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1

Propensity Score Methods for Creating Covariate Balance in Observational Studies  

Microsoft Academic Search

Randomization of treatment assignment in experiments generates treatment groups with approximately balanced baseline covariates. However, in observational studies, where treatment assignment is not random, patients in the active treatment and control groups often differ on crucial covariates that are related to outcomes. These covariate imbalances can lead to biased treatment effect estimates. The propensity score is the probability that a

Cassandra W. Pattanayak; Donald B. Rubin; Elizabeth R. Zell

2011-01-01

2

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

3

The method of interlapping observation in the study of personality in culture  

Microsoft Academic Search

Interlapping observation may be illustrated by the following: one group of subjects would be studied during their first and second years, another group studied during their second and third years, etc., until the entire career line from birth to old age would be observed in a succession of two-year periods. The method keeps cultural contexts at the center of interest;

H. D. Lasswell

1937-01-01

4

Methods for Extremely Large Scale Media Experiments and Observational Studies Gary King, Benjamin Schneer & Ariel White  

E-print Network

) � The goal of media outlets (and our study) is activated opinion � Goal: influence "the conversation": people engaging with others, trying to influence politics � Social media is of direct interest, highlyMethods for Extremely Large Scale Media Experiments and Observational Studies Gary King, Benjamin

5

Validation and statistical power comparison of methods for analyzing free-response observer performance studies  

PubMed Central

Rationale and Objectives The aim of this work was to validate and compare the statistical powers of proposed methods for analyzing free-response data using a search-model based simulator. Materials and Methods A free-response data simulator is described that can model a single reader interpreting the same cases in two modalities, or two CAD algorithms, or two human observers, interpreting the same cases in one modality. A variance components model, analogous to the Roe and Metz receiver operating characteristic (ROC) data simulator, is described, that models intra-case and inter-modality correlations in free-response studies. Two generic observers were simulated: a quasi-human observer and a quasi-CAD algorithm. Null hypothesis (NH) validity and statistical powers of ROC, jackknife alternative free-response operating characteristic (JAFROC), a variant of JAFROC termed JAFROC-1, initial detection and candidate analysis (IDCA) and a non-parametric (NP) approach were investigated. Results All methods had valid NH behavior over a wide range of simulator parameters. For equal numbers of normal and abnormal cases, for the human observer, the statistical power ranking of the methods was JAFROC-1 > JAFROC > (IDCA ~ NP) > ROC. For the CAD algorithm the ranking was (NP ~ IDCA) > (JAFROC-1~JAFROC) > ROC. In either case the statistical power of the highest ranked method exceeded that of the lowest ranked method by about a factor of two. Dependence of statistical power on simulator parameters followed expected trends. For data sets with more abnormal cases than normal cases, JAFROC-1 power significantly exceeded JAFROC power. Conclusion Based on this work the recommendation is to use JAFROC-1 for human observers (including human-observers with CAD assist) and the NP method for evaluating CAD algorithms. PMID:19000872

Chakraborty, Dev P.

2009-01-01

6

International Halley watch amateur observers' manual for scientific comet studies. Part 1: Methods  

NASA Technical Reports Server (NTRS)

The International Halley Watch is described as well as comets and observing techniques. Information on periodic Comet Halley's apparition for its 1986 perihelion passage is provided. Instructions are given for observation projects valuable to the International Halley Watch in six areas of study: (1) visual observations; (2) photography; (3) astrometry; (4) spectroscopic observations; (5) photoelectric photometry; and (6) meteor observations.

Edberg, S. J.

1983-01-01

7

Are Private Schools Better Than Public Schools? Appraisal for Ireland by Methods for Observational Studies  

PubMed Central

In observational studies the assignment of units to treatments is not under control. Consequently, the estimation and comparison of treatment effects based on the empirical distribution of the responses can be biased since the units exposed to the various treatments could differ in important unknown pretreatment characteristics, which are related to the response. An important example studied in this article is the question of whether private schools offer better quality of education than public schools. In order to address this question we use data collected in the year 2000 by OECD for the Programme for International Student Assessment (PISA). Focusing for illustration on scores in mathematics of 15-years old pupils in Ireland, we find that the raw average score of pupils in private schools is higher than of pupils in public schools. However, application of a newly proposed method for observational studies suggests that the less able pupils tend to enroll in public schools, such that their lower scores is not necessarily an indication of bad quality of the public schools. Indeed, when comparing the average score in the two types of schools after adjusting for the enrollment effects, we find quite surprisingly that public schools perform better on average. This outcome is supported by the methods of instrumental variables and latent variables, commonly used by econometricians for analyzing and evaluating social programs. PMID:22242110

Pfeffermann, Danny; Landsman, Victoria

2011-01-01

8

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

9

A Comparison Study on Three Adaptive Observation Methods for Northwest Pacific Tropical Cyclones  

Microsoft Academic Search

Three adaptive observation methods, the conditional nonlinear optimal perturbation (CNOP), the first singular vector (FSV) and the ensemble transform Kalman filter (ET KF) are compared for 36-hours forecast of two northwest Pacific TC cases named Matsa in 2005 and Nock-Ten in 2004. Rankings of hypothetical test probes are designed respectively according to the above three methods, to identify the proper

Xiaohao Qin; Mu Mu

2010-01-01

10

The barrier method as a new tool to assist in career selection: covert observational study  

PubMed Central

Objective To determine if senior doctors parking habits and skills are associated with clinical specialty and, if so, whether observation of junior doctors parking could provide guidance in choice of specialty. Design Covert observational study. Setting Pass-card controlled consultants car park (parking lot), December 2009. Participants 103 consultants entering the car park on three consecutive mornings. Main outcome measures The outcomes were specialty and sex of the consultants, manner of approaching the barrier (pass-card ready or not), and time taken to park, exit the vehicle, and walk to a designated point. Results Approaches to the barrier and parking were recorded for 103 consultants (79 men, 24 women): 28 anaesthetists (22 men, six women), 29 physicians (internists, 18 men, 11 women), 14 radiologists (nine men, five women), and 32 surgeons (30 men, two women). The manner of approaching the barrier (card ready) differed by specialty but not by sex. The total time taken to park (seconds) differed significantly between specialties: surgery (median 68, interquartile range 61-71 seconds), anaesthesia (82, 76-91), radiology (86, 70-103), and general medicine (112, 96-136). The time taken to park was overall longer among women, but this was explained by their specialty (men and women matched by specialty did not differ). Conclusions The total time taken to park and manner of approaching the barrier to gain entry to the car park differed across specialties. Surgical consultants were fastest, followed by consultant anaesthetists and consultant radiologists, with physicians slowest. Sex was not an influencing factor. If reproducible in studies of a similar nature the barrier method could allow for a low cost means of guiding junior doctors in career selection. PMID:21159762

2010-01-01

11

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

12

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

13

A Comparison Study on Three Adaptive Observation Methods for Northwest Pacific Tropical Cyclones  

NASA Astrophysics Data System (ADS)

Three adaptive observation methods, the conditional nonlinear optimal perturbation (CNOP), the first singular vector (FSV) and the ensemble transform Kalman filter (ET KF) are compared for 36-hours forecast of two northwest Pacific TC cases named Matsa in 2005 and Nock-Ten in 2004. Rankings of hypothetical test probes are designed respectively according to the above three methods, to identify the proper sites to deploy the dropwindsondes, by investigating the reduction of forecast-error variance (signal variance) of each individual hypothetical test probes. The signal variance obtained by the best test probe designed according to the sensitive regions calculated by the CNOP is more than that of FSV, both of which are much more than the best track designed uising the ET KF. That is to say, the sensitive regions calculated by the CNOP and FSV are sufficient for adaptive observation. It is not necessary to design as many as possible test probes as the ET KF does, which could save computation cost. Moreover, the CNOP could locate more sensitive regions for adaptive observations.

Qin, Xiaohao; Mu, Mu

2010-05-01

14

Lack of agreement between different observers and methods in the measurement of capillary refill time in healthy volunteers: an observational study  

PubMed Central

Objective Peripheral perfusion abnormalities are relevant manifestations of shock. Capillary refill time is commonly used for their evaluation. However, the reproducibility of capillary refill time measurements and their correlation with other variables of peripheral perfusion, have not been comprehensively evaluated. Our goal was to determine, in healthy volunteers, the agreement between different methods of capillary refill time quantification and different observers, as well as their correlation with other markers of peripheral perfusion. Methods We studied 63 healthy volunteers. Two observers measured capillary refill time by means of two methods, direct view (CRTchronometer) and video analysis (CRTvideo). We also measured perfusion index (PI) derived from pulse plethysmography and finger pad temperature (Tperipheral). The agreement between observers and methods was assessed using the Bland and Altman method. Correlations were calculated using Pearson's correlation. A p-value<0.05 was considered significant. Results The 95% limits of agreement between the two observers were 1.9 sec for CRTchronometer and 1.7 sec for CRTvideo. The 95% limits of agreement between CRTchronometer and CRTvideo were 1.7 sec for observer 1 and 2.3 sec for observer 2. Measurements of CRTchronometer performed by the two observers were correlated with Tperipheral. Measurements of CRTvideo performed by the two observers were correlated with Tperipheral and perfusion index. Conclusion In healthy volunteers, measurements of capillary refill time performed by either different observers or different methods showed poor agreement. Nevertheless, capillary refill time still reflected peripheral perfusion as shown by its correlation with objective variables of peripheral perfusion. PMID:25295821

Espinoza, Emilio Daniel Valenzuela; Welsh, Sebastian; Dubin, Arnaldo

2014-01-01

15

Development of a method to study positron diffusion in metals by the observation of positronium negative ions  

NASA Astrophysics Data System (ADS)

We have developed a new method to study positron diffusion in metals. In this method, we observe positronium negative ions emitted from the sample surfaces after coating with alkali-metals to evaluate the yields of the positrons which return to the surfaces. ?-rays from the ions accelerated using an electric field are clearly distinguished from those emitted from pair-annihilation of positrons in the bulk or on the surface and self-annihilation of emitted positronium atoms. Reliable studies on positron diffusion in metals have been enabled by this method.

Suzuki, Takuji; Terabe, Hiroki; Iida, Shimpei; Yamashita, Takashi; Nagashima, Yasuyuki

2014-09-01

16

A most stubborn bias: no adjustment method fully resolves confounding by indication in observational studies  

Microsoft Academic Search

ObjectiveTo evaluate the effectiveness of methods that control for confounding by indication, we compared breast cancer recurrence rates among women receiving adjuvant chemotherapy with those who did not.

Jaclyn L. F. Bosco; Rebecca A. Silliman; Soe Soe Thwin; Ann M. Geiger; Diana S. M. Buist; Marianne N. Prout; Marianne Ulcickas Yood; Reina Haque; Feifei Wei; Timothy L. Lash

2010-01-01

17

Modern Asteroid Occultation Observing Methods  

NASA Astrophysics Data System (ADS)

This presentation reviews current working methods for asteroid occultations developed by the International Occultation Timing Association (IOTA). Reduc- tion of multiple tracks or "chords" observed during stellar occultations pro- vides valuable measures of the relative sizes and shapes of asteroids. Tradi- tionally, predictions for asteroid occultations were prepared by regional IOTA computors, distributed annually in "hard copy" format to IOTA subscrib- ers and in publications such as Sky & Telescope magazine and the annual RASC Observers Handbook. IOTA - like many other organizations - is now using worldwide internet services and e-mail to distribute frequently-updated pre- dictions based upon the latest astrometry. The IOTA web pages provide an easily accessible, centralized source of information on lunar and solar sys- tem occultation events. IOTA's web pages feature a variety of articles on current activities, plans for observing campaigns and expeditions, and "how to do it" information on the latest technology and techniques. The latest up- dated predictions for asteroid events are made available as they are pro- duced, providing more accurate observing tracks and efficient coordination of observers. The IOTA e-mail list provides a dynamic forum for the exchange of technical information and com-munication of observing plans in a timely man- ner. Individuals may now generate customized occultation predictions using the WinOccult software package. The author presents some examples of recent occultation events, showing the benefits of coordinated observations. Also described are some of the latest innovations, featuring low-cost video camera equipment, devices for time insertion based on Global Positioning Satellite (GPS) technology, and a new approach using unattended secondary field station equipment to multiply the number of tracks observed.

Lucas, G. A.

2004-05-01

18

Studies That Observe Humans  

MedlinePLUS

... trying to guess at the cause and even writing about it as if the guess were fact. For instance, there were studies some years ago that linked gum disease with heart attacks. News reports talked about this link, with many theories about ...

19

Comparative Effectiveness of Cognitive Therapies Delivered Face-to-Face or over the Telephone: An Observational Study Using Propensity Methods  

PubMed Central

Objectives To compare the clinical and cost-effectiveness of face-to-face (FTF) with over-the-telephone (OTT) delivery of low intensity cognitive behavioural therapy. Design Observational study following SROBE guidelines. Selection effects were controlled using propensity scores. Non-inferiority comparisons assessed effectiveness. Setting IAPT (improving access to psychological therapies) services in the East of England. Participants 39,227 adults referred to IAPT services. Propensity score strata included 4,106 individuals; 147 pairs participated in 1?1 matching. Intervention Two or more sessions of computerised cognitive behavioural therapy (CBT). Main outcome measures Patient-reported outcomes: Patient Health Questionnaire (PHQ-9) for depression; Generalised Anxiety Disorder questionnaire (GAD-7); Work and Social Adjustment Scale (WSAS). Differences between groups were summarised as standardised effect sizes (ES), adjusted mean differences and minimally important difference for PHQ-9. Cost per session for OTT was compared with FTF. Results Analysis of covariance controlling for number of assessments, provider site, and baseline PHQ-9, GAD-7 and WSAS indicated statistically significantly greater reductions in scores for OTT treatment with moderate (PHQ-9: ES: 0.14; GAD-7: ES: 0.10) or small (WSAS: ES: 0.03) effect sizes. Non-inferiority in favour of OTT treatment for symptom severity persisted as small to moderate effects for all but individuals with the highest symptom severity. In the most stringent comparison, the one-to-one propensity matching, adjusted mean differences in treatment outcomes indicated non-inferiority between OTT versus FTF treatments for PHQ-9 and GAD-7, whereas the evidence was moderate for WSAS. The per-session cost for OTT was 36.2% lower than FTF. Conclusions The clinical effectiveness of low intensity CBT-based interventions delivered OTT was not inferior to those delivered FTF except for people with more severe illness where FTF was superior. This provides evidence for better targeting of therapy, efficiencies for patients, cost savings for services and greater access to psychological therapies for people with common mental disorders. PMID:23028436

Hammond, Geoffrey C.; Croudace, Tim J.; Radhakrishnan, Muralikrishnan; Lafortune, Louise; Watson, Alison; McMillan-Shields, Fiona; Jones, Peter B.

2012-01-01

20

Observations on some acoustic methods used in studying the elastic properties of metals. [resonant frequency measurements on metal beams  

NASA Technical Reports Server (NTRS)

An experimental setup is reported that permits very accurate measurements of the resonance frequencies of long cylindrical beams fixed in the middle and whose size can vary within wide limits. It also permits measurement of the width of the resonance curve. It is shown that the Poisson effect can be brought to light for relatively long beams and for relatively short beams. Poisson ratio, values obtained with this method argue in favor of using the low frequency region for determining elastic constants of solids.

Velceanu, C. I.

1974-01-01

21

Observational Studies: Cohort and Case-Control Studies  

PubMed Central

Observational studies are an important category of study designs. To address some investigative questions in plastic surgery, randomized controlled trials are not always indicated or ethical to conduct. Instead, observational studies may be the next best method to address these types of questions. Well-designed observational studies have been shown to provide results similar to randomized controlled trials, challenging the belief that observational studies are second-rate. Cohort studies and case-control studies are two primary types of observational studies that aid in evaluating associations between diseases and exposures. In this review article, we describe these study designs, methodological issues, and provide examples from the plastic surgery literature. PMID:20697313

Song, Jae W.; Chung, Kevin C.

2010-01-01

22

Adapting group sequential methods to observational postlicensure vaccine safety surveillance: results of a pentavalent combination DTaP-IPV-Hib vaccine safety study.  

PubMed

To address gaps in traditional postlicensure vaccine safety surveillance and to promote rapid signal identification, new prospective monitoring systems using large health-care database cohorts have been developed. We newly adapted clinical trial group sequential methods to this observational setting in an original safety study of a combination diphtheria and tetanus toxoids and acellular pertussis adsorbed (DTaP), inactivated poliovirus (IPV), and Haemophilus influenzae type b (Hib) conjugate vaccine (DTaP-IPV-Hib) among children within the Vaccine Safety Datalink population. For each prespecified outcome, we conducted 11 sequential Poisson-based likelihood ratio tests during September 2008-January 2011 to compare DTaP-IPV-Hib vaccinees with historical recipients of other DTaP-containing vaccines. No increased risk was detected among 149,337 DTaP-IPV-Hib vaccinees versus historical comparators for any outcome, including medically attended fever, seizure, meningitis/encephalitis/myelitis, nonanaphylactic serious allergic reaction, anaphylaxis, Guillain-Barr syndrome, or invasive Hib disease. In end-of-study prespecified subgroup analyses, risk of medically attended fever was elevated among 1- to 2-year-olds who received DTaP-IPV-Hib vaccine versus historical comparators (relative risk = 1.83, 95% confidence interval: 1.34, 2.50) but not among infants under 1 year old (relative risk = 0.83, 95% confidence interval: 0.73, 0.94). Findings were similar in analyses with concurrent comparators who received other DTaP-containing vaccines during the study period. Although lack of a controlled experiment presents numerous challenges, implementation of group sequential monitoring methods in observational safety surveillance studies is promising and warrants further investigation. PMID:23292957

Nelson, Jennifer C; Yu, Onchee; Dominguez-Islas, Clara P; Cook, Andrea J; Peterson, Do; Greene, Sharon K; Yih, W Katherine; Daley, Matthew F; Jacobsen, Steven J; Klein, Nicola P; Weintraub, Eric S; Broder, Karen R; Jackson, Lisa A

2013-01-15

23

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

24

Calibrating sensitivity analyses to observed covariates in observational studies.  

PubMed

In medical sciences, statistical analyses based on observational studies are common phenomena. One peril of drawing inferences about the effect of a treatment on subjects using observational studies is the lack of randomized assignment of subjects to the treatment. After adjusting for measured pretreatment covariates, perhaps by matching, a sensitivity analysis examines the impact of an unobserved covariate, u, in an observational study. One type of sensitivity analysis uses two sensitivity parameters to measure the degree of departure of an observational study from randomized assignment. One sensitivity parameter relates u to treatment and the other relates u to response. For subject matter experts, it may be difficult to specify plausible ranges of values for the sensitivity parameters on their absolute scales. We propose an approach that calibrates the values of the sensitivity parameters to the observed covariates and is more interpretable to subject matter experts. We will illustrate our method using data from the U.S. National Health and Nutrition Examination Survey regarding the relationship between cigarette smoking and blood lead levels. PMID:24328711

Hsu, Jesse Y; Small, Dylan S

2013-12-01

25

Observational studies of Saturn's rings  

NASA Technical Reports Server (NTRS)

Several noteworthy phenomena in Saturn's rings were investigated which have until now received an inadequate amount of attention. Among these are the periodic variation of the spokes in the B ring and eccentric features throughout the rings. One of the major discoveries by Voyager was the existence of eccentric features within the predominantly circular rings of Saturn. Several of these nonaxisymmetric features are narrow elliptical rings which share many characteristics with the rings of Uranus. In recent work, two narrow ringlets were added to the list of eccentric features in the rings of Saturn. Voyager imaging and occultation data are now in hand, as well as image-processing software which allows accurate absolute positional measurements to be made in Voyager imaging data. Work is in progress to re-examine this region of Saturn's rings and to study the possibility of a dynamical interaction between the outer B ring edge, the Huygens ringlet and the nearby Mimas 2:1 resonance. An understanding of the kinematics and dynamics of this region promises to yield important clues to a matter of great interest in both theoretical and observation ring studies.

Porco, Carolyn C.

