beginning of the next years¿ lecture series and were assessed in the same way.ResultsIn this study, we demonstrated a significant improvement in the lecturers¿ scores in the categories `content and organisation¿ and `visualisation¿ in response to written feedback. The highest and most significant improvements after written peer feedback were detected in the items `provides a brief outline¿, `provides a conclusion for the talk¿ and `clearly states goal of the talk¿.ConclusionThis study demonstrates the significant impact of a single standardized written peer feedback on a lecturer¿s performance. PMID:25472430

Ruesseler, Miriam; Kalozoumi-Paizi, Faidra; Schill, Anna; Knobe, Matthias; Byhahn, Christian; Müller, Michael P; Marzi, Ingo; Walcher, Felix

2014-12-01

265

Automated Parameter Studies Using a Cartesian Method  

NASA Technical Reports Server (NTRS)

Computational Fluid Dynamics (CFD) is now routinely used to analyze isolated points in a design space by performing steady-state computations at fixed flight conditions (Mach number, angle of attack, sideslip), for a fixed geometric configuration of interest. This "point analysis" provides detailed information about the flowfield, which aides an engineer in understanding, or correcting, a design. A point analysis is typically performed using high fidelity methods at a handful of critical design points, e.g. a cruise or landing configuration, or a sample of points along a flight trajectory.

Murman, Scott M.; Aftosimis, Michael J.; Nemec, Marian

2004-01-01

266

Study of the low latitude ionospheric turbulence observed by DEMETER  

NASA Astrophysics Data System (ADS)

Following previous works from Molchanov et al 2002a 2002b 2004a 2004b and Hobara et al 2005 data bases dedicated to the systematic analysis of the power and spectral indices of the electric field have been elaborated Two data bases are considered one for the survey mode and the other for the burst mode For the survey mode estimations of the turbulence parameters are performed from the 8 first Fourier components of the averaged power spectra 0-150 Hz frequency band A single slope power law model f - alpha is assumed A quality factor allows to test that hypothesis For the burst mode the power spectra are derived from the waveforms One and two slope models are systematically tested Results are presented and the possibility to use these data bases for correlation with seismic activity is discussed Y Hobara F Lefeuvre M Parrot and O A Molchanov Low-latitude ionospheric turbulence observed by Aureol-3 satellite Annales Geophysicae 23 1259--1270 2005 Molchanov O A Hayakawa M Afonin V V Akentieva O A and Mareev E A Possible influence of seismicity by gravity waves on ionospheric equatorial anomaly from data of IK-24 satellite 1 Search for idea of seismo-ionosphere coupling Seismo Electromagnetics Lithosphere-Atmosphere-Ionosphere Coupling edited by Hayakawa M and Molchanov O A TERRAPUB Tokyo 275--285 2002a Molchanov O A Hayakawa M Afonin V V Akentieva O A Mareev E A and Trakhtengerts V Yu Possible influence of seismicity by gravity waves on ionospheric

Li, F.; Lefeuvre, F.; Parrot, M.

267

A new method of observing weak extended x-ray sources with RHESSI  

E-print Network

We present a new method, fan-beam modulation, for observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). This space-based solar x-ray and gamma-ray telescope has much greater sensitivity than previous experiments in the 3-25 keV range, but is normally not well suited to detecting extended sources since their signal is not modulated by RHESSI's rotating grids. When the spacecraft is offpointed from the target source, however, the fan-beam modulation time-modulates the transmission by shadowing resulting from exploiting the finite thickness of the grids. In this paper we detail how the technique is implemented and verify its consistency with sources with clear known signals that have occurred during RHESSI offpointing: microflares and the Crab Nebula. In both cases the results are consistent with previous and complementary measurements. Preliminary work indicates that this new technique allows RHESSI to observe the integrated hard x-ray spectrum of weak extended sources on the quiet Sun.

Iain G. Hannah; Gordon J. Hurford; Hugh S. Hudson; Robert P. Lin

2007-02-08

268

Observing power blackouts from space - A disaster related study  

NASA Astrophysics Data System (ADS)

In case of emergency disaster managers worldwide require immediate information on affected areas and estimations of the number of affected people. Natural disasters such as earthquakes, hurricanes, tornados, wind and ice storms often involve failures in the electrical power generation system and grid. Near real time identification of power blackouts gives a first impression of the area affected by the event (Elvidge et al. 2007), which can subsequently be linked to population estimations. Power blackouts disrupt societal activities and compound the difficulties associated with search and rescue, clean up, and the provision of food and other supplies following a disastrous event. Locations and spatial extents of power blackouts are key considerations in planning and execution of the primary disaster missions of emergency management organizations. To date only one satellite data source has been used successfully for the detection of power blackouts. Operated by NOAA's National Geophysical Data Center (NGDC) the U.S. Air Force Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) offers a unique capability to observe lights present at the Earth's surface at night. Including a pair of visible and thermal spectral bands and originally designed to detect moonlit clouds, this sensor enables mapping of lights from cities and towns, gas flares and offshore platforms, fires, and heavily lit fishing boats. The low light imaging of the OLS is accomplished using a photomultiplier tube (PMT) which intensifies the visible band signal at night. With 14 orbits collected per day and a 3.000 km swath width, each OLS is capable of collecting a complete set of images of the Earth every 24 hours. NGDC runs the long-term archive for OLS data with the digital version extending back to 1992. OLS data is received by NGDC in near real time (1-2 hours from acquisition) and subscription based services for the near real time data are provided for users all over the world. Elvidge et al. (1998) first demonstrated that under certain conditions a detection of power outages is possible using OLS data. A standard procedure for visual detection of power outages has been developed. The procedure is based on identifying locations where consistently observed lighting is missing or reduced following a disaster event. Visible and thermal spectral bands of the event-related OLS data are compared to a recent cloud-free composite of nighttime lights by producing a color (RGB) composite image. For the cloud-free nighttime lights composite serving as reference information both monthly and annual composites can be used, depending on the respective availability and suitability of OLS data. The RGB color composite uses the reference lights as red (R), the current visible band as green (G) and the current thermal band as blue (B). The thermal band is typically inverted to make clouds appear bright. As clouds are typically colder than the surface of the Earth, in the thermal band higher values are observed on cloud-free areas, which thus appear brighter in standard visualization modes. The resulting color composite is visually interpreted to identify power outages, which show up as red lights on a dark (cloud-free) background. Red color stands for high values in the reference data (red band of the RGB composite) compared to low values in the event data (green and blue bands of the RGB composite), thus showing the disaster-related absence or reduction of lighting. Heavy cloud cover also obscures lights, resulting in red lights on a blue background. Yellow color in the RGB composite indicates areas where the lights are on, i.e. both red and green band (reference composite and visible band of the event image) feature high values with no cloud cover present (low values in the blue band). Under ideal conditions the presented procedure detects individual cities and towns where power has been lost or has been reduced. Conditions reducing or eliminating the capability of detecting power blackouts in OLS data have been identified (e.g. sunlight, heavy

Aubrecht, C.; Elvidge, C. D.; Ziskin, D.; Baugh, K. E.; Tuttle, B.; Erwin, E.; Kerle, N.

2009-04-01

269

Xenon consumption during general surgery: a retrospective observational study  

PubMed Central

Background High costs still limits the widespread use of xenon in the clinical practice. Therefore, we evaluated xenon consumption of different delivery modes during general surgery. Methods A total of 48 patients that underwent general surgery with balanced xenon anaesthesia were retrospectively analysed according to the mode of xenon delivery during maintenance phase (ECO mode, AUTO mode or MANUAL mode). Results Xenon consumption was highest during the wash-in phase (9.4?±?2.1l) and further decreased throughout maintenance of anaesthesia. Comparison of different xenon delivery modes revealed significant reduced xenon consumption during ECO mode (18.5?±?3.7L (ECO) vs. 24.7?±?11.5L (AUTO) vs. 29.6?±?14.3L (MANUAL); p?=?0.033). No differences could be detected with regard to anaesthetic depth, oxygenation or performance of anaesthesia. Conclusion The closed-circuit respirator Felix Dual offers effective reduction of xenon consumption during general surgery when ECO mode is used. PMID:23758970

2013-01-01

270

Gender differences in young children’s temperament traits: Comparisons across observational and parent-report methods  

PubMed Central

Objective Evidence supporting the continuity between child temperament and adult personality traits is accumulating. One important indicator of continuity is the presence of reliable gender differences in traits across the lifespan. A substantial literature demonstrates gender differences on certain adult personality traits and recent meta-analytic work on child samples suggests similar gender differences for some broad and narrow domains of temperament. However, most existing studies of children rely only on parent-report measures. The present study investigated gender differences in temperament traits assessed by laboratory observation, maternal-report, and paternal-report measures. Methods Across three independent samples, behavioral observations, maternal-report, and paternal-report measures of temperament were collected on 463 boys and 402 girls. Results Across all three methods, girls demonstrated higher positive affect and fear and lower activity level than boys. For laboratory measures, girls demonstrated higher levels of sociability and lower levels of overall negative emotionality (NE), sadness, anger and impulsivity than boys. However, girls demonstrated higher levels of overall NE and sadness than boys when measured by maternal reports. Finally, girls demonstrated lower levels of sociability based on paternal reports. Conclusions Results are discussed in relation to past meta-analytic work and developmental implications of the findings. PMID:22924826

Olino, Thomas M.; Durbin, C. Emily; Klein, Daniel N.; Hayden, Elizabeth P.; Dyson, Margaret W.

2012-01-01

271

Atmospheric correction of Earth-observation remote sensing images by Monte Carlo method  

NASA Astrophysics Data System (ADS)

In earth observation, the atmospheric particles contaminate severely, through absorption and scattering, the reflected electromagnetic signal from the earth surface. It will be greatly beneficial for land surface characterization if we can remove these atmospheric effects from imagery and retrieve surface reflectance that characterizes the surface properties with the purpose of atmospheric correction. Giving the geometric parameters of the studied image and assessing the parameters describing the state of the atmosphere, it is possible to evaluate the atmospheric reflectance, and upward and downward transmittances which take part in the garbling data obtained from the image. To that end, an atmospheric correction algorithm for high spectral resolution data over land surfaces has been developed. It is designed to obtain the main atmospheric parameters needed in the image correction and the interpretation of optical observations. It also estimates the optical characteristics of the Earth-observation imagery (LANDSAT and SPOT). The physics underlying the problem of solar radiation propagations that takes into account multiple scattering and sphericity of the atmosphere has been treated using Monte Carlo techniques.

Hadjit, Hanane; Oukebdane, Abdelaziz; Belbachir, Ahmad Hafid

2013-10-01

272

Inferring CO2 sources and sinks from satellite observations: Method and application to TOVS data  

NASA Astrophysics Data System (ADS)

Properly handling satellite data to constrain the inversion of CO2 sources and sinks at the Earth surface is a challenge motivated by the limitations of the current surface observation network. In this paper we present a Bayesian inference scheme to tackle this issue. It is based on the same theoretical principles as most inversions of the flask network but uses a variational formulation rather than a pure matrix-based one in order to cope with the large amount of satellite data. The minimization algorithm iteratively computes the optimum solution to the inference problem as well as an estimation of its error characteristics and some quantitative measures of the observation information content. A global climate model, guided by analyzed winds, provides information about the atmospheric transport to the inversion scheme. A surface flux climatology regularizes the inference problem. This new system has been applied to 1 year's worth of retrievals of vertically integrated CO2 concentrations from the Television Infrared Observation Satellite Operational Vertical Sounder (TOVS). Consistent with a recent study that identified regional biases in the TOVS retrievals, the inferred fluxes are not useful for biogeochemical analyses. In addition to the detrimental impact of these biases, we find a sensitivity of the results to the formulation of the prior uncertainty and to the accuracy of the transport model. Notwithstanding these difficulties, four-dimensional inversion schemes of the type presented here could form the basis of multisensor data assimilation systems for the estimation of the surface fluxes of key atmospheric compounds.

Chevallier, F.; Fisher, M.; Peylin, P.; Serrar, S.; Bousquet, P.; BréOn, F.-M.; ChéDin, A.; Ciais, P.

2005-12-01

273

Attention-Deficit/Hyperactivity Disorder Drugs and Growth: An Italian Prospective Observational Study  

PubMed Central

Abstract Objective This study was conducted to assess the long-term effect of methylphenidate (MPH) or atomoxetine (ATX) on growth in attention-deficit/hyperactivity disorder (ADHD) drug-naïve children. Design The study was an observational, post-marketing, fourth phase study. Methods Data on height and weight were collected at baseline and every 6 months up to 24 months. Results Both ATX and MPH lead to decreased height gain (assessed by means of z-scores); the effect was significantly higher for ATX than for MPH. At any time, height z-score decrease in the ATX group was higher than the corresponding decrease observed in the MPH group, but the difference was significantly relevant only during the first year of treatment. An increment of average weight was observed both in patients treated with MPH and in those treated with ATX. However, using Tanner's percentile, a subset of patients showed a degree of growth lower than expected. This negative effect was significantly higher for ATX than for MPH. Conclusions We conclude that ADHD drugs show a negative effect on linear growth in children in middle term. Such effect appears more evident for ATX than for MPH. PMID:24024538

Germinario, Elena A.P.; Arcieri, Romano; Bonati, Maurizio; Zuddas, Alessandro; Masi, Gabriele; Vella, Stefano; Chiarotti, Flavia

2013-01-01

274

Sexual dysfunction (K?cchra Vyav?ya) in obesity (Sthaulya): Validation by an observational study  

PubMed Central

Objective: The present study intends to evaluate the relationship between Sthaulya (obesity) and K?cchra Vyav?ya (sexual dysfunction) with respect to different phases of sexual intercourse through a single-centered, observational study in male patients of obesity. Materials and Methods: The study involved 33 obese males from the outpatient department of the Institution whose sexual functioning was assessed using an International Index of Erectile Function questionnaire, which was meant to assess five specific areas of sexual functioning. Results: A varying degree of sexual dysfunction was observed in four out of five areas of sexual functioning viz. erectile function (P < 0.02), orgasmic function (P < 0.02), sexual desire (P < 0.08), and overall satisfaction (P < 0.000) in obese individuals. Statistically significant dysfunction was not observed in intercourse satisfaction. Conclusions: Varying degree of sexual dysfunction is present in obese males, suggesting that obesity has a possible role in reducing the quality of sexual functioning in males as indicated in the classical ayurvedic literature. PMID:24167331

Geetha, Parampalli; Aravind, B.S.; Pallavi, G.; Rajendra, V.; Rao, Radhakrishna; Akhtar, Naseema

2012-01-01

275

Drug and alcohol misuse in first episode psychosis: An observational study  

PubMed Central

Background There have been very few observational studies of drug and alcohol misuse in first-episode psychosis in the UK. Method Using an observational database of first episode psychosis in Northumberland, a county in Northern England, information on patients aged 16 to 36 years were collected at presentation and annual follow-up between October 1998 and October 2005. Patterns of drug and alcohol misuse were compared using hospitalization as an outcome measure, and violence rates were examined retrospectively. Results Drug misuse without alcohol misuse was associated with a highly significant increase in hospital days. An alcohol problem, either with or without coexisting drug misuse, was not predictive of increased hospital days. Drug and alcohol misuse together was associated with violence. Conclusions This paper lends some support to those Early Intervention in Psychosis (EIP) teams currently advising patients that drug misuse may have a greater impact than alcohol use on the outcome of first-episode psychosis. PMID:18728795

Crebbin, Kathleen; Mitford, Emma; Paxton, Roger; Turkington, Douglas

2008-01-01

276

cAMP signaling microdomains and their observation by optical methods  

PubMed Central

The second messenger cyclic AMP (cAMP) is a major intracellular mediator of many hormones and neurotransmitters and regulates a myriad of cell functions, including synaptic plasticity in neurons. Whereas cAMP can freely diffuse in the cytosol, a growing body of evidence suggests the formation of cAMP gradients and microdomains near the sites of cAMP production, where cAMP signals remain apparently confined. The mechanisms responsible for the formation of such microdomains are subject of intensive investigation. The development of optical methods based on fluorescence resonance energy transfer (FRET), which allow a direct observation of cAMP signaling with high temporal and spatial resolution, is playing a fundamental role in elucidating the nature of such microdomains. Here, we will review the optical methods used for monitoring cAMP and protein kinase A (PKA) signaling in living cells, providing some examples of their application in neurons, and will discuss the major hypotheses on the formation of cAMP/PKA microdomains. PMID:25389388

Calebiro, Davide; Maiellaro, Isabella

2014-01-01

277

A Hilbert transform method for parameter identification of time-varying structures with observer techniques  

NASA Astrophysics Data System (ADS)

This paper presents a recursive Hilbert transform method for the time-varying property identification of large-scale shear-type buildings with limited sensor deployments. An observer technique is introduced to estimate the building responses from limited available measurements. For an n-story shear-type building with l measurements (l ? n), the responses of other stories without measurements can be estimated based on the first r mode shapes (r ? l) as-built conditions and l measurements. Both the measured responses and evaluated responses and their Hilbert transforms are then used to track any variation of structural parameters of a multi-story building over time. Given floor masses, both the stiffness and damping coefficients of the building are identified one-by-one from the top to the bottom story. When variations of parameters are detected, a new developed branch-and-bound technique can be used to update the first r mode shapes with the identified parameters. A 60-story shear building with abruptly varying stiffness at different floors is simulated as an example. The numerical results indicate that the proposed method can detect variations of the parameters of large-scale shear-type buildings with limited sensor deployments at appropriate locations.

Wang, Zuo-Cai; Ren, Wei-Xin; Chen, Gen-Da

2012-10-01

278

Thermoacoustic CT of the breast: pilot study observations  

NASA Astrophysics Data System (ADS)

In order to assess the potential clinical utility of using thermoacoustic computer tomography (TCT) to image the breast, we conducted a retrospective pilot study of 78 patients. We recruited patients in three age groups (<40,40-50,>50 years). The study population was further segregated into normal and suspicious based on the results of the previous x-ray mammography and ultrasound. Image quality was evaluated qualitatively by consensus of two trained mammographers using a 4-point scale. The appearance of normal anatomy, cysts, benign disease and cancer was noted. Patients were also asked to rate the comfort of the TCT exam and to indicate a personal preference for x-ray mammography or TCT. Analysis of the data indicated that TCT image quality was dependent upon both patient age and breast density, improving with both increasing breast density and decreasing patient age. Fibrocystic disease was well seen, cysts appearing as areas of low RF absorption. Fibroadenomas did not demonstrate contrast enhancement with the exception of one patient with associated atypical hyperplasia. Cancer displayed higher RF absorption than surrounding tissues in 4/7 patients in whom cancer was confirmed, including one patient with a 7-mm ductal carcinoma in situ (DCIS).

Kruger, Robert A.; Kiser, William L., Jr.; Romilly, A. P.; Scmidt, Phyllis

2001-06-01

279

An observational and theoretical study of Colorado lee cyclogenesis  

NASA Technical Reports Server (NTRS)

A cyclogenesis event that occurred over Colorado in early March of 1981 is the focus of this study. Two features that seemed to play a role in storm initiation were a traveling upper troposphere disturbance associated with an undulation on the subtropical front and a warm-cored shallow surface trough that was guided along the eastern slope of the Rockies from Canada to Colorado. The arrival of the latter feature initiated a sudden shift of the surface flow from upslope to downslope on the eastern side of the continental divide. A time-dependent quasi-geostrophic model was used to study the interaction of the traveling short wave and a broad topographic surface ridge in the presence of a baroclinic mainly westerly background flow. Westerly and easterly background surface winds were used to determine whether the surface trough arrival had any influence on the vigor of lee cyclogenesis initiated by the upper troposphere short-wave trough. With surface westerlies rapid cyclogenesis occurred, while with surface easterlies little cyclogenesis was found to the east of the Rockies. Thus, the shallow surface trough's arrival seemed to be crucial to storm initiation. These findings were based on a linear model. It is shown, however, that the height of the Rockies necessitates the inclusion of finite amplitude effects associated with the lower boundary into the model.