1987-01-01

26

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

27

A pragmatic method for electronic medical record-based observational studies: developing an electronic medical records retrieval system for clinical research  

PubMed Central

Objective The use of electronic medical record (EMR) data is necessary to improve clinical research efficiency. However, it is not easy to identify patients who meet research eligibility criteria and collect the necessary information from EMRs because the data collection process must integrate various techniques, including the development of a data warehouse and translation of eligibility criteria into computable criteria. This research aimed to demonstrate an electronic medical records retrieval system (ERS) and an example of a hospital-based cohort study that identified both patients and exposure with an ERS. We also evaluated the feasibility and usefulness of the method. Design The system was developed and evaluated. Participants In total, 800?000 cases of clinical information stored in EMRs at our hospital were used. Primary and secondary outcome measures The feasibility and usefulness of the ERS, the method to convert text from eligible criteria to computable criteria, and a confirmation method to increase research data accuracy. Results To comprehensively and efficiently collect information from patients participating in clinical research, we developed an ERS. To create the ERS database, we designed a multidimensional data model optimised for patient identification. We also devised practical methods to translate narrative eligibility criteria into computable parameters. We applied the system to an actual hospital-based cohort study performed at our hospital and converted the test results into computable criteria. Based on this information, we identified eligible patients and extracted data necessary for confirmation by our investigators and for statistical analyses with our ERS. Conclusions We propose a pragmatic methodology to identify patients from EMRs who meet clinical research eligibility criteria. Our ERS allowed for the efficient collection of information on the eligibility of a given patient, reduced the labour required from the investigators and improved the reliability of the results. PMID:23117567

Yamamoto, Keiichi; Sumi, Eriko; Yamazaki, Toru; Asai, Keita; Yamori, Masashi; Teramukai, Satoshi; Bessho, Kazuhisa; Yokode, Masayuki; Fukushima, Masanori

2012-01-01

28

Study 1: Method Demographics  

E-print Network

Study 1: Method Demographics ·346 men and 299 women · 41.1% Dating, 18.2% Cohabiting, 4.2% Engaged domains, they reported more authenticity doubts and insecurity (Study 1). When they received criticism insecurities perpetuates them. Journal of Personality and Social Psychology, 95, 420-441. Lemay, E. P., Jr

New Hampshire, University of

29

An Alternative IRT Observed Score Equating Method. CRESST Report 751  

ERIC Educational Resources Information Center

In this report, an alternative item response theory (IRT) observed score equating method was newly developed. The proposed equating method was illustrated with two real data sets and the equating results were compared to those of traditional IRT true score and IRT observed score equating methods. Using three loss indices, the new method appeared

Kang, Taehoon; Chen, Troy T.

2009-01-01

30

Measuring agreement between rating interpretations and binary clinical interpretations of images: a simulation study of methods for quantifying the clinical relevance of an observer performance paradigm  

NASA Astrophysics Data System (ADS)

Laboratory receiver operating characteristic (ROC) studies, that are often used to evaluate medical imaging systems, differ from live clinical interpretations in several respects which could compromise their clinical relevance. The aim was to develop methodology for quantifying the clinical relevance of a laboratory ROC study. A simulator was developed to generate ROC ratings data and binary clinical interpretations classified as correct or incorrect for a common set of images interpreted under clinical and laboratory conditions. The area under the trapezoidal ROC curve (AUC) was used as the laboratory figure-of-merit and the fraction of correct clinical decisions as the clinical figure-of-merit. Conventional agreement measures (Pearson, Spearman, Kendall and kappa) between the bootstrap-induced fluctuations of the two figures of merit were estimated. A jackknife pseudovalue transformation applied to the figures of merit was also investigated as a way to capture agreement existing at the individual image level that could be lost at the figure-of-merit level. It is shown that the pseudovalues define a relevance-ROC curve. The area under this curve (rAUC) measures the ability of the laboratory figure-of-merit-based pseudovalues to correctly classify incorrect versus correct clinical interpretations. Therefore, rAUC is a measure of the clinical relevance of an ROC study. The conventional measures and rAUC were compared under varying simulator conditions. It was found that design details of the ROC study, namely the number of bins, the difficulty level of the images, the ratio of disease-present to disease-absent images and the unavoidable difference between laboratory and clinical performance levels, can lead to serious underestimation of the agreement as indicated by conventional agreement measures, even for perfectly correlated data, while rAUC showed high agreement and was relatively immune to these details. At the same time rAUC was sensitive to factors such as intrinsic correlation between the laboratory and clinical decision variables and differences in reporting thresholds that are expected to influence agreement both at the individual image level and at the figure-of-merit level. Suggestions are made for how to conduct relevance-ROC studies aimed at assessing agreement between laboratory and clinical interpretations. The method could be used to evaluate the clinical relevance of alternative scalar figures of merit, such as the sensitivity at a predifined specificity.

Chakraborty, Dev P.

2012-05-01

31

Parent-Collected Behavioral Observations: An Empirical Comparison of Methods  

ERIC Educational Resources Information Center

Treatments for disruptive behaviors are often guided by parent reports on questionnaires, rather than by multiple methods of assessment. Professional observations and clinic analogs exist to complement questionnaires, but parents can also collect useful behavioral observations to inform and guide treatment. Two parent observation methods of child

Nadler, Cy B.; Roberts, Mark W.

2013-01-01

32

A new method for astrometric observations of asteroids  

NASA Technical Reports Server (NTRS)

In this paper we propose a new method for photographic astrometric observations of asteroids. We discuss its advantages and disadvantages and compare them to the advantages and disadvantages of the classical photographic methods. The new method is best suited for observations on a spot where no CCD cameras, blink or stereo comparators are available and when a fast detection of unknown objects is required.

Pauwels, Thierry

1992-01-01

33

[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 websites 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:18711640

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

2008-01-01

34

[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 che-cklist 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 websites 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:18420014

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

2008-01-01

35

Earth Observing System: Global Observations to Study the Earth's Environment  

NASA Technical Reports Server (NTRS)

The Earth Observing System (EOS) is a space-based observing system comprised of a series of satellite sensors by which scientists can monitor the Earth, a Data and Information System (EOSDIS) enabling researchers worldwide to access the satellite data, and an interdisciplinary science research program to interpret the satellite data. During the last couple of years, four EOS science missions were launched, representing observations of (i) total solar irradiance, (ii) Earth radiation budget, (iii) land cover & land use change, (iv) ocean processes (vector wind, sea surface temperature, and ocean color), (v) atmospheric processes (aerosol and cloud properties, water vapor, and temperature and moisture profiles), and (vi) tropospheric chemistry. In succeeding years many more satellites will be launched that will contribute immeasurably to our understanding of the Earth's environment. In this presentation I will describe how scientists are using NASA's Earth science data to examine land use and natural hazards, environmental air quality, including: dust storms over the worlds deserts, cloud and radiation properties, sea surface temperature, and winds over the ocean, with a special emphasis on satellite observations available for studying the southern African environment.

King, Michael D.

2003-01-01

36

A non-invasive method for observing hippocampal function.  

PubMed

A non-invasive method for observing the functioning of the hippocampus could be invaluable in understanding the role of hippocampal abnormalities in many brain disorders. Transverse patterning, a hippocampal-dependent memory task, was used in an attempt to study the functioning hippocampus. Subjects performed transverse patterning while whole-head MEG data were collected. The MEG data were analyzed using a spatial-temporal multiple-dipole approach. Controls showed right hippocampal activation. Patients with unilateral hippocampal damage showed activation in undamaged hippocampus. MEG during transverse patterning performance is a promising, non-invasive tool for assessing hippocampal function. PMID:14561928

Hanlon, Faith M; Weisend, Michael P; Huang, Mingxiong; Lee, Roland R; Moses, Sandra N; Paulson, Kim M; Thoma, Robert J; Miller, Gregory A; Caive, Jose M

2003-10-27

37

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

38

Methods for studying oogenesis.  

PubMed

Drosophila oogenesis is an excellent system for the study of developmental cell biology. Active areas of research include stem cell maintenance, gamete development, pattern formation, cytoskeletal regulation, intercellular communication, intercellular transport, cell polarity, cell migration, cell death, morphogenesis, cell cycle control, and many more. The large size and relatively simple organization of egg chambers make them ideally suited for microscopy of both living and fixed whole mount tissue. A wide range of tools is available for oogenesis research. Newly available shRNA transgenic lines provide an alternative to classic loss-of-function F2 screens and clonal screens. Gene expression can be specifically controlled in either germline or somatic cells using the Gal4/UAS system. Protein trap lines provide fluorescent tags of proteins expressed at endogenous levels for live imaging and screening backgrounds. This review provides information on many available reagents and key methods for research in oogenesis. PMID:24440745

Hudson, Andrew M; Cooley, Lynn

2014-06-15

39

Measuring agreement between ratings interpretations and binary clinical interpretations of images: a simulation study of methods for quantifying the clinical relevance of an observer performance paradigm  

PubMed Central

Laboratory receiver operating characteristic (ROC) studies, that are often used to evaluate medical imaging systems, differ from live clinical interpretations in several respects which could compromise their clinical relevance. The aim was to develop methodology for quantifying the clinical relevance of a laboratory ROC study. A simulator was developed to generate ROC ratings data and binary clinical interpretations classified as correct or incorrect for a common set of images interpreted under clinical and laboratory conditions. The area under the trapezoidal ROC curve was used as the laboratory figure-of-merit and the fraction of correct clinical decisions as the clinical figure-of-merit. Conventional agreement measures (Pearson, Spearman, Kendall and kappa) between the bootstrap-induced fluctuations of the two figures-of-merit were estimated. A jackknife pseudovalue transformation applied to the figures-of-merit was also investigated as a way to capture agreement existing at the individual image level that could be lost at the figure-of-merit level. It is shown that the pseudovalues define a relevance ROC curve the area under which (rAUC) measures the ability of the laboratory figure-of-merit based pseudovalues to correctly classify incorrect vs. correct clinical interpretations, and is a measure of the clinical relevance of an ROC study. The conventional measures and rAUC were compared under varying simulator conditions. It was found that design details of the ROC study, namely the number of bins, the difficulty level of the images, the ratio of disease-present to disease-absent images, and the unavoidable difference between laboratory and clinical performance levels, can seriously underestimate the agreement as indicated by conventional agreement measures, even for perfectly correlated data, while rAUC showed high agreement and was relatively immune to these details. At the same time rAUC was sensitive to factors such as intrinsic correlation between the laboratory and clinical decision variables and differences in reporting thresholds that are expected to influence agreement both at the individual image level and at the figure-of-merit level. Suggestions are made for how to conduct relevance ROC studies aimed at assessing agreement between laboratory and clinical interpretations. PMID:22516804

Chakraborty, Dev P.

2012-01-01

40

RECORDS AND OBSERVATIONS FROM PLANKTON GRID STUDIES OFF BAJA  

E-print Network

422 RECORDS AND OBSERVATIONS FROM PLANKTON GRID STUDIES OFF BAJA CALIFORNIA, APRIL 1952 SPECIAL AND OBSERVATIONS FROM PLANKTON GRID STUDIES OFF BAJA CALIFORNIA, APRIL 1952 by David Kramer United States Fish;#12;CONTENTS Page Introduction 1 Survey design 2 Methods of sampling 2 Sardine eggs 2 Fish larvae 11 Plankton

41

Effects of creative and social activity on the health and well-being of socially isolated older people: outcomes from a multi-method observational study.  

PubMed

Depression and social isolation affect one in seven people over 65 and there is increasing recognition that social isolation adversely affects long-term health. Research indicates that interventions, which promote active social contact, which encourage creativity, and which use mentoring, are more likely to positively affect health and well-being. The purpose of this study was to evaluate a complex intervention for addressing social isolation in older people, embodying these principles: The Upstream Healthy Living Centre. Mentors delivered a series of individually-tailored activities, with support tailing off over time. Two hundred and twenty-nine participants were offered the Geriatric Depression Scale, SF12 Health Quality of Life, and Medical Outcomes Social Support scale at baseline, then 6 months and 12 months post intervention. Semi-structured interviews were conducted with 26 participants, five carers and four referring health professionals to provide a deeper understanding of outcomes. Data were available for 172 (75%) participants at baseline, 72 (53% of those eligible) at 6 months and 51 (55%) at 12 months. Baseline scores indicated social isolation and high morbidity for mental and physical health. The intervention was successful in engaging this population (80% of referrals were engaged in some form of activity). At 6 months, there were significant improvements in SF12 mental component, and depression scores, but not in perceived physical health or social support. At 12 months, there were significant improvements in depression and social support and a marginally significant improvement in SF12 physical component (p = 0.06), but the SF12 mental component change was not maintained. The qualitative data showed that the intervention was well-received by participants. The data indicated a wide range of responses (both physical and emotional), including increased alertness, social activity, self-worth, optimism about life, and positive changes in health behaviour. Stronger, 'transformational' changes were reported by some participants. Individual tailoring seemed to be a key mediator of outcomes, as was overcoming barriers relating to transport and venues. Key processes underlying outcomes were the development of a positive group identity, and building of confidence/self-efficacy. The Upstream model provides a practical way of engaging socially isolated elderly people and generating social networks. The data suggest a range of psychosocial and physical health benefits. Although there are limitations in attributing causality in uncontrolled studies, the data seem to indicate a reversal of the expected downward trends in some aspects of participants' health, and suggest that this approach is worth further investigation. PMID:16739619

Greaves, Colin J; Farbus, Lou

2006-05-01

42

A Numerical Climate Observing Network Design Study  

NASA Technical Reports Server (NTRS)

This project was concerned with three related questions of an optimal design of a climate observing system: 1. The spatial sampling characteristics required from an ARGO system. 2. The degree to which surface observations from ARGO can be used to calibrate and test satellite remote sensing observations of sea surface salinity (SSS) as it is anticipated now. 3. The more general design of an climate observing system as it is required in the near future for CLIVAR in the Atlantic. An important question in implementing an observing system is that of the sampling density required to observe climate-related variations in the ocean. For that purpose this project was concerned with the sampling requirements for the ARGO float system, but investigated also other elements of a climate observing system. As part of this project we studied the horizontal and vertical sampling characteristics of a global ARGO system which is required to make it fully complementary to altimeter data with the goal to capture climate related variations on large spatial scales (less thanAttachment: 1000 km). We addressed this question in the framework of a numerical model study in the North Atlantic with an 1/6 horizontal resolution. The advantage of a numerical design study is the knowledge of the full model state. Sampled by a synthetic float array, model results will therefore allow to test and improve existing deployment strategies with the goal to make the system as optimal and cost-efficient as possible. Attachment: "Optimal observations for variational data assimilation".

Stammer, Detlef

2003-01-01

43

Special Section: Observational Studies Sampling Considerations for Disease Surveillance in  

E-print Network

animals within sampled areas using a convenience sampling method. (JOURNAL OF WILDLIFE MANAGEMENT 72Special Section: Observational Studies Sampling Considerations for Disease Surveillance in Wildlife. OTIS, United States Geological Survey, Iowa Cooperative Fish and Wildlife Research Unit, 342 Science II

Clark, William R.

44

Workplace Education Initiative: Case Studies and Observations.  

ERIC Educational Resources Information Center

Seven workplace education projects funded in the first year of the Massachusetts Workplace Education Initiative are reported. This report includes both general observations and specific information in case studies of the projects. Overall information is provided on students served, the importance of partnerships, the emphasis on

Astrein, Bruce; And Others

45

Earth Observing System: Global Observations to Study the Earth's Environment  

NASA Technical Reports Server (NTRS)

The Earth Observing System (EOS) is a space-based observing system comprised of a series of satellite sensors by which scientists can monitor the Earth, a Data and Information System (EOSDIS) enabling researchers worldwide to access the satellite data, and an interdisciplinary science research program to interpret the satellite data. During the last couple of years, four EOS science missions were launched, representing observations of (1) total solar irradiance, (2) Earth radiation budget, (3) land cover & land use change, (4) ocean processes (vector wind, sea surface temperature, and ocean color), (5) atmospheric processes (aerosol and cloud properties, water vapor, and temperature and moisture profiles), and (6) tropospheric chemistry. In succeeding years many more satellites will be launched that will contribute immeasurably to our understanding of the Earth's environment. In this presentation I will describe how scientists are using NASA's Earth science data to examine land use and natural hazards, environmental air quality, including dust storms over the world's deserts, cloud and radiation properties, sea surface temperature, and winds over the ocean.

King, Michael D.

2001-01-01

46

What health care managers do: applying Mintzberg's structured observation method.  

PubMed

Aim The aim of the present study was to explore and describe what characterizes first- and second-line health care managers' use of time. Background Many Swedish health care managers experience difficulties managing their time. Methods Structured and unstructured observations were used. Ten first- and second-line managers in different health care settings were studied in detail from 3.5 and 4 days each. Duration and frequency of different types of work activities were analysed. Results The individual variation was considerable. The managers' days consisted to a large degree of short activities (<9 minutes). On average, nearly half of the managers' time was spent in meetings. Most of the managers' time was spent with subordinates and <1% was spent alone with their superiors. Sixteen per cent of their time was spent on administration and only a small fraction on explicit strategic work. Conclusions The individual variations in time use patterns suggest the possibility of interventions to support changes in time use patterns. Implications for nursing management A reliable description of what managers do paves the way for analyses of what they should do to be effective. PMID:19694915

Arman, Rebecka; Dellve, Lotta; Wikstrm, Ewa; Trnstrm, Linda

2009-09-01

47

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

48

Observer ratings of neighborhoods: comparison of two methods  

PubMed Central

Background Although neighborhood characteristics have important relationships with health outcomes, direct observation involves imperfect measurement. The African American Health (AAH) study included two observer neighborhood rating systems (5-item Krause and 18-item AAH Neighborhood Assessment Scale [NAS]), initially fielded at two different waves. Good measurement characteristics were previously shown for both, but there was more rater variability than desired. In 2010 both measures were re-fielded together, with enhanced training and field methods implemented to decrease rater variability while maintaining psychometric properties. Methods AAH included a poor inner city and more heterogeneous suburban areas. Four interviewers rated 483 blocks, with 120 randomly-selected blocks rated by two interviewers. We conducted confirmatory factor analysis of scales and tested the Krause (5-20 points), AAH 18-item NAS (0-28 points), and a previous 7-item and new 5-item versions of the NAS (0-17 points, 0-11 points). Retest reliability for items (kappa) and scales (Intraclass Correlation Coefficient [ICC]) were calculated overall and among pre-specified subgroups. Linear regression assessed interviewer effects on total scale scores and assessed concurrent validity on lung and lower body functions. Mismeasurement effects on self-rated health were also assessed. Results Scale scores were better in the suburbs than in the inner city. ICC was poor for the Krause scale (ICC=0.19), but improved if the retests occurred within 10 days (ICC=0.49). The 7- and 5-item NAS scales had better ICCs (0.56 and 0.62, respectively), and were higher (0.71 and 0.73) within 10 days. Rater variability for the Kraus and 5- and 7-item NAS scales was 1-3 points (compared to the supervising rater). Concurrent validity was modest, with residents living in worse neighborhood conditions having worse function. Unadjusted estimates were biased towards the null compared with measurement-error corrected estimates. Conclusions Enhanced field protocols and rater training did not improve measurement quality. Specifically, retest reliability and interviewer variability remained problematic. Measurement error partially reduced, but did not eliminate concurrent validity, suggesting there are robust associations between neighborhood characteristics and health outcomes. We conclude that the 5-item AAH NAS has sufficient reliability and validity for further use. Additional research on the measurement properties of environmental rating methods is encouraged. PMID:24168373

2013-01-01

49

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

50

Meteorological radar methods for validating space observations of precipitation  

NASA Technical Reports Server (NTRS)

Meteorological approaches to verification of space measurements of rainfall are examined; validation of Tropical Rainfall Measuring Mission (TRMM) observations is expected to depend significantly on ground-based radars. Two methods of comparison are initially contemplated. TRMM rainfall data over time periods of a month for large areas (500 x 500 km) are averaged and compared with similarly averaged ground truth measurements. Both the rainfall and height distribution data from TRMM are compared with the instantaneous values observed at one or more 'ground truth' stations and from airborne radar and radiometers as available.

Thiele, Otto W.

1991-01-01

51

Computational observers and visualization methods for stereoscopic medical imaging.  