Clark, John H. E.

1990-01-01

280

[Studies on male infertility: 6. Clinical observation on male infertility].  

PubMed

Results of clinical observations of male infertility cases seen in S eoul, Korea, National University's Department of Urology between January 1955 and December 1969 are presented. 920 infertile men were seen, repr esenting 3.2% of 36,071 urological outpatients, and 3.9% of 30,125 male outpatients seen during this 15-year period. The number of male inferti lity cases has increased from 10 (1.09%) cases in 1955 to 166 (18.04%) cases in 1969. Primary sterility was found in 78% of the 920 infertile cases in 1969. Primary sterility was found in 22%. The ages of the infertile men ranged from 24 to 61 years (mean=35); the ages of their sp ouses ranged from 24 to 49 years (mean=32). Infertile marital life ranged from 1 to 40 years (mean=7). The duration of infertility cases seen between 1955 and 1959 was 10 years, between 1960 and 1964, 8 years; and between 1965 and 1969, 6 years. There was no close correlation between incidence of infertility and occupation (290 cases were white-collar workers and 414 were physical laborers). Etiological classifications indicate that 40% of the male infertility cases were due to faulty spermatogenesis, 21% due to faulty transportation, 14% due to faulty seminal composition, .5% due to faulty ejaculation, and 24% from unknown causes. In 840 cases where semen was analyzed, 51% had azoospermia, 34% had oligospermia, and 7% had normospermia. In 41 cases analysis revealed normal semen, however, no children have been conceived in 3 years. Testicular biopsies of azoospermias revealed 30% hypospermatogenesis, 27% germinal aplasia, 20% germinal cell arrest, 11% efferent duct occlusion, 9% peritubular fibrosis, and 3% normospermatogenesis. There was no significant difference in average frequency of sexual intercourse between fertile and infertile couples. Medical treatment combined with various drugs (e.g., testosterone, vitamedine) for 3-12 months was most effective in oligospermia (52 out of 101 cases) and azoospermia (13 out of 126 cases). In 22 cases of bilateral epididymal obstruction treated by epidiymovasostomy, viable sperm appeared in the ejaculates of 9. Vasovasostomy performed on 85 previously vasectomized men yielded successful results in 62 of 71 azoospermia cases in which the semen could be repeatedly examined. PMID:12177911

Lee, H Y

1970-12-01

281

A New Method to Constrain Supernova Fractions Using X-Ray Observations of Clusters of Galaxies  

NASA Astrophysics Data System (ADS)

Supernova (SN) explosions enrich the intracluster medium (ICM) both by creating and dispersing metals. We introduce a method to measure the number of SNe and relative contribution of Type Ia supernovae (SNe Ia) and core-collapse supernovae (SNe cc) by directly fitting X-ray spectral observations. The method has been implemented as an XSPEC model called snapec. snapec utilizes a single-temperature thermal plasma code (apec) to model the spectral emission based on metal abundances calculated using the latest SN yields from SN Ia and SN cc explosion models. This approach provides a self-consistent single set of uncertainties on the total number of SN explosions and relative fraction of SN types in the ICM over the cluster lifetime by directly allowing these parameters to be determined by SN yields provided by simulations. We apply our approach to XMM-Newton European Photon Imaging Camera (EPIC), Reflection Grating Spectrometer (RGS), and 200 ks simulated Astro-H observations of a cooling flow cluster, A3112. We find that various sets of SN yields present in the literature produce an acceptable fit to the EPIC and RGS spectra of A3112. We infer that 30.3% ± 5.4% to 37.1% ± 7.1% of the total SN explosions are SNe Ia, and the total number of SN explosions required to create the observed metals is in the range of (1.06 ± 0.34) × 109 to (1.28 ± 0.43) × 109, from snapec fits to RGS spectra. These values may be compared to the enrichment expected based on well-established empirically measured SN rates per star formed. The proportions of SNe Ia and SNe cc inferred to have enriched the ICM in the inner 52 kpc of A3112 is consistent with these specific rates, if one applies a correction for the metals locked up in stars. At the same time, the inferred level of SN enrichment corresponds to a star-to-gas mass ratio that is several times greater than the 10% estimated globally for clusters in the A3112 mass range.

Bulbul, Esra; Smith, Randall K.; Loewenstein, Michael

2012-07-01

282

A NEW METHOD TO CONSTRAIN SUPERNOVA FRACTIONS USING X-RAY OBSERVATIONS OF CLUSTERS OF GALAXIES  

SciTech Connect

Supernova (SN) explosions enrich the intracluster medium (ICM) both by creating and dispersing metals. We introduce a method to measure the number of SNe and relative contribution of Type Ia supernovae (SNe Ia) and core-collapse supernovae (SNe cc) by directly fitting X-ray spectral observations. The method has been implemented as an XSPEC model called snapec. snapec utilizes a single-temperature thermal plasma code (apec) to model the spectral emission based on metal abundances calculated using the latest SN yields from SN Ia and SN cc explosion models. This approach provides a self-consistent single set of uncertainties on the total number of SN explosions and relative fraction of SN types in the ICM over the cluster lifetime by directly allowing these parameters to be determined by SN yields provided by simulations. We apply our approach to XMM-Newton European Photon Imaging Camera (EPIC), Reflection Grating Spectrometer (RGS), and 200 ks simulated Astro-H observations of a cooling flow cluster, A3112. We find that various sets of SN yields present in the literature produce an acceptable fit to the EPIC and RGS spectra of A3112. We infer that 30.3% {+-} 5.4% to 37.1% {+-} 7.1% of the total SN explosions are SNe Ia, and the total number of SN explosions required to create the observed metals is in the range of (1.06 {+-} 0.34) Multiplication-Sign 10{sup 9} to (1.28 {+-} 0.43) Multiplication-Sign 10{sup 9}, from snapec fits to RGS spectra. These values may be compared to the enrichment expected based on well-established empirically measured SN rates per star formed. The proportions of SNe Ia and SNe cc inferred to have enriched the ICM in the inner 52 kpc of A3112 is consistent with these specific rates, if one applies a correction for the metals locked up in stars. At the same time, the inferred level of SN enrichment corresponds to a star-to-gas mass ratio that is several times greater than the 10% estimated globally for clusters in the A3112 mass range.

Bulbul, Esra; Smith, Randall K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Loewenstein, Michael, E-mail: ebulbul@cfa.harvard.edu [CRESST and X-Ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States)

2012-07-01

283

A New Method to Constrain Supernova Fractions Using X-ray Observations of Clusters of Galaxies  

NASA Technical Reports Server (NTRS)

Supernova (SN) explosions enrich the intracluster medium (ICM) both by creating and dispersing metals. We introduce a method to measure the number of SNe and relative contribution of Type Ia supernovae (SNe Ia) and core-collapse supernovae (SNe cc) by directly fitting X-ray spectral observations. The method has been implemented as an XSPEC model called snapec. snapec utilizes a single-temperature thermal plasma code (apec) to model the spectral emission based on metal abundances calculated using the latest SN yields from SN Ia and SN cc explosion models. This approach provides a self-consistent single set of uncertainties on the total number of SN explosions and relative fraction of SN types in the ICM over the cluster lifetime by directly allowing these parameters to be determined by SN yields provided by simulations. We apply our approach to XMM-Newton European Photon Imaging Camera (EPIC), Reflection Grating Spectrometer (RGS), and 200 ks simulated Astro-H observations of a cooling flow cluster, A3112.We find that various sets of SN yields present in the literature produce an acceptable fit to the EPIC and RGS spectra of A3112. We infer that 30.3% plus or minus 5.4% to 37.1% plus or minus 7.1% of the total SN explosions are SNe Ia, and the total number of SN explosions required to create the observed metals is in the range of (1.06 plus or minus 0.34) x 10(exp 9), to (1.28 plus or minus 0.43) x 10(exp 9), fromsnapec fits to RGS spectra. These values may be compared to the enrichment expected based on well-established empirically measured SN rates per star formed. The proportions of SNe Ia and SNe cc inferred to have enriched the ICM in the inner 52 kiloparsecs of A3112 is consistent with these specific rates, if one applies a correction for the metals locked up in stars. At the same time, the inferred level of SN enrichment corresponds to a star-to-gas mass ratio that is several times greater than the 10% estimated globally for clusters in the A3112 mass range.

Bulbul, Esra; Smith, Randall K.; Loewenstein, Michael

2012-01-01

284

An observational study of a shallow gravity current triggered by katabatic flow  

NASA Astrophysics Data System (ADS)

Observations from a wind profiler and a meteorological tower are utilized to study the evolution of a gravity current that passed over the Meteorological Research Institute's (MRI) field site in Tsukuba, Japan. The gravity current was created by katabatic flow originating on the mountainous slopes west of the field site. The passage of the shallow current was marked by a pronounced pressure disturbance and was accompanied by vertical circulations seen in the tower and profiler data. Direct vertical-beam measurements are difficult, especially at low heights during high-gradient events like density currents. In this study vertical velocities from the profiler are derived from the four oblique beams by use of the Minimizing the Variance of the Differences (MVD) method. The vertical velocities derived from the MVD method agree well with in situ vertical velocities measured by a sonic anemometer on the tower. The gravity current is analyzed with surface observations, the wind profiler/RASS and tower-mounted instruments. Observations from the profiler/RASS and the tower-mounted instruments illustrate the structure of the gravity current in both wind and temperature fields. The profiler data reveal that there were three regions of waves in the vertical velocity field: lee-type waves, a solitary wave and Kelvin-Helmholtz waves. The lee-type waves in the head region of the gravity current seem to have been generated by the gravity current acting as an obstacle to prefrontal flow. The solitary wave was formed from the elevated head of the gravity current that separated from the feeder flow. Profiler vertical-motion observations resolve this wave and enable us to classify it as a Benjamin-Davis-Ono (BDO) type solitary wave. The ducting mechanism that enabled the solitary wave to propagate is also revealed from the wind profiler/RASS measurements. The combination of high-resolution instruments at the MRI site allow us to develop a uniquely detailed picture of a shallow gravity current structure.

Adachi, A.; Clark, W.; Hartten, L.; Gage, K.; Kobayashi, T.

2004-11-01

285

Acid suppressive drugs and gastric cancer: A meta-analysis of observational studies  

PubMed Central

AIM: To evaluate the association between acid suppressive drug use and the development of gastric cancer. METHODS: A systematic search of relevant studies that were published through June 2012 was conducted using the MEDLINE (PubMed), EMBASE, and Cochrane Library databases. The search included observational studies on the use of histamine 2-receptor antagonists (H2RAs) or proton pump inhibitors and the associated risk of gastric cancer, which was measured using the adjusted odds ratio (OR) or the relative risk and 95%CI. An independent extraction was performed by two of the authors, and a consensus was reached. RESULTS: Of 4595 screened articles, 11 observational studies (n = 94558) with 5980 gastric cancer patients were included in the final analyses. When all the studies were pooled, acid suppressive drug use was associated with an increased risk of gastric cancer risk (adjusted OR = 1.42; 95%CI: 1.29-1.56, I2 = 48.9%, P = 0.034). The overall risk of gastric cancer increased among H2RA users (adjusted OR = 1.40; 95%CI: 1.24-1.59, I2 = 59.5%, P = 0.008) and PPI users (adjusted OR = 1.39; 95%CI: 1.19-1.64, I2 = 0.0%, P = 0.377). CONCLUSION: Acid suppressive drugs are associated with an increased risk of gastric cancer. Further studies are needed to test the effect of acid suppressive drugs on gastric cancer. PMID:23674860

Ahn, Jeong Soo; Eom, Chun-Sick; Jeon, Christie Y; Park, Sang Min

2013-01-01

286

Control of a Non Observable Double Inverted Pendulum Using a Novel Active Learning Method Based State Estimator  

Microsoft Academic Search

In this paper a novel fuzzy approach exploiting Active Learning Method is employed in order to estimate the immeasurable states required to control a non-observable double inverted pendulum. Active Learning Method (ALM) is a fuzzy modeling method which exploits Ink Drop Spread (IDS) as its main engine. IDS is a universal fuzzy modeling technique which is very similar to the

Alireza Ghatreh Samani; Saeed Bagheri Shouraki; Reza Eghbali; Mohammad Ghomi Rostami

2010-01-01

287

UFOs in the LHC: Observations, studies and extrapolations  

E-print Network

Unidentified falling objects (UFOs) are potentially a major luminosity limitation for nominal LHC operation. They are presumably micrometer sized dust particles which lead to fast beam losses when they interact with the beam. With large-scale increases and optimizations of the beam loss monitor (BLM) thresholds, their impact on LHC availability was mitigated from mid 2011 onwards. For higher beam energy and lower magnet quench limits, the problem is expected to be considerably worse, though. In 2011/12, the diagnostics for UFO events were significantly improved: dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. The state of knowledge, extrapolations for nominal LHC operation and mitigation strategies are presented

Baer, T; Cerutti, F; Ferrari, A; Garrel, N; Goddard, B; Holzer, EB; Jackson, S; Lechner, A; Mertens, V; Misiowiec, M; Nebot del Busto, E; Nordt, A; Uythoven, J; Vlachoudis, V; Wenninger, J; Zamantzas, C; Zimmermann, F; Fuster, N

2012-01-01

288

Unintentional Child Neglect: Literature Review and Observational Study.  

PubMed

Child abuse is a problem that affects over six million children in the United States each year. Child neglect accounts for 78 % of those cases. Despite this, the issue of child neglect is still not well understood, partially because child neglect does not have a consistent, universally accepted definition. Some researchers consider child neglect and child abuse to be one in the same, while other researchers consider them to be conceptually different. Factors that make child neglect difficult to define include: (1) Cultural differences; motives must be taken into account because parents may believe they are acting in the child's best interests based on cultural beliefs (2) the fact that the effect of child abuse is not always immediately visible; the effects of emotional neglect specifically may not be apparent until later in the child's development, and (3) the large spectrum of actions that fall under the category of child abuse. Some of the risk factors for increased child neglect and maltreatment have been identified. These risk factors include socioeconomic status, education level, family composition, and the presence of dysfunction family characteristics. Studies have found that children from poorer families and children of less educated parents are more likely to sustain fatal unintentional injuries than children of wealthier, better educated parents. Studies have also found that children living with adults unrelated to them are at increased risk for unintentional injuries and maltreatment. Dysfunctional family characteristics may even be more indicative of child neglect. Parental alcohol or drug abuse, parental personal history of neglect, and parental stress greatly increase the odds of neglect. Parental depression doubles the odds of child neglect. However, more research needs to be done to better understand these risk factors and to identify others. Having a clearer understanding of the risk factors could lead to prevention and treatment, as it would allow for health care personnel to screen for high-risk children and intervene before it is too late. Screening could also be done in the schools and organized after school activities. Parenting classes have been shown to be an effective intervention strategy by decreasing parental stress and potential for abuse, but there has been limited research done on this approach. Parenting classes can be part of the corrective actions for parents found to be neglectful or abusive, but parenting classes may also be useful as a preventative measure, being taught in schools or readily available in higher-risk communities. More research has to be done to better define child abuse and neglect so that it can be effectively addressed and treated. PMID:25398462

Friedman, Emily; Billick, Stephen B

2014-11-15

289

A Case Study Method For Landscape Architecture  

Microsoft Academic Search

Case studies are widely used in most professions, including medicine, law, engineering, business, planning, and architecture. This practice is becoming increasingly com- mon in landscape architecture as well. The primary body of knowledge in landscape architec- ture is contained in the written and visual documentation—that is, stories—of projects, be it well-known ones such as New York's Central Park, or more

Mark Francis

290

A study of the threshold method utilizing raingage data  

NASA Technical Reports Server (NTRS)

The threshold method for estimation of area-average rain rate relies on determination of the fractional area where rain rate exceeds a preset level of intensity. Previous studies have shown that the optimal threshold level depends on the climatological rain-rate distribution (RRD). It has also been noted, however, that the climatological RRD may be composed of an aggregate of distributions, one for each of several distinctly different synoptic conditions, each having its own optimal threshold. In this study, the impact of RRD variations on the threshold method is shown in an analysis of 1-min rainrate data from a network of tipping-bucket gauges in Darwin, Australia. Data are analyzed for two distinct regimes: the premonsoon environment, having isolated intense thunderstorms, and the active monsoon rains, having organized convective cell clusters that generate large areas of stratiform rain. It is found that a threshold of 10 mm/h results in the same threshold coefficient for both regimes, suggesting an alternative definition of optimal threshold as that which is least sensitive to distribution variations. The observed behavior of the threshold coefficient is well simulated by assumption of lognormal distributions with different scale parameters and same shape parameters.

Short, David A.; Wolff, David B.; Rosenfeld, Daniel; Atlas, David

1993-01-01

291

Association between metabolic syndrome and bone fractures: a meta-analysis of observational studies  

PubMed Central

Background Emerging epidemiological evidence suggest an association between metabolic syndrome and fractures. However, whether metabolic syndrome is an independent risk or protective factor of fractures remains controversial. Our goal is to provide a quantitative assessment of the association between metabolic syndrome and bone fractures by conducting a meta-analysis of observational studies. Methods The PubMed and Embase database were searched through to March 2013 to identify studies that met pre-established inclusion criteria. Reference lists of retrieved articles were also reviewed. Summary effect estimates with 95% confidence intervals (CI) were derived using a fixed or random effects model, depending on the heterogeneity of the included studies. Results Eight epidemiologic studies involving 39,938 participants were included in the meta-analysis. In overall analysis, metabolic syndrome was not associated with prevalent fractures [pooled odds ratio (OR) 0.93, 95% CI 0.84 - 1.03] in cross-sectional studies or incident fractures [pooled relative risk (RR) 0.88, 95% CI 0.37 - 2.12] in prospective cohort studies. No evidence of heterogeneity was found in cross-sectional studies (p?=?0.786, I 2 ?=?0.0%). A substantial heterogeneity was detected in cohort studies (p?=?0.001, I 2 ?=?85.7%). No indication of significant publication bias was found either from Begg’s test or Egger’s test. Estimates of total effects were substantially consistent in the sensitivity and stratification analyses. Conclusions The present meta-analysis of observational studies suggests that the metabolic syndrome has no explicit effect on bone fractures. PMID:24506931

2014-01-01

292

Variability of linezolid concentrations after standard dosing in critically ill patients: a prospective observational study  

PubMed Central

Introduction Severe infections in intensive care patients show high morbidity and mortality rates. Linezolid is an antimicrobial drug frequently used in critically ill patients. Recent data indicates that there might be high variability of linezolid serum concentrations in intensive care patients receiving standard doses. This study was aimed to evaluate whether standard dosing of linezolid leads to therapeutic serum concentrations in critically ill patients. Methods In this prospective observational study, 30 critically ill adult patients with suspected infections received standard dosing of 600 mg linezolid intravenously twice a day. Over 4 days, multiple serum samples were obtained from each patient, in order to determine the linezolid concentrations by liquid chromatography tandem mass spectrometry. Results A high variability of serum linezolid concentrations was observed (range of area under the linezolid concentration time curve over 24 hours (AUC24) 50.1 to 453.9 mg/L, median 143.3 mg*h/L; range of trough concentrations (Cmin)?observed for 63% and 50% of the patients, respectively. Finally, potentially toxic levels (defined as AUC24?>?400 mg*h/L and Cmin?>?10 mg/L) were observed for 7 of the patients. Conclusions A high variability of linezolid serum concentrations with a substantial percentage of potentially subtherapeutic levels was observed in intensive care patients. The findings suggest that therapeutic drug monitoring of linezolid might be helpful for adequate dosing of linezolid in critically ill patients. Trial registration Clinicaltrials.gov NCT01793012. Registered 24 January 2013. PMID:25011656

2014-01-01

293

Can we observe and study the Mediterranean outflow and meddies from satellite remote sensing?  