PubMed

As stereoscopic display devices become common, their image quality assessment evaluation becomes increasingly important. Most studies conducted on 3D displays are based on psychophysics experiments with humans rating their experience based on detection tasks. The physical measurements do not map to effects on signal detection performance. Additionally, human observer study results are often subjective and difficult to generalize. We designed a computational stereoscopic observer approach inspired by the mechanisms of stereopsis in human vision for task-based image assessment that makes binary decisions based on a set of image pairs. The stereo-observer is constrained to a left and a right image generated using a visualization operator to render voxel datasets. We analyze white noise and lumpy backgrounds using volume rendering techniques. Our simulation framework generalizes many different types of model observers including existing 2D and 3D observers as well as providing flexibility to formulate a stereo model observer approach following the principles of stereoscopic viewing. This methodology has the potential to replace human observer studies when exploring issues with stereo display devices to be used in medical imaging. We show results quantifying the changes in performance when varying stereo angle as measured by an ideal linear stereoscopic observer. Our findings indicate that there is an increase in performance of about 13-18% for white noise and 20-46% for lumpy backgrounds, where the stereo angle is varied from 0 to 30. The applicability of this observer extends to stereoscopic displays used for in the areas of medical and entertainment imaging applications. PMID:25321697

Zafar, Fahad; Yesha, Yaacov; Badano, Aldo

2014-09-22

52

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...

53

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

54

The Geyser Observation and Study Association  

NSDL National Science Digital Library

The Geyser Observation and Study Association is a non-profit scientific and educational corporation who's purpose is the "collection and dissemination of information about geysers and other geothermal phenomena in Yellowstone National Park and elsewhere". The Web site has descriptions and photographs of geysers from around the world with an emphasis on Yellowstone and Old Faithful. Other features include recent and historical geyser activity information, a glossary of geyser terms, an index to geysers described on the site, a "guess the geyser" game, and other interesting links round out the site nicely.

1997-01-01

55

Memantine (Ebixa) in Clinical Practice Results of an Observational Study  

Microsoft Academic Search

Background\\/Aims: In a post-marketing observational study, the efficacy and tolerability of memantine were examined in patients with moderate to severe Alzheimers disease. Methods: The patients were treated with 20 mg\\/day of memantine for a 6-month period. The efficacy of memantine was evaluated using the Mini-Mental State Examination, the Nurses Observation Scale for Geriatric Patients (NOSGER) and the Explorationsmodul Demenz (EMD)

Pasquale Calabrese; Ute Essner; Hans Frstl

2007-01-01

56

Overview of the Ocean Observer Satellite Study  

NASA Astrophysics Data System (ADS)

A two-year study of ocean satellite remote sensing requirements and instrument/satellite options is nearing completion. This Ocean Observer Study was sponsored by the U.S. Dept. of Commerce/Dept. of Defense/National Aeronautics and Space Administration Integrated Program Office, whose mission is to develop the future U.S. National Polar-Orbiting Operational Environmental Satellite System (NPOESS). A comprehensive Ocean Observer User Requirements Document has been drafted by a team of over 150 government, academic, and private sector scientists, engineers, and administrators. Included are requirements for open and coastal ocean surface, cryospheric, hydrologic, and some land/hazard and atmospheric boundary layer parameters. This document was then used as input to the instrument and satellite study (conducted by the Jet Propulsion Laboratory) which produced five different instrument/satellite configuration options designed to address the maximum number of requirements which will not be met with the already-approved NPOESS instruments. Instruments studied include a synthetic aperture radar (SAR), an altimeter, and a hyper-spectral coastal infrared/visible imager. After analyzing the alternatives, it appears that one of the best options is a two-satellite system consisting of (1) an altimeter mission in the Topex/Poseidon orbit carrying both wide-swath and delayed doppler altimeters, and (2) a multi-polarization, multi-frequency, multi-mode interferometric SAR mission including a coastal imager in a polar sun-synchronous orbit. This paper summarizes the user requirements process, briefly describes the notional satellite configuration, and presents some of the capabilities of the instruments.

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

2002-12-01

57

Journalistic Observation as a Qualitative Research Method for Sociology.  

ERIC Educational Resources Information Center

A comparison is made between the tools of observation and research used by journalists to study society and the media, and the qualitative and clinical research tools used in the social and psychological sciences. The first part of the paper, a journalistic approach to sociology, traces the notion of the sociologist as a super-reporter using

Burd, Gene

58

Influence of the discretization method on the integration accuracy of observers with continuous feedback  

Microsoft Academic Search

The paper discusses the problem of integrating the equations of state observers associated with direct field orientation (DFO) of motor drives and studies the influence of the discretization method used on the accuracy of integration. In a typical implementation, discrete-time integration is done using Euler's discretization method (forward rectangular rule) - the method is simple and integration is accurate when

Mihai Comanescu

2011-01-01

59

Assessing Postoperative Pain in Neonates: A Multicenter Observational Study  

Microsoft Academic Search

OBJECTIVE.A multicenter observational study was conducted to evaluate the practices of postoperative pain assessment and management in neonates to identify specific targets for improvement in clinical practice. METHODS.Ten participating NICUs collected data for the 72 hours after a surgical operation on 25 consecutive neonates (N 250), including demographics, prin- cipal diagnoses, operative procedure, other painful procedures, pain assessments, interventions (pharmacologic

Bonnie J. Taylor; James M. Robbins; Jeffrey I. Gold; Tina R. Logsdon; T. M. Bird; K. J. S. Anand

60

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

61

The Home Observation Assessment Method (HOAM): Real-Time Naturalistic Observation of Families in Their Homes.  

ERIC Educational Resources Information Center

The vast bulk of psychosocial research data about the family are derived from two basic sources: self-report, retrospective data obtained by questionnaires or interviews; and direct observations of behavior occurring in a laboratory or treatment setting. Despite an emerging enthusiasm for the notion of studying behavior in its natural environment

Steinglass, Peter

62

A method for combining passive microwave and infrared rainfall observations  

NASA Technical Reports Server (NTRS)

Because passive microwave instruments are confined to polar-orbiting satellites, rainfall estimates must interpolate across long time periods, during which no measurements are available. In this paper the authors discuss a technique that allows one to partially overcome the sampling limitations by using frequent infrared observations from geosynchronous platforms. To accomplish this, the technique compares all coincident microwave and infrared observations. From each coincident pair, the infrared temperature threshold is selected that corresponds to an area equal to the raining area observed in the microwave image. The mean conditional rainfall rate as determined from the microwave image is then assigned to pixels in the infrared image that are colder than the selected threshold. The calibration is also applied to a fixed threshold of 235 K for comparison with established infrared techniques. Once a calibration is determined, it is applied to all infrared images. Monthly accumulations for both methods are then obtained by summing rainfall from all available infrared images. Two examples are used to evaluate the performance of the technique. The first consists of a one-month period (February 1988) over Darwin, Australia, where good validation data are available from radar and rain gauges. For this case it was found that the technique approximately doubled the rain inferred by the microwave method alone and produced exceptional agreement with the validation data. The second example involved comparisons with atoll rain gauges in the western Pacific for June 1989. Results here are overshadowed by the fact that the hourly infrared estimates from established techniques, by themselves, produced very good correlations with the rain gauges. The calibration technique was not able to improve upon these results.

Kummerow, Christian; Giglio, Louis

1995-01-01

63

Steel Production Methods Improvement Study  

Microsoft Academic Search

We present a three-phase, interdisciplinary study undertaken to improve methods of steel production within timing and capital investment constraints. The defined objective of this study was to increase the throughput of the hydrogen annealing process via assessment of various operating policies and resource levels. The three phases of the study successively involved work measurement project management, and discrete process simulation.

Edward J. Williams; Celia Ortiz

64

Observations from the CDX Nonlinear Sawtooth Study  

NASA Astrophysics Data System (ADS)

We present two separate sets of observations from modeling sawteeth in the CDX tokamak with the M3D code [1] as part of a cross-code benchmark. One is that, in addition to the internal kink, the starting equilibrium is linearly unstable to a range of high-n resistive ballooning-like modes [2], which can only be suppressed by the assumption of extremely high perpendicular heat transport. There is evidence that such transport is present in CDX itself, possibly induced by the edge modes [3], which would thereby saturate nonlinearly. Analysis of field line stochasticity as a mechanism for this saturation will be presented. The second topic is the finding that the sawtooth, though fundamentally a 1,1 mode, has considerable structure in the toroidal direction which is not easily resolved even with the retention of tens of mode numbers in the nonlinear run. The demands of a convergence study are therefore more stringent than might at first be supposed; implications for the development of predictive capability are discussed. [1] W. Park et al., Phys. Plasmas 6, 1796 (1999). [2] H.R. Strauss. Phys. Fluids 24, 2004 (1981). [3] B.A. Carreras and P.H. Diamond, Phys. Fluids B 1, 1011 (1989).

Breslau, J.; Park, W.; Hudson, S.; Jardin, S.; Strauss, H.

2006-04-01

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

Combining observations to study heliospheric phenomena  

NASA Astrophysics Data System (ADS)

There is currently a more diverse range of observatories scattered around the solar system than at any time in the past. As a consequence, heliophysics - the study of the effect of the Sun on the Solar System - has entered a boom period. The Heliophysics Integrated Observatory, HELIO, has established a collaborative environment where scientists can discover, understand and model the connection between solar phenomena, interplanetary disturbances and their effects on the planets. The project is designed around a serviceoriented architecture with needed capabilities that support metadata curation and search, data location and retrieval, and data processing and storage being established as independent services. HELIO provides integrated access to the data and metadata from the domains that constitute heliophysics - solar, heliospheric, geophysics and planetary. More than 50 event catalogues can be used in the search, together with10 feature catalogues; data from more than 150 instruments from nearly 50 observatories can be accessed. A comprehensive user interface is available and the services can also be accessed through IDL; a workflow tool provides the ability to combine services together and it is possible to execute programmes on demand including propagation models. We will show how HELIO can be used to explore how phenomena evolve as they propagate through the Solar System. Effects related to structures in the solar wind, coronal mass ejections and particle events are reported using observations from multiple platforms, including occasions where the same phenomenon interacts with multiple planetary environments. The HELIO Consortium includes thirteen groups from the UK, France, Ireland, Italy, Switzerland, Spain and the US; the project started in June 2009 and has a duration of 42 months.

Bentley, R. D.

2012-09-01

67

Review of Observational Methods in Attention Deficit Hyperactivity Disorder (ADHD): Implications for Diagnosis  

Microsoft Academic Search

Reviewed 39 empirical studies in which direct observational methods were used to assess children in whom attention deficit hyperactivity disorder (ADHD) had been diagnosed. Classroom studies distinguished ADHD children from comparison groups better than laboratory studies. Behaviors that most consistently distinguished ADHD children from comparison groups included measures of attention, activity, and vocalization. Suggests ways to improve the efficiency and

Kathleen A. Platzman; Mary R. Stoy; Ronald T. Brown; Claire D. Coles; Iris E. Smith; Arthur Falek

1992-01-01

68

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

69

Research Methods for Genetic Studies  

Microsoft Academic Search

This chapter introduces the basic concepts of genes and genetic studies to clinicians. Some of the relevant methods and issues\\u000a in genetic epidemiology studies are briefly discussed with an emphasis on single nucleotide polymorphism based association\\u000a studies which are currently the main focus of clinical and translational genetics.\\u000a \\u000a Genetics is the fundamental basis of any organism so understanding of genetics

Sadeep Shrestha; Donna K. Arnett

70

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

Microsoft Academic Search

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

Daniel Doktor

2010-01-01

71

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

72

Estimation methods for marginal and association parameters for longitudinal binary data with nonignorable missing observations.  

PubMed

In longitudinal studies, missing observations occur commonly. It has been well known that biased results could be produced if missingness is not properly handled in the analysis. Authors have developed many methods with the focus on either incomplete response or missing covariate observations, but rarely on both. The complexity of modeling and computational difficulty would be the major challenges in handling missingness in both response and covariate variables. In this paper, we develop methods using the pairwise likelihood formulation to handle longitudinal binary data with missing observations present in both response and covariate variables. We propose a unified framework to accommodate various types of missing data patterns. We evaluate the performance of the methods empirically under a variety of circumstances. In particular, we investigate issues on efficiency and robustness. We analyze longitudinal data from the National Population Health Study with the use of our methods. PMID:22833460

Li, Haocheng; Yi, Grace Y

2013-02-28

73

Observational constraints on well-posed reconstruction methods and the optimization-Grad-Rubin method  

NASA Astrophysics Data System (ADS)

Context. Grad-Rubin type methods are interesting candidates for reconstructing the force-free magnetic field of a solar coronal region. As input these methods, however, require the normal component Bn of the field on the whole boundary of the numerical box and the force-free function ? on the part of the boundary where Bn > 0 (or Bn < 0), while observations provide data only on its lower photospheric part. Moreover, they introduce an unpleasing asymmetry between the opposite polarity parts of the boundary, and certainly do not take full advantage of the available data on ?. Aims: We address these issues resulting from observations. We present a possible way to supply the missing information about Bn and ? on the non-photospheric sides of the box, and to use more effectively the data provided by the measurements. Methods: We introduce the optimization-Grad-Rubin method (OGRM), which is in some sense midway between optimization methods and the standard Grad-Rubin methods. It is based on an iterative scheme in which the ? used as a boundary condition is imposed to take identical values at both footpoints of any field line and to be as close as possible to the ? provided by the measurements on the photosphere. The degree of closeness is measured by an error functional containing a weight function reflecting the confidence that can be placed on the observational data. Results: The new method is implemented in our code XTRAPOL, along with some technical improvements. It is thus tested for two specific choices of the weight function by reconstructing a force-free field from data obtained by perturbing in either a random or a non-random way boundary values provided by an exact solution.

Amari, T.; Aly, J.-J.

2010-11-01

74

Carbon Dioxide Observational Platform System (CO-OPS), feasibility study  

NASA Technical Reports Server (NTRS)

The Carbon Dioxide Observational Platform System (CO-OPS) is a near-space, geostationary, multi-user, unmanned microwave powered monitoring platform system. This systems engineering feasibility study addressed identified existing requirements such as: carbon dioxide observational data requirements, communications requirements, and eye-in-the-sky requirements of other groups like the Defense Department, the Forestry Service, and the Coast Guard. In addition, potential applications in: earth system science, space system sciences, and test and verification (satellite sensors and data management techniques) were considered. The eleven month effort is summarized. Past work and methods of gathering the required observational data were assessed and rough-order-of magnitude cost estimates have shown the CO-OPS system to be most cost effective (less than $30 million within a 10 year lifetime). It was also concluded that there are no technical, schedule, or obstacles that would prevent achieving the objectives of the total 5-year CO-OPS program.

Bouquet, D. L.; Hall, D. W.; Mcelveen, R. P.

1987-01-01

75

Observing Reel Life: Using Feature Films To Teach Ethnographic Methods.  

ERIC Educational Resources Information Center

Extends the methods of using film as a tool to teach content analysis and examines the use of feature films in teaching ethnographic methods. Explores how feature films are a valuable pedagogical tool in qualitative methods instruction by drawing from an assignment developed for a course on youth subcultures. (DSK)

Leblanc, Lauraine

1998-01-01

76

A Multimedia Demonstration and Comparison of Three Structured Observational Methods.  

ERIC Educational Resources Information Center

This social psychological laboratory activity permits the systematic observation of spontaneous human behavior as simulated on television and provides one way to effectively demonstrate and compare time sampling, event sampling, and trait rating techniques. The preparation involves videotaping a popular television show that depicts observable

Zeren, Andrea S.

77

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 and methods Results & Discussion Context Previous Observations Motivation Goal: Understand the distribution

Demoulin, Pascal

78

Driving violations observed: an Australian study.  

PubMed

This study analyses 2,765 cases of driving behaviours in three Australian states - New South Wales, Queensland and Victoria. Data were gathered from in-car coordinated video and audio recording sequences in free-flowing traffic along two-, three- and four-lane highways with varying speed limits on all days of the week in daylight and fine weather conditions. Explanatory variables included driver age group and gender, passenger characteristics and vehicle age and type. Response variables included driving violations and other driving behaviours, including lane use, speeding, close following (tailgating), driver's hands position and mobile phone use. Data were analysed qualitatively and quantitatively. By focusing upon vehicle and driver characteristics, and their impact on driving behaviours, including identified violations, this study explores some implications both for future research and for traffic policy makers. PMID:17558663

Glendon, A Ian

2007-08-01

79

ACORN-SAT surface air temperature observing methods document  

E-print Network

-resistance sensors used in Bureau AWS since the 1980s. 22 Figures #12;Table 1 Observation times in Australia of the change in uncertainties for metrology laboratory calibrations and verification since 1908. 29 Tables #12

Greenslade, Diana

80

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

81

The impact of verification area design on tropical cyclone targeted observations based on the CNOP method  

Microsoft Academic Search

This study investigated the impact of different verification-area designs on the sensitive areas identified using the conditional\\u000a nonlinear optimal perturbation (CNOP) method for tropical cyclone targeted observations. The sensitive areas identified using\\u000a the first singular vector (FSV) method, which is the linear approximation of CNOP, were also investigated for comparison.\\u000a By analyzing the validity of the sensitive areas, the proper

Feifan Zhou; Mu Mu

2011-01-01

82

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

83

An analytical method for predicting surface soil moisture from rainfall observations  

E-print Network

content in the upper several meters of soil that is available for plant growth. It affects land surfaceAn analytical method for predicting surface soil moisture from rainfall observations Feifei Pan for estimating surface soil moisture directly from rainfall data is proposed and studied. Soil moisture dynamics

Pan, Feifei

84

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

85

Observer Evaluations of Wavelet Methods for the Enhancement and ...  

E-print Network

In this paper, we will report the ... The reason for this lies in our past efforts ... Our studies were approved by the institutional review board as a research study us- ing existing medical records and exempted from individual patient consent...

Maria Kallergi, John J. Heine, and Bradley J. Lucier

2006-05-17

86

The Application of the TDI Method to Observations of Lunar Occultations  

NASA Astrophysics Data System (ADS)

In my dissertation, I discuss how the time delay integration (TDI) method can be applied to observations of lunar occultations. The TDI method allows us to track the diffraction pattern of an occulted star by stepping the photon-generated charge packages in a CCD array placed in the pupil plane of a large telescope. The use of TDI should considerably improve the signal-to-noise ratio that can be reached in occultation observations compared with that which can be obtained currently using conventional high-speed photometers. This novel method could extend lunar occultation studies to faint stars and telescopes with large apertures without the aperture distortion effect inherent in the conventional method. The high signal-to-noise ratio allows us to obtain stellar angular diameters with accuracy better than 2% for mv<5 and ? >1 mas as well as more accurate photometry in close double systems.

Sturmann, Laszlo

1997-12-01

87

Factors affecting recruitment to an observational multicentre palliative care study  

PubMed Central

Objectives To identify those factors which adversely affected recruitment to a large multicentre palliative care study. Methods Patient accrual to a multicentre, observational, palliative care study was monitored at three critical junctures in the research process. (1) Eligibilitydid the patient fulfil the study entry criteria? (2) Accessibilitywas it possible to access the patient to be able to inform them about the study? (3) Consentdid the patient agree to participate in the study? The reasons why patients were ineligible, inaccessible or refused consent were recorded. Results 12?412 consecutive referrals to participating clinical services were screened for study inclusion of whom 5394 (43%) were deemed to be ineligible. Of the remaining patients 4617/7018 (66%) were inaccessible to the research team. The most common reasons being precipitous death, gatekeeping by clinical staff or rapid discharge. Of the 2410 patients who were visited by the research team and asked to participate in the study 1378 (57%) declined. Overall 8.2% (1018/12?412) of patients screened participated in the study. There were significant differences in recruitment patterns between hospice inpatient units, hospital support and community palliative care teams. Conclusions Systematic monitoring and analysis of patient flows through the clinical trial accrual process provided valuable insights about the reasons for failure to recruit patients to a clinical trial and may help to improve recruitment in future studies. PMID:24644750

Stone, Patrick C; Gwilliam, Bridget; Keeley, Vaughan; Todd, Chris; Kelly, Laura C; Barclay, Stephen

2013-01-01

88

Observational and numerical modeling methods for quantifying coastal ocean turbulence and mixing  

NASA Astrophysics Data System (ADS)

In this review paper, state-of-the-art observational and numerical modeling methods for small scale turbulence and mixing with applications to coastal oceans are presented in one context. Unresolved dynamics and remaining problems of field observations and numerical simulations are reviewed on the basis of the approach that modern process-oriented studies should be based on both observations and models. First of all, the basic dynamics of surface and bottom boundary layers as well as intermediate stratified regimes including the interaction of turbulence and internal waves are briefly discussed. Then, an overview is given on just established or recently emerging mechanical, acoustic and optical observational techniques. Microstructure shear probes although developed already in the 1970s have only recently become reliable commercial products. Specifically under surface waves turbulence measurements are difficult due to the necessary decomposition of waves and turbulence. The methods to apply Acoustic Doppler Current Profilers (ADCPs) for estimations of Reynolds stresses, turbulence kinetic energy and dissipation rates are under further development. Finally, applications of well-established turbulence resolving particle image velocimetry (PIV) to the dynamics of the bottom boundary layer are presented. As counterpart to the field methods the state-of-the-art in numerical modeling in coastal seas is presented. This includes the application of the Large Eddy Simulation (LES) method to shallow water Langmuir Circulation (LC) and to stratified flow over a topographic obstacle. Furthermore, statistical turbulence closure methods as well as empirical turbulence parameterizations and their applicability to coastal ocean turbulence and mixing are discussed. Specific problems related to the combined wave-current bottom boundary layer are discussed. Finally, two coastal modeling sensitivity studies are presented as applications, a two-dimensional study of upwelling and downwelling and a three-dimensional study for a marginal sea scenario (Baltic Sea). It is concluded that the discussed methods need further refinements specifically to account for the complex dynamics associated with the presence of surface and internal waves.