NASA Astrophysics Data System (ADS)

Previous studies of the Mediterranean outflow and meddies (O&M) were limited by poor spatial and temporal resolution of the conventional observations. Little is known about meddies formation and transport, and the spatial and temporal variation of its trajectories. Generally speaking, most of the satellite observations are confined to the ocean's surface or its surface layer, while meddies were located, on an average, at a depth of 1000m. We developed a new remote sensing method to observe and study the O&M through unique approaches in satellite multi-sensor data integration analyses. Satellite altimeter, scatterometer, SST and XBT data were used to detect and calculate the trajectories and the relative transport of the O&M. We found that more northwestward meddies occurred in the spring and more southward meddies occurred in the fall than previously thought. Since the O&M play a significant role in carrying salty water from the Mediterranean into the Atlantic and contribute to the North Atlantic Deep Water (NADW) formation, such new knowledge about their trajectories, transport and life histories is important to understand their mixing and interaction with the North Atlantic water, adn hence, to lead to a better understanding of the global ocean circulation and the global change.

Yan, Xiao-Hai; Jo, Young-Heon; Liu, W. Timothy; He, Ming-Xia

2004-02-01

294

Detection Method of Lightning and TLEs by JEM-GLIMS Nadir Observation  

NASA Astrophysics Data System (ADS)

A scientific payload named JEM-GLIMS aboard the International Space Station (ISS) is aimed at observing lightning and Transient Luminous Events (TLEs) globally. Keeping its field-of-view toward the nadir direction, GLIMS clarifies the horizontal structures of lightning and TLEs, which is a crucial issue to understand the electrodynamic coupling between the troposphere and ionosphere. A difficult point, however, is that careful analyses are necessary to separate the emissions of lightning and TLEs which spatially overlap along the line-of-sights in the case of nadir observation. In this study, we analyze the multi-wavelength optical data obtained by GLIMS to identify lightning and TLEs. The main data analyzed are those of imager (LSI) and spectrophotometer (PH). LSI consists of two cameras equipped with a broadband red filter and a narrowband 762-nm filter, respectively, and obtains imagery at a spatial resolution of 400 m/pixel on the ground surface. PH detects time-resolved emission intensity at a sampling rate of 20 kHz by six photometer channels measuring at 150-280, 337, 762, 600-900, 316 and 392 nm, respectively. During a period between November 2012 and June 2013, GLIMS observed 815 lightning and/or TLE events, and in 494 of them, both LSI and PH data showed clear signals above the noise level. As the first step, we carried out case study using an event observed at 09:50:47UT on Jan 29 2013 which did not cause strong saturation on the LSI and PH data. The estimated peak irradiance was 1.38x10^(-3) W/m^(2) at 600-900 nm, which is equivalent to the top 10 % bright lightning events observed by FORTE satellite in the past. This finding suggests that GLIMS selectively observes the most optically-powerful events. The peak irradiance was estimated also for the other PH channels. At all visible channels other than a far ultra violet (FUV) channel, the peak irradiance was estimated to be in good agreement with the atmospheric transmittance curve calculated between 10 km and ISS altitude. We therefore primarily attribute the visible emissions of this event to lightning discharge occurring in the troposphere. Interestingly, GLIMS also detected the FUV emission which is significantly stronger than that expected for tropospheric lightning. This finding suggests that TLE also occurred at higher altitudes where the FUV emission is not affected by atmospheric attenuation. As such, it is clear that GLIMS is able to discriminate optical emissions of lightning and TLEs occurring in the nadir direction. In the conference, we will examine the identification technique in details and, by applying it to all the events, will discuss the validity and limitation.

Adachi, T.; Sato, M.; Ushio, T.; Yamazaki, A.; Suzuki, M.; Masayuki, K.; Takahashi, Y.; Inan, U.; Linscott, I.; Hobara, Y.

2013-12-01

295

Development of observation method for hydrothermal flows with acoustic video camera  

NASA Astrophysics Data System (ADS)

DIDSON (Dual-Frequency IDentification SONar) is acoustic lens-based sonar. It has sufficiently high resolution and rapid refresh rate that it can substitute for optical system in turbid or dark water where optical systems fail. Institute of Industrial Science, University of Tokyo (IIS) has understood DIDSON's superior performance and tried to develop a new observation method based on DIDSON for hydrothermal discharging from seafloor vent. We expected DIDSON to reveal whole image of hydrothermal plume as well as detail inside the plume. In October 2009, we conducted seafloor reconnaissance using a manned deep-sea submersible Shinkai6500 in Central Indian Ridge 18-20deg.S, where hydrothermal plume signatures were previously perceived. DIDSON was equipped on the top of Shinkai6500 in order to get acoustic video images of hydrothermal plumes. The acoustic video images of the hydrothermal plumes had been captured in three of seven dives. These are only a few acoustic video images of the hydrothermal plumes. We could identify shadings inside the acoustic video images of the hydrothermal plumes. Silhouettes of the hydrothermal plumes varied from second to second, and the shadings inside them varied their shapes, too. These variations corresponded to internal structures and flows of the plumes. We are analyzing the acoustic video images in order to deduce information of their internal structures and flows in plumes. On the other hand, we are preparing a tank experiment so that we will have acoustic video images of water flow under the control of flow rate. The purpose of the experiment is to understand relation between flow rate and acoustic video image quantitatively. Results from this experiment will support the aforementioned image analysis of the hydrothermal plume data from Central Indian Ridge. We will report the overview of the image analysis and the tank experiments, and discuss possibility of DIDSON as an observation tool for seafloor hydrothermal activity.

Mochizuki, M.; Asada, A.; Kinoshita, M.; Tamura, H.; Tamaki, K.

2011-12-01

296

Generalizability and Decision Studies to Inform Observational and Experimental Research in Classroom Settings  

ERIC Educational Resources Information Center

Attaining reliable estimates of observational measures can be challenging in school and classroom settings, as behavior can be influenced by multiple contextual factors. Generalizability (G) studies can enable researchers to estimate the reliability of observational data, and decision (D) studies can inform how many observation sessions are…

Bottema-Beutel, Kristen; Lloyd, Blair; Carter, Erik W.; Asmus, Jennifer M.

2014-01-01

297

Depression and Oxidative Stress: Results From a Meta-Analysis of Observational Studies  

PubMed Central

Objective To perform a systematic review and meta-analysis that quantitatively tests and summarizes the hypothesis that depression results in elevated oxidative stress and lower antioxidant levels. Methods We performed a meta-analysis of studies that reported an association between depression and oxidative stress and/or antioxidant status markers. PubMed and EMBASE databases were searched for articles published from January 1980 through December 2012. A random-effects model, weighted by inverse variance, was performed to pool standard deviation (Cohen’s d) effect size estimates across studies for oxidative stress and antioxidant status measures, separately. Results Twenty-three studies with 4980 participants were included in the meta-analysis. Depression was most commonly measured using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. A Cohen’s d effect size of 0.55 (95% confidence interval = 0.47–0.63) was found for the association between depression and oxidative stress, indicating a roughly 0.55 of 1-standard-deviation increase in oxidative stress among individuals with depression compared with those without depression. The results of the studies displayed significant heterogeneity (I2 = 80.0%, p < .001). A statistically significant effect was also observed for the association between depression and antioxidant status markers (Cohen’s d = ?0.24, 95% confidence interval = ?0.33 to ?0.15). Conclusions This meta-analysis observed an association between depression and oxidative stress and antioxidant status across many different studies. Differences in measures of depression and markers of oxidative stress and antioxidant status markers could account for the observed heterogeneity. These findings suggest that well-established associations between depression and poor heath outcomes may be mediated by high oxidative stress. PMID:24336428

Palta, Priya; Samuel, Laura J.; Miller, Edgar R.; Szanton, Sarah L.

2014-01-01

298

A comparison of methods for smoothing and gap filling time series of remote sensing observations - application to MODIS LAI products  

NASA Astrophysics Data System (ADS)

Moderate resolution satellite sensors including MODIS (Moderate Resolution Imaging Spectroradiometer) already provide more than 10 yr of observations well suited to describe and understand the dynamics of earth's surface. However, these time series are associated with significant uncertainties and incomplete because of cloud cover. This study compares eight methods designed to improve the continuity by filling gaps and consistency by smoothing the time course. It includes methods exploiting the time series as a whole (iterative caterpillar singular spectrum analysis (ICSSA), empirical mode decomposition (EMD), low pass filtering (LPF) and Whittaker smoother (Whit)) as well as methods working on limited temporal windows of a few weeks to few months (adaptive Savitzky-Golay filter (SGF), temporal smoothing and gap filling (TSGF), and asymmetric Gaussian function (AGF)), in addition to the simple climatological LAI yearly profile (Clim). Methods were applied to the MODIS leaf area index product for the period 2000-2008 and over 25 sites showed a large range of seasonal patterns. Performances were discussed with emphasis on the balance achieved by each method between accuracy and roughness depending on the fraction of missing observations and the length of the gaps. Results demonstrate that the EMD, LPF and AGF methods were failing because of a significant fraction of gaps (more than 20%), while ICSSA, Whit and SGF were always providing estimates for dates with missing data. TSGF (Clim) was able to fill more than 50% of the gaps for sites with more than 60% (80%) fraction of gaps. However, investigation of the accuracy of the reconstructed values shows that it degrades rapidly for sites with more than 20% missing data, particularly for ICSSA, Whit and SGF. In these conditions, TSGF provides the best performances that are significantly better than the simple Clim for gaps shorter than about 100 days. The roughness of the reconstructed temporal profiles shows large differences between the various methods, with a decrease of the roughness with the fraction of missing data, except for ICSSA. TSGF provides the smoothest temporal profiles for sites with a % gap > 30%. Conversely, ICSSA, LPF, Whit, AGF and Clim provide smoother profiles than TSGF for sites with a % gap < 30%. Impact of the accuracy and smoothness of the reconstructed time series were evaluated on the timing of phenological stages. The dates of start, maximum and end of the season are estimated with an accuracy of about 10 days for the sites with a % gap < 10% and increases rapidly with the % gap. TSGF provides more accurate estimates of phenological timing up to a % gap < 60%.

Kandasamy, S.; Baret, F.; Verger, A.; Neveux, P.; Weiss, M.

2013-06-01

299

A comparison of methods for smoothing and gap filling time series of remote sensing observations: application to MODIS LAI products  

NASA Astrophysics Data System (ADS)

Moderate resolution satellite sensors including MODIS already provide more than 10 yr of observations well suited to describe and understand the dynamics of the Earth surface. However, these time series are incomplete because of cloud cover and associated with significant uncertainties. This study compares eight methods designed to improve the continuity by filling gaps and the consistency by smoothing the time course. It includes methods exploiting the time series as a whole (Iterative caterpillar singular spectrum analysis (ICSSA), empirical mode decomposition (EMD), low pass filtering (LPF) and Whittaker smoother (Whit)) as well as methods working on limited temporal windows of few weeks to few months (Adaptive Savitzky-Golay filter (SGF), temporal smoothing and gap filling (TSGF) and asymmetric Gaussian function (AGF)) in addition to the simple climatological LAI yearly profile (Clim). Methods were applied to MODIS leaf area index product for the period 2000-2008 over 25 sites showing a large range of seasonal patterns. Performances were discussed with emphasis on the balance achieved by each method between accuracy and roughness depending on the fraction of missing observations and the length of the gaps. Results demonstrate that EMD, LPF and AGF methods were failing in case of significant fraction of gaps (%Gap > 20%), while ICSSA, Whit and SGF were always providing estimates for dates with missing data. TSGF (respectively Clim) was able to fill more than 50% of the gaps for sites with more than 60% (resp. 80%) fraction of gaps. However, investigation of the accuracy of the reconstructed values shows that it degrades rapidly for sites with more than 20% missing data, particularly for ICSSA, Whit and SGF. In these conditions, TSGF provides the best performances significantly better than the simple Clim for gaps shorter than about 100 days. The roughness of the reconstructed temporal profiles shows large differences between the several methods, with a decrease of the roughness with the fraction of missing data, except for ICSSA. TSGF provides the smoothest temporal profiles for sites with %Gap > 30%. Conversely, ICSSA, LPF, Whit, AGF and Clim provide smoother profiles than TSGF for sites with %Gap < 30%. Impact of the accuracy and smoothness of the reconstructed time series were evaluated on the timing of phenological stages. The dates of start, maximum and end of the season are estimated with an accuracy of about 10 days for the sites with %Gap < 10% and increases rapidly with %Gap. TSGF provides the more accurate estimates of phenological timing up to %Gap < 60%.

Kandasamy, S.; Baret, F.; Verger, A.; Neveux, P.; Weiss, M.

2012-12-01

300

Causal inference methods to study nonrandomized, preexisting development interventions  

PubMed Central

Empirical measurement of interventions to address significant global health and development problems is necessary to ensure that resources are applied appropriately. Such intervention programs are often deployed at the group or community level. The gold standard design to measure the effectiveness of community-level interventions is the community-randomized trial, but the conditions of these trials often make it difficult to assess their external validity and sustainability. The sheer number of community interventions, relative to randomized studies, speaks to a need for rigorous observational methods to measure their impact. In this article, we use the potential outcomes model for causal inference to motivate a matched cohort design to study the impact and sustainability of nonrandomized, preexisting interventions. We illustrate the method using a sanitation mobilization, water supply, and hygiene intervention in rural India. In a matched sample of 25 villages, we enrolled 1,284 children <5 y old and measured outcomes over 12 mo. Although we found a 33 percentage point difference in new toilet construction [95% confidence interval (CI) = 28%, 39%], we found no impacts on height-for-age Z scores (adjusted difference = 0.01, 95% CI = ?0.15, 0.19) or diarrhea (adjusted longitudinal prevalence difference = 0.003, 95% CI = ?0.001, 0.008) among children <5 y old. This study demonstrates that matched cohort designs can estimate impacts from nonrandomized, preexisting interventions that are used widely in development efforts. Interpreting the impacts as causal, however, requires stronger assumptions than prospective, randomized studies. PMID:21149699

Arnold, Benjamin F.; Khush, Ranjiv S.; Ramaswamy, Padmavathi; London, Alicia G.; Rajkumar, Paramasivan; Ramaprabha, Prabhakar; Durairaj, Natesan; Hubbard, Alan E.; Balakrishnan, Kalpana; Colford, John M.

2010-01-01

301

Statistical analysis of observational study of the influence of radon and other risk factors on lung cancer incidence.  

PubMed

An observational study is a type of epidemiological study when the researcher observes the situation but is not able to change the conditions of the experiment. The statistical analysis of the observational study of the population of Lermontov city (North Caucasus) was conducted. In the initial group, there were 121 people with lung cancer diagnosis and 196 people of the control group. Statistical analysis was performed only for men (95 cases and 76 controls). The use of logistic regression with correction on age gives the value of odds ratio 1.95 (0.87÷4.37; 90% CI) per 100 working levels per month of combined (occupational and domestic) radon exposure. It was demonstrated that chronic lung diseases are an additional risk factor for uranium miners but it is not a significant risk factor for general population. Thus, the possibility of obtaining statistically reliable results in the observational studies when using the correct methods of analysis is demonstrated. PMID:24714108

Zhukovsky, Michael; Varaksin, Anatole; Pakholkina, Olga

2014-07-01

302

Narrative Inquiry as Travel Study Method: Affordances and Constraints  

ERIC Educational Resources Information Center

This article maps how narrative inquiry--the use of story to study human experience--has been employed as both method and form to capture cross-cultural learning associated with Western doctoral students' travel study to eastern destinations. While others were the first to employ this method in the travel study domain, we are the first to…

Craig, Cheryl J.; Zou, Yali; Poimbeauf, Rita

2014-01-01

303

Calcium Channel Blockers and Risk of Breast Cancer: A Meta-Analysis of 17 Observational Studies  

PubMed Central

Purpose Studies on the association between the use of calcium channel blockers (CCBs) and breast cancer risk have reported inconsistent results. We quantitatively assessed this association by conducting a meta-analysis based on the evidence from observational studies. Methods We searched PubMed, MEDLINE, EMBASE and the Cochrane Library for relevant studies published up to and including December 31, 2013. We calculated pooled risk ratios (RRs) for cancer risk. Results A total of 17 studies (9 cohort studies, 8 case-control studies) were selected for further study. These studies included 149,607 female subjects, of which 53,812 were CCBs users, who were followed for 2–16 years. The risks of breast cancer among patients receiving CCBs were significantly different for the pooled RRs (95% confidence interval) of cohort studies 1.08 (0.95, 1.20) and case-control studies 0.98 (0.86, 1.09). Differences were also noted for cancer risk, for CCBs use of <5 years 0.96 (0.78, 1.15), and for >5 years 1.01 (0.74, 1.28), as well as for ever used 1.08 (0.95, 1.20), and for current use 1.13 (0.83, 1.42). The RR for studies longer than 10 years was 1.71 (1.01, 2.42), and for studies evaluating nifedipine was 1.10 (0.87, 1.33) and diltiazem was 0.75 (0.40, 1.10). Conclusions The long-term use of CCBs appears to have a significant relationship with breast cancer. Well-designed clinical trials are needed to optimize the doses and types of these drugs needed to minimize their carcinogenic potential. PMID:25184210

Li, Wen; Shi, Qi; Wang, Weibing; Liu, Jianrong; Li, Qi; Hou, Fenggang

2014-01-01

304

Obesity and risk of thyroid cancer: evidence from a meta-analysis of 21 observational studies.  