Burchard, Hans; Craig, Peter D.; Gemmrich, Johannes R.; van Haren, Hans; Mathieu, Pierre-Philippe; Meier, H. E. Markus; Smith, W. Alex M. Nimmo; Prandke, Hartmut; Rippeth, Tom P.; Skyllingstad, Eric D.; Smyth, William D.; Welsh, David J. S.; Wijesekera, Hemantha W.

2008-03-01

89

How Safe Do Teenagers Behave on Facebook? An Observational Study  

PubMed Central

The substantial use of social network sites by teenagers has raised concerns about privacy and security. Previous research about behavior on social network sites was mostly based on surveys and interviews. Observational research overcomes problems inherent to this research method, for example social desirability. However, existing observational research mostly focuses on public profiles of young adults. Therefore, the current observation-study includes 1050 public and non-public Facebook-profiles of teenagers (1318) to investigate (1) what kind of information teenagers post on their profile, (2) to what extent they protect this information using privacy-settings and (3) how much risky information they have on their profile. It was found that young people mostly post pictures, interests and some basic personal information on their profile. Some of them manage their privacy-settings as such that this information is reserved for friends' eyes only, but a lot of information is accessible on the friends-of-friends' pages. Although general risk scores are rather low, more detailed analyses show that teenagers nevertheless post a significant amount of risky information. Moreover, older teenagers and girls post more (risky) information while there are no differences in applying privacy settings. We found no differences in the Facebook behavior of teenagers enrolled in different education forms. Implications of these results are discussed. PMID:25162234

Vanderhoven, Ellen; Schellens, Tammy; Valcke, Martin; Raes, Annelies

2014-01-01

90

How safe do teenagers behave on Facebook? An observational study.  

PubMed

The substantial use of social network sites by teenagers has raised concerns about privacy and security. Previous research about behavior on social network sites was mostly based on surveys and interviews. Observational research overcomes problems inherent to this research method, for example social desirability. However, existing observational research mostly focuses on public profiles of young adults. Therefore, the current observation-study includes 1050 public and non-public Facebook-profiles of teenagers (13-18) to investigate (1) what kind of information teenagers post on their profile, (2) to what extent they protect this information using privacy-settings and (3) how much risky information they have on their profile. It was found that young people mostly post pictures, interests and some basic personal information on their profile. Some of them manage their privacy-settings as such that this information is reserved for friends' eyes only, but a lot of information is accessible on the friends-of-friends' pages. Although general risk scores are rather low, more detailed analyses show that teenagers nevertheless post a significant amount of risky information. Moreover, older teenagers and girls post more (risky) information while there are no differences in applying privacy settings. We found no differences in the Facebook behavior of teenagers enrolled in different education forms. Implications of these results are discussed. PMID:25162234

Vanderhoven, Ellen; Schellens, Tammy; Valcke, Martin; Raes, Annelies

2014-01-01

91

Oscillations and running waves observed in sunspots. III. Multilayer study  

NASA Astrophysics Data System (ADS)

We continue our study of waves and oscillations observed in sunspots using an improved method for enhancing the waves, giving the opportunity to identify them and determine their properties in far H? wings. We found that the running penumbral waves are observable at least up to the formation height of the H? +/- 0.5 line, but not in the H? +/- 0.75 or the Fe I+/-0.12 . We found a time lag between the waves in the blue and the red wing of the H? line corresponding to a phase shift of 180o, that indicates a pure Doppler shift of the line. There is a lag in the propagation of the waves seen at H? center and at H? wings. Also there is a lag in the variation of the umbral oscillations as they are observed from lower to higher atmospheric layers. The correlation between umbral oscillations at various atmospheric heights and running penumbral waves strongly indicates that the latter are excited by photospheric umbral oscillations and not the chromospheric ones. We found a new category of photospheric waves that originate at approximately 0.7 of the distance between the umbra and the penumbra boundary and propagate beyond the outer penumbra boundary with a velocity of the order of 3-4 km s-1. Further, we found 3 min penumbral oscillations apparent in the inner penumbra at lower chromospheric layers (far H? wings). Based on observations performed on the NSO/SPO Richard B. Dunn Solar Telescope (DST)

Christopoulou, E. B.; Georgakilas, A. A.; Koutchmy, S.

2001-08-01

92

Conditional Permutation Tests and the Propensity Score in Observational Studies  

Microsoft Academic Search

In observational studies, the distribution of treatment assignments is unknown, and therefore randomization tests are not generally applicable. However, permutation tests that condition on sample information about the treatment assignment mechanism can be applicable in observational studies, provided treatment assignment is strongly ignorable. These tests use the conditional distribution of the treatment assignments given a sufficient statistic for the unknown

Paul R. Rosenbaum

1984-01-01

93

Analysis of subprotonospheric whistlers observed by DEMETER: A case study  

E-print Network

Analysis of subprotonospheric whistlers observed by DEMETER: A case study Jaroslav Chum,1 Ondrej km. We have used wave-normal angles and plasma characteristics measured by the DEMETER microsatellite), Analysis of subprotonospheric whistlers observed by DEMETER: A case study, J. Geophys. Res., 114, A02307

Santolik, Ondrej

94

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...

95

A Comparison of Three Methods of Measuring Dementia-Specific Quality of Life: Perspectives of Residents, Staff, and Observers  

Microsoft Academic Search

Purpose: This exploratory study compared three methods of assessing dementia specific quality of life, corresponding to the perspectives of residents, staff members, and trained observers. Design and Methods: We collected data on 172 residents with dementia in four special care nursing facilities and three assisted living facilities. Analyses assessed the relationship of each quality-of-life method or perspec- tive to the

Perry Edelman; Bradley R. Fulton; Daniel Kuhn; Chih-Hung Chang

96

Concatenation of Observed Grasp Phases with Observer's Distal Movements: A Behavioural and TMS Study  

PubMed Central

The present study aimed at determining how actions executed by two conspecifics can be coordinated with each other, or more specifically, how the observation of different phases of a reaching-grasping action is temporary related to the execution of a movement of the observer. Participants observed postures of initial finger opening, maximal finger aperture, and final finger closing of grasp after observation of an initial hand posture. Then, they opened or closed their right thumb and index finger (experiments 1, 2 and 3). Response times decreased, whereas acceleration and velocity of actual finger movements increased when observing the two late phases of grasp. In addition, the results ruled out the possibility that this effect was due to salience of the visual stimulus when the hand was close to the target and confirmed an effect of even hand postures in addition to hand apparent motion due to the succession of initial hand posture and grasp phase. In experiments 4 and 5, the observation of grasp phases modulated even foot movements and pronunciation of syllables. Finally, in experiment 6, transcranial magnetic stimulation applied to primary motor cortex 300 ms post-stimulus induced an increase in hand motor evoked potentials of opponens pollicis muscle when observing the two late phases of grasp. These data suggest that the observation of grasp phases induced simulation which was stronger during observation of finger closing. This produced shorter response times, greater acceleration and velocity of the successive movement. In general, our data suggest best concatenation between two movements (one observed and the other executed) when the observed (and simulated) movement was to be accomplished. The mechanism joining the observation of a conspecifics action with our own movement may be precursor of social functions. It may be at the basis for interactions between conspecifics, and related to communication between individuals. PMID:24278395

De Stefani, Elisa; Innocenti, Alessandro; De Marco, Doriana; Gentilucci, Maurizio

2013-01-01

97

Cause versus association in observational studies in psychopharmacology.  

PubMed

Hypotheses may be generated (and conclusions drawn) from observational studies in areas where information from randomized controlled trials (RCTs) is unavailable. However, observational studies can only establish that significant associations exist between predictor and outcome variables. Observational studies cannot establish that the associations identified represent cause-and-effect relationships. This article discusses examples of associations that were identified in observational studies and that were subsequently refuted in RCTs. Examples are also provided of associations that have yet to be confirmed or refuted but that are nevertheless influential in psychopharmacologic practice. Explanations are offered about how confounding might explain significant relationships between variables that are not related by cause and effect. As a conclusion of this exercise, clinicians are cautioned against placing too much reliance on the findings of observational research. PMID:25191914

Andrade, Chittaranjan

2014-08-01

98

A non-parametric permutation method for assessing agreement for distance matrix observations.  

PubMed

Distance matrix data are occurring ever more frequently in medical research, particularly in fields such as genetics, DNA research, and image analysis. We propose a non-parametric permutation method for assessing agreement when the data under study are distance matrices. We apply agglomerative hierarchical clustering and accompanying dendrograms to visualize the internal structure of the matrix observations. The accompanying test is based on random permutations of the elements within individual matrix observations and the corresponding matrix mean of these permutations. We compare the within-matrix element sum of squares (WMESS) for the observed mean against the WMESS for the permutation means. The methodology is exemplified using simulations and real data from magnetic resonance imaging. PMID:23946159

Rislien, Jo; Samset, Eigil

2014-01-30

99

Material and Methods -Study sites  

E-print Network

were always collected at the same lunar phase (after new moon-until full moon). The cellular changes us to study the gametogenic phases by examining sexual and nutritive cell in the tissues (Walker et

Hernández, José Carlos

100

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

101

Application of an optimal estimation inverse method to GPS/MET bending angle observations  

NASA Astrophysics Data System (ADS)

Palmer et al. [2000] describes an optimal estimation inverse method for radio occultation (RO) bending angle measurements to retrieve simultaneously temperature, humidity, and surface pressure; outlines quality control procedures for retrieved profiles; and investigates the results from numerical simulations. Here we present retrievals that use bending angle observations from the Global Positioning System Meteorology (GPS/MET) satellite instrument and a priori information from the European Centre for Medium-Range Weather Forecasts analyses. Retrieved profiles are compared with correlative radiosondes, United Kingdom Meterological Office (UKMO) model analyses, and retrievals from the conventional inverse method. Retrieved temperature profiles are generally colder than analyses but agree with the conventional inverse method to within 1 K. Water vapor retrievals are generally drier than the UKMO analyses and wetter than the radiosonde profiles. Quality of retrieved surface pressure values are related to the extent to which RO observations reach into the troposphere. Low-latitude retrievals make large adjustments to surface pressure and tropospheric temperatures, which are directly linked to the lack of water vapor above 300 hPa in the inverse model, consistent with previous studies. A study of individual occultations at low and high latitude shows that the optimal retrievals are able to resolve small-scale atmospheric structure exhibited by the conventional inverse method and collocated radiosondes, not shown by analyses.

Palmer, Paul I.; Barnett, John J.

2001-01-01

102

Design of a practical model-observer-based image quality assessment method for CT imaging systems  

NASA Astrophysics Data System (ADS)

The channelized Hotelling observer (CHO) is a powerful method for quantitative image quality evaluations of CT systems and their image reconstruction algorithms. It has recently been used to validate the dose reduction capability of iterative image-reconstruction algorithms implemented on CT imaging systems. The use of the CHO for routine and frequent system evaluations is desirable both for quality assurance evaluations as well as further system optimizations. The use of channels substantially reduces the amount of data required to achieve accurate estimates of observer performance. However, the number of scans required is still large even with the use of channels. This work explores different data reduction schemes and designs a new approach that requires only a few CT scans of a phantom. For this work, the leave-one-out likelihood (LOOL) method developed by Hoffbeck and Landgrebe is studied as an efficient method of estimating the covariance matrices needed to compute CHO performance. Three different kinds of approaches are included in the study: a conventional CHO estimation technique with a large sample size, a conventional technique with fewer samples, and the new LOOL-based approach with fewer samples. The mean value and standard deviation of area under ROC curve (AUC) is estimated by shuffle method. Both simulation and real data results indicate that an 80% data reduction can be achieved without loss of accuracy. This data reduction makes the proposed approach a practical tool for routine CT system assessment.

Tseng, Hsin-Wu; Fan, Jiahua; Cao, Guangzhi; Kupinski, Matthew A.; Sainath, Paavana

2014-03-01

103

CHEMICAL METHODS vs PHYSICAL METHODS FOR PDVF MORPHOLOGY STUDIES  

Microsoft Academic Search

Morphology of poly(vinylidene fluoride) PDVF is of practical concern, this polymer may be processed to give a number of different crystal forms such as ?, ?, ? and these may exhibit a wide range of different morphologies. Due to the difficulty of the PVDF material presents to be observed by electron microscopy techniques, Vaughan developed a method that implies chemical

C. Urbina de Navarro; N. Daz; M. Prez-De

104

An Observational Study of Social Processes in Microcomputer Classrooms.  

ERIC Educational Resources Information Center

This observational study examined student and teacher verbal and nonverbal behaviors in microcomputer classrooms in a high school where most of the students are Black, Hispanic, or Asian, and almost half of them are classified as economically disadvantaged. A total of 125 students in grades 9 to 12 were observed, with 47 students in marketing, 18

Feldmann, Shirley C.; And Others

105

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

106

MOOSES: Multiple Option Observation System for Experimental Studies.  

ERIC Educational Resources Information Center

The Multiple Option Observation System for Experimental Studies (MOOSES) is a flexible data collection and analysis package for applied behavioral research that addresses the needs of researchers interested in live coding of observational data. MOOSES allows the researcher to design a coding system for a particular research question. General types

Tapp, Jon; Wehby, Joseph

107

A useful method for observing intracellular structures of free and cultured cells by scanning electron microscopy.  

PubMed

Scanning electron microscopy (SEM) using osmium-maceration methods has been used for analyzing the three-dimensional structure of cell organelles in tissue samples, but it has been quite difficult to observe free and cultured cells with this technique. The present study was performed to develop a method that can be applied to free and cultured cells for SEM studies of intracellular structures after osmium maceration. The method was also applied to light microscopy (LM) and to transmission electron microscopy (TEM). HeLa cells and human leukocytes were fixed with a mixture of 0.5% paraformaldehyde and 0.5% glutaraldehyde followed by an additional fixation with 1% osmium tetroxide. These cells were embedded in low-melting-point agarose. A temperature-responsive dish was also used for collection of cultured cells before embedding. For LM and TEM, the cell-embedded agarose was further embedded in epoxy resin, and semi- and ultrathin sections were examined conventionally. For SEM, the agarose was freeze-fractured in 50% dimethyl sulfoxide, processed for osmium maceration and observed in a high-resolution SEM. Low-melting-point agarose was useful as an embedding medium for SEM, because it was well preserved during prolonged osmication for SEM. Thus, the fine structure of cell organelles was clearly analyzed by SEM after osmium-maceration treatment. These SEM images could also be compared with those of LM and TEM of the agarose-embedded tissues. PMID:22257590

Koga, Daisuke; Nakajima, Masato; Ushiki, Tatsuo

2012-04-01

108

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 29, METHOD 624--PURGEABLES  

EPA Science Inventory

The work which is described in the report was performed for the purpose of validating, through an interlaboratory study, Method 624 for the analysis of the volatile organic priority pollutants. This method is based on purging and concentration of the various analytes on an adsorb...

109

Case study as a research method  

Microsoft Academic Search

Although case study methods remain a controversial approach to data collection, they are widely recognised in many social science studies especially when in-depth explanations of a social behaviour are sought after. This article, therefore, discusses several aspects of case studies as a research method. These include the design and categories of case studies and how their robustness can be achieved.

Zaidah Zainal

2007-01-01

110

An Appraisal of Study Methods Inventories.  

ERIC Educational Resources Information Center

The significance of study method inventories in higher education is explored. A brief history of study skills inventories is presented along with justifications for using a study method approach. Research indicates the student most likely to be more successful than others may exhibit better study habits and adapt more easily to academic norms and

Thompson, Mark E.

111

Information exchange networks for chronic illness care in primary care practices: an observational study  

Microsoft Academic Search

BACKGROUND: Information exchange networks for chronic illness care may influence the uptake of innovations in patient care. Valid and feasible methods are needed to document and analyse information exchange networks in healthcare settings. This observational study aimed to examine the usefulness of methods to study information exchange networks in primary care practices, related to chronic heart failure, diabetes and chronic

Michel Wensing; Jan van Lieshout; Jan Koetsenruijter; David Reeves

2010-01-01

112

Observation impact estimation using a forecast sensitivity to observation (FSO) method in the global and east Asia regions  

NASA Astrophysics Data System (ADS)

This study investigated the observation impact to the forecast for the summer and winter months (i.e., JJA 2011 and DJF 2011-2012) in the global and east Asia regions, using the forecast sensitivity to observation (FSO) tool in the Korea Meteorological Administration (KMA) Unified Model (UM). The SONDE, AIRCRAFT, SURFACE, BOGUS, NOAA ATOVS, MetOp2 ATOVS, IASI, AIRS, GPSRO, SSMIS, Communication, Ocean and Meteorological Satellite (COMS) of KMA, AMV of JMA, ESA, GEOS, MSG, and ASCAT observations were used to estimate the observation impact to the forecast. Overall each observation showed consistent contribution to the forecast error reduction for summer and winter months. In the global region, the observation impact to the forecast error reduction depended on the number of observations assimilated in the numerical model. The contribution of the SONDE to the forecast error reduction is the largest, followed by NOAA / MetOp2 ATOVS and IASI. In satellite sounding observations, the contribution of channel number 5, 6, 7 of NOAA AMSU-A and channel number 56-215, 271-280 of IASI to the forecast error reduction were large. In the east Asia region, the contribution of the SONDE to the forecast error reduction was the largest, similar to that in the global region. However, the contribution of the satellite data to the forecast error reduction was decreased when compared to that in the global region because of exception of millions of satellite observations located the ocean and southern hemisphere. Especially, Atmospheric Motion Vector (AMV) observations of COMS launched in 2009 showed the largest impact among several Imager sensors.

Kim, Sung-Min; Kim, Hyun Mee

2013-04-01

113

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

114

Driving performance while using cell phones: an observational study  

Microsoft Academic Search

IntroductionThrough spontaneous driving observations, this study sought to examine the impact of using a hands-free cell phone while driving on speed and safe gap keeping behaviors. The study also examined the association between the measure of disturbance created by using a cell phone and the driver's awareness of the disturbance.

Tova Rosenbloom

2006-01-01

115

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

116

Radiation energy budget studies using collocated AVHRR and ERBE observations  

NASA Technical Reports Server (NTRS)

Changes in the energy balance at the top of the atmosphere are specified as a function of atmospheric and surface properties using observations from the Advanced Very High Resolution Radiometer (AVHRR) and the Earth Radiation Budget Experiment (ERBE) scanner. By collocating the observations from the two instruments, flown on NOAA-9, the authors take advantage of the remote-sensing capabilities of each instrument. The AVHRR spectral channels were selected based on regions that are strongly transparent to clear sky conditions and are therefore useful for characterizing both surface and cloud-top conditions. The ERBE instruments make broadband observations that are important for climate studies. The approach of collocating these observations in time and space is used to study the radiative energy budget of three geographic regions: oceanic, savanna, and desert.