PubMed

Background Several studies have evaluated the association between obesity and thyroid cancer risk. However, the results remain uncertain. In this study, we conducted a meta-analysis to assess the association between obesity and thyroid cancer risk. Material and Methods Published literature from PubMed, EMBASE, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) were retrieved before 10 August 2014. We included all studies that reported adjusted risk ratios (RRs), hazard ratios (HRs) or odds ratios (ORs), and 95% confidence intervals (CIs) of thyroid cancer risk. Results Thirty-two studies (n=12 620 676) were included in this meta-analysis. Obesity was associated with a significantly increased risk of thyroid cancer (adjusted RR=1.33; 95% CI, 1.24-1.42; I2=25%). In the subgroup analysis by study type, increased risk of thyroid cancer was found in cohort studies and case-control studies. In subgroup analysis by sex, both obese men and women were at significantly greater risk of thyroid cancer than non-obese subjects. When stratified by ethnicity, significantly elevated risk was observed in Caucasians and in Asians. In the age subgroup analysis, both young and old populations showed increased thyroid cancer risk. Subgroup analysis on smoking status showed that increased thyroid cancer risks were found in smokers and in non-smokers. In the histology subgroup analyses, increased risks of papillary thyroid cancer, follicular thyroid cancer, and anaplastic thyroid cancer were observed. However, obesity was associated with decreased risk of medullary thyroid cancer. Conclusions Our results indicate that obesity is associated with an increased thyroid cancer risk, except medullary thyroid cancer. PMID:25612155

Ma, Jie; Huang, Min; Wang, Li; Ye, Wei; Tong, Yan; Wang, Hanmin

2015-01-01

305

Obesity and Risk of Thyroid Cancer: Evidence from a Meta-Analysis of 21 Observational Studies  

PubMed Central

Background Several studies have evaluated the association between obesity and thyroid cancer risk. However, the results remain uncertain. In this study, we conducted a meta-analysis to assess the association between obesity and thyroid cancer risk. Material/Methods Published literature from PubMed, EMBASE, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) were retrieved before 10 August 2014. We included all studies that reported adjusted risk ratios (RRs), hazard ratios (HRs) or odds ratios (ORs), and 95% confidence intervals (CIs) of thyroid cancer risk. Results Thirty-two studies (n=12 620 676) were included in this meta-analysis. Obesity was associated with a significantly increased risk of thyroid cancer (adjusted RR=1.33; 95% CI, 1.24–1.42; I2=25%). In the subgroup analysis by study type, increased risk of thyroid cancer was found in cohort studies and case-control studies. In subgroup analysis by sex, both obese men and women were at significantly greater risk of thyroid cancer than non-obese subjects. When stratified by ethnicity, significantly elevated risk was observed in Caucasians and in Asians. In the age subgroup analysis, both young and old populations showed increased thyroid cancer risk. Subgroup analysis on smoking status showed that increased thyroid cancer risks were found in smokers and in non-smokers. In the histology subgroup analyses, increased risks of papillary thyroid cancer, follicular thyroid cancer, and anaplastic thyroid cancer were observed. However, obesity was associated with decreased risk of medullary thyroid cancer. Conclusions Our results indicate that obesity is associated with an increased thyroid cancer risk, except medullary thyroid cancer. PMID:25612155

Ma, Jie; Huang, Min; Wang, Li; Ye, Wei; Tong, Yan; Wang, Hanmin

2015-01-01

306

Studies of non-ideal'' superconductors using dc magnetic methods  

SciTech Connect

Among the most informative and facile methods for investigations of a superconductor are measurements of its static magnetization. The objective of this paper is to analyze some experimental features frequently observed in static (dc) magnetization studies of conventional and high-{Tc} superconductors. We shall discuss investigations employing measurement protocols in which the sample is cooled through the superconductive transition temperature in a finite magnetic field ( field cooled'') and compare this with zero-field-cooled studies. Also considered are reversible and irreversible materials; particle size effects; some effects of granular and multiply-connected materials; penetration depth studies of type 2 materials in the vortex state; and fine scale multi-connected'' materials produced by heavy ion irradiation that produces very significant enhancements of the critical current density J{sub c} in the high temperature superconductor Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7}. Many of these superconductors are non-ideal'' in that they may contain defects and inhomogeneities or may have small dimensions comparable with miscroscopic superconductive lengths. Practically speaking, however, such materials are often encountered experimentally and can have very desirable physical properties, such as high J{sub c} values in the ion-irradiated crystal. 33 refs., 9 figs., 1 tab.

Thompson, J.R. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA). Dept. of Physics); Christen, D.K. Kerchner, H.R.; Boatner, L.A.; Sales, B.C.; Chakoumakos, B.C.; Hsu, H.; Brynestad, J.; Kroeger, D.M.; Williams, R.K.; Feenstra, R. (Oak Ridge National Lab., TN (USA)); Sun, Yang Ren; Kim, Y.C.; Ossandon, J.G. (Tennessee Univ., Knoxville, TN (USA). Dept. of Physics); Malozemoff, A.P.; Civa

1991-01-01

307

Methods for studying drug effects on superficial human veins.  

PubMed

Direct effects of vasoactive substances on superficial human veins in vivo can be investigated by measuring changes in the diameter of a superficial vein at a standardized congestion pressure which reflect changes in venous tone before and after local infusion of the drugs. The diameter of a superficial hand vein is measured with the aid of a linear variable differential transformer mounted directly on the back of the hand. The central core of the transformer positioned over the summit of the vein moves simultaneously with changes in venous diameter and allows continuous recording of these alterations. A series of ergot alkaloids were investigated with this technique and found to elicit a direct constrictor action when infused locally. Studies on the mode of action of the venoconstrictor effects of ergot alkaloids suggest that they are mediated by stimulation of alpha- and 5-HT-receptors. Similarly, guanfacine, a centrally-acting antihypertensive drug, reduces venous compliance after direct local administration as a result of alpha-adrenoceptor stimulation. The venodilator effect of isoprenaline can be shown in veins preconstricted with noradrenaline, whereas with nitroglycerine, venodilatation is observed by local infusions in veins not preconstricted. This method is therefore useful for studying the direct effects of venoconstrictor and venodilator drugs in man. The technique can also be used to study interactions between different agents and thus to investigate the mode of action of drugs. Drugs can be infused locally at doses which do not elicit systemic effects. PMID:3840550

Aellig, W H

1985-06-01

308

Event-by-event study of neutron observables in spontaneous and thermal fission  

SciTech Connect

The event-by-event fission model FREYA is extended to spontaneous fission of actinides and a variety of neutron observables are studied for spontaneous fission and fission induced by thermal neutrons with a view towards possible applications for SNM detection. We have shown that event-by-event models of fission, such as FREYA, provide a powerful tool for studying fission neutron correlations. Our results demonstrate that these correlations are significant and exhibit a dependence on the fissioning nucleus. Since our method is phenomenological in nature, good input data are especially important. Some of the measurements employed in FREYA are rather old and statistics limited. It would be useful to repeat some of these studies with modern detector techniques. In addition, most experiments made to date have not made simultaneous measurements of the fission products and the prompt observables, such as neutron and photons. Such data, while obviously more challenging to obtain, would be valuable for achieving a more complete understanding of the fission process.

Vogt, R; Randrup, J

2011-09-14

309

A portable ergonomic observation method (PEO) for computerized on-line recording of postures and manual handling  

Microsoft Academic Search

A new portable ergonomic observation method (PEO) is presented. It is applicable to most professions and work tasks and requires only moderate human resources for data collection and analysis. Observations are made in real time directly at the workplace using a portable personal or hand-held computer, and data are accessible for immediate analysis and presentation. Duration and number of events

C Fransson-Hall

1995-01-01

310

Long-Term Treatment of ADHD with Stimulants: A Large Observational Study of Real-Life Patients  

ERIC Educational Resources Information Center

Objective: To evaluate 410 real-life patients treated with stimulants and assessed systematically over several years. Method: Naturalistic observational study. A database was compiled on the basis of a review of the medical charts of patients attending a specialized ADHD clinic. Results: The diversity of ADHD patients was evident from the…

Powell, Shelagh G.; Thomsen, Per Hove; Frydenberg, Morten; Rasmussen, Helle

2011-01-01

311

Physiological Measurements as Validation of Alertness Observations: An Exploratory Case Study of Three Individuals with Profound Intellectual and Multiple Disabilities  

ERIC Educational Resources Information Center

Although observation largely takes into account the needs and abilities of individuals with profound intellectual and multiple disabilities, several difficulties are related to this assessment method as well. Our aim in this study was to investigate what possibilities the use of physiological measurements make available to validate alertness…

Munde, Vera; Vlaskamp, Carla; Vos, Pieter; Maes, Bea; Ruijssenaars, Wied

2012-01-01

312

Dietary Patterns Predict Subsequent Coronary Heart Disease Risk In Postmenopausal Women : The Women’s Health Initiative Observational Cohort Study  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background: Evidence suggests that dietary patterns predispose to the development of coronary heart disease (CHD). The relationship between dietary patterns and CHD risk was assessed in postmenopausal women participating in the Women’s Health Initiative Observational Study (WHI-OS). Methods: Case-co...

313

Global asteroseismic properties of solar-like oscillations observed by Kepler: a comparison of complementary analysis methods  

Microsoft Academic Search

We present the asteroseismic analysis of 1948 F-, G- and K-type main-sequence and subgiant stars observed by the National Aeronautics and Space Administration Kepler mission. We detect and characterize solar-like oscillations in 642 of these stars. This represents the largest cohort of main-sequence and subgiant solar-like oscillators observed to date. The photometric observations are analysed using the methods developed by

G. A. Verner; Y. Elsworth; W. J. Chaplin; T. L. Campante; E. Corsaro; P. Gaulme; S. Hekker; D. Huber; C. Karoff; S. Mathur; B. Mosser; T. Appourchaux; J. Ballot; T. R. Bedding; A. Bonanno; A.-M. Broomhall; R. A. García; R. Handberg; R. New; D. Stello; C. Régulo; I. W. Roxburgh; D. Salabert; T. R. White; D. A. Caldwell; J. L. Christiansen; M. N. Fanelli

2011-01-01

314

Survey of robust residual generation and evaluation methods in observer-based fault detection systems  

Microsoft Academic Search

The paper outlines recent advances of the theory of observer-based fault diagnosis in dynamic systems towards the design of robust techniques of residual generation and residual evaluation. Emphasis will be placed upon the latest contributions using frequency domain techniques including H? theory, nonlinear unknown input observer theory, adaptive observer theory, artificial intelligence including fuzzy logic, knowledge-based techniques and the natural

P. M. Frank; X. Ding

1997-01-01

315

Smoking close to others and butt littering at bus stops: pilot observational study  

PubMed Central

Background. Transportation settings such as bus stops and train station platforms are increasingly the target for new smokefree legislation. Relevant issues include secondhand smoke exposure, nuisance, litter, fire risks and the normalization of smoking. We therefore aimed to pilot study aspects of smoking behavior and butt disposal at bus stops. Methods. Systematic observation of smoking and butt disposal by smokers at bus stops. The selection of 11 sites was a mix of convenience and purposeful (bus stops on main routes) in two New Zealand cities. Results. During 27 h of observation, a total of 112 lit cigarettes were observed being smoked. Smoking occurred in the presence of: just adults (46%), both young people and adults (44%), just young people (6%) and alone (5%). An average of 6.3 adults and 3.8 young people were present at the bus stops while smoking occurred, at average minimum distances of 1.7 and 2.2 m respectively. In bus stops that included an enclosed shelter, 33% of the cigarettes were smoked inside the shelter with others present. Littering was the major form of cigarette disposal with 84% of cigarettes smoked being littered (95% CI; 77%–90%). Also, 4% of disposals were into vegetation, which may pose a fire risk. Conclusions. This pilot study is limited by its small size and various methodological aspects but it appears to be a first attempt to provide observational evidence around smoking at bus stops. The issues described could be considered by policy makers who are investigating national smokefree laws or by-laws covering transportation settings. PMID:24688851

Oliver, Jane; Thomson, George

2014-01-01

316

Time-averaged shadow-moiré method for studying vibrations.  

PubMed

A time-averaged shadow-moiré method is presented which permits the determination of the amplitude distribution of the deflection of a plate in steady state vibration. No stroboscope is required, and the recording is done statically. The method is less sensitive than holographic methods and is therefore suitable for studying relatively large amplitudes. PMID:20168777

Hung, Y Y; Liang, C Y; Hovanesian, J D; Durelli, A J

1977-06-01

317

Qualitative Methods in Empirical Studies of Software Engineering  

E-print Network

of research. Along with new research questions, new research methods are needed to study nontechnical aspects of software engineering. In many other disciplines, qualitative research methods have been developed]. Qualitative research methods were designed, mostly by educational researchers and other social scientists [19

318

Impulsivity-hyperactivity and subtypes of aggression in early childhood: an observational and short-term longitudinal study  

Microsoft Academic Search

This short-term longitudinal study (N = 112) was conducted to explore the concurrent and prospective associations between teacher-reported impulsive-hyperactive\\u000a behavior and observed relational and physical aggression during early childhood (M = 45.54 months old, SD = 9.07). Multiple informants and methods including observational methods (i.e., 160 min per child)\\u000a were used to assess aggression and impulsivity-hyperactivity. All measures were found to be valid and reliable. Prospective\\u000a hierarchical regression

Jamie M. Ostrov; Stephanie A. Godleski

2009-01-01

319

EXPOSURE ASSESSMENT METHODS DEVELOPMENT PILOTS FOR THE NATIONAL CHILDREN'S STUDY  

EPA Science Inventory

Accurate exposure classification tools are needed to link exposure with health effects. EPA began methods development pilot studies in 2000 to address general questions about exposures and outcome measures. Selected pilot studies are highlighted in this poster. The ?Literature Re...

320

Oxygen diffusion-concentration product in rhodopsin as observed by a pulse ESR spin labeling method.  

PubMed Central

Permeation of molecular oxygen in rhodopsin, an integral membrane protein, has been investigated by monitoring the bimolecular collision rate between molecular oxygen and the nitroxide spin label using a pulse electron spin resonance (ESR) T1 method. Rhodopsin was labeled by regeneration with the spin-labeled 9-cis retinal analogue in which the beta-ionone ring of retinal is replaced by the nitroxide tetramethyl-oxypyrrolidine ring. The bimolecular collision rate was evaluated in terms of an experimental parameter W(x), defined as T1(-1)(air,x)--T1(-1)(N2,x) where T1's are the spin-lattice relaxation times of the nitroxide in samples equilibrated with atmospheric air and nitrogen respectively, which is proportional to the product of local oxygen concentration and local diffusion coefficient (transport). W-values at the beta-ionone binding site in spin-labeled rhodopsin are in the range of 0.02-0.13 microseconds-1, which are 10-60 times smaller than W's in water and 1.1-20 times smaller than in model membranes in the gel phase, indicating that membrane proteins create significant permeation resistance to transport of molecular oxygen inside and across the membrane. W(thereby the oxygen diffusion-concentration product) is larger in the meta II-enriched sample than in rhodopsin, indicating light-induced conformational changes of opsin around the beta-ionone binding site. W decreases with increase of temperature for both rhodopsin and meta II-enriched samples, suggesting that temperature-induced conformational changes take place in both samples. These changes were not observable using conventional ESR spectroscopy. It is concluded that W is a sensitive monitor of conformational changes of proteins. PMID:1330032

Subczynski, W K; Renk, G E; Crouch, R K; Hyde, J S; Kusumi, A

1992-01-01

321

First Year Wilkinson Microwave Anisotropy Probe(WMAP) Observations: Data Processing Methods and Systematic Errors Limits  

NASA Technical Reports Server (NTRS)

We describe the calibration and data processing methods used to generate full-sky maps of the cosmic microwave background (CMB) from the first year of Wilkinson Microwave Anisotropy Probe (WMAP) observations. Detailed limits on residual systematic errors are assigned based largely on analyses of the flight data supplemented, where necessary, with results from ground tests. The data are calibrated in flight using the dipole modulation of the CMB due to the observatory's motion around the Sun. This constitutes a full-beam calibration source. An iterative algorithm simultaneously fits the time-ordered data to obtain calibration parameters and pixelized sky map temperatures. The noise properties are determined by analyzing the time-ordered data with this sky signal estimate subtracted. Based on this, we apply a pre-whitening filter to the time-ordered data to remove a low level of l/f noise. We infer and correct for a small (approx. 1 %) transmission imbalance between the two sky inputs to each differential radiometer, and we subtract a small sidelobe correction from the 23 GHz (K band) map prior to further analysis. No other systematic error corrections are applied to the data. Calibration and baseline artifacts, including the response to environmental perturbations, are negligible. Systematic uncertainties are comparable to statistical uncertainties in the characterization of the beam response. Both are accounted for in the covariance matrix of the window function and are propagated to uncertainties in the final power spectrum. We characterize the combined upper limits to residual systematic uncertainties through the pixel covariance matrix.

Hinshaw, G.; Barnes, C.; Bennett, C. L.; Greason, M. R.; Halpern, M.; Hill, R. S.; Jarosik, N.; Kogut, A.; Limon, M.; Meyer, S. S.

2003-01-01

322

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 16, METHOD 606--PHTHALATE ESTERS  

EPA Science Inventory

This report describes the results obtained and data analysis from an interlaboratory method study of EPA Method 606 (Phthalate Esters). The method is designed to analyze for six phthalate esters: dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, benzylbutyl phthalate, ...

323

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 25, METHOD 602, PURGEABLE AROMATICS  

EPA Science Inventory

The experimental design and the results of an interlaboratory study for an analytical method to detect purgeable aromatics in water are described herein. The method, EPA Method 602, Purgeable Aromatics, employs a purge-and-trap chromatographic technique for determination of seven...

324

Prospective observational cohort studies for studying rare diseases: the European PedNet Haemophilia Registry.  

PubMed

Haemophilia is a rare disease. To improve knowledge, prospective studies of large numbers of subjects are needed. To establish a large well-documented birth cohort of patients with haemophilia enabling studies on early presentation, side effects and outcome of treatment. Twenty-one haemophilia treatment centres have been collecting data on all children with haemophilia with FVIII/IX levels up to 25% born from 2000 onwards. Another eight centres collected data on severe haemophilia A only. At baseline, details on delivery and diagnosis, gene mutation, family history of haemophilia and inhibitors are collected. For the first 75 exposure days, date, reason, dose and product are recorded for each infusion. Clinically relevant inhibitors are defined as follows: at least two positive inhibitor titres and a FVIII/IX recovery <66% of expected. For inhibitor patients, results of all inhibitor- and recovery tests are collected. For continued treatment, data on bleeding, surgery, prophylaxis and clotting factor consumption are collected annually. Data are downloaded for analysis annually. In May 2013, a total of 1094 patients were included: 701 with severe, 146 with moderate and 247 with mild haemophilia. Gene defect data were available for 87.6% of patients with severe haemophilia A. The first analysis, performed in May 2011, lead to two landmark publications. The outcome of this large collaborative research confirms its value for the improvement of haemophilia care. High-quality prospective observational cohorts form an ideal source to study natural history and treatment in rare diseases such as haemophilia. PMID:24784937

Fischer, K; Ljung, R; Platokouki, H; Liesner, R; Claeyssens, S; Smink, E; van den Berg, H M

2014-07-01

325

A tool for selecting SNPs for association studies based on observed linkage disequilibrium patterns.  

PubMed

The design of genetic association studies using single-nucleotide polymorphisms (SNPs) requires the selection of subsets of the variants providing high statistical power at a reasonable cost. SNPs must be selected to maximize the probability that a causative mutation is in linkage disequilibrium (LD) with at least one marker genotyped in the study. The HapMap project performed a genome-wide survey of genetic variation with about a million SNPs typed in four populations, providing a rich resource to inform the design of association studies. A number of strategies have been proposed for the selection of SNPs based on observed LD, including construction of metric LD maps and the selection of haplotype tagging SNPs. Power calculations are important at the study design stage to ensure successful results. Integrating these methods and annotations can be challenging: the algorithms required to implement these methods are complex to deploy, and all the necessary data and annotations are deposited in disparate databases. Here, we present the SNPbrowser Software, a freely available tool to assist in the LD-based selection of markers for association studies. This stand-alone application provides fast query capabilities and swift visualization of SNPs, gene annotations, power, haplotype blocks, and LD map coordinates. Wizards implement several common SNP selection workflows including the selection of optimal subsets of SNPs (e.g. tagging SNPs). Selected SNPs are screened for their conversion potential to either TaqMan SNP Genotyping Assays or the SNPlex Genotyping System, two commercially available genotyping platforms, expediting the set-up of genetic studies with an increased probability of success. PMID:17094263

De La Vega, Francisco M; Isaac, Hadar I; Scafe, Charles R

2006-01-01

326

NATO PILOT STUDY ON ADVANCED CANCER RISK ASSESSMENT METHODS  

EPA Science Inventory

NCEA scientists are participating in a study of advanced cancer risk assessment methods, conducted under the auspices of NATO's Committee on the Challenges of Modern Society. The product will be a book of case studies that illustrate advanced cancer risk assessment methods, avail...

327

TOOLS AND METHODS FOR STUDIES IN COASTAL ECOLOGY  

E-print Network

TOOLS AND METHODS FOR STUDIES IN COASTAL ECOLOGY OF THE BAHAMAS Version 1.2. April 2006 #12;TOOLS AND METHODS IN COASTAL ECOLOGY 2006 2 Copyright 2006 K Sullivan Sealey Contributing Authors Kathleen Semon for Coastal Ecological Studies of The Bahamas. University of Miami, Coral Gables, Fl. 33124. 111 pp. #12;TOOLS

Sealey, Kathleen Sullivan

328

Diet Studies of Seabirds: a Review of Methods DAVIDCAMERONDUFFYAND SUSANJACKSON  

E-print Network

Diet Studies of Seabirds: a Review of Methods DAVIDCAMERONDUFFYAND SUSANJACKSON Pcrcy Fitr.-Mcthods of collecting, analysiog and presenting data on the diets of se;ibirrls are reviewed, with consideration of methods employed in diet studies of other organisms. Killing or hi& continues to bc the primary source

Duffy, David Cameron

329

Nuclear-based methods for the study of selenium  

SciTech Connect

The essentiality of selenium to the human being and in particular its deficiency state, associated with prolonged inadequate dietary intake, have received considerable attention. In addition, the possible relationship between selenium and cancer and the claim that selenium may possess cancer-prevention properties have focused research effort. It has been observed in a number of studies on laboratory animals that selenium supplementation protects the animals against carcinogen-induced neoplastic growth in various organ sites, reduces the incidence of spontaneous mammary tumors, and suppresses the growth of transplanted tumor cells. In these research programs on the relationship between trace element levels and senile dementia and depression and the elemental changes in blood associated with selenium supplementation in a normal group of volunteers, it became obvious that in addition to establishing normal levels of elements in the population of interest, there was a more fundamental requirement for methods to be developed that would allow the study of the distribution of selenium in the body and its binding sites. The authors propose emission tomography and perturbed angular correlation as techniques worth exploring.

Spyrou, N.M.; Akanle, O.A.; Dhani, A. (Univ. of Surrey (England))

1988-01-01

330

New Electrochemical Methods for Studying Nanoparticle Electrocatalysis and Neuronal Exocytosis  

NASA Astrophysics Data System (ADS)

This dissertation presents the construction and application of micro and nanoscale electrodes for electroanalytical analysis. The studies presented herein encompass two main areas: electrochemical catalysis, and studies of the dynamics of single cell exocytosis. The first portion of this dissertation engages the use of Pt nanoelectrodes to study the stability and electrocatalytic properties of materials. A single nanoparticle electrode (SNPE) was fabricated by immobilizing a single Au nanoparticle on a Pt disk nanoelectrode via an amine-terminated silane cross linker. In this manner we were able to effectively study the electrochemistry and electrocatalytic activity of single Au nanoparticles and found that the electrocatalytic activity is dependent on nanoparticle size. This study can further the understanding of the structure-function relationship in nanoparticle based electrocatalysis. Further work was conducted to probe the stability of Pt nanoelectrodes under conditions of potential cycling. Pt based catalysts are known to deteriorate under such conditions due to losses in electrochemical surface area and Pt dissolution. By using Pt disk nanoelectrodes we were able to study Pt dissolution via steady-state voltammetry. We observed an enhanced dissolution rate and higher charge density on nanoelectrodes than that previously found on macro scale electrodes. The goal of the second portion of this dissertation is to develop new analytical methods to study the dynamics of exocytosis from single cells. The secretion of neurotransmitters plays a key role in neuronal communication, and our studies highlight how bipolar electrochemistry can be employed to enhance detection of neurotransmitters from single cells. First, we developed a theory to quantitatively characterize the voltammetric behavior of bipolar carbon fiber microelectrodes and secondly applied those principles to single cell detection. We showed that by simply adding an additional redox mediator to the back-fill solution of a carbon fiber microelectrode, there is a significant enhancement in detection. Additionally we used solid state nanopores to detect individual phospholipid vesicles in solution. Vesicles are key cellular components that play essential biological roles especially in neurotransmission. This work represents preliminary studies in detection and size determination from vesicles isolated from individual cells.

Cox, Jonathan T.

331

Major bleeding in patients with atrial fibrillation receiving vitamin K antagonists: a systematic review of randomized and observational studies  

PubMed Central

Aims Clinical trials have shown that anticoagulation with vitamin K antagonists (VKAs), e.g. warfarin, decreases the risk of stroke in patients with atrial fibrillation (AF); however, increased bleeding risk is one of the safety concerns. The primary objective was to conduct a systematic review of the published literature, assessing the risk of major bleeding and mortality in patients with AF treated with VKAs. Methods and results Online searches of MEDLINE, EMBASE, BIOSIS, and the Cochrane Library were performed to a pre-specified protocol from 1960 to March 2012 for randomized controlled trials (RCTs) and from January 1990 to March 2012 for observational studies. A total of 47 studies (16 RCTs and 31 observational studies) were included. Cumulative follow-up was 61 563 patient-years for RCTs and 484 241 patient-years for observational studies. The overall median incidence of major bleeding was 2.1 per 100 patient-years (range, 0.9–3.4 per 100 patient-years) for RCTs and 2.0 per 100 patient-years (range, 0.2–7.6 per 100 patient-years) for observational studies. With study year as a proxy for changing management patterns, some evidence of bleeding rates and/or their reporting increasing over time was noted. Mortality rates from observational studies were inadequately reported to allow comparison with those from RCT data. Conclusion The median rate of major bleeding in observational studies and RCTs is similar. The larger heterogeneity in bleeding rates observed in a real-life setting could reflect a high variability in standard of care of patients on VKAs and/or methodological differences between observational studies and/or variability in data sources. PMID:23407628

Roskell, Neil S.; Samuel, Miny; Noack, Herbert; Monz, Brigitta U.

2013-01-01

332

METHODS ADVANCEMENT FOR MILK ANALYSIS: THE MAMA STUDY  

EPA Science Inventory

The Methods Advancement for Milk Analysis (MAMA) study was designed by US EPA and CDC investigators to provide data to support the technological and study design needs of the proposed National Children=s Study (NCS). The NCS is a multi-Agency-sponsored study, authorized under the...

333

Analyzing Propensity Matched Zero-Inflated Count Outcomes in Observational Studies  

PubMed Central

Determining the effectiveness of different treatments from observational data, which are characterized by imbalance between groups due to lack of randomization, is challenging. Propensity matching is often used to rectify imbalances among prognostic variables. However, there are no guidelines on how appropriately to analyze group matched data when the outcome is a zero inflated count. In addition, there is debate over whether to account for correlation of responses induced by matching, and/or whether to adjust for variables used in generating the propensity score in the final analysis. The aim of this research is to compare covariate unadjusted and adjusted zero-inflated Poisson models that do and do not account for the correlation. A simulation study is conducted, demonstrating that it is necessary to adjust for potential residual confounding, but that accounting for correlation is less important. The methods are applied to a biomedical research data set. PMID:24298197

DeSantis, Stacia M.; Lazaridis, Christos; Ji, Shuang; Spinale, Francis G.

2013-01-01

334

How accurately do drivers evaluate their own driving behavior? An on-road observational study.  

PubMed

Self-assessment of driving skills became a noteworthy research subject in traffic psychology, since by knowing one's strenghts and weaknesses, drivers can take an efficient compensatory action to moderate risk and to ensure safety in hazardous environments. The current study aims to investigate drivers' self-conception of their own driving skills and behavior in relation to expert evaluations of their actual driving, by using naturalistic and systematic observation method during actual on-road driving session and to assess the different aspects of driving via comprehensive scales sensitive to different specific aspects of driving. 19-63 years old male participants (N=158) attended an on-road driving session lasting approximately 80min (45km). During the driving session, drivers' errors and violations were recorded by an expert observer. At the end of the driving session, observers completed the driver evaluation questionnaire, while drivers completed the driving self-evaluation questionnaire and Driver Behavior Questionnaire (DBQ). Low to moderate correlations between driver and observer evaluations of driving skills and behavior, mainly on errors and violations of speed and traffic lights was found. Furthermore, the robust finding that drivers evaluate their driving performance as better than the expert was replicated. Over-positive appraisal was higher among drivers with higher error/violation score and with the ones that were evaluated by the expert as "unsafe". We suggest that the traffic environment might be regulated by increasing feedback indicators of errors and violations, which in turn might increase the insight into driving performance. Improving self-awareness by training and feedback sessions might play a key role for reducing the probability of risk in their driving activity. PMID:24269581

Amado, Sonia; Ar?kan, Elvan; Kaça, Gülin; Koyuncu, Mehmet; Turkan, B Nilay

2014-02-01

335

Using peer observers to assess the quality of cancer multidisciplinary team meetings: a qualitative proof of concept study  

PubMed Central

Background Multidisciplinary team (MDT) working is well established as the foundation for providing cancer services in the UK and elsewhere. A core activity is the weekly meeting (or case conference/tumor boards) where the treatment recommendations for individual patients are agreed. Evidence suggests that the quality of team working varies across cancer teams, and this may impact negatively on the decision-making process, and ultimately patient care. Feedback on performance by expert observers may improve performance, but can be resource-intensive to implement. This proof of concept study sought to: develop a structured observational assessment tool for use by peers (managers or clinicians from the local workforce) and explore its usability; assess the feasibility of the principle of observational assessment by peers; and explore the views of MDT members and observers about the utility of feedback from observational assessment. Methods For tool development, the content was informed by national clinical consensus recommendations for best practice in cancer MDTs and developed in collaboration with an expert steering group. It consisted of ten subdomains of team working observable in MDT meetings that were rated on a 10-point scale (very poor to very good). For observational assessment, a total of 19 peer observers used the tool (assessing performance in 20 cancer teams from four hospitals). For evaluation, telephone interviews with 64 team members and all peer observers were analyzed thematically. Results The tool was easy to use and areas for refinement were identified. Peer observers were identified and most indicated that undertaking observation was feasible. MDT members generally reported that observational assessment and feedback was useful, with the potential to facilitate improvements in team working. Conclusion This study suggests that observation and feedback by peers may provide a feasible and acceptable approach to enhance MDT performance. Further tool refinement and validation is required. PMID:25143743

Harris, Jenny; Green, James SA; Sevdalis, Nick; Taylor, Cath

2014-01-01

336

Detection Method and Observed Data of High-energy Gamma Rays under the Influence of Quantum Gravity  

NASA Astrophysics Data System (ADS)

The interaction of high-energy particles affected by quantum gravity is argued from the experimental viewpoint of raising a question, ``our detection method for high-energy ?-rays supplies trustworthy observation data and we are now seeing the true image of the universe through high-energy ?-rays?" The modified dispersion relation (MDR) for particles' energy and momentum is applied to the equation of energy-momentum conservation in particle reactions, to study the restriction imposed on the kinematic state of high-energy particles by the Lorentz invariance violation (LIV) due to quantum gravity, as a function of the incident particle energy of the reaction. The result suggests that the interaction utilized for ?-ray detection is not free from the effect of quantum gravity when ?-ray energy is higher than 1013 ~ 1017 eV depending on models of MDR. Discussion is presented on the prospect of finding clear evidence of the LIV effect from ?-ray observations, as well as on the radiation and propagation mechanism of ?-rays under the influence of the LIV effect.

Kifune, T.

2014-05-01

337

Hyperuricemia and Risk of Incident Hypertension: A Systematic Review and Meta-Analysis of Observational Studies  

PubMed Central

Background Observational studies of the relationship between hyperuricemia and the incidence of hypertension are controversial. We conducted a systematic review and meta-analysis to assess the association and consistency between uric acid levels and the risk of hypertension development. Methods We searched MEDLINE, EMBASE, CBM (Chinese Biomedicine Database) through September 2013 and reference lists of retrieved studies to identify cohort studies and nested case-control studies with uric acid levels as exposure and incident hypertension as outcome variables. Two reviewers independently extracted data and assessed study quality using Newcastle-Ottawa Scale. Extracted information included study design, population, definition of hyperuricemia and hypertension, number of incident hypertension, effect sizes, and adjusted confounders. Pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) for the association between hyperuricemia and risk of hypertension were calculated using a random-effects model. Results We included 25 studies with 97,824 participants assessing the association between uric acid and incident hypertension in our meta-analysis. The quality of included studies is moderate to high. Random-effects meta-analysis showed that hyperuricemia was associated with a higher risk of incident hypertension, regardless of whether the effect size was adjusted or not, whether the data were categorical or continuous as 1 SD/1 mg/dl increase in uric acid level (unadjusted: RR?=?1.73, 95% CI 1.46?2.06 for categorical data, RR?=?1.22, 95% CI 1.03?1.45 for a 1 SD increase; adjusted: RR?=?1.48, 95% CI 1.33?1.65 for categorical data, RR?=?1.15, 95% CI 1.06?1.26 for a 1 mg/dl increase), and the risk is consistent in subgroup analyses and have a dose-response relationship. Conclusions Hyperuricemia may modestly increase the risk of hypertension incidence, consistent with a dose-response relationship. PMID:25437867

Chen, Jianrong; Li, Yulin; Wang, Ling; Huang, He; Li, Jing

2014-01-01

338

Impact of social and technological distraction on pedestrian crossing behaviour: an observational study  

PubMed Central

Objectives The objective of the present work was to study the impact of technological and social distraction on cautionary behaviours and crossing times in pedestrians. Methods Pedestrians were observed at 20 high-risk intersections during 1 of 3 randomly assigned time windows in 2012. Observers recorded demographic and behavioural information, including use of a mobile device (talking on the phone, text messaging, or listening to music). We examined the association between distraction and crossing behaviours, adjusting for age and gender. All multivariate analyses were conducted with random effect logistic regression (binary outcomes) and random effect linear regression (continuous outcomes), accounting for clustering by site. Results Observers recorded crossing behaviours for 1102 pedestrians. Nearly one-third (29.8%) of all pedestrians performed a distracting activity while crossing. Distractions included listening to music (11.2%), text messaging (7.3%) and using a handheld phone (6.2%). Text messaging, mobile phone use and talking with a companion increased crossing time. Texting pedestrians took 1.87 additional seconds (18.0%) to cross the average intersection (3.4 lanes), compared to undistracted pedestrians. Texting pedestrians were 3.9 times more likely than undistracted pedestrians to display at least 1 unsafe crossing behaviour (disobeying the lights, crossing mid-intersection, or failing to look both ways). Pedestrians listening to music walked more than half a second (0.54) faster across the average intersection than undistracted pedestrians. Conclusions Distracting activity is common among pedestrians, even while crossing intersections. Technological and social distractions increase crossing times, with text messaging associated with the highest risk. Our findings suggest the need for intervention studies to reduce risk of pedestrian injury. PMID:23243104

Thompson, Leah L; Rivara, Frederick P; Ayyagari, Rajiv C; Ebel, Beth E

2013-01-01

339

Trough colistin plasma level is an independent risk factor for nephrotoxicity: a prospective observational cohort study  

PubMed Central

Background Data regarding the most efficacious and least toxic schedules for the use of colistin are scarce. The aim of this study was to determine the incidence and the potential risk factors of colistin-associated nephrotoxicity including colistin plasma levels. Methods A prospective observational cohort study was conducted for over one year in patients receiving intravenous colistin methanesulfonate sodium (CMS). Blood samples for colistin plasma levels were collected immediately before (Cmin) and 30 minutes after CMS infusion (Cmax). Renal function was assessed at baseline, on day 7 and at the end of treatment (EOT). Severity of acute kidney injury (AKI) was defined by the RIFLE (risk, injury, failure, loss, and end-stage kidney disease) criteria. Results One hundred and two patients met the inclusion criteria. AKI related to CMS treatment on day 7 and at the end of treatment (EOT) was observed in 26 (25.5%) and 50 (49.0%) patients, respectively. At day 7, Cmin (OR, 4.63 [2.33-9.20]; P < 0.001) was the only independent predictor of AKI. At EOT, the Charlson score (OR 1.26 [1.01-1.57]; P = 0.036), Cmin (OR 2.14 [1.33-3.42]; P = 0.002), and concomitant treatment with ? 2 nephrotoxic drugs (OR 2.61 [1.0-6.8]; P = 0.049) were independent risk factors for AKI. When Cmin was evaluated as a categorical variable, the breakpoints that better predicted AKI were 3.33 mg/L (P < 0.001) on day 7 and 2.42 mg/L (P < 0.001) at EOT. Conclusions When using the RIFLE criteria, colistin-related nephrotoxicity is observed in a high percentage of patients. Cmin levels are predictive of AKI. Patients who receive intravenous colistin should be closely monitored and Cmin might be a new useful tool to predict AKI. PMID:23957376

2013-01-01

340

Critical role of bioanalytical strategies in investigation of clinical PK observations, a Phase I case study.  

PubMed

RG7652 is a human immunoglobulin 1 (IgG1) monoclonal antibody (mAb) targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) and is designed for the treatment of hypercholesterolemia. A target-binding enzyme-linked immunosorbent assay (ELISA) was developed to measure RG7652 levels in human serum in a Phase I study. Although target-binding assay formats are generally used to quantify free therapeutic, the actual therapeutic species being measured are affected by assay conditions, such as sample dilution and incubation time, and levels of soluble target in the samples. Therefore, in the presence of high concentrations of circulating target, the choice of reagents and assay conditions can have a significant effect on the observed pharmacokinetic (PK) profiles. Phase I RG7652 PK analysis using the ELISA data resulted in a nonlinear dose normalized exposure. An investigation was conducted to characterize the ELISA to determine whether the assay format and reagents may have contributed to the PK observation. In addition, to confirm the ELISA results, a second orthogonal method, liquid chromatography tandem mass spectrometry (LC-MS/MS) using a signature peptide as surrogate, was developed and implemented. A subset of PK samples, randomly selected from half of the subjects in the 6 single ascending dose (SAD) cohorts in the Phase I clinical study, was analyzed with the LC-MS/MS assay, and the data were found to be comparable to the ELISA data. This paper illustrates the importance of reagent characterization, as well as the benefits of using an orthogonal approach to eliminate bioanalytical contributions when encountering unexpected observations. PMID:25484037

Peng, Kun; Xu, Keyang; Liu, Luna; Hendricks, Robert; Delarosa, Reginald; Erickson, Rich; Budha, Nageshwar; Leabman, Maya; Song, An; Kaur, Surinder; Fischer, Saloumeh K

2014-01-01

341

The association of DNA Repair with breast cancer risk in women. A comparative observational study  

PubMed Central

Background Previous studies have found a link between a low DNA repair capacity (DRC) level and increased cancer risk. Our aim was to assess the statistical association of DRC level and breast cancer (BC) using a case–control epidemiological study in a Hispanic community. Methods We conducted a comparative observational study to assess the validity of DRC in detecting BC in 824 women throughout Puerto Rico. Over a 6-year period, we compared 285 women newly diagnosed with BC to 539 without BC. DRC levels were measured in lymphocytes by means of a host-cell reactivation assay. We assessed the sensitivity, specificity, and association using the receiver operating characteristic curve analysis. Multiple logistic regression-adjusted odds ratios were estimated with 95% confidence level to measure the strength of the association of DRC and BC after adjusting for all confounders simultaneously. Results Compared to women without cancer, women with BC showed an average decrease of 60% in their DRC levels (p < 0.001). Validity of the association of DRC as a measure of BC risk showed a sensitivity of 83.2% and specificity of 77.6% (p < 0.0001). Conclusions Our results support the usefulness of DRC level as a measure of BC risk. Additional studies in other populations are needed to further verify its usefulness. PMID:23088658

2012-01-01

342

Hyperthermic intraperitoneal chemotherapy with cisplatin and paclitaxel in advanced ovarian cancer: a multicenter prospective observational study  

PubMed Central

Objective Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have been recently reported with favorable oncological outcomes as treatment of advanced epithelial ovarian cancer (EOC). The aim of this study was to demonstrate the feasibility of CRS+HIPEC with cisplatin and paclitaxel for the treatment of advanced EOC. Methods This is a prospective observational study of 54 patients, from April 2007 to October 2013, with primary or recurrent peritoneal carcinomatosis due to EOC. The mean age was 54.51±9.34. Thirty patients (59%) had primary EOC, and 24 patients (41%) had recurrent disease. Results Mean peritoneal cancer index was 10.11 (range, 0 to 28), complete cytoreduction (CC0) was achieved for 47 patients (87%), CC1 for seven patients (13%). Patients with suboptimal cytoreduction (CC2 and CC3) were not included in the study. The mean stay in intensive care unit was 4.73±5.51 days and the mean hospitalization time was 24.0±10.03 days. We did not observe any intraoperative death. Seven patients (13%) required additional operations. Three patients (5.6%) died within 30 days from the procedure. Severe complications were seen in 19 patients (35.2%). During the follow-up period, disease recurred in 33 patients (61.1%); the median disease-free survival time was 12.46 months and the median overall survival time was 32.91 months. Conclusion CRS+HIPEC with cisplatin and paclitaxel for advanced EOC is feasible with acceptable morbidity and mortality. Additional follow-up and further studies are needed to determine the effects of HIPEC on long term survival. PMID:25376916

Coccolini, Federico; Campanati, Luca; Catena, Fausto; Ceni, Valentina; Jimenez Cruz, Jorge; Lotti, Marco; Magnone, Stefano; Napoli, Josephine; Rossetti, Diego; De Iaco, Pierandrea; Frigerio, Luigi; Pinna, Antonio; Runnebaum, Ingo; Ansaloni, Luca

2015-01-01

343

Deciding on success criteria for predictability of pharmacokinetic parameters from in vitro studies: an analysis based on in vivo observations.  