Ackerman, Steven A.; Inoue, Toshiro

1994-01-01

117

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

118

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) 1.323.04]. 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 2.285.42) and for the next 2 yr of 2.44 (P<0.001; 95% CI 1.623.65), 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

119

New method for reduction of astrolabe observations using rectangular coordinates on the celestial sphere  

Microsoft Academic Search

A new reduction method usingx, y, z-coordinates is derived for astrolabe observations. By this method, the latitude and the longitude of the station are computed\\u000a without the need of a priori knowledge of the station position. This method is a significant development in data reduction\\u000a of astrolabe and other almucantar observations due to its mathematical exactness, simplicity, and the ease

L. A. Kivioja; J. A. Mihalko

1985-01-01

120

Using Kinect sensor in observational methods for assessing postures at work.  

PubMed

This paper examines the potential use of Kinect range sensor in observational methods for assessing postural loads. Range sensors can detect the position of the joints at high sampling rates without attaching sensors or markers directly to the subject under study. First, a computerized OWAS ergonomic assessment system was implemented to permit the data acquisition from Kinect and data processing in order to identify the risk level of each recorded postures. Output data were compared with the results provided by human observers, and were used to determine the influence of the sensor view angle relative to the worker. The tests show high inter-method agreement in the classification of risk categories (Proportion agreement index = 0.89 ? = 0.83) when the tracked subject is facing the sensor. The camera's point of view relative to the position of the tracked subject significantly affects the correct classification of the postures. Although the results are promising, some aspects involved in the use of low-cost range sensors should be further studied for their use in real environments. PMID:24370268

Diego-Mas, Jose Antonio; Alcaide-Marzal, Jorge

2014-07-01

121

A (Revised) Survey of Approximate Methods for Solving Partially Observable Markov Decision Processes  

Microsoft Academic Search

Partially observable Markov decision processes (POMDPs) are inter- esting because they provide a general framework for learning in the pres- ence of multiple forms of uncertainty. We survey methods for learning within the POMDP framework. Because exact methods are intractable we concentrate on approximate methods. We explore two versions of the POMDP training problem: learning when a model of the

Douglas Aberdeen

122

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 ...

123

Propensity Score Estimation With Boosted Regression for Evaluating Causal Effects in Observational Studies  

Microsoft Academic Search

Causal effect modeling with naturalistic rather than experimental data is challenging. In observational studies participants in different treatment conditions may also differ on pretreatment characteristics that influence outcomes. Propensity score methods can theoretically eliminate these confounds for all observed covariates, but accurate estimation of propensity scores is impeded by large numbers of covariates, uncertain functional forms for their associations with

Daniel F. McCaffrey; Greg Ridgeway; Andrew R. Morral

2004-01-01

124

Propensity Score Estimation With Boosted Regression for Evaluating Causal Effects in Observational Studies  

ERIC Educational Resources Information Center

Causal effect modeling with naturalistic rather than experimental data is challenging. In observational studies participants in different treatment conditions may also differ on pretreatment characteristics that influence outcomes. Propensity score methods can theoretically eliminate these confounds for all observed covariates, but accurate

McCaffrey, Daniel F.; Ridgeway, Greg; Morral, Andrew R.

2004-01-01

125

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 Rnyi 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

126

ACTIVATING TEACHING METHODS, STUDYING RESPONSES AND LEARNING  

Microsoft Academic Search

Students' study strategies when exposed to activating teaching methods are meas- ured, analysed and compared to study strategies in more traditional lecture-based teaching. The resulting learning outcome is discussed. Workshop topic Beyond active learning

Hans Peter Christensen; Martin E. Vigild; Erik V. Thomsen; Peter Szabo; Andy Horsewell; DTU Nanotech

127

An analytical method for predicting surface soil moisture from rainfall observations  

SciTech Connect

A simple analytical method for estimating surface soil moisture directly from rainfall data is proposed and studied. Soil moisture dynamics are represented by a linear stochastic partial differential equation ( Entekhabi and Rodriguez-Iturbe, 1994 ). A diagnostic equation is derived from the soil moisture dynamics equation by eliminating the diffusion term. The derived daily soil moisture function is a time-weighted average of previous cumulative rainfall over a given period (e.g., >14 days). The advantage of this method is that information on the initial condition of soil moisture, which is often not available at all times and locations, is not needed. The loss coefficient in the diagnostic equation for soil moisture can be estimated from land surface characteristics and soil properties. The method for determining the averaging window size, the loss coefficient, and the infiltration coefficient are described and demonstrated. The soil moisture data observed during three field experiments, i.e., Monsoon'90, Washita'92, and SGP'97, are compared to the calculated soil moisture. The results indicate that the proposed method is robust and has the potential for useful soil moisture predictions.

Sale, Michael J [ORNL; Pan, Feifei [Georgia Institute of Technology; Peters-Lidard, C. D. [Georgia Institute of Technology

2003-11-01

128

Comparison of wave hindcasts, using Wilson's method, with observation and with other hindcast methods  

E-print Network

in the spectrum, The wave height is related to this value Flerson (19523 has also given methods of considering the decaying efi"ect on spectras, as they leave the fetch area, based on dispersion and angular spreading. 11 B. Stt. t CP bl There are two main ob..., ls reached (Fig. 9), The maximum wave height (H ), wave period F ' (TF), decay distance (the distance between the point of' maximum wave height and the coast) and the time of the maximum wave height is read from the graph. The decay curves...

Srivastava, Parmatma Saran

2012-06-07

129

ORIGINAL CONTRIBUTION An Observational Study of Cognitive Impairment  

E-print Network

ORIGINAL CONTRIBUTION An Observational Study of Cognitive Impairment in Amyotrophic Lateral, PhD Background: Cognitive impairment is increasingly recognized in patients with amyotrophic lateral was not related to site of onset or survival. Arch Neurol. 2006;63:345-352 A LTHOUGH AMYOTROPHIC lateral sclerosis

130

Observational Studies of Retarded Children with Multiple Stereotyped Movements.  

ERIC Educational Resources Information Center

Three relatively long-term observational studies, involving seven retarded preschool children, each of whom exhibited multiple stereotypes, were conducted to determine the extent to which the type of activity or setting had any effect upon the rates of stereotyped movements. (Author)

Baumeister, Alfred A.; And Others

1980-01-01

131

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

132

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...

133

An Observational Study of Post-Asymptotic Giant Branch Stars  

E-print Network

An Observational Study of Post-Asymptotic Giant Branch Stars A thesis submitted for the degree model atmosphere analyses of a group of early B-type post- asymptotic giant branch (pAGB) stars. With initial masses 9M, post-AGB stars form an important group of evolved stars and provide a unique

134

Leisure-Time Physical Activity in School Environments: An Observational Study Using SOPLAY  

Microsoft Academic Search

Background. Schools provide settings for physical activity (PA), but objective tools for measuring PA are lacking. We assessed an instrument to directly observe group PA and measured the leisure-time PA of adolescents throughout the school day.Methods. Leisure-time PA was studied by direct observation in 24 middle schools in Southern California using SOPLAY (System for Observing Play and Leisure Activity in

Thomas L. McKenzie; Simon J. Marshall; James F. Sallis; Terry L. Conway

2000-01-01

135

Methods for estimating subgroup effects in cost-effectiveness analyses that use observational data.  

PubMed

Decision makers require cost-effectiveness estimates for patient subgroups. In nonrandomized studies, propensity score (PS) matching and inverse probability of treatment weighting (IPTW) can address overt selection bias, but only if they balance observed covariates between treatment groups. Genetic matching (GM) matches on the PS and individual covariates using an automated search algorithm to directly balance baseline covariates. This article compares these methods for estimating subgroup effects in cost-effectiveness analyses (CEA). The motivating case study is a CEA of a pharmaceutical intervention, drotrecogin alfa (DrotAA), for patient subgroups with severe sepsis (n = 2726). Here, GM reported better covariate balance than PS matching and IPTW. For the subgroup at a high level of baseline risk, the probability that DrotAA was cost-effective ranged from 30% (IPTW) to 90% (PS matching and GM), at a threshold of 20 000 per quality-adjusted life-year. We then compared the methods in a simulation study, in which initially the PS was correctly specified and then misspecified, for example, by ignoring the subgroup-specific treatment assignment. Relative performance was assessed as bias and root mean squared error (RMSE) in the estimated incremental net benefits. When the PS was correctly specified and inverse probability weights were stable, each method performed well; IPTW reported the lowest RMSE. When the subgroup-specific treatment assignment was ignored, PS matching and IPTW reported covariate imbalance and bias; GM reported better balance, less bias, and more precise estimates. We conclude that if the PS is correctly specified and the weights for IPTW are stable, each method can provide unbiased cost-effectiveness estimates. However, unlike IPTW and PS matching, GM is relatively robust to PS misspecification. PMID:22691446

Kreif, Noemi; Grieve, Richard; Radice, Rosalba; Sadique, Zia; Ramsahai, Roland; Sekhon, Jasjeet S

2012-01-01

136

Mixing and administration times of bypassing agents: observations from the Dosing Observational Study in Hemophilia (DOSE).  

PubMed

DOSE (Dosing Observational Study in Hemophilia) was a prospective, observational diary study designed to evaluate the use of bypassing agents in patients prescribed recombinant activated factor VII (rFVIIa) as first-line treatment in the home setting. Patients with congenital hemophilia with inhibitors and caregivers participated, and as part of the study, the time spent preparing and administering product was recorded for bypassing agent (BPA) infusions. The aim of this manuscript is to present the results of the analysis of the time spent preparing and administering a single dose of either rFVIIa or plasma-derived activated prothrombin complex concentrate (pd-aPCC). Diaries were completed for 18 adult patients and 19 caregivers of 21 children with 176 BPA-treated bleeding episodes and 1,350 BPA infusions (1,270 rFVIIa, 80 pd-aPCC). The median preparation and administration times were 5.0 minutes and 5.0 minutes for rFVIIa and 29.0 minutes and 24.5 minutes for pd-aPCC, respectively. Preparation and administration times were significantly shorter with rFVIIa than pd-aPCC (P<0.0001). The significantly shorter combined preparation and administration time of rFVIIa, taking into consideration the faster-than-recommended aPCC infusion rates, suggests that rFVIIa permits a rapid and safe initiation of treatment once a bleeding episode is identified and a decision is made to treat at home. PMID:25187744

Maahs, Jennifer; Donkin, Jennifer; Recht, Michael; Cooper, David L

2014-01-01

137

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

138

The Molecular Beam Electric Resonance Method Study of Thallium Monochloride  

Microsoft Academic Search

The hyperfine structure of the first rotational state of TlCl35 and TlCl37 was studied by the molecular beam electric resonance method. Two types of molecular transitions were observed: the conventional mj transition in very weak and in strong Stark fields, the type previously studied in several alkali fluorides; the DeltaJ transition (J=0-->J=1), a molecular transition observed for the first time

R. O. Carlson; C. A. Lee; B. P. Fabricand

1952-01-01

139

Observational and Theoretical Studies of Low-Mass Star Formation  

NASA Technical Reports Server (NTRS)

Under this grant we have pursued studies of low-mass star formation with observations of candidate star-forming regions, (1) to determine the incidence of "infall asymmetry" in the spectral lines from very red young stellar objects; (2) to make detailed maps of candidate infall regions to determine the spatial extent of their infall asymmetry; (3) to compare the spatial and velocity structure of candidate infall regions with single dish and interferometer resolution; and (4) to begin a program of observations of starless dense cores to detect the presence or absence of infall motions.

Myers, Philip C.

1998-01-01

140

Method for digitizing paper archive of solar radio observations made with Large Pulkovo Radio Telescope  

NASA Astrophysics Data System (ADS)

Valuable large archive of solar radio observations has been accumulated by the Pulkovo solar radio group. But big part of data is recorded on paper. We describe a method and software for transferring data recorded on paper to FITS format.

Abramov-Maximov, Vladimir E.

141

Breaking the Barriers to Successful Refactoring: Observations and Tools for Extract Method  

E-print Network

Breaking the Barriers to Successful Refactoring: Observations and Tools for Extract Method Emerson Murphy-Hill and Andrew P. Black Portland State University, P.O. Box 751 Portland, OR 97201-0751 {emerson

Murphy-Hill, Emerson

142

Observational constraints on common envelope binary population synthesis studies  

NASA Astrophysics Data System (ADS)

Binary population synthesis studies are powerful and extensively used tools to, e.g., reproduce the present-day population of close white dwarf binaries, or to predict the rate of Type Ia supernovae in the Galaxy. However, in these studies the common envelope (CE) phase is described by a simple parameterised energy equation in which a fraction of the orbital energy (the CE efficiency) is used to unbind the CE. Even worse, the CE efficiency is very uncertain and lacks observational constraints. During the last few years, our team has performed a large-scale observational population study of close white dwarf-main sequence binaries, which has provided the first strong observational evidence for the CE efficiency being small. However, we cannot rule out the possibility that this result is a consequence of selection effects, as white dwarfs can only be easily identified in the optical when the secondary is a low-mass star, i.e., an M dwarf. In order to test possible dependencies of the CE efficiency on the mass of the secondary star, we have initiated an observational campaign dedicated to identifying a large sample of close white dwarf-main sequence binaries containing F, G or K star companions and to measure their orbital periods. Here, I explain the methodology of our strategy and present the first results of this survey.

Rebassa-Mansergas, Alberto; Gaensicke, Boris; Schreiber, Matthias; Zorotovic, Monica; Parsons, Steven; Han, Zhanwen

2014-09-01

143

The Urban Environment and Childhood Asthma (URECA) birth cohort study: design, methods, and study population  

Microsoft Academic Search

BACKGROUND: The incidence and morbidity of wheezing illnesses and childhood asthma is especially high in poor urban areas. This paper describes the study design, methods, and population of the Urban Environment and Childhood Asthma (URECA) study, which was established to investigate the immunologic causes of asthma among inner-city children. METHODS AND RESULTS: URECA is an observational prospective study that enrolled

James E Gern; Cynthia M Visness; Peter J Gergen; Robert A Wood; Gordon R Bloomberg; George T O'Connor; Meyer Kattan; Hugh A Sampson; Frank R Witter; Megan T Sandel; Wayne G Shreffler; Rosalind J Wright; Samuel J Arbes Jr; William W Busse

2009-01-01

144

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

145

The Effects of Three Methods of Observation on Couples in Interactional Research.  

ERIC Educational Resources Information Center

Assessed the effects of three different methods of observation of couples (one-way mirror, audio recording, and video recording) on 30 volunteer, nonclinical married couples. Results suggest that types of observation do not produce significantly different effects on nonclinical couples. (Author/ABL)

Carpenter, Linda J.; Merkel, William T.

1988-01-01

146

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

147

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

148

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

149

Discrete element method study of abrasion  

Microsoft Academic Search

Abrasion is a surface breakage event where irregular surfaces of particles are removed. In other words, in milling it is the process which produces sphere like particles by comminuting asperities. Extensive experimental work has been performed to study abrasion events and their process parameters. Very few studies have used the discrete element method (DEM) to study the abrasion behavior of

Manoj Khanal; Rob Morrison

2008-01-01

150

Brief hospitalizations of elderly patients: a retrospective, observational study  

PubMed Central

Background Crowded departments are a common problem in Danish hospitals, especially in departments of internal medicine, where a large proportion of the patients are elderly. We therefore chose to investigate the number and character of hospitalizations of elderly patients with a duration of less than 24hours, as such short admissions could indicate that the patients had not been severely ill and that it might have been possible in these cases to avoid hospitalization. Methods Medical records were examined to determine the number of patients aged 75 or more who passed through the emergency department over a period of two months, and the proportion of those patients who were discharged after less than 24hours. The reasons for the hospitalization, the diagnoses and the treatment given were noted. Results There was a total of 595 hospitalizations of patients aged 75 or above in the emergency department during the period. Twenty-four percent of the older patients were discharged after less than 24hours. Of these, 40% were discharged from the emergency department. The most common problems leading to hospitalization were change in contact or level of consciousness, focal neurological change, red, swollen or painful leg conditions, dyspnea, suspected parenchyma surgical disease and problems with the urinary system or catheters. The most common diagnoses given at hospital were chronic cardiovascular disease, bacterial infection, symptoms deriving from bone, muscle or connective tissue, liquid or electrolyte derangement and observation for suspected stroke or transient cerebral ischemia. Eight percent of the patients required telemetry, 27% received intravenous liquids, 30% had diagnostic radiology procedures performed and 3% needed invasive procedures. Other types of treatment given included electrocardiography, laboratory examinations, oxygen supplements, urinary catheterization and medicine administered orally, subcutaneously, as an intramuscular injection or as an inhalation. Conclusion There appears to be a group of patients who cannot be adequately handled with the resources of the primary health care sector, yet who do not belong at the emergency department. Further studies are needed to create a suitable service for these patients, and to improve the continuity of the treatment and the cooperation between hospitals and the primary health care sector. PMID:24606987

2014-01-01

151

Handover patterns: an observational study of critical care physicians  

PubMed Central

Background Handover (or 'handoff') is the exchange of information between health professionals that accompanies the transfer of patient care. This process can result in adverse events. Handover 'best practices', with emphasis on standardization, have been widely promoted. However, these recommendations are based mostly on expert opinion and research on medical trainees. By examining handover communication of experienced physicians, we aim to inform future research, education and quality improvement. Thus, our objective is to describe handover communication patterns used by attending critical care physicians in an academic centre and to compare them with currently popular, standardized schemes for handover communication. Methods Prospective, observational study using video recording in an academic intensive care unit in Ontario, Canada. Forty individual patient handovers were randomly selected out of 10 end-of-week handover sessions of attending physicians. Two coders independently reviewed handover transcripts documenting elements of three communication schemes: SBAR (Situation, Background, Assessment, Recommendations); SOAP (Subjective, Objective, Assessment, Plan); and a standard medical admission note. Frequency and extent of questions asked by incoming physicians were measured as well. Analysis consisted of descriptive statistics. Results Mean ( standard deviation) duration of patient-specific handovers was 2 min 58 sec ( 57 sec). The majority of handovers' content consisted of recent and current patient status. The remainder included physicians' interpretations and advice. Questions posed by the incoming physicians accounted for 5.8% ( 3.9%) of the handovers' content. Elements of all three standardized communication schemes appeared repeatedly throughout the handover dialogs with no consistent pattern. For example, blocks of SOAP's Assessment appeared 5.2 ( 3.0) times in patient handovers; they followed Objective blocks in only 45.9% of the opportunities and preceded Plan in just 21.8%. Certain communication elements were occasionally absent. For example, SBAR's Recommendation and admission note information about the patient's Past Medical History were absent from 22 (55.0%) and 20 (50.0%), respectively, of patient handovers. Conclusions Clinical handover practice of faculty-level critical care physicians did not conform to any of the three predefined structuring schemes. Further research is needed to examine whether alternative approaches to handover communication can be identified and to identify features of high-quality handover communication. PMID:22233877

2012-01-01

152

The new worlds observer: The astrophysics strategic mission concept study  

NASA Astrophysics Data System (ADS)

We present some results of the Astrophysics Strategic Mission Concept Study for the New Worlds Observer (NWO). We show that the use of starshades is the most effective and affordable path to mapping and understanding our neighboring planetary systems, to opening the search for life outside our solar system, while serving the needs of the greater astronomy community. A starshade-based mission can be implemented immediately with a near term program of technology demonstration.

Cash, W.

2011-07-01

153

The New Worlds Observer: The Astrophysics Strategic Mission Concept Study  

NASA Astrophysics Data System (ADS)

We present some results of the Astrophysics Strategic Mission Concept Study for the New Worlds Observer (NWO). We show that the use of starshades is the most effective and affordable path to mapping and understanding our neighboring planetary systems, to opening the search for life outside our solar system, while serving the needs of the greater astronomy community. A starshade-based mission can be implemented immediately with a near term program of technology demonstration.

Cash, W.; New Worlds Study Team

2010-10-01

154

The New Worlds Observer: the astrophysics strategic mission concept study  

NASA Astrophysics Data System (ADS)

We present the results of the Astrophysics Strategic Mission Concept Study for the New Worlds Observer (NWO). We show that the use of starshades is the most effective and affordable path to mapping and understanding our neighboring planetary systems, to opening the search for life outside our solar system, while serving the needs of the greater astronomy community. A starshade-based mission can be implemented immediately with a near term program of technology demonstration.