PubMed

Prediction accuracy of pharmacokinetic parameters is often assessed using prediction fold error, i.e., being within 2-, 3-, or n-fold of observed values. However, published studies disagree on which fold error represents an accurate prediction. In addition, "observed data" from only one clinical study are often used as the gold standard for in vitro to in vivo extrapolation (IVIVE) studies, despite data being subject to significant interstudy variability and subjective selection from various available reports. The current study involved analysis of published systemic clearance (CL) and volume of distribution at steady state (Vss) values taken from over 200 clinical studies. These parameters were obtained for 17 different drugs after intravenous administration. Data were analyzed with emphasis on the appropriateness to use a parameter value from one particular clinical study to judge the performance of IVIVE and the ability of CL and Vss values obtained from one clinical study to "predict" the same values obtained in a different clinical study using the n-fold criteria for prediction accuracy. The twofold criteria method was of interest because it is widely used in IVIVE predictions. The analysis shows that in some cases the twofold criteria method is an unreasonable expectation when the observed data are obtained from studies with small sample size. A more reasonable approach would allow prediction criteria to include clinical study information such as sample size and the variance of the parameter of interest. A method is proposed that allows the "success" criteria to be linked to the measure of variation in the observed value. PMID:24989891

Abduljalil, Khaled; Cain, Theresa; Humphries, Helen; Rostami-Hodjegan, Amin

2014-09-01

344

Studies on sulfate attack: Mechanisms, test methods, and modeling  

NASA Astrophysics Data System (ADS)

The objective of this research study was to investigate various issues pertaining to the mechanism, testing methods, and modeling of sulfate attack in concrete. The study was divided into the following segments: (1) effect of gypsum formation on the expansion of mortars, (2) attack by the magnesium ion, (3) sulfate attack in the presence of chloride ions---differentiating seawater and groundwater attack, (4) use of admixtures to mitigate sulfate attack---entrained air, sodium citrate, silica fume, and metakaolin, (5) effects of temperature and concentration of the attack solution, (6) development of new test methods using concrete specimens, and (7) modeling of the sulfate attack phenomenon. Mortar specimens using portland cement (PC) and tricalcium silicate (C 3S), with or without mineral admixtures, were prepared and immersed in different sulfate solutions. In addition to this, portland cement concrete specimens were also prepared and subjected to complete and partial immersion in sulfate solutions. Physical measurements, chemical analyses and microstructural studies were performed periodically on the specimens. Gypsum formation was seen to cause expansion of the C3S mortar specimens. Statistical analyses of the data also indicated that the quantity of gypsum was the most significant factor controlling the expansion of mortar bars. The attack by magnesium ion was found to drive the reaction towards the formation of brucite. Decalcification of the C-S-H and its subsequent conversion to the non-cementitious M-S-H was identified as the mechanism of destruction in magnesium sulfate attack. Mineral admixtures were beneficial in combating sodium sulfate attack, while reducing the resistance to magnesium sulfate attack. Air entrainment did not change the measured physical properties, but reduced the visible distress of the mortars. Sodium citrate caused a substantial reduction in the rate of damage of the mortars due to its retarding effect. Temperature and concentration of the solution were seen to change the rate and mechanism of the attack in both sodium and magnesium sulfate solutions. The test results from these experiments were used to generate models for prediction of physical properties such as expansion and mass change, which could be used either for service life predictions, or for designing more reliable laboratory tests. Lastly, mechanisms for the attack by sodium and magnesium sulfate were proposed, based on the observations in the various studies. These mechanisms were able to simplify the understanding of the sulfate attack phenomenon.

Santhanam, Manu

345

IRT studies of many groups: the alignment method  

PubMed Central

Asparouhov and Muthén (2014) presented a new method for multiple-group confirmatory factor analysis (CFA), referred to as the alignment method. The alignment method can be used to estimate group-specific factor means and variances without requiring exact measurement invariance. A strength of the method is the ability to conveniently estimate models for many groups, such as with comparisons of countries. This paper focuses on IRT applications of the alignment method. An empirical investigation is made of binary knowledge items administered in two separate surveys of a set of countries. A Monte Carlo study is presented that shows how the quality of the alignment can be assessed. PMID:25309470

Muthén, Bengt; Asparouhov, Tihomir

2014-01-01

346

Methodical questions and accuracy problems of GPS observations by the example of the geodynamic proving ground in Bishkek  

NASA Astrophysics Data System (ADS)

The key questions concerning the modern methodical tasks and accuracy of GPS measurements of crustal motion spanning are discussed for a full cycle of the survey from the organization of the field operations to the interpretation of the final results. The presented data rely on the 20-year experience of the geophysicists of the Research Station of the Russian Academy of Sciences in Bishkek (RS RAS) in GPS monitoring at the Geodynamic Proving Ground in Bishkek (GPGB) and in a large part of Central Asia. The comparative characteristics of the constellations of visible GPS and GLONASS satellites are analyzed from the standpoint of their practical application for precise scientific observations of crustal motions. The studies of the contemporary movements of the Earth's crust by the methods of satellite geodesy generally comprise three stages: (1) organization of the measurement networks and acquisition of the data; (2) data processing; and (3) interpretation of the results. Each stage is associated with its own block of the tasks and problems, and neither is guaranteed against uncertainties and errors which may affect the results, conclusions, and reconstructions.

Kuzikov, S. I.

2014-11-01

347

A Study Of Facial Asymmetries By The Stereometric Method  

NASA Astrophysics Data System (ADS)

In order to determine the part played in facial dissymmetry observed on a living person by the various constitutive elements of the cephalic tip (the soft parts - skin, muscles and the underlying bone structure) we undertook, using a biostereometric method, to evaluate asymmetries between homologous right and left dimensions on a living person's face and on a skeleton. While in an individual, a marked degree of facial dissymmetry can sometimes be observed; average differences between the right and left sides of the face may nethertheless balance out, and remain slight. Conventional anthropometrics techniques do not show up such slight values. With a view to securing a higher degree of accuracy, study of the stereometric technique of measurements. Using this technique, quasi imperceptible differences between the right and the left sides of the face on a living person as well as on a skeleton, together with variations in the orientation or angulation of anatomical segments in a three-dimensional space can be measured. We were thus able to detect, in a number of dry skulls, average differences of approxi-mately a millimetre between the two sides of the face which cannot be attributed to back of accuracy in measurements. Although statistically the difference are not always significant, the para-metric values of facial dimensions are invariably greater for the left side. On the other hand, for the sample of living subjects as a whole, the differences between homologous distances are not statistically significant. But it may be that, on a living subject, the experimenter is inclined to take measurements that are susceptible of symmetrization (for instance, the nasion in the median sagittal plane) whereas on a dry skull anatomical reference marks can be determined with the utmost accuracy. It may be inferred from there results that the softer parts tend, as a rule, to correct the dissymmetry of the underlying skeleton.

Crete, N.; Deloison, Y.; Mollard, R.

1980-07-01

348

A study of numerical methods for hyperbolic conservation laws with stiff source terms  

NASA Technical Reports Server (NTRS)

The proper modeling of nonequilibrium gas dynamics is required in certain regimes of hypersonic flow. For inviscid flow this gives a system of conservation laws coupled with source terms representing the chemistry. Often a wide range of time scales is present in the problem, leading to numerical difficulties as in stiff systems of ordinary differential equations. Stability can be achieved by using implicit methods, but other numerical difficulties are observed. The behavior of typical numerical methods on a simple advection equation with a parameter-dependent source term was studied. Two approaches to incorporate the source term were utilized: MacCormack type predictor-corrector methods with flux limiters, and splitting methods in which the fluid dynamics and chemistry are handled in separate steps. Various comparisons over a wide range of parameter values were made. In the stiff case where the solution contains discontinuities, incorrect numerical propagation speeds are observed with all of the methods considered. This phenomenon is studied and explained.

Leveque, R. J.; Yee, H. C.

1988-01-01

349

Contemporary methods of surface analysis in the study of glass  

SciTech Connect

The surface state of a glass, its structure, and its composition determine many mechanical and physicochemical properties of the glass. This paper examines the common methods in electron- and ion-spectroscopy for analyzing the surface of glass. The X-ray photoelectron spectroscopy method (XPS) or the electron spectroscopy for chemical analysis (ESCA) method is based on the irradiation of a specimen by photons followed by the recording of the secondary photoelectrons. Another method described is Auger electron spectroscopy (AES) based on the effect discovered by P. Auger in 1925. The secondary-ion mass spectroscopy (SIMS) method is a third method and is based on the mass-spectroscopy recording of ions emitted from the surface of a specimen bombarded by a beam of primary ions at a fairly high energy (units of keV). Also described is the ion etching method. The range of application of the surface-analysis methods described to study glass are broad and the authors briefly consider the experimental results obtained in the most important fields of application of these methods. In addition to the purely element analysis, electron spectroscopic methods of studying the surface make it possible to study the crystal and electron structure of the surface of a solid.

Milovanov, A.P.; Moiseev, V.V.; Portnyagin, V.I.

1985-11-01

350

Long-term effectiveness of intralesional triamcinolone acetonide therapy in orofacial granulomatosis: an observational cohort study  

PubMed Central

Summary Background It has been suggested that intralesional triamcinolone injections represent a safe and effective therapeutic strategy in controlling the permanent disfiguring swelling of orofacial granulomatosis (OFG). However, robust supporting evidence is lacking, due to the variable and inconsistent design of available studies. Objectives To investigate whether a standardized regimen of intralesional triamcinolone has beneficial long-term effects on orofacial swelling of OFG. We also studied potential associations with a number of prognostic factors. Methods We designed a retrospective observational study of a homogeneous cohort of 22 well-phenotyped patients with OFG. The primary outcome was defined as a statistically significant decrease in post-treatment disease severity. Statistically significant association with prognostic factors was the secondary outcome. Statistical analysis included Wilcoxon signed-rank tests and logistic regression. Results Compared with pretreatment, there were statistically significant decreases in disease severity scores at all time points until 48 months post-treatment (P < 0·01). Logistic regression analysis showed there was no independent prognostic variable of statistical significance (P > 0·05). The majority of patients (14/22, 63·6%) received one course of intralesional triamcinolone and did not experience disease recurrence. The mean disease-free period after the first course of intralesional therapy was 28·9 ± 18 months (95% confidence interval 28·7–29·1). No adverse effects were reported. Conclusions This is the first study to have employed robust cohort methodology and sound statistics to demonstrate long-term effectiveness of intralesional triamcinolone in controlling the disfiguring swelling of OFG. Because of limitations inherent in observational studies, further research in the form of randomized case-control trials is needed to confirm the present findings. What's already known about this topic? It has been suggested that intralesional corticosteroid therapy is effective in controlling the permanent disfiguring swelling of orofacial granulomatosis (OFG); however, robust supporting evidence is lacking due to the variable and inconsistent design of available studies. What does this study add? This is the first cohort study on intralesional therapy to employ robust cohort design, consistent methodology and a standardized regimen of triamcinolone injections. It provides reliable evidence of long-term effectiveness in reducing the orofacial swelling of OFG. PMID:24088036

Fedele, S; Fung, PPL; Bamashmous, N; Petrie, A; Porter, S

2014-01-01

351

Application of ground-penetrating-radar methods in hydrogeologic studies  

USGS Publications Warehouse

A ground-penetrating-radar system was used to study selected stratified-drift deposits in Connecticut. Ground-penetrating radar is a surface-geophysical method that depends on the emission, transmission, reflection, and reception of an electromagnetic pulse and can produce continuous high-resolution profiles of the subsurface rapidly and efficiently. Traverse locations on land included a well field in the town of Mansfield, a sand and gravel pit and a farm overlying a potential aquifer in the town of Coventry, and Haddam Meadows State Park in the town of Haddam. Traverse locations on water included the Willimantic River in Coventry and Mansfield Hollow Lake in Mansfield. The penetration depth of the radar signal ranged from about 20 feet in fine-grained glaciolacustrine sediments to about 70 feet in coarse sand and gravel. Some land records in coarse-grained sediments show a distinct, continuous reflection from the water table about 5 to 11 feet below land surface. Parallel reflectors on the records are interpreted as fine-grained sediments. Hummocky or chaotic reflectors are interpreted as cross-bedded or coarse-grained sediments. Other features observed on some of the radar records include the till and bedrock surface. Records collected on water had distinct water-bottom multiples (more than one reflection) and diffraction patterns from boulders. The interpretation of the radar records, which required little or no processing, was verified by using lithologic logs from test holes located along some of the land traverses and near the water traverses.

Beres, Milan, Jr.; Haeni, F.P.

1991-01-01

352

Microcirculatory changes in term newborns with suspected infection: an observational prospective study.  

PubMed

Background. In adults severely disturbed microcirculatory flow can be observed by Orthogonal Polarized Spectral (OPS) imaging techniques during sepsis. Therefore we set out to assess for microcirculatory changes in term newborns with suspected early onset infection using OPS. Methods. OPS images were obtained prospectively from the vascular bed of the ear conch and upper arm of 47 newborns on their 1st, 2nd, and 3rd day of life. OPS sequences were analyzed semiquantitatively offline and blinded to clinical status of the infant. Flow in vessels was classified as continuous or noncontinuous flow and given as proportion of total vessels per image as in the studies in adults. Results. The proportion of vessels with continuous flow was significantly lower in the infants with infection (69% [56-81] versus 90% [87-94] (P = 0.0003)). None of the infants with infection was in shock or severely septic. Conclusion. In term neonates the microcirculatory flow is impaired in a large proportion of vessels even in mild to moderate infection. These changes can be observed at the onset of disease at the external ear, an optimal site for microcirculatory measurements in term infants. PMID:23365583

Alba-Alejandre, Irene; Hiedl, Stephan; Genzel-Boroviczény, Orsolya

2013-01-01

353

Microcirculatory Changes in Term Newborns with Suspected Infection: An Observational Prospective Study  

PubMed Central

Background. In adults severely disturbed microcirculatory flow can be observed by Orthogonal Polarized Spectral (OPS) imaging techniques during sepsis. Therefore we set out to assess for microcirculatory changes in term newborns with suspected early onset infection using OPS. Methods. OPS images were obtained prospectively from the vascular bed of the ear conch and upper arm of 47 newborns on their 1st, 2nd, and 3rd day of life. OPS sequences were analyzed semiquantitatively offline and blinded to clinical status of the infant. Flow in vessels was classified as continuous or noncontinuous flow and given as proportion of total vessels per image as in the studies in adults. Results. The proportion of vessels with continuous flow was significantly lower in the infants with infection (69% [56–81] versus 90% [87–94] (P = 0.0003)). None of the infants with infection was in shock or severely septic. Conclusion. In term neonates the microcirculatory flow is impaired in a large proportion of vessels even in mild to moderate infection. These changes can be observed at the onset of disease at the external ear, an optimal site for microcirculatory measurements in term infants. PMID:23365583

Alba-Alejandre, Irene; Hiedl, Stephan; Genzel-Boroviczény, Orsolya

2013-01-01

354

Why use DFT methods in the study of carbohydrates?  

Technology Transfer Automated Retrieval System (TEKTRAN)

The recent advances in density functional theory (DFT) and computer technology allow us to study systems with more than 100 atoms routinely. This makes it feasible to study large carbohydrate molecules via quantum mechanical methods, whereas in the past, studies of carbohydrates were restricted to ...

355

Safety of Intravenous Application of Mistletoe (Viscum album L.) Preparations in Oncology: An Observational Study.  

PubMed

Background. Traditional mistletoe therapy in cancer patients involves subcutaneous applications of Viscum album L. preparations, with doses slowly increasing based on patient responses. Intravenous infusion of high doses may improve therapeutic outcomes and is becoming more common. Little is known about the safety of this "off-label" application of mistletoe. Methods. An observational study was performed within the Network Oncology. Treatment with intravenous mistletoe applications is described. The frequency of adverse drug reactions (ADRs) to intravenous mistletoe applications was calculated and compared to ADR data from a study on subcutaneous applications. Results. Of 475 cancer patients who received intravenous infusions of Helixor, Abnoba viscum, or Iscador mistletoe preparations, 22 patients (4.6%) reported 32 ADRs of mild (59.4%) or moderate severity (40.6%). No serious ADRs occurred. ADRs were more frequently reported to i.v. mistletoe administered alone (4.3%), versus prior to chemotherapy (1.6%). ADR frequency differed with respect to preparation type, with Iscador preparations showing a higher relative frequency, compared to Abnoba viscum and Helixor. Overall, patients were almost two times less likely to experience an ADR to intravenous compared to subcutaneous application of mistletoe. Conclusion. Intravenous mistletoe therapy was found to be safe and prospective studies for efficacy are recommended. PMID:24955100

Steele, Megan L; Axtner, Jan; Happe, Antje; Kröz, Matthias; Matthes, Harald; Schad, Friedemann

2014-01-01

356

Legume Consumption and Colorectal Adenoma Risk: A Meta-Analysis of Observational Studies  

PubMed Central

Background The anticancer effects of legumes have been explored extensively, but evidence from epidemiologic studies on colorectal adenoma is controversial. We performed a meta-analysis to assess these issues. Methods A systemic search of several databases was conducted for relevant studies evaluating the relationship between legume intake and adenoma risk, with no language restriction, from January 1, 1966, to April 1, 2013. Results Three cohort and eleven case control studies with 8,380 cases and a total of 101,856 participants were included in the analysis; the pooled odds ratio (95% confidence interval) for the highest vs. lowest consumption categories was 0.83 (0.75–0.93), with moderate level of heterogeneity (I2?=?25.9% and P?=?0.146) based on a random effects model. A decreased risk of adenoma was also observed in most of our subgroup meta-analyses. Conclusions Higher intake of legumes significantly reduced the risk of colorectal adenoma in our meta-analysis. Nevertheless, due to possible confounders and bias, further investigations are warranted to confirm this relationship. PMID:23826270

Wang, Yunqian; Wang, Zhenhua; Fu, Linna; Chen, Yingxuan; Fang, Jingyuan

2013-01-01

357

The Dominance Behavioral System and Psychopathology: Evidence from Self-Report, Observational, and Biological Studies  

PubMed Central

The dominance behavioral system (DBS) can be conceptualized as a biologically-based system which guides dominance motivation, dominant and subordinate behavior, and responsivity to perceptions of power and subordination. A growing body of research suggests that problems with the DBS are evident across a broad range of psychopathologies. We begin by describing psychological, social, and biological correlates of the dominance behavioral system (DBS). Extensive research suggests that externalizing disorders, mania-proneness, and narcissistic traits are related to heightened dominance motivation and behaviors. Mania and narcissistic traits also appear related to inflated self-perceptions of power. Anxiety and depression are related to subordination and submissiveness, as well as a desire to avoid subordination. Models of the DBS have received support from research with humans and animals; from self-report, observational, and biological methods; and using naturalistic and experimental paradigms. Limitations of available research include the relative lack of longitudinal studies using multiple measures of the DBS and the absence of relevant studies using diagnosed samples to study narcissistic personality disorder and bipolar disorder. We provide suggestions for future research on the DBS and psychopathology, including investigations of whether the DBS can be used to differentiate specific disorder outcomes; the need for more sophisticated biological research; and the value of longitudinal dynamical research. Implications of using the DBS as a tool in clinical assessment and treatment are discussed. PMID:22506751

Johnson, Sheri L.; Leedom, Liane J.; Muhtadie, Luma

2012-01-01

358

Safety of Intravenous Application of Mistletoe (Viscum album L.) Preparations in Oncology: An Observational Study  

PubMed Central

Background. Traditional mistletoe therapy in cancer patients involves subcutaneous applications of Viscum album L. preparations, with doses slowly increasing based on patient responses. Intravenous infusion of high doses may improve therapeutic outcomes and is becoming more common. Little is known about the safety of this “off-label” application of mistletoe. Methods. An observational study was performed within the Network Oncology. Treatment with intravenous mistletoe applications is described. The frequency of adverse drug reactions (ADRs) to intravenous mistletoe applications was calculated and compared to ADR data from a study on subcutaneous applications. Results. Of 475 cancer patients who received intravenous infusions of Helixor, Abnoba viscum, or Iscador mistletoe preparations, 22 patients (4.6%) reported 32 ADRs of mild (59.4%) or moderate severity (40.6%). No serious ADRs occurred. ADRs were more frequently reported to i.v. mistletoe administered alone (4.3%), versus prior to chemotherapy (1.6%). ADR frequency differed with respect to preparation type, with Iscador preparations showing a higher relative frequency, compared to Abnoba viscum and Helixor. Overall, patients were almost two times less likely to experience an ADR to intravenous compared to subcutaneous application of mistletoe. Conclusion. Intravenous mistletoe therapy was found to be safe and prospective studies for efficacy are recommended. PMID:24955100

Steele, Megan L.; Axtner, Jan; Happe, Antje; Kröz, Matthias; Matthes, Harald; Schad, Friedemann

2014-01-01

359

Robust methods for population stratification in genome wide association studies  

PubMed Central

Background Genome-wide association studies can provide novel insights into diseases of interest, as well as to the responsiveness of an individual to specific treatments. In such studies, it is very important to correct for population stratification, which refers to allele frequency differences between cases and controls due to systematic ancestry differences. Population stratification can cause spurious associations if not adjusted properly. The principal component analysis (PCA) method has been relied upon as a highly useful methodology to adjust for population stratification in these types of large-scale studies. Recently, the linear mixed model (LMM) has also been proposed to account for family structure or cryptic relatedness. However, neither of these approaches may be optimal in properly correcting for sample structures in the presence of subject outliers. Results We propose to use robust PCA combined with k-medoids clustering to deal with population stratification. This approach can adjust for population stratification for both continuous and discrete populations with subject outliers, and it can be considered as an extension of the PCA method and the multidimensional scaling (MDS) method. Through simulation studies, we compare the performance of our proposed methods with several widely used stratification methods, including PCA and MDS. We show that subject outliers can greatly influence the analysis results from several existing methods, while our proposed robust population stratification methods perform very well for both discrete and admixed populations with subject outliers. We illustrate the new method using data from a rheumatoid arthritis study. Conclusions We demonstrate that subject outliers can greatly influence the analysis result in GWA studies, and propose robust methods for dealing with population stratification that outperform existing population stratification methods in the presence of subject outliers. PMID:23601181

2013-01-01

360

Comparison of different methods for monitoring glacier changes observed by Landsat images  

NASA Astrophysics Data System (ADS)

With the acceleration of global warming, it has been increasingly important to investigate the roles of glaciers as freshwater sources and sensitive indicators of climate change. Thus, it is of great significance to acquire accurate information on glacier changes. However, few papers have focused on the comparison of glacier monitoring methods. The objectives of this paper are to (1) present three methods for classifying glacier boundaries, including visual interpretation, ratio between TM channels 4 and 5 as well as Normalized Difference Snow Index (NDSI); (2) compare the tree methods to give users some advice on how to choose an appropriate method; (3) analyze the relationship between glacier change and the trends of precipitation and temperature. Current distribution and glacier changes since the 1980s were mapped using multi-temporal optical remote sensing data from the Landsat series. Thematic maps were then generated using three classification methods. Furthermore, GIS-supported investigation was also conducted to get information of glacier changes. Finally, the results were compared. The results indicated that: (1) the visual interpretation method is accurate but time-consuming and operator-dependent; (2) the ratioing method using channel 4 and 5 of Landsat image is fast, accurate but need too much follow-up work; (3) NDSI cannot classify snow and glacier very well, and it sometimes misclassifies snow into glaciers; (4) analyses of precipitation and temperature indicate that global warming is a major factor affecting changes of glaciers.

Man, Q. X.; Guo, H. D.; Liu, G.; Dong, P. L.

2014-03-01

361

Observational study on Takotsubo-like cardiomyopathy: clinical features, diagnosis, prognosis and follow-up  

PubMed Central

Objectives The present study attempts to identify appropriate elements that may contribute to clarify the broad clinical features (diagnosis, care, complication and prognosis) of Takotsubo-like cardiomyopathy for improving its management. Design study Observational study. Setting Primary level of care referred to the emergency department of Vannini Hospital, Rome, Italy. Participants The study population consisted of 75 patients, 72 of the them were women and 3 were men with a mean age of 71.9±9.6?years. Methods From February 2004 to November 2010, prospectively included 84 consecutive patients diagnosed for suspected Takotsubo-like cardiomyopathy. To be eligible, patients had to meet all the Mayo clinic criteria in the absence of neurological trauma or intracranial haemorrhage. Moreover, those patients that at follow-up still presented alteration of acute phase at ECG and echocardiogram were excluded. Thus, 75 patients comprised the study population. To follow-up 19 patients were lost. Results None of 75 patients died in acute phase. All patients were promptly discharged (8.4±4.4?days), since they recovered their normal functional status without symptoms. Follow-up information was available for 56 patients. At a mean follow-up time of 2.2±2?years (range, 0.1–6.8?years) two octogenarian patients (2.6%) died because of sudden cardiac death and pulmonary embolism, respectively. The Takotsubo-like cardiomyopathy recurred in one patient. Conclusions The results of this study support the previous reports about the good prognosis, also in critically ill patients, of Takotsubo-like cardiomyopathy. Further assessment will be needed to determine a careful and sustained follow-up for choosing the best care and foreseeing the recurrences of this emerging condition. PMID:23065445

Cacciotti, Luca; Passaseo, Ilaria; Marazzi, Giuseppe; Camastra, Giovanni; Campolongo, Giuseppe; Beni, Sergio; Lupparelli, Fabrizio; Ansalone, Gerardo

2012-01-01

362

The treatment of hypertension in people with dementia: a systematic review of observational studies  

PubMed Central

Background Hypertension is very common in older people and a number of trials of antihypertensives have demonstrated benefit from treatment in even the oldest old. However, people with dementia were significantly under-represented in these studies and as a population are more likely to be physically frail, to suffer orthostatic hypotension and to experience adverse effects from polypharmacy at a lower drug count. It may be that different thresholds for commencement and cessation of treatment should be considered and may already be used for this group. Against this background this review sets out to describe the prevalence of hypertension in people with dementia, its treatment, change in treatment over time and the achievement of blood pressure (BP) control. Methods The PubMed, Cochrane, Embase and PsychINFO databases were searched for observational studies involving people with dementia and a diagnosis of hypertension. The search was limited to English language articles involving adults and humans published from 1990 onwards. Abstracts and titles were then reviewed with eligible articles read in full. Bibliographies were examined for further relevant studies. The final selection of studies was then analysed and appraised. Results Thirteen articles were identified for analysis. The prevalence of hypertension in people with dementia was 45% (range 35%-84%). 73% of these were on at least one antihypertensive, with diuretics being the most common. The reported prevalence of hypertension in study populations remained unchanged over time. ACEi/ARBs and calcium channel blockers were prescribed more frequently in more recent studies whilst use of ?-blockers and diuretics remained unchanged. Target blood pressure was achieved in 55% of those on treatment. Conclusion Hypertension is as common in people with dementia as in other populations and is as commonly treated with antihypertensive drugs. The findings presented here will support further work to establish the risk-benefit of antihypertensive treatment in patients with dementia and, if differing ratios are identified, to establish dementia-specific guidelines for management. PMID:24520843

2014-01-01

363

A Study of Methods for Estimating Distributions of Test Scores.  

ERIC Educational Resources Information Center

This study compared five density estimation techniques applied to samples from a population of 272,244 examinees' ACT English Usage and Mathematics Usage raw scores. Unsmoothed frequencies, kernel method, negative hypergeometric, four-parameter beta compound binomial, and Cureton-Tukey methods were applied to 500 replications of random samples of…

Cope, Ronald T.; Kolen, Michael J.

364

Studying Organizational Computing Infrastructures: Multi-method Approaches  

Microsoft Academic Search

This paper provides guidelines for developing multi-method research approaches, provides several examples of their use, and discusses experiences with conducting a multi-method study of one organization's computing infrastructure changes. The focus on organizationa l computing infrastructures is due to the contemporary belief that these are increasingly critical to organizational success. However, understanding the value of an organization's computing infrastructure is

Steve Sawyer

2000-01-01

365

Three Strategies for Teaching Research Methods: A Case Study  

ERIC Educational Resources Information Center

The authors provide a brief case study of a three-strategy approach for teaching undergraduate research methods that (1) incorporates active learning assignments and discussion-based learning, (2) integrates a cross-discipline and cross-method faculty guest discussion facilitators series, and (3) focuses on the challenges and rewards of conducting…

Pfeffer, Carla A.; Rogalin, Christabel L.

2012-01-01

366

Culture method to study fungal growth in solid fermentation  

Microsoft Academic Search

A new culture method is described to study the growth of Aspergillus niger on cassava meal in the solid state. This method uses preparations of the cooked starchy substrate as a homogeneous granulated product containing spores, salts and water. An incubation device aerates the mass with humidified air at a controlled temperature. Homogeneous development of mycelia, without sporulation, occurred in

Maurice Raimbault; Didier Alazard

1980-01-01

367

Engineering Study of 500 ML Sample Bottle Transportation Methods  

SciTech Connect

This engineering study reviews and evaluates all available methods for transportation of 500-mL grab sample bottles, reviews and evaluates transportation requirements and schedules and analyzes and recommends the most cost-effective method for transporting 500-mL grab sample bottles.

BOGER, R.M.

1999-08-25

368

Using Diary Methods to Study Marital and Family Processes  

Microsoft Academic Search

Diary methods allow researchers to study marital and family processes within the context of daily life in a way that is not possible with more traditional methods. The authors review applications of diary designs in marital and family research and detail the types of research questions that can uniquely be asked of dyadic\\/family diary data. Technological developments for the use

Jean-Philippe Laurenceau; Niall Bolger

2005-01-01

369

Generalizability and decision studies to inform observational and experimental research in classroom settings.  

PubMed

Attaining reliable estimates of observational measures can be challenging in school and classroom settings, as behavior can be influenced by multiple contextual factors. Generalizability (G) studies can enable researchers to estimate the reliability of observational data, and decision (D) studies can inform how many observation sessions are necessary to achieve a criterion level of reliability. We conducted G and D studies using observational data from a randomized control trial focusing on social and academic participation of students with severe disabilities in inclusive secondary classrooms. Results highlight the importance of anchoring observational decisions to reliability estimates from existing or pilot data sets. We outline steps for conducting G and D studies and address options when reliability estimates are lower than desired. PMID:25354126

Bottema-Beutel, Kristen; Lloyd, Blair; Carter, Erik W; Asmus, Jennifer M

2014-11-01

370

Thrombocytopenia in vivax and falciparum malaria: an observational study of 131 patients in Karnataka, India  

PubMed Central

Background: Thrombocytopenia has been reported in the majority of malaria studies. Some but not all studies suggest the possible role of platelets in the pathology of severe malaria. We assess the association of admission platelet count with malaria complications and mortality in vivax and falciparum malaria. Methods: This is a prospective, observational study of patients aged 18 years and above admitted in a tertiary care teaching hospital from August 2004 to July 2006 in Manipal, India. Malaria was diagnosed based on clinical features along with positive Quantitative Buffy Coat method (QBC MP) or thin blood smear examination (Giemsa stain). Platelet counts were measured using Coulter LH 756 Analyser. Thrombocytopenia was defined as a platelet count <150×109/l. Results: A total of 131 consecutive patients were included. Sixty patients (46%) were infected with Plasmodium vivax and the rest with Plasmodium falciparum. Forty-six (35%) patients had non-severe and 24 (18%) had severe falciparum infection. The prevalence of thrombocytopenia was similar in vivax and falciparum malaria. Patients with severe falciparum malaria had a statistically significant lower platelet count (P?=?0.01) compared to non-severe falciparum malaria. Severe malaria patients with renal failure (P?=?0.02) or hyperparasitaemia (P?=?0.03) had a statistically significant lower mean platelet count compared to non-severe falciparum malaria. Patients with involvement of more than one organ system had a lower mean platelet count compared to those with single organ involvement. Conclusions: The incidence of thrombocytopenia was similar in vivax and falciparum malaria. The admission platelet count is significantly lower in patients who have hyperparasitaemia and acute renal failure compared to patients without complications. PMID:22325818

Saravu, K; Docherla, M; Vasudev, A; Shastry, B A

2011-01-01

371

Prevalence of dysglycemia in Calabar: a cross-sectional observational study among residents of Calabar, Nigeria  

PubMed Central

Objective Population data on dysglycemia are scarce in West Africa. This study aimed to determine the pattern of dysglycemia in Calabar city in South East Nigeria. Design This was a cross-sectional observational study. Methods 1134 adults in Calabar were recruited. A multistage sampling method randomly selected 4 out of 22 wards, and 50 households from each ward. All adults within each household were recruited and an oral glucose tolerance test was performed. Dysglycemia was defined as any form of glucose intolerance, including: impaired fasting glucose (blood glucose level 110–125?mg/dL), impaired glucose tolerance (blood glucose level ?140?mg/dL 2?h after consuming 75?g of glucose), or diabetes mellitus (DM), as defined by fasting glucose level ?126?mg/dL, or a blood glucose level ?200?mg/dL, 2?h after a 75?g glucose load. Results Mean values of fasting plasma glucose were 95?mg/dL (95% CI 92.1 to 97.5) for men and 96?mg/dL (95% CI 93.2 to 98.6) for women. The overall prevalence of dysglycemia was 24%. The prevalence of impaired fasting glucose was 9%, the prevalence of impaired glucose tolerance 20%, and the prevalence of undiagnosed DM 7%. All values were a few percentage points higher for men than women. Conclusions The prevalence of undiagnosed DM among residents of Calabar is similar to studies elsewhere in Nigeria but much higher than the previous national prevalence survey, with close to a quarter of the adults having dysglycemia and 7% having undiagnosed DM. This is a serious public health problem requiring a programme of mass education and case identification and management in all health facilities. Trial registration number CRS/MH/CR-HREC/020/Vol.8/43 PMID:25452872

Enang, O E; Otu, A A; Essien, O E; Okpara, H; Fasanmade, O A; Ohwovoriole, A E; Searle, J

2014-01-01

372

Qualitative PCR method for Roundup Ready soybean: interlaboratory study.  

PubMed

Quantitative and qualitative methods based on PCR have been developed for genetically modified organisms (GMO). Interlaboratory studies were previously conducted for GMO quantitative methods; in this study, an interlaboratory study was conducted for a qualitative method for a GM soybean, Roundup Ready soy (RR soy), with primer pairs designed for the quantitative method of RR soy studied previously. Fourteen laboratories in Japan participated. Each participant extracted DNA from 1.0 g each of the soy samples containing 0, 0.05, and 0.10% of RR soy, and performed PCR with primer pairs for an internal control gene (Le1) and RR soy followed by agarose gel electrophoresis. The PCR product amplified in this PCR system for Le1 was detected from all samples. The sensitivity, specificity, and false-negative and false-positive rates of the method were obtained from the results of RR soy detection. False-negative rates at the level of 0.05 and 0.10% of the RR soy samples were 6.0 and 2.3%, respectively, revealing that the LOD of the method was somewhat below 0.10%. The current study demonstrated that the qualitative method would be practical for monitoring the labeling system of GM soy in kernel lots. PMID:21391499

Kodama, Takashi; Kasahara, Masaki; Minegishi, Yasutaka; Futo, Satoshi; Sawada, Chihiro; Watai, Masatoshi; Akiyama, Hiroshi; Teshima, Reiko; Kurosawa, Yasunori; Furui, Satoshi; Hino, Akihiro; Kitta, Kazumi

2011-01-01

373

Clinical predictive value of manual muscle strength testing during critical illness: an observational cohort study  

PubMed Central

Introduction Impaired skeletal muscle function has important clinical outcome implications for survivors of critical illness. Previous studies employing volitional manual muscle testing for diagnosing intensive care unit-acquired weakness (ICU-AW) during the early stages of critical illness have only provided limited data on outcome. This study aimed to determine inter-observer agreement and clinical predictive value of the Medical Research Council sum score (MRC-SS) test in critically ill patients. Methods Study 1: Inter-observer agreement for ICU-AW between two clinicians in critically ill patients within ICU (n = 20) was compared with simulated presentations (n = 20). Study 2: MRC-SS at awakening in an unselected sequential ICU cohort was used to determine the clinical predictive value (n = 94) for outcomes of ICU and hospital mortality and length of stay. Results Although the intra-class correlation coefficient (ICC) for MRC-SS in the ICU was 0.94 (95% CI 0.85–0.98), ? statistic for diagnosis of ICU-AW (MRC-SS <48/60) was only 0.60 (95% CI 0.25–0.95). Agreement for simulated weakness presentations was almost complete (ICC 1.0 (95% CI 0.99–1.0), with a ? statistic of 1.0 (95% CI 1.0–1.0)). There was no association observed between ability to perform the MRC-SS and clinical outcome and no association between ICU-AW and mortality. Although ICU-AW demonstrated limited positive predictive value for ICU (54.2%; 95% CI 39.2–68.6) and hospital (66.7%; 95% CI 51.6–79.6) length of stay, the negative predictive value for ICU length of stay was clinically acceptable (88.2%; 95% CI 63.6–98.5). Conclusions These data highlight the limited clinical applicability of volitional muscle strength testing in critically ill patients. Alternative non-volitional strategies are required for assessment and monitoring of muscle function in the early stages of critical illness. PMID:24112540