Cash, Webster; Kendrick, Stephen; Noecker, Charley; Bally, John; Demarines, Julia; Green, James; Oakley, Phillip; Shipley, Ann; Benson, Scott; Oleson, Steve; Content, David; Folta, Dave; Garrison, Sharon; Gendreau, Keith; Hartman, Kate; Howard, Joseph; Hyde, Tupper; Lakins, Darryl; Leitner, Jesse; Leviton, Douglas; Luquette, Rich; Oegerley, Bill; Richon, Karen; Roberge, Aki; Tompkins, Steve; Tveekrem, June; Woodgate, Bruce; Turnbull, Margaret; Dailey, Dean; Decker, Kent; Dehmohseni, Reza; Gaugh, Brian; Glassman, Tiffany; Haney, Mickey; Hejal, Reem; Lillie, Charles; Lo, Amy; O'Conner, David; Oleas, Gina; Polidan, Ronald; Samuele, Rocco; Shields, Stephen; Shirvanian, James; Soohoo, David; Tinetti, Giovanna; Dorland, Bryan; Dudik, Rachel; Gaume, Ralph; Mason, Brian

2009-08-01

155

Critical Appraisal of Mixed Methods Studies  

ERIC Educational Resources Information Center

In several subdomains of the social, behavioral, health, and human sciences, research questions are increasingly answered through mixed methods studies, combining qualitative and quantitative evidence and research elements. Accordingly, the importance of including those primary mixed methods research articles in systematic reviews grows. It is

Heyvaert, Mieke; Hannes, Karin; Maes, Bea; Onghena, Patrick

2013-01-01

156

Ten Inquiry Methods Used in Curriculum Studies.  

ERIC Educational Resources Information Center

Ten different methods of inquiry are outlined in this overview of research methodologies currently being employed in the field of curriculum studies: (1) philosophical, (2) historical, (3) scientific, (4) artistic, (5) moral, (6) religious, (7) interpretive, (8) instrumental, (9) deliberative, and (10) action oriented. Each of the 10 methods is

Short, Edmund C.

157

The impact of verification area design on tropical cyclone targeted observations based on the CNOP method  

NASA Astrophysics Data System (ADS)

This study investigated the impact of different verification-area designs on the sensitive areas identified using the conditional nonlinear optimal perturbation (CNOP) method for tropical cyclone targeted observations. The sensitive areas identified using the first singular vector (FSV) method, which is the linear approximation of CNOP, were also investigated for comparison. By analyzing the validity of the sensitive areas, the proper design of a verification area was developed. Tropical cyclone Rananim, which occurred in August 2004 in the northwest Pacific Ocean, was studied. Two sets of verification areas were designed; one changed position, and the other changed both size and position. The CNOP and its identified sensitive areas were found to be less sensitive to small variations of the verification areas than those of the FSV and its sensitive areas. With larger variations of the verification area, the CNOP and the FSV as well as their identified sensitive areas changed substantially. In terms of reducing forecast errors in the verification area, the CNOP-identified sensitive areas were more beneficial than those identified using FSV. The design of the verification area is important for cyclone prediction. The verification area should be designed with a proper size according to the possible locations of the cyclone obtained from the ensemble forecast results. In addition, the development trend of the cyclone analyzed from its dynamic mechanisms was another reference. When the general position of the verification area was determined, a small variation in size or position had little influence on the results of CNOP.

Zhou, Feifan; Mu, Mu

2011-09-01

158

An inverse method for estimating the spatial variability of soil textures from observed soil moisture fields  

NASA Astrophysics Data System (ADS)

Soil texture (sand, clay, silt 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. To study water cycle regionally or globally, we must have a regional or global soil texture database. At the present stage, three soil geographic data bases are commonly used, i.e., the Soil Survey Geographic (SSURGO) database, the State Soil Geographic (STATSGO) database, and the National Soil Geographic (NATSGO) database. Those soil data are map-unit-based, which are associated with a great uncertainty. Ground soil survey is one way to reduce this uncertainty. However, ground survey is time consuming and labor intensive. In this study, a simple method for estimating mean and standard deviation of soil texture from observed soil moisture fields is proposed and applied to Throughfall Displacement Experiment (TDE) sites in Walker Branch Watershed (WBW) in eastern Tennessee. The results indicate that the suggested method is feasible and has potential for retrieving soil texture information globally from remotely sensed soil moisture data.

Pan, F.; King, A. W.; Sale, M. J.

2003-12-01

159

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, ...

Quiones, Lisandro E. (Quiones Ortiz)

2008-01-01

160

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

161

Tropospheric Chemistry Studies using Observations from GOME and TOMS  

NASA Technical Reports Server (NTRS)

Studies to quantitatively determine trace gas and aerosol amounts from the Global Ozone Monitoring Experiment (GOME) and the Total Ozone Monitoring Experiment (TOMS) and to perform chemical modeling studies which utilize these results are given. This includes: 1. Analysis of measurements from the GOME and TOMS instruments for troposphere distributions of O3 and HCHO; troposphere enhancements of SO2, NO2 and aerosols associated with major sources; and springtime events of elevated BrO in the lower Arctic troposphere. 2. Application of a global 3-dimensional model of troposphere chemistry to interpret the GOME observations in terms of the factors controlling the abundances of troposphere ozone and OH.

Chance, Kelly; Spurr, Robert J. D.; Kurosu, Thomas P.; Jacob, Daniel J.; Gleason, James F.

2003-01-01

162

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

163

Acid regurgitation associated with persistent cough after pulmonary resection: an observational study  

Microsoft Academic Search

BACKGROUND: Following a pulmonary resection, some patients suffer from persistent coughing, which may have a relationship with acid regurgitation. Since few physiological studies have been reported regarding this issue, we conducted the present observational study. METHODS: Persistent cough after pulmonary resection (CAP) was defined as non-productive coughing that occurred after a pulmonary resection in patients with stable chest X-ray results

Noriyoshi Sawabata; Shin-ichi Takeda; Toshiteru Tokunaga; Masayoshi Inoue; Hajime Maeda

2006-01-01

164

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 19782012, 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 0.52.0), 24.5% (246/1002) a moderate association (OR/RR 0.250.5 or 2.04.0) 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

165

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 studys 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

166

Evaluating Processes, Parameters and Observations Using Cross Validation and Computationally Frugal Sensitivity Analysis Methods  

NASA Astrophysics Data System (ADS)

Sensitivity analysis methods are used to identify measurements most likely to provide important information for model development and predictions and therefore identify critical processes. Methods range from computationally demanding Monte Carlo and cross-validation methods, to very computationally efficient linear methods. The methods are able to account for interrelations between parameters, but some argue that because linear methods neglect the effects of model nonlinearity, they are not worth considering when examining complex, nonlinear models of environmental systems. However, when faced with computationally demanding models needed to simulate, for example, climate change, the chance of obtaining fundamental insights (such as important and relationships between predictions and parameters) with few model runs is tempting. In the first part of this work, comparisons of local sensitivity analysis and cross-validation are conducted using a nonlinear groundwater model of the Maggia Valley, Southern Switzerland; sensitivity analysis are then applied to an integrated hydrological model of the same system where the impact of more processes and of using different sets of observations on the model results are considered; applicability to models of a variety of situations (climate, water quality, water management) is inferred. Results show that the frugal linear methods produced about 70% of the insight from about 2% of the model runs required by the computationally demanding methods. Regarding important observations, linear methods were not always able to distinguish between moderately and unimportant observations. However, they consistently identified the most important observations which are critical to characterize relationships between parameters and to assess the worth of potential new data collection efforts. Importance both to estimate parameters and predictions of interest was readily identified. The results suggest that it can be advantageous to consider local sensitivity analysis in model evaluation, possibly as a preliminary step to provide insights that can be used to improve the design of more demanding methods. This can be foreseen as a promising direction of future research where frugal and complex methods are combined to provide insights on model development and model results.

Foglia, L.; Mehl, S.; Hill, M. C.

2013-12-01

167

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 (22.59N, 113.97E), 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

168

A framework for the study of vision in active observers  

NASA Astrophysics Data System (ADS)

We present a framework for the study of active vision, i.e., the functioning of the visual system during actively self-generated body movements. In laboratory settings, human vision is usually studied with a static observer looking at static or, at best, dynamic stimuli. In the real world, however, humans constantly move within dynamic environments. The resulting visual inputs are thus an intertwined mixture of self- and externally-generated movements. To fill this gap, we developed a virtual environment integrated with a head-tracking system in which the influence of self- and externally-generated movements can be manipulated independently. As a proof of principle, we studied perceptual stationarity of the visual world during lateral translation or rotation of the head. The movement of the visual stimulus was thus parametrically tethered to self-generated movements. We found that estimates of object stationarity were less biased and more precise during head rotation than translation. In both cases the visual stimulus had to partially follow the head movement to be perceived as immobile. We discuss a range of possibilities for our setup among which the study of shape perception in active and passive conditions, where the same optic flow is replayed to stationary observers.

Nicolini, Carlo; Fantoni, Carlo; Mancuso, Giovanni; Volcic, Robert; Domini, Fulvio

2014-02-01

169

Observation of a freezing drizzle episode: A case study  

NASA Astrophysics Data System (ADS)

On 5 February 2012 an episode of freezing precipitation took place in the Guadarrama Mountains, at the center of the Iberian Peninsula. This precipitation affected high elevations, where temperatures remained below freezing because of snow cover that had accumulated from snowfall during the previous days. The case study was recorded by surface synoptic observations (SYNOP) at Navacerrada Pass meteorological observatory (belonging to the National Weather Service of Spain). To study winter cloud systems during the TEcoAgua project, a multichannel ground-based microwave radiometer (MMWR), Micro Rain Radar (MRR-2), and isothermal cloud chamber were installed in the study area, thus permitting the monitoring of the freezing precipitation event. Analysis using Meteosat Second Generation (MSG) satellite data and observations permitted the determination of factors that triggered the freezing precipitation event. Freezing drizzle was interspersed with the passage of a warm and cold front. During frontal passage, mid-level clouds inhibited the generation of freezing drizzle, with snowfall recorded in the study area. However, during the period between the two fronts, an absence of mid-level clouds permitted low-level orographic clouds to persist upwind of the mountain system, producing freezing drizzle at the surface. The decisive factors for the generation of freezing drizzle were high humidity at low levels, weak mesoscale updrafts caused by the topography, stability at mid levels, cloud-top temperatures warmer than - 15 C, and low concentrations of ice nuclei.

Fernndez-Gonzlez, S.; Valero, F.; Sanchez, Jose L.; Gascn, E.; Lpez, L.; Garca-Ortega, E.; Merino, A.

2014-11-01

170

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

171

A stepwedge-based method for measuring breast density: observer variability and comparison with human reading  

NASA Astrophysics Data System (ADS)

Breast density is positively linked to the risk of developing breast cancer. We have developed a semi-automated, stepwedge-based method that has been applied to the mammograms of 1,289 women in the UK breast screening programme to measure breast density by volume and area. 116 images were analysed by three independent operators to assess inter-observer variability; 24 of these were analysed on 10 separate occasions by the same operator to determine intra-observer variability. 168 separate images were analysed using the stepwedge method and by two radiologists who independently estimated percentage breast density by area. There was little intra-observer variability in the stepwedge method (average coefficients of variation 3.49% - 5.73%). There were significant differences in the volumes of glandular tissue obtained by the three operators. This was attributed to variations in the operators' definition of the breast edge. For fatty and dense breasts, there was good correlation between breast density assessed by the stepwedge method and the radiologists. This was also observed between radiologists, despite significant inter-observer variation. Based on analysis of thresholds used in the stepwedge method, radiologists' definition of a dense pixel is one in which the percentage of glandular tissue is between 10 and 20% of the total thickness of tissue.

Diffey, Jenny; Berks, Michael; Hufton, Alan; Chung, Camilla; Verow, Rosanne; Morrison, Joanna; Wilson, Mary; Boggis, Caroline; Morris, Julie; Maxwell, Anthony; Astley, Susan

2010-04-01

172

Business Research Methods: A Study Guide.  

ERIC Educational Resources Information Center

This study guide provides an overview and model of business research. First, introductory material defines research and discusses the benefits of studying business research methods for both producers and consumers of research. In the next section different types of research are discussed, including experimental, ex post facto, quasi-experimental,

Dawson, George

173

Case study research methods for theory building  

Microsoft Academic Search

This article provides a new definition for case study research. Achieving deep understanding of processes and other concept variables (e.g. actors perceptions of their own thinking processes, intentions and contextual influences) is identified as the principal objective of case study research. Using multiple methods to triangulate (i.e. confirm and deepen understanding by using multiple sources all focusing on the same

Arch G. Woodside; Elizabeth J. Wilson

2003-01-01

174

The ZH ratio method for long-period seismic data: sensitivity kernels and observational techniques  

NASA Astrophysics Data System (ADS)

Amplitude ratio between vertical and horizontal components of Rayleigh waves is controlled by structure beneath a seismic station. This ratio, measured as a function of frequency, has been extensively analysed for shallow crustal structure study in earthquake engineering and applied seismology. This quantity, termed the ZH ratio in this paper, may be useful for deep earth structure study and its feasibility for the frequency range between 0.004 and 0.05 Hz (period 20-250 s) is explored in this paper. For depth sensitivity kernels, we demonstrate that a numerical approach is practical and provides sufficient accuracy for structural inversion. Depth extent of sensitivity kernels are about half of depth extent in phase velocity kernels, indicating that the ZH ratio is useful for studying the lithospheric structure. Two observational approaches for measurement of the ZH ratio are presented; the first approach uses simple envelope amplitude ratio and the second approach uses waveform correlation technique between vertical and horizontal components. The ZH ratio data alone only constrains structure beneath seismic stations but recent densification of seismic networks may make it possible to extend the analysis to regional scale structure. A greater opportunity may exist in combination of the ZH ratio method and the phase and group velocity measurements.

Tanimoto, T.; Rivera, L.

2008-01-01

175

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; G?tzsche, Peter C; Mulrow, Cynthia D; Pocock, Stuart J; Poole, Charles; Schlesselman, James J; Egger, Matthias

2007-01-01

176

Geomagnetic induction studies in Scandinavia. III Magnetotelluric observations  

NASA Astrophysics Data System (ADS)

Magnetic observations recorded by two instruments of the Scandinavian Magnetometer Array are combined with telluric measurements made at the same locations, and the joint data sets are analyzed in order to derive the magnetotelluric (MT) response functions for those locations. Audiomagnetotelluric measurements were also made at one of the locations. The analytic methods employed are discussed and a general technique for reducing any possible timing discrepancy between the telluric and magnetic data sets is described and utilized. Models consistent with the resulting MT response functions from the two locations are discovered by a Monte Carlo random search of the parameter spaces, and resistivity-depth profiles are presented. The acceptable models are shown to be highly compatible with those for horizontal spatial gradient data.

Jones, A. G.; Olafsdottir, B.; Tiikkainen, J.

177

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

178

URBAN STUDIES-315W URBAN STUDIES RESEARCH METHODS  

E-print Network

" and collaborative observation Jacobs FEB 8 The nature of surveys, developing survey and interview questions Suminski analysis Gilbert (mainly focus on pp. 603-616) MAR 6 An interview study with policy analysis Mitchell

Pillow, Jonathan

179

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

180

An observational study of the dynamics of molecular cloud cores  

SciTech Connect

How are stars formed This is one of the most fundamental questions in astronomy. It is therefore ironic that to date, no object has been unambiguously identified as a true protostar; an object has derives the bulk of its luminosity from accretion. While this may be ironic, it is not surprising. Stars are believed to form as a result of the gravitational collapse of a portion of a molecular cloud. Theory predicts that the cloud core in which the star is formed will be cold, dense and possess hundreds of magnitudes of extinction, rendering it opaque at visible and near-infrared wavelengths. Continuum observations at far-infrared, submillimeter, and millimeter wavelengths can be used to identify candidate protostars, but spectroscopic observations are needed to detect infall. The difficulties arise when there are systematic velocity fields present in the cloud core which are not the result of infall, such as would be produced by either a molecular outflow or rotation. In this dissertation the authors uses both observations and theoretical models to sort through these problems and develop a strategy which could be used to identify and study protostars.

Walker, C.K.

1988-01-01

181

Study of a microflare observed with SUMER and TRACE  

NASA Astrophysics Data System (ADS)

We study a GOES-A1 microflare, observed in active region NOAA 8541 on May 15, 1999 with TRACE images, SUMER spectra and MDI magnetograms. In TRACE filtergrams of 171A and 195A, the microflare is composed of two interacting, 20Mm long, loops. SUMER observations include four spectral lines: the Si II 1533A (a chromospheric line), the C IV 1548A, 1550 A (transition region lines) and the Ne VIII 770 A (a coronal line). These spectra record the impulsive stage of the microflare, which appears as a bright feature at the west footpoint of the TRACE loops. In an area adjacent to the microflare we observe, for the first time on the solar disk, a region where the lines intensity ratio 1548A/1550A equals to 4 which means that resonant scattering dominates the emission process. Over the microflare, the SUMER spectral lines are blue shifted, indicating upflows due to explosive evaporation, as well as red shifted, indicating, cooling downward motions. Moreover, the C IV microflare spectral profiles, indicate upflows of ~200 km/s even if most of them are damaged due to the SUMER detector over exposure, while the Si II 1533A profiles are self-reversed due to opacity effects.

Gontikakis, C.; Winebarger, A. R.

2012-01-01

182

Evaluation of imputation methods for microbial surface water quality studies.  

PubMed

Longitudinal studies of microbial water quality are subject to missing observations. This study evaluates multiple imputation (MI) against data deletion, mean or median imputation for replacing missing microbial water quality data. The specific context is data collected in Chicago Area Waterway System (2007-2009), where 45% of Escherichia coli and 53% of enterococci densities were missing owing to sample analysis deficiencies. Imputation methods were compared performing a simulation study using complete observations with introduced missing values and subsequently compared with the original data with missing observations. Coefficients for E. coli densities in linear regression models predicting somatic coliphages density show that MI introduces the least bias among other methods while controlling Type I error. Further exploration of utilizing different MI implementations is recommended to address the influence of missing percentage on MI performance and to explore sensitivity to the degree of violation of the missing completely at random assumption. PMID:24705739

Nieh, Chiping; Dorevitch, Samuel; Liu, Li C; Jones, Rachael M

2014-05-01

183

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

184

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

185

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

DOEpatents

A method 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.

Sinha, Dipen N. (Los Alamos, NM); Anthony, Brian W. (Clearfield, PA)

1997-01-01

186

Repeated indentation method for studying cyclic fatigue in ceramics  

Microsoft Academic Search

A new method for studying cyclic fatigue in ceramics is proposed. It is based on the repeated indentation of the ceramic surface with a sharp indenter and on the relation between the indentation load and the number of indentation cycles needed to produce chipping. The technique is analyzed on the basis of observation on the development of the lateral cracks

Michael Reece; Frank Guiu

1990-01-01

187

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

188

Complete control, direct observation and study of molecular super rotors  

E-print Network

Extremely fast rotating molecules carrying significantly more energy in their rotation than in any other degree of freedom are known as "super rotors". It has been speculated that super rotors may exhibit a number of unique and intriguing properties. Theoretical studies showed that ultrafast molecular rotation may change the character of molecular scattering from solid surfaces, alter molecular trajectories in external fields, make super rotors surprisingly stable against collisions, and lead to the formation of gas vortices. New ways of molecular cooling and selective chemical bond breaking by ultrafast spinning have been proposed. Owing to the fundamental laws of nature, bringing a large number of molecules to fast, directional and synchronous rotation is rather challenging. As a result, only indirect evidence of super rotors has been reported to date. Here we demonstrate the first controlled creation, direct observation and study of molecular super rotors. Using intense laser pulses tailored to produce an ...

Korobenko, Aleksey; Milner, Valery

2013-01-01

189

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

190

Computational and Observational Studies of Interstellar Thioformaldehyde Masers  

NASA Astrophysics Data System (ADS)

Interstellar spectroscopy of thioformaldehyde (H2CS) holds considerable promise because of the close relationship between the H2CS molecule and the well-studied formaldehyde (H2CO) molecule. In particular, the well-known J(Ka,Kc) = 1(1,0) to 1(1,1) transition of H2CO at 6 cm (4.8 GHz) has an analogous H2CS transition at 1046 MHz. However, the 1046-MHz line of H2CS has never been detected astronomically. We present here a summary of: (1) a computational investigation of H2CS level populations related to known H2CO 6-cm masers, and (2) an observational campaign of four isotopologues of H2CS. Maser emission from H2CO has been observed at 6 cm for which Boland and de Jong (1981) have developed a pump model. We have extended this model to H2CS and we present preliminary calculations for a 1046-MHz maser. We intend to develop a quantitative tool for interpreting H2CS observations toward Galactic and extragalactic locations of H2CO maser emission by constructing a radiative-transfer maser model for H2CS. Thioformaldehyde has been detected in a few Galactic sources via J>1 transitions. However, interpretation of these results has two outstanding problems: the H2CS/H2CO abundances do not agree with known sulfur-to-oxygen ratios nor do the J>1 populations have the expected Boltzmann relationship to the J=1 states. A detection of the 1046-MHz transition of H2CS with J=1 would alleviate many of the ambiguities in the interpretation of existing observational results. We describe our forthcoming experiment to search in a Galactic star-forming region for thermal and nonthermal emission and absorption from four thioformaldehyde isotopologues: H2(12C)(32S), H2(13C)(32S), H2(12C)(34S), and D2(12C)(32S). Taken together, both parts of this research effort will provide valuable and novel constraints on H2CS and H2CO. New observations of H2CS isotopologues will yield new measurements of deuterium-to-hydrogen and sulfur-to-oxygen ratios in star-forming environments. Also, the application of the H2CO maser pump model to H2CS will provide new insights on the rare and enigmatic H2CO masers in the Galaxy. This work is supported by Wittenberg University through the Physics Department and the Student Development Board.

Simpson, Lisa; Hoffman, I. M.

2013-06-01

191

The accuracy of self-report and trained observer methods for obtaining estimates of peak load information during industrial work  

Microsoft Academic Search

The purpose of this study was to determine how well self-report (questionnaire=QR) and trained observer (checklist=OBS) data recording methods compared with more expensive video analysis (VID) for estimating various peak physical loading exposure variables on the low backs of 99 employees during work in an automobile assembly plant. The variables studied were L4\\/L5 spine compression and shear forces, L4\\/L5 moment,

David M Andrews; Robert W Norman; Richard P Wells; Patrick Neumann

1997-01-01

192

Observer-Independent Method for Microstructural Parcellation of Cerebral Cortex: A Quantitative Approach to Cytoarchitectonics  

Microsoft Academic Search

We describe a new, observer-independent procedure for identifying boundaries between cortical areas. The method is useful for images obtained from sections which provide microstructural information on the cortical laminar pattern, e.g., Nissl-, myelin-, or immunohistochemically stained sections or receptor autoradiographs. The laminar pattern is represented by profile curves extending from the cortical surface to the white matter boundary. These profiles

A. Schleicher; K. Amunts; S. Geyer; P. Morosan; K. Zilles

1999-01-01

193

A method for classifying offer strategies observed in an electricity market  

E-print Network

A method for classifying offer strategies observed in an electricity market HyungSeon Oha,*, Robert that humans adopt one of a small number of offer strategies for any given market design. So, a simulation in deregulated markets based on double layer diffusion. D 2004 Elsevier B.V. All rights reserved. Keywords

194

A Method to Assess the Regional Wind Power Fluctuation Based on the Meteorological Observing System  

Microsoft Academic Search

In China, the wind power fluctuation has become the main barrier for wind integration. The limitation of wind observation both in time and space makes it difficult for the planners to assess the wind power fluctuation over the country's territory. This paper proposes a method to profile the multi-regional wind power fluctuations based on the meteorological data obtained from the

Dayang Yu; Xueshan Han; Jianguo Zhao

2010-01-01

195

Generation and observation of ultrasonic waves on liquid surfaces by transient reflecting grating method  

Microsoft Academic Search

We generated and observed GHz ultrasonic waves on liquid surfaces for the first time using the transient reflecting grating (TRG) method. Three samples were used for measurement: two types of black inks and an aqueous solution of crystal violet (CV). We have investigated the pump power and the solute concentration dependencies of the intensities of the TRG signals from surfaces

Sachiyo Ikeda; Kenji Katayama; Isao Tsuyumoto; Akira Harata; Takehiko Kitamori; Tsuguo Sawada

1999-01-01

196

Psychometrics and Observations: Issues in a Dual Approach to the Study of Classroom Learning Environments.  

ERIC Educational Resources Information Center

Anthropological methods of classroom observation were combined with the results of student responses to three questionnaires in a study of classroom learning environments. The questionnaires were: Learning Environment Inventory, Class Activities Questionnaire, and ALP (Authenticity, Legitimacy, Productivity) Ethos Instrument. Although the

Cichon, Donald J.; Olson, George E.

197

Susceptibility to Insulin Resistance after Kidney Donation: A Pilot Observational Study  

Microsoft Academic Search

Background: In chronic kidney disease the contribution of decreased glomerular filtration rate (GFR) versus enhanced inflammation to cause insulin resistance (IR) is controversial. Aim: This pilot observational study examines, therefore, the prevalence of IR after kidney donation and factors that may determine its level. Methods: Insulin, proinsulin, adiponectin, malondialdehyde, and hsCRP were measured by conventional techniques in 14 previous kidney

Walid Shehab-Eldin; Sabry Shoeb; Said Khamis; Yassien Salah; Ahmed Shoker

2009-01-01

198

A Multicenter prospective study of poor-grade aneurysmal subarachnoid hemorrhage (AMPAS): observational registry study  

PubMed Central

Background Poor-grade aneurysmal subarachnoid hemorrhage (aSAH) is associated with very high mortality and morbidity. Our limited knowledge on predictors of long-term outcome in poor-grade patients with aSAH definitively managed comes from retrospective and prospective studies of small case series of patients in single center. The purpose of the AMPAS is to determine the long-term outcomes in poor-grade patients with different managements within different time after aSAH, and identify the independent predictors of the outcome that help guide the decision on definitive management. Methods/design The AMPAS study is a prospective, multicenter, observational registry of consecutive hospitalized patients with poor grade aSAH (WFNS grade IV and V). The aim is to enroll at least 226 poor-grade patients in 11 high-volume medical centers (eg, >150 aSAH cases per year) affiliated to different universities in China. This study will describe poor grade patients and aneurysm characteristics, treatment strategies (modality and time of definitive management), hospitalization complications and outcomes evolve over time. The definitive management is ruptured aneurysm treatment. Outcomes at 3, 6, 12months after the management were measured using the Glasgow Outcome Scale and the Modified Rankin Scale. Discussion The AMPAS is the first prospective, multicenter, observational registry of poor grade aSAH with any management. This study will contribute to a better understanding of significant predictors of outcome in poor grade patients and help guide future treatment of the worst patients after aSAH. Trial registration Chinese Clinical Trial Registry: ChiCTR-TNRC-10001041. PMID:24742248

2014-01-01

199

Simulation of Satellite Observations of Induced Magnetic Fields using Scripted Finite Element Methods  

NASA Astrophysics Data System (ADS)

Scripted finite element methods allow flexible investigations of the influence of asymmetric external source fields and 3-dimensional (3D) internal electrical conductivity structure in the problem of global geomagnetic depth sounding. Our forward modeling is performed in the time and frequency domains via FlexPDE, a commercial finite element modeling package, and the technique has been validated against known solutions to 3D steady state and time-dependent problems. The induction problem is formulated in terms of the magnetic vector potential and electric scalar potential, and mesh density is managed both explicitly and through adaptive mesh refinement. We investigate the effects of 3D Earth conductivity on both satellite and ground-based magnetic field observations in the form of a geographically varying conductance map of the crust and oceans overlying a radially symmetric core and mantle. This map is used in conjunction with a novel boundary condition based on Ampere's Law to model variable near-surface induction without the computational expense of a 3D crust/ocean mesh and is valid for magnetic signals in the frequency range of interest for satellite induction studies. The simulated external magnetic field is aligned with Earth's magnetic pole, rather than its rotational pole, and increases in magnitude along the Earth/Sun axis. Earth rotates through this field with a period of 24 hours. Electromagnetic c-responses estimated from satellite data under the assumption that the primary and induced fields are dipolar in structure are known to be biased with respect to local time. We investigate the influence of Earth's rotation through the non-uniform external field on these c-responses, to determine whether this can explain the observed local time bias.

Ribaudo, J. T.; Constable, C.; Parker, R. L.

2009-12-01

200

Active region studies with coordinated SOHO, microwave, and magnetograph observations  

NASA Technical Reports Server (NTRS)

The scientific justification for an observing campaign to study the quantitative magnetic and plasma properties of coronal loops in active regions is presented. The SOHO (Solar and Heliospheric Observatory) instruments of primary relevance are CDS (Coronal Diagnostic Spectrometer), EIT, SUMER (Solar Ultraviolet Measurement of Emitted Radiation), and MDI. The primary ground based instruments would be the VLA (Very Large Array), the Owens Valley Radio Observatory, and vector and longitudinal field magnetographs. Similar campaigns have successfully been carried out with the Solar Maximum Mission x-ray polychromator and the Soft X-ray Imaging Sounding Rocket Payload (CoMStOC '87), the Goddard Solar EUV Rocket Telescope and Spectrograph, the Lockheed Solar Plasma Diagnostics Experiment rocket payload, and the Soft X-ray Telescope in Yohkoh (CoMStoc '92). The scientific payoff from such a campaign is discussed in light of the results from these previous campaigns.

Holman, Gordon D.

1992-01-01

201

Comparison of clustering algorithms on generalized propensity score in observational studies: a simulation study  

Microsoft Academic Search

In observational studies, unbalanced observed covariates between treatment groups often cause biased inferences on the estimation of treatment effects. Recently, generalized propensity score (GPS) has been proposed to overcome this problem; however, a practical technique to apply the GPS is lacking. This study demonstrates how clustering algorithms can be used to group similar subjects based on transformed GPS. We compare

Chunhao Tu; Shuo Jiao; Woon Yuen Koh

2012-01-01

202

Observational Studies of Pre-Main Sequence Stars  

NASA Astrophysics Data System (ADS)

This work investigates selected young stars paying particular attention to their photometric and polarimetric characteristics. The stars observed represent particular sub-classes of the Orion Population of young stars: T Tauri stars of about one solar mass (RY Lup, RU Lup, CoD -33o10685 and AK Sco); Herbig Ae/Be stars of a few solar masses (TY CrA, R CrA, T CrA and V856 Sco); a YY Ori star which is thought to be still accreting matter (S CrA); and an 'isolated' T Tauri star which lies away from a star-forming cloud (V4046 Sgr). Data was acquired at ultraviolet, optical and infrared wavelengths, along with optical polarimetric data. The subsequent analysis of data for the well-studied stars can be summarised as follows: the spectroscopic characteristics of the star are defined; possible mechanisms for the photometric variability are discussed; and given the spectral type of the star, the intrinsic flux distribution is determined and the parameters of the optical and infrared emission are thereby determined. The implications of any photometric variability found are also discussed. A possible model of polarisation is discussed and the wavelength dependence of polarisation in eleven young stars is analysed. It is found that the circumstellar environment plays a role in many of the observed characteristics of the stars studied. Several of the stellar spectra show lines which form in a stellar envelope. Each star is found to be affected by circumstellar extinction and to exhibit infrared emission from circumstellar dust. In most cases the circumstellar dust also gives rise to the optical polarisation. The photometric and/or polarimetric variability exhibited by some of the stars is ascribable to changes in the circumstellar dust shell opacity

Hutchinson, M. G.

1988-12-01

203

Foreground separation methods for satellite observations of the cosmic microwave background  

E-print Network

A maximum entropy method (MEM) is presented for separating the emission due to different foreground components from simulated satellite observations of the cosmic microwave background radiation (CMBR). In particular, the method is applied to simulated observations by the proposed Planck Surveyor satellite. The simulations, performed by Bouchet and Gispert (1998), include emission from the CMBR, the kinetic and thermal Sunyaev-Zel'dovich (SZ) effects from galaxy clusters, as well as Galactic dust, free-free and synchrotron emission. We find that the MEM technique performs well and produces faithful reconstructions of the main input components. The method is also compared with traditional Wiener filtering and is shown to produce consistently better results, particularly in the recovery of the thermal SZ effect.

MP Hobson; AW Jones; AN Lasenby; FR Bouchet

1998-06-30

204

Complementary methods of system usability evaluation: surveys and observations during software design and development cycles.  

PubMed

Poor usability of clinical information systems delays their adoption by clinicians and limits potential improvements to the efficiency and safety of care. Recurring usability evaluations are therefore, integral to the system design process. We compared four methods employed during the development of outpatient clinical documentation software: clinician email response, online survey, observations and interviews. Results suggest that no single method identifies all or most problems. Rather, each approach is optimal for evaluations at a different stage of design and characterizes different usability aspect. Email responses elicited from clinicians and surveys report mostly technical, biomedical, terminology and control problems and are most effective when a working prototype has been completed. Observations of clinical work and interviews inform conceptual and workflow-related problems and are best performed early in the cycle. Appropriate use of these methods consistently during development may significantly improve system usability and contribute to higher adoption rates among clinicians and to improved quality of care. PMID:20546936

Horsky, Jan; McColgan, Kerry; Pang, Justine E; Melnikas, Andrea J; Linder, Jeffrey A; Schnipper, Jeffrey L; Middleton, Blackford

2010-10-01

205

Automatic Method for Identifying Photospheric Bright Points and Granules Observed by Sunrise  

NASA Astrophysics Data System (ADS)

In this study, we propose methods for the automatic detection of photospheric features (bright points and granules) from ultra-violet (UV) radiation, using a feature-based classifier. The methods use quiet-Sun observations at 214 nm and 525 nm images taken by Sunrise on 9 June 2009. The function of region growing and mean shift procedure are applied to segment the bright points (BPs) and granules, respectively. Zernike moments of each region are computed. The Zernike moments of BPs, granules, and other features are distinctive enough to be separated using a support vector machine (SVM) classifier. The size distribution of BPs can be fitted with a power-law slope -1.5. The peak value of granule sizes is found to be about 0.5 arcsec^2. The mean value of the filling factor of BPs is 0.01, and for granules it is 0.51. There is a critical scale for granules so that small granules with sizes smaller than 2.5 arcsec^2 cover a wide range of brightness, while the brightness of large granules approaches unity. The mean value of BP brightness fluctuations is estimated to be 1.2, while for granules it is 0.22. Mean values of the horizontal velocities of an individual BP and an individual BP within the network were found to be 1.6 km/s and 0.9 km/s, respectively. We conclude that the effect of individual BPs in releasing energy to the photosphere and maybe the upper layers is stronger than what the individual BPs release into the network.

Javaherian, M.; Safari, H.; Amiri, A.; Ziaei, S.

2014-10-01

206

Exploring the Ethics of Observational Research: The Case of an HIV Study in Tanzania  

PubMed Central

Background Observational studies have generally been viewed as incurring minimal risk to participants, resulting in fewer ethical obligations for investigators than intervention studies. In 2004, the lead author (AN) carried out an observational study measuring sexual behavior and the prevalence of HIV, syphilis, and herpes simplex virus type 2 (HSV-2), among Tanzanian agricultural plantation residents (results reported elsewhere). This article uses an ethical lens to consider the consequences of the observational study and explore what, if any, effects it had on participants and their community. Methods Using a case study approach, we critically examine three core principles of research ethicsrespect for persons/autonomy; beneficence/nonmaleficence; and distributive justiceas manifested in the 2004 observational study. We base our findings on three sources: discussions with plantation residents following presentations of observational research findings; in-depth interviews with key informants; and researcher observations. Results The observational research team was found to have ensured confidentiality and noncoercive recruitment. Ironically, maintenance of confidentiality and voluntary participation led some participants to doubt study results. Receiving HIV test results was important for participants and contributed to changing community norms about HIV testing. Conclusions Observational studies may act like de facto intervention studies and thus incur obligations similar to those of intervention studies. We found that ensuring respect for persons may have compromised the principles of beneficence and distributive justice. While in theory these three ethical principles have equal moral force, in practice, researchers may have to prioritize one over the others. Careful community engagement is necessary to promote well-considered ethical decisions. PMID:24069546

Norris, Alison; Jackson, Ashley; Khoshnood, Kaveh

2013-01-01

207

Feeling grateful: a parse research method study.  

PubMed

The author in this article reports a Parse research method study on the universal experience of feeling grateful with 10 participants living in community. The central finding of this study is the structure: The living experience of feeling grateful is potent elation amid tribulation arises with the assuredness-unassuredness of benevolent alliances. The findings are discussed in relation to the humanbecoming school of thought and related literature. New knowledge generated from this study: (a) explicates unique ways of becoming related to feeling grateful, (b) enhances understanding of ways of connecting with persons in practice, and (c) reveals phenomena for further research. PMID:23575493

Hart, Judith D

2013-04-01

208

Comparison of Observation Impacts in Two Forecast Systems using Adjoint Methods  

NASA Technical Reports Server (NTRS)

An experiment is being conducted to compare directly the impact of all assimilated observations on short-range forecast errors in different operational forecast systems. We use the adjoint-based method developed by Langland and Baker (2004), which allows these impacts to be efficiently calculated. This presentation describes preliminary results for a "baseline" set of observations, including both satellite radiances and conventional observations, used by the Navy/NOGAPS and NASA/GEOS-5 forecast systems for the month of January 2007. In each system, about 65% of the total reduction in 24-h forecast error is provided by satellite observations, although the impact of rawinsonde, aircraft, land, and ship-based observations remains significant. Only a small majority (50- 55%) of all observations assimilated improves the forecast, while the rest degrade it. It is found that most of the total forecast error reduction comes from observations with moderate-size innovations providing small to moderate impacts, not from outliers with very large positive or negative innovations. In a global context, the relative impacts of the major observation types are fairly similar in each system, although regional differences in observation impact can be significant. Of particular interest is the fact that while satellite radiances have a large positive impact overall, they degrade the forecast in certain locations common to both systems, especially over land and ice surfaces. Ongoing comparisons of this type, with results expected from other operational centers, should lead to more robust conclusions about the impacts of the various components of the observing system as well as about the strengths and weaknesses of the methodologies used to assimilate them.

Gelaro, Ronald; Langland, Rolf; Todling, Ricardo

2009-01-01

209

A Method to Simulate the Observed Surface Properties of Proton Irradiated Silicon Strip Sensors  

E-print Network

During the scheduled high luminosity upgrade of LHC, the world's largest particle physics accelerator at CERN, the position sensitive silicon detectors installed in the vertex and tracking part of the CMS experiment will face more intense radiation environment than the present system was designed for. To upgrade the tracker to required performance level, extensive measurements and simulations studies have already been carried out. A defect model of Synopsys Sentaurus TCAD simulation package for the bulk properties of proton irradiated devices has been producing simulations closely matching with measurements of silicon strip detectors. However, the model does not provide expected behavior due to the fluence increased surface damage. The solution requires an approach that does not affect the accurate bulk properties produced by the proton model, but only adds to it the required radiation induced properties close to the surface. These include the observed position dependency of the strip detector's charge collection efficiency (CCE). In this paper a procedure to find a defect model that reproduces the correct CCE loss, along with other surface properties of a strip detector up to a fluence $1.5\\times10^{15}$ 1 MeV n$_{\\textrm{eq}}$ cm$^{-2}$, will be presented. When applied with CCE loss measurements at different fluences, this method may provide means for the parametrization of the accumulation of oxide charge at the SiO2/Si interface as a function of dose.