2013-01-01

374

Comparative effectiveness of microdecompression and laminectomy for central lumbar spinal stenosis: study protocol for an observational study  

PubMed Central

Introduction This observational study is designed to test the equivalence between the clinical effectiveness of microdecompression and laminectomy in the surgical treatment of central lumbar spinal stenosis. Lumbar spinal stenosis is the most frequent indication for spinal surgery in the elderly, and as the oldest segment of the population continues to grow its prevalence is likely to increase. However, data on surgical outcomes are limited. Open or wide decompressive laminectomy, often combined with medial facetectomy and foraminotomy, was formerly the standard treatment. In recent years a growing tendency towards less invasive decompressive procedures has emerged. At present, many spine surgeons perform microdecompression for central lumbar spinal stenosis. Methods and analysis Prospectively registered treatment and outcome data are obtained from the Norwegian Registry for Spine Surgery. The primary outcome measure is change in Oswestry disability index between baseline and 12-month follow-up. Secondary outcome measures are changes in health-related quality of life measured by the Euro-Qol-5D between baseline and 12-month follow-up, perioperative complications, and duration of surgical procedures and length of hospital stay. Ethics and dissemination The study has been evaluated and approved by the regional committee for medical research in central Norway and all participants provided written informed consent. The findings of this study will be disseminated through peer-reviewed publications. Trial registration number Clinicaltrials.gov (NCT02006901). PMID:24650809

Nerland, Ulf S; Jakola, Asgeir S; Solheim, Ole; Weber, Clemens; Rao, Vidar; Lønne, Greger; Solberg, Tore K; Salvesen, Øyvind; Carlsen, Sven M; Nygaard, Øystein P; Gulati, Sasha

2014-01-01

375

A Sparse Representation-Based Deployment Method for Optimizing the Observation Quality of Camera Networks  

PubMed Central

Deployment is a critical issue affecting the quality of service of camera networks. The deployment aims at adopting the least number of cameras to cover the whole scene, which may have obstacles to occlude the line of sight, with expected observation quality. This is generally formulated as a non-convex optimization problem, which is hard to solve in polynomial time. In this paper, we propose an efficient convex solution for deployment optimizing the observation quality based on a novel anisotropic sensing model of cameras, which provides a reliable measurement of the observation quality. The deployment is formulated as the selection of a subset of nodes from a redundant initial deployment with numerous cameras, which is an ?0 minimization problem. Then, we relax this non-convex optimization to a convex ?1 minimization employing the sparse representation. Therefore, the high quality deployment is efficiently obtained via convex optimization. Simulation results confirm the effectiveness of the proposed camera deployment algorithms. PMID:23989826

Wang, Chang; Qi, Fei; Shi, Guangming; Wang, Xiaotian

2013-01-01

376

The Embedded Researcher Method for Involving Undergraduates in Research: New Data and Observations  

ERIC Educational Resources Information Center

Undergraduate research provides multiple educational advantages, and Hispanic students may reap particular benefits. The "embedded researcher" method avoids difficulties inherent in traditional apprenticeship models, providing meaningful research experience to multiple students within a standard didactic course structure while yielding…

Rogers, Darrin L.; Kranz, Peter L.; Ferguson, Christopher J.

2013-01-01

377

Methods to Collect, Compile, and Analyze Observed Short-lived Fission Product Gamma Data  

SciTech Connect

A unique set of fission product gamma spectra was collected at short times (4 minutes to 1 week) on various fissionable materials. Gamma spectra were collected from the neutron-induced fission of uranium, neptunium, and plutonium isotopes at thermal, epithermal, fission spectrum, and 14-MeV neutron energies. This report describes the experimental methods used to produce and collect the gamma data, defines the experimental parameters for each method, and demonstrates the consistency of the measurements.

Finn, Erin C.; Metz, Lori A.; Payne, Rosara F.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Pierson, Bruce D.; Ellis, Tere A.

2011-09-29

378

EPA (ENVIONMENTAL PROTECTION AGENCY) METHOD STUDY 20, METHOD 610--PNA'S (POLYNUCLEAR AROMATIC HYDROCARBONS)  

EPA Science Inventory

Sixteen laboratories participated in an interlaboratory study conducted to provide precision and accuracy statements for the proposed EPA Method 610 for 16 selected polynuclear aromatic hydrocarbons(PNA's) which may be present in municipal and industrial aqueous discharges. Metho...

379

Methods for the Study of Verticillium chlamydosporium in the Rhizosphere  

PubMed Central

Methods for screening isolates of the nematophagous fungus, V. chlamydosporium, for their ability to colonize the surface of plant roots are described. Significant differences in the extent of colonization were observed in sterile conditions and in soil; plant species and cultivars also differed in their ability to support a selected isolate of the fungus. Although fungal density could be estimated using a semi-selective medium, it was not possible to separate differences in vegetative growth from differences in sporulation. There was a weak positive correlation between estimates of fungal density on the roots of plants grown in sterile conditions and the extent of hyphal growth measured by direct observation. PMID:19279929

Bourne, J. M.; Kerry, B. R.; de Leij, F. A. A. M.

1994-01-01

380

Saving time: New methods and instrumentation for radio variability studies  

NASA Astrophysics Data System (ADS)

My thesis describes new instrumentation and signal processing techniques developed for time-domain studies of the radio sky and applies these techniques to a variety of radio astronomical data. Time-domain algorithms were developed for the SERENDIP V survey, a commensal SETI survey operating at the Arecibo Observatory. Along with collaborators at the University of California at Berkeley, I helped develop the high frequency resolution digital FFT spectrometers used to collected the data. No signal with the characteristics of being from an extraterrestrial intelligence was observed. A method for automatically classifying broadband and narrowband signals in raw frequency-time data is presented. It uses both the first and second moments of a spectrum to characterize the how broad or narrowband a signal is. Our applications of this technique to real data show that this algorithm is an effective tool for radio frequency interference excision. A survey for rare, bright radio transients was undertaken with a 3.8 m radio telescope on the roof of the Space Sciences Building on Cornell's campus. This survey involved the end-to-end development of the hardware, software, and data analysis. The data were searched from single, dispersed pulses, but none were found. Multi-frequency observations of the eclipsing, binary white dwarf system J0651 were conducted at the Arecibo Observatory to search for variable emission, both short-duration, "burst-like" and periodic emission. The system has an orbital period of only 12.75 min, and this fast rotation may generate radio emission if the stars are magnetic, but no emission was seen. Five new pulsars, including three Rotating Radio Transients (RRATs), were discovered in a single pulse analysis of 23 months of Pulsar ALFA (PALFA) data collected with the Mock spectrometers. We expanded the existing pipeline to include several new algorithms, including the spectral modulation index and a single pulse rating. In addition to the new discoveries, forty-seven previously known pulsars were redetected. From this work I conclude that considering the time domain is key to fully understanding the radio sky. Time-domain studies require special algorithms and instrumentation and particular attention must be made to managing radio frequency interference.

Spitler, Laura Grace

381

Birth weight of offspring and mortality in the Renfrew and Paisley study: prospective observational study.  

PubMed Central

OBJECTIVE: To investigate the association between birth weight of offspring and mortality among fathers and mothers in the west of Scotland. DESIGN: Prospective observational study. PARTICIPANTS: 794 married couples in Renfrew district of the west of Scotland. MAIN OUTCOME MEASURES: Mortality from all causes and from cardiovascular disease over 15 year follow up. RESULTS: Women who had heavier babies were taller, had higher body mass index and better lung function, and were less likely to be smokers than mothers of lighter babies. Fathers of heavier babies were taller and less likely to be smokers than fathers of lighter babies. Mortality was inversely related to offspring's birth weight for both mothers (relative rate for a 1 kg lower birth weight 1.82 (95% confidence interval 1.23 to 2.70)) and fathers (relative rate 1.35 (1.03 to 1.79)). For mortality from cardiovascular disease, inverse associations were seen for mothers (2.00 (1.18 to 3.33)) and fathers (1.52 (1.03 to 2.17)). Adjustment for blood pressure, plasma cholesterol, body mass index, height, social class, area based deprivation category, smoking, lung function, angina, bronchitis, and electrocardiographic evidence of ischaemia had little effect on these risk estimates, although levels of statistical significance were reduced. CONCLUSIONS: Birth weight of offspring was related inversely to mortality, from all causes and cardiovascular disease, in this cohort. The strength of this association was greater than would have been expected by the degree of concordance of birth weights across generations, but an extensive range of potential confounding factors could not account for the association. Mortality is therefore influenced by a factor related to birth weight that is transmissible across generations. PMID:9393220

Davey Smith, G.; Hart, C.; Ferrell, C.; Upton, M.; Hole, D.; Hawthorne, V.; Watt, G.

1997-01-01

382

Study design and methods of the Ansan Geriatric Study (AGE study)  

PubMed Central

Background The overall objective of the Ansan Geriatric Study (AGE study) was to describe the prevalence, incidence, and related risk factors for geriatric diseases in elderly Koreans. Methods/Design The AGE study was designed as a population-based prospective cohort study on health, aging, and common geriatric diseases of elderly Koreans aged 60 to 84 years. The inception cohort was recruited in May 2002. The first-wave and second-wave studies were performed using uniform and structured procedures. At the screening study, 2,767 participants were enrolled. Participants (1391 in the first wave study and 841 in the second wave study) were recruited and completed the evaluation. The prevalence of geriatric disease and related factors in elderly Koreans were estimated. Discussion Here, we report the design and sampling participants, measurement tools, and characteristics of the AGE study. This cohort study will allow a detailed study of the longitudinal comprehensive data on health information of elderly Koreans, thereby contributing to policy formulation and planning of health, welfare management, and other social services in Korea. PMID:19236723

Han, Changsu; Jo, Sangmee Ahn; Kim, Nan Hee; Jo, Inho; Park, Moon Ho

2009-01-01

383

A study of stepped acoustic resonator with transfer matrix method  

NASA Astrophysics Data System (ADS)

Transfer matrix method was applied in the study of stepped acoustic resonators. Transfer matrix method was more competent in comparison with analytic method to investigate the acoustic properties of stepped acoustic resonator, especially multi-step acoustic resonator. With the help of the numerical solution, the resonance frequencies, the phase angles and the radiation impedances of stepped acoustic resonators which consisted of one to five sub-tubes were studied theoretically and experimentally. The numerical solutions were in excellent agreement with the experimental results.

Min, Qi; He, Wan-Quan; Wang, Quan-Biao; Tian, Jia-Jin; Zhang, Qing-You

2014-07-01

384

Observational learning of an acquired maternal behaviour pattern by working dog pups: an alternative training method?  

Microsoft Academic Search

German shepherd pups from untrained bitches and bitches trained in the location of narcotics were either separated from their mothers at 6 weeks (standard raised) or at 3 months of age (extended maternal care). Pups with extended maternal care which were allowed to observe their trained mothers locating and retrieving a sachet of odour-producing narcotic between the ages of 6

J. M. Slabbert; O. Anne E. Rasa

1997-01-01

385

A survey of algorithmic methods for partially observed Markov decision processes  

Microsoft Academic Search

A partially observed Markov decision process (POMDP) is a generalization of a Markov decision process that allows for incomplete information regarding the state of the system. The significant applied potential for such processes remains largely unrealized, due to an historical lack of tractable solution methodologies. This paper reviews some of the current algorithmic alternatives for solving discrete-time, finite POMDPs over

William S. Lovejoy

1991-01-01

386

Estimating Probabilities of Detection for Bat Echolocation Calls: An Application of the Double-Observer Method  

Microsoft Academic Search

Differential detectability is an issue of great practical importance in bat species (Order Chiroptera) surveys. Bat echolocation recorders increasingly are being used in survey efforts, but recorder-based surveys have not measured differences in detection probability quantitatively. A recently developed avian survey technique uses 2 observers at a site to estimate the probability of detection by comparing birds recorded independently by

JOSEPH E. DUCHAMP; MARK YATES; ROSE-MARIE MUZIKA; ROBERT K. SWIHART

2006-01-01

387

Missing data methods in PCA and PLS: Score calculations with incomplete observations  

Microsoft Academic Search

A very important problem in industrial applications of PCA and PLS models, such as process modelling or monitoring, is the estimation of scores when the observation vector has missing measurements. The alternative of suspending the application until all measurements are available is usually unacceptable. The problem treated in this work is that of estimating scores from an existing PCA or

Philip R. C. Nelson; Paul A. Taylor; John F. MacGregor

1996-01-01

388

An observational study on cough in children: epidemiology, impact on quality of sleep and treatment outcome  

PubMed Central

Background Cough is one of the most frequent symptoms in children and is the most common symptom for which children visit a health care provider. Methods This is an observational study on acute cough associated with upper respiratory tract infection (URTI) in children. The study evaluates the epidemiology and impact of cough on quality of sleep and children's activities, and the outcome of cough with antitussive treatments in pediatric routine clinical practice. Study assessments were performed through a pediatric cough questionnaire (PCQ), developed by the Italian Society of Cough Study. A total of 433 children visited by family care pediatricians for acute cough due to a URTI were enrolled in this study, with mean age of 6.1 years (SD 3.6). Cough type, duration, severity and frequency, cough impact on sleep disturbances of children and parents and on school and sport activities were assessed at baseline. In a subset of 241 children who were either treated with antitussive drugs (levodropropizine n = 101, central antitussives n = 60) or received no treatment (n = 80), the outcome of cough after 6 days was analyzed in terms of resolution, improvement, no change, or worsening. Descriptive analysis, ?2 test, and multivariate analysis with stepwise logistic regression were performed. Results Cough disturbed sleep in 88% of children and 72% of parents. In children treated with cough suppressants, the duration, type, intensity, and frequency cough were similar at baseline in the two groups respectively treated with levodropropizine and central antitussives (cloperastine and codeine). Both levodropropizine and central drugs reduced cough intensity and frequency. However, percentage of cough resolution was higher with levodropropizine than with central antitussives (47% vs. 28% respectively, p = 0.0012). Conclusions Acute cough disturbs sleep in most children and their parents. Both levodropropizine and central antitussives reduced cough intensity, with levodropropizine producing a higher cough resolution rate. PMID:22269875

2012-01-01

389

Clinical questions raised by providers in the care of older adults: a prospective observational study  

PubMed Central

Objective To characterise clinical questions raised by providers in the care of complex older adults in order to guide the design of interventions that can help providers answer these questions. Materials and methods To elicit clinical questions, we observed and audio recorded outpatient visits at three healthcare organisations. At the end of each appointment, providers were asked to identify clinical questions raised in the visit. Providers rated their questions based on their urgency, importance to the patient's care and difficulty in finding a useful answer to. Transcripts of the audio recordings were analysed to identify ageing-specific factors that may have contributed to the nature of the questions. Results We observed 36 patient visits with 10 providers at the three study sites. Providers raised 70 clinical questions (median of 2 clinical questions per patient seen; range 0–12), pursued 50 (71%) and successfully answered 34 (68%) of the questions they pursued. Overall, 36 (51%) of providers’ questions were not answered. Over one-third of the questions were about treatment alternatives and adverse effects. All but two clinical questions were motivated either directly or indirectly by issues related to ageing, such as the normal physiological changes of ageing and diseases with higher prevalence in the elderly. Conclusions The frequency of clinical questions was higher than in previous studies conducted in general primary care patient populations. Clinical questions were predominantly influenced by ageing-related issues. We propose a series of recommendations that may be used to guide the design of solutions to help providers answer their clinical questions in the care of older adults. PMID:24996915

Del Fiol, Guilherme; Weber, Alice I; Brunker, Cherie P; Weir, Charlene R

2014-01-01

390

Feasibility study for Geo-Stationary satellite observation of tropospheric pollutants  

NASA Astrophysics Data System (ADS)

Geostationary Earth Orbit (GEO) satellites are useful to monitor variations and transport of tropospheric pollutants because of the achievable time resolution (1-2 hour) and horizontal resolution, and because they can perform day and night observations. The Japan Society of Atmospheric Chemistry (JSAC) and the Japanese Space Exploration Agency (JAXA) initiated concept studies for a geostationary satellite to observe pollutant species in Asia1). Instruments operating in three distinct spectral domains: ultraviolet/visible (UV/VIS), thermal infrared (TIR), and microwave are considered for this project. We present the sensitivity studies for a TIR instrument. The necessary trade-off between the signal-to-noise ratio (SNR) and the frequency resolution is a key factor in the definition of the instrumental design. The purpose of this study is to determine the instrumental frequency resolution needed to optimize the trade-off between the sensor parameters (SNR) and the scientific requirements of the project ("Detection of ozone variations in the boundary layer, and tropospheric CO measurements). The scientific requirements in terms of minimum precision (or error) values are 10% for ozone in the boundary layer and 20% for CO tropospheric column. The forward calculation and the retrieval simulations, including a complete error analysis, were performed using the AMATERAS model developed within the NICT-THz remote sensing project2). Retrieval calculation and error analysis are based on the optimal estimation method2). Two scenarii are used for the simulation: an Asian background case and a city polluted case. O3 can be retrieved in the boundary layer with a maximum error of 14% for a frequency resolution = 0.2 cm-1and an instrumental SNR = 600, in the Asian background case. TIR is not the optimal frequency domain for observing tropospheric CO with good sensitivity, but is adequate to measure the altitude abundance profile and the day and night variations of CO at 2000 cm-1. The frequency resolution used must be better than 0.2 cm-1 (SNR = 40) or 0.1 cm-1 (SNR = 20) in polluted conditions, in order to achieve an error level of less than 20%. 1) http://www.stelab.nagoya-u.ac.jp/ste-www1/div1/taikiken/eisei/eisei2.pdf Japanese version only. English version will be available in March 2009. 2) Baron, P., Mendrok, J., Kasai, Y., Ochiai, S., Seta, T., Sagi, K., Suzuki, K., Sagawa, H., and Urban, J., "AMATERASU: Model for Atmospheric TeraHertz Radiation Analysis and Simulation", Journal of the National Institute of Information and Communications Technology, 55, 109-121 (2008).

Sagi, K.; Baron, P.; Dupuy, E.; Suzuki, K.; Kita, K.; Imasu, R.; Kasai, Y.

2009-04-01

391

A comparative study of two stochastic mode reduction methods  

SciTech Connect

We present a comparative study of two methods for thereduction of the dimensionality of a system of ordinary differentialequations that exhibits time-scale separation. Both methods lead to areduced system of stochastic differential equations. The novel feature ofthese methods is that they allow the use, in the reduced system, ofhigher order terms in the resolved variables. The first method, proposedby Majda, Timofeyev and Vanden-Eijnden, is based on an asymptoticstrategy developed by Kurtz. The second method is a short-memoryapproximation of the Mori-Zwanzig projection formalism of irreversiblestatistical mechanics, as proposed by Chorin, Hald and Kupferman. Wepresent conditions under which the reduced models arising from the twomethods should have similar predictive ability. We apply the two methodsto test cases that satisfy these conditions. The form of the reducedmodels and the numerical simulations show that the two methods havesimilar predictive ability as expected.

Stinis, Panagiotis

2005-09-01

392

An improved method of constructing a database of monthly climate observations and associated high-resolution grids  

Microsoft Academic Search

ABSTRACT A database of monthly,climate observations from meteorological,stations is constructed. The database includes six climate elements,and extends over the global land surface. The database is checked,for inhomogeneities,in the station records using an automated,method,that refines previous methods,by using incomplete,and partially overlapping,records and by detecting inhomogeneities,with opposite signs in different seasons. The method,includes the development,of reference series using neighbouring stations. Information from

Timothy D. Mitchell; Philip D. Jones

2005-01-01

393