Timo Peltola; Ashutosh Bhardwaj; Ranjeet Dalal; Robert Eber; Thomas Eichhorn; Kavita Lalwani; Alberto Messineo; Martin Printz; Kirti Ranjan

2014-09-24

210

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

211

Phytoplankton dynamics studying using observation and biophysical modeling  

NASA Astrophysics Data System (ADS)

Continental shelf phytoplankton bloom dynamics are associated with meteorological, oceanographic and coastal forcing mechanisms. Mixing related to stratification and de-stratification is a key process of the physical environment that can control the timing and magnitude of blooms. Using data from satellite, coastal ocean observatory and bio-physical model, this study investigated the seasonal and decadal variability of chlorophyll in the Mid-Atlantic Bight and how different forcing mechanisms affect the phytoplankton bloom. The temporal and spatial distribution of chlorophyll a in the MAB was quantified using satellite data collected by the Sea-viewing Wide Field of view Sensor (SeaWiFS). The MAB undergoes a fall-winter bloom in the middle-outer shelf region and spring bloom in the shelf-break region. The interannual variability of bloom magnitude is associated with wind-induced mixing. Mixing has been recognized as having an important role in influencing underwater light and nutrient budgets and thus regulating phytoplankton bloom. The ratio of light over mixed layer depth (MLD) was used to determine the trade-off effects of mixing on phytoplankton bloom activity. We find that a critical light value around 60 (W m-2) for the shelf region and 150 (W m-2) for the shelf-break front region in promoting maximum phytoplankton biomass and there is a predictable linear regression relationship between the critical light value and depth. The bio-physical model identified the wind-induced mixing, net heat flux and river run-off are the most important factors influencing water column stability. Sensitivity studies showed that the timing of the destratification and initiation of fall bloom was closely related to the wind forcing. The river's role in bringing buoyancy was significant in increasing phytoplankton bloom. The decadal declines in the seasonal satellite estimates of chlorophyll a&barbelow; concentrations have been observed in the fall and winter in the MAB and are hypothesized to reflect shifts in the Atlantic Multidecadal Oscillation (AMO) that alters wind stress, river discharge, and net heat flux. This work prototypes the integration of observation and modeling in a coastal environment and demonstrates the use of 3D coupled physical-biological model forced with realistic atmospheric forcing to study the phytoplankton dynamics in the MAB.

Xu, Yi

212

Study of the NWC electrons belt observed on DEMETER Satellite  

E-print Network

We analyzed the data from 2007 to 2008, which is observed by IDP onboard DEMETER satellite, during ten months of NWC working and seven months of NWC shutdown. The characteristic of the space instantaneous electron belts, which come from the influence of the VLF transmitted by NWC, is studied comprehensively. The main distribution region of the NWC electron belts and the flux change are given. We also studied the distribution characteristic of the average energy spectrum in different magnetic shell at the height of DEMETER orbit and the difference of the average energy spectrum of the electrons in the drift loss-cone between day and night. As a result, the powerful power of NWC transmitter and the 19.8 kHz narrow bandwidth VLF emission not only created a momentary electrons enhancement region, which strides 180 degree in them longitude direction and from 1.6 to 1.9 in L value, with the rise of the electrons flux reaching to 3 orders of magnitude mostly, but also induced the enhancement or loss of electrons in ...

Li, Xinqiao; Wang, Ping; Wang, Huanyu; Lu, Hong; Zhang, Xuemin; Huang, Jianping; Shi, Feng; Yu, Xiaoxia; Xu, Yanbing; Meng, Xiangcheng; Wang, Hui; Zhao, Xiaoyun; Parrot, M

2010-01-01

213

Comparison of GP and nurse practitioner consultations: an observational study  

PubMed Central

Background Studies show that satisfaction with nurse practitioner care is high when compared with GPs. Clinical outcomes are similar. Nurse practitioners spend significantly longer on consultations. Aim We aimed to discover what nurse practitioners do with the extra time, and how their consultations differ from those of GPs. Design of study Comparative content analysis of audiotape transcriptions of 18 matched pairs of nurse practitioner and GP consultations. Setting Nine general practices in south Wales and south west England. Method Consultations were taped and clinicians' utterances coded into categories developed inductively from the data, and deductively from the literature review. Results Nurse practitioners spent twice as long with their patients and both patients and clinicians spoke more in nurse consultations. Nurses talked significantly more than GPs about treatments and, within this, talked significantly more about how to apply or carry out treatments. Weaker evidence was found for differences in the direction of nurses being more likely to: discuss social and emotional aspects of patients' lives; discuss the likely course of the patient's condition and side effects of treatments; and to use humour. Some of the extra time was also spent in getting doctors to approve treatment plans and sign prescriptions. Conclusions The provision of more information in the longer nurse consultations may explain differences in patient satisfaction found in other studies. Clinicians need to consider how much information it is appropriate to provide to particular patients. PMID:16378563

Seale, Clive; Anderson, Elizabeth; Kinnersley, Paul

2005-01-01

214

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

215

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

216

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

217

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

218

Canadian Outcomes Study in Dementia: Study Methods and Patient Characteristics  

Microsoft Academic Search

Methods: COSID is a 3-year prospective study of dementia patients living in the community at the time of study registration. We assessed patients' cognition, behaviour, and functioning every 6 months, using the Modified Mini-Mental State Examination (3MS), the Neuropsychiatric Inventory (NPI), and the Functional Autonomy Measurement System (SMAF), respectively. We assessed caregivers, using the Zarit Burden Interview (ZBI). Additional information

Robert Sambrook; Nathan Herrmann; Rjean Hbert; Peter McCracken; Alain Robillard; Doanh Luong; Amanda Yu

2004-01-01

219

Does smoking protect against osteoarthritis? Meta-analysis of observational studies  

Microsoft Academic Search

ObjectivesTo determine whether smoking is protective against the development of osteoarthritis (OA).MethodsObservational studies for the association between smoking and OA were systematically searched through Medline (1950), Embase (1980), Web of Science (1960), PubMed, Google and relevant references. ORs and 95% CIs were directly retrieved or calculated. Current standards for reporting using MOOSE were followed. Quality-related aspects such as study design,

Michelle Hui; Michael Doherty; Weiya Zhang

2011-01-01

220

Water birth, more than a trendy alternative: a prospective, observational study  

Microsoft Academic Search

ObjectiveTo prospectively assess the effect of water birth on maternal and fetal outcomes in a selected low-risk collective of a tertiary obstetrical unit.MethodIn this prospective observational study, 513 patients of a low-risk collective, who requested a water birth, were studied during the years 19982002. Primary outcome measurements included the maternal and fetal parameters. Secondary outcome measurements comprised data on the

Rosanna Zanetti-Dllenbach; Olav Lapaire; Anne Maertens; Wolfgang Holzgreve; Irene Hsli

2006-01-01

221

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 plantsobservers 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 animalsamphibians, birds, fish, insects, mammals, and reptileswe 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

222

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

PubMed

We investigated the prevalence of postpartum infections among women giving birth during 1year in a population-based observational/questionnaire study at seven hospitals in the southeast region of Sweden. Of the women >99% (n=11124) received a questionnaire to inquire if they had endometritis, mastitis, or wound, urinary tract or any other infection within 2months 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

223

A Method to Retrieve Rainfall Rate Over Land from TRMM Microwave Imager Observations  

NASA Technical Reports Server (NTRS)

Over tropical land regions, rain rate maxima in mesoscale convective systems revealed by the Precipitation Radar (PR) flown on the Tropical Rainfall Measuring Mission (TRMM) satellite are found to correspond to thunderstorms, i.e., Cbs. These Cbs are reflected as minima in the 85 GHz brightness temperature, T85, observed by the TRMM Microwave Imager (TMI) radiometer. Because the magnitude of TMI observations do not discriminate satisfactorily convective and stratiform rain, we developed here a different TMI discrimination method. In this method, two types of Cbs, strong and weak, are inferred from the Laplacian of T85 at minima. Then, to retrieve rain rate, where T85 is less than 270 K, a weak (background) rain rate is deduced using T85 observations. Furthermore, over a circular area of 10 km radius centered at the location of each T85 minimum, an additional Cb component of rain rate is added to the background rain rate. This Cb component of rain rate is estimated with the help of (T19-T37) and T85 observations. Initially, our algorithm is calibrated with the PR rain rate measurements from 20 MCS rain events. After calibration, this method is applied to TMI data taken from several tropical land regions. With the help of the PR observations, we show that the spatial distribution and intensity of rain rate over land estimated from our algorithm are better than those given by the current TMI-Version-5 Algorithm. For this reason, our algorithm may be used to improve the current state of rain retrievals on land.

Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Lau, William K. M. (Technical Monitor)

2002-01-01

224

Methods to interpolate soil categorical variables from profile observations: Lessons from Iran  

Microsoft Academic Search

The paper compares semi-automated interpolation methods to produce soil-class maps from profile observations and by using multiple auxiliary predictors such as terrain parameters, remote sensing indices and similar. The Soil Profile Database of Iran, consisting of 4250 profiles, was used to test different soil-class interpolators. The target variables were soil texture classes and World Reference Base soil groups. The predictors

Tomislav Hengl; Norair Toomanian; Hannes I. Reuter; Mohammad J. Malakouti

2007-01-01

225

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

Microsoft Academic Search

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

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

2012-01-01

226

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

227

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 3days 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

228

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

229

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 17, METHOD 607 (NITROSAMINES)  

EPA Science Inventory

This report describes the results obtained and data analyses from an interlaboratory evaluation of EPA Method 607 (Nitrosamines). The method is designed to analyze for three nitrosamines, N-nitrosodimethylamine, N-nitrosodi-n-propylamine, and N-nitroso-diphenylamine, in water and...

230

TECHNIQUES AND METHODS Methods for Developmental Studies of Fear  

E-print Network

childhood (Pine et al 1998), there is a great need for research linking adult anxiety disorders to risk- der. These data suggest that aspects of amygdala function may index childhood risk for anxiety. Recent) and air-puff UCS methods from Grillon et al (1998, 1999). Methods and Materials Subjects Seven right

Burgess, Neil

231

GaAs Epitaxy by a Molecular Beam Method: Observations of Surface Structure on the (001) Face  

Microsoft Academic Search

The epitaxial growth of GaAs by a molecular beam deposition method on bromine-methanol etched (001) GaAs substrate has been studied in situ in an ultrahigh vacuum high-energy electron diffraction system. GaAs (001)?C(28) and (001)?C(82) surface structures were observed during growth: one is arsenic stabilized, the other is gallium stabilized, and they are rotated 90 about the [001] axis from each

A. Y. Cho

1971-01-01

232

AphasiaBank: Methods for Studying Discourse.  

PubMed

BACKGROUND: AphasiaBank is a computerized database of interviews between persons with aphasia (PWAs) and clinicians. By February 2011, the database had grown to include 145 PWAs and 126 controls from 12 sites across the United States. The data and related analysis programs are available free over the web. AIMS: The overall goal of AphasiaBank is the construction of a system for accumulating and sharing data on language usage by PWAs. To achieve this goal, we have developed a standard elicitation protocol and systematic automatic and manual methods for transcription, coding, and analysis. METHODS #ENTITYSTARTX00026; PROCEDURES: We present sample analyses of transcripts from the retelling of the Cinderella story. These analyses illustrate the application of our methods for the study of phonological, lexical, semantic, morphological, syntactic, temporal, prosodic, gestural, and discourse features. MAIN CONTRIBUTION: AphasiaBank will allow researchers access to a large, shared database that can facilitate hypothesis testing and increase methodological replicability, precision, and transparency. CONCLUSIONS: AphasiaBank will provide researchers with an important new tool in the study of aphasia. PMID:22923879

Macwhinney, Brian; Fromm, Davida; Forbes, Margaret; Holland, Audrey

2011-01-01

233

AphasiaBank: Methods for Studying Discourse  

PubMed Central

Background AphasiaBank is a computerized database of interviews between persons with aphasia (PWAs) and clinicians. By February 2011, the database had grown to include 145 PWAs and 126 controls from 12 sites across the United States. The data and related analysis programs are available free over the web. Aims The overall goal of AphasiaBank is the construction of a system for accumulating and sharing data on language usage by PWAs. To achieve this goal, we have developed a standard elicitation protocol and systematic automatic and manual methods for transcription, coding, and analysis. Methods & Procedures We present sample analyses of transcripts from the retelling of the Cinderella story. These analyses illustrate the application of our methods for the study of phonological, lexical, semantic, morphological, syntactic, temporal, prosodic, gestural, and discourse features. Main Contribution AphasiaBank will allow researchers access to a large, shared database that can facilitate hypothesis testing and increase methodological replicability, precision, and transparency. Conclusions AphasiaBank will provide researchers with an important new tool in the study of aphasia. PMID:22923879

MacWhinney, Brian; Fromm, Davida; Forbes, Margaret; Holland, Audrey

2011-01-01

234

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.

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

2014-01-01

235

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

236

Determining the orientation of the observed object in threedimensional space using stereo vision methods  

NASA Astrophysics Data System (ADS)

The task of matching image of an object with its template is central for many optoelectronic systems. Solution of the matching problem in three-dimensional space in contrast to the structural alignment in the image plane allows using a larger amount of information about the object for determining its orientation, which may increase the probability of correct matching. In the case of stereo vision methods for constructing a three-dimensional image of the object, it becomes possible to achieve invariance w.r.t. background and distance to the observed object. Only three of the orientation angle of the object relative to the camera are uncertain and require measurements. This paper proposes a method for determining the orientation angles of the observed object in three-dimensional space, which is based on the processing of stereo image sequences. Disparity map segmentation method that allows one to ensure the invariance of the background is presented. Quantitative estimates of the effectiveness of the proposed method are presented and discussed.

Ponomarev, S.

2014-09-01

237

A Method to Retrieve Rainfall Rate over Land from TRMM Observations  

NASA Technical Reports Server (NTRS)

Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) observations over mesoscale convective systems (MCSs) reveal that there are localized maxima in the rain rate with a scale of about 10 to 20 km that represent thunderstorms (Cbs). Some of these Cbs are developing or intense, while others are decaying or weak. These Cbs constitute only about 20 % of the rain area of a given MCS. Outside of Cbs, the average rain rate is much weaker than that within Cbs. From an analysis of the PR data, we find that the spatial distribution of rain and its character, convective or stratiform, is highly inhomogeneous. This complex nature of rain exists on a scale comparable to that of a Cb. The 85 GHz brightness temperature, T85, observations of the TRMM Microwave Imager (TMI) radiometer taken over an MCS reflect closely the PR rain rate pattern over land. Local maxima in rain rate shown by PR are observed as local minima in T85. Where there are no minima in T85, PR observations indicate there is light rain. However, the TMI brightness temperature measurements (Tbs) have poor ability to discriminate convective rain from stratiform rain. For this reason, a TMI rain retrieval procedure that depends primarily on the magnitude of Tbs performs poorly. In order to retrieve rain rate from TMI data on land one has to include the spatial distribution information deduced from the T85 data in the retrieval method. Then, quantitative estimation of rain rate can be accomplished. A TMI rain retrieval method developed along these lines can yield estimates of rain rate and its frequency distribution which agree closely with that given by PR. We find the current TRMM project TMI (Version 5) rain retrieval algorithm on land could be improved with the retrieval scheme developed here. To support the conceptual frame work of the rain retrieval method developed here, a theoretical analysis of the TMI brightness temperatures in convective and stratiform regions is presented.

Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

2002-01-01

238

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

239

Development of Technologies for Coastal Observing Systems and the Study of Benthic Boundary Layer Processes  

NSF Publications Database

Development of Technologies for Coastal Observing Systems and the Study of Benthic Boundary Layer ... Information Program Title: Development of Technologies for Coastal Observing Systems and the Study ...

240

Accuracy of physical activity assessment during pregnancy: an observational study  

PubMed Central

Background Prenatal physical activity may improve maternal and infant health and lower future disease risk for both mother and baby; however, very few physical activity assessment methods have been validated for use during pregnancy. The purpose of this study was to evaluate the accuracy of a subjective physical activity record (PAR) and an objective activity monitor, against a reference standard to quantify moderate and vigorous physical activity (MVPA) in pregnant women. The reference standard was based on participant interviews to determine if a woman was an exerciser and confirmed with information obtained from the PAR and a heart rate monitor. Methods Fifty-two pregnant women completed a physical activity record (PAR) and wore a SenseWear Mini Armband (SWA) activity monitor over a 7-day period at 18 weeks gestation. Total minutes spent in MVPA were totaled from both modalities and evaluated against the reference standard using contingency analysis and Pearson's chi-square test to evaluate the number of women meeting minimum prenatal physical activity recommendations (at least 3, 30 minute sessions of exercise per week). Both modalities were also tested individually and collectively to assess their ability as indicators of activity using empirically determined cut-offs as indicated by receiver-operator characteristic curves. These experimentally-derived criteria were also tested with Pearson's chi-square test. Results According to the reference standard, 13 of 52 participants (25%) met the criterion of 3, 30 minute sessions of volitional, moderate-intensity activity. When compared to the reference standard, both the PAR and SWA overestimated exercise status; 42 (81%) and 52 (100%) participants, respectively, achieved 90 minutes of MVPA (P < 0.0001 for both comparisons). Single-modality predictors of MVPA did not show a significant correlation. A composite predictor of MVPA offered the most favorable option for sensitivity and specificity (true positives, n = 8 and true negatives, n = 36) using cut-offs of 280 and 385 minutes/week for the PAR and SWA, respectively. Conclusion Compared to the reference standard, time spent in MVPA obtained from the PAR or SWA overestimated the prevalence of women meeting prenatal exercise recommendations. The most accurate predictor of women meeting current prenatal exercise guidelines was identified by using the PAR and SWA collectively. PMID:22039863

2011-01-01

241

Relevance of the expression obs stable in nursing observations: retrospective study  

PubMed Central

Objective To ascertain whether use of the term obs stable with respect to the nursing observations is so liberal as to render it meaningless. Design Retrospective study. Setting Three teaching hospitals in London, United Kingdom. Methods We searched progress notes for the current admission of 46 inpatients for entries containing the phrases obs stable and observations stable, and reviewed the nursing observations recorded during the 24 hour period preceding each entry containing at least one phrase. We calculated the frequency of abnormalities and of persistent abnormalities (defined as occurring in every observation) observed during these 24 hour periods, and the range of observation values over a 24 hour period if at least two observations had been recorded. Results We found at least one entry in 36 (78%) progress notes (95% confidence interval 66% to 90%). Observations in the 24 hours preceding an entry included at least one abnormality for 113 (71%) of 159 cases and at least one persistent abnormality for 31 (19%). The most frequently occurring abnormalities were tachypnoea (respiratory rate ?20 breaths/min) and hypotension (systolic blood pressure <100 mm Hg). An abnormality occurred in the observations immediately preceding an entry in 42% of cases. Mean ranges of observations over 24 hours were within the limits of normal diurnal variation, although we found that some instances of greater than normal variability were described as stable. Conclusions The expression obs stable does not reliably indicate normal observations or variations in observations within physiological limits. Doctors should avoid using the expression altogether or clarify it with further information. PMID:22187323

2011-01-01

242

Novel method of fast satellite movement information acquisition from VLBI observations  

NASA Astrophysics Data System (ADS)

Very Long Baseline Interferometry (VLBI) is a radio astronomy technique. The diameter of a VLBI synthetic telescope equals the longest baseline (>1000 Km). Therefore, VLBI can achieve very high angular resolution, and has unique advantage in the deep space tracking compared with the traditional radio ranging and Doppler tracking technologies. In the satellite VLBI observations, the spacecraft movement information such as delay or delay rate observable is very useful in the spacecraft position and orbit determination. This paper introduces an algorithm of obtaining satellite VLBI delay and delay rate based on short time correlation. Using the Differential One-way Doppler of the telemetry carrier, this method is able to complete fast fringe search, correlation, producing delay and delay rate with high accuracy from the satellite telemetry signals automatically, without any apriori orbit information. A special software correlator--Fast Fringe Searcher (FFS) was developed and successfully used in the data processing of the satellite VLBI experiments, such as the Chinese TC-1 Geospace satellite and the European SMART-1 lunar probe VLBI observations. The delay and delay rate produced by FFS were used in TC-1 orbit determination, which was the first Chinese VLBI satellite orbit determination experiment. Besides, an accurate VLBI correlator delay model can be constructed from FFS output. According to this model, a general VLBI correlator can produce more precise delay and delay rate through long time integration. This method will be applied to the real-time VLBI correlator system of the Chinese lunar exploration project in the near future.

Zheng, Weimin; Yang, Yan

2005-10-01

243

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

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

2014-01-01

244

Three-dimensional domain observations of magnetite and titanomagnetites using the dried colloid SEM method  

NASA Astrophysics Data System (ADS)

Dried colloid scanning electron microscopy (SEM) has been applied for the study of Bitter patterns on unpolished and uneven surfaces of microcrystals of natural ferrites (hydrothermally grown magnetite, synthetic TM70 and TM50 removed from a basaltic rock matrix). By the simultaneous observation of domain walls on crystal surfaces of different orientation with high resolution, information is obtained on the volume domain structure underneath. The observation confirms the presence of lamellae-shaped volume domains associated with closure domains on the surface for the reduction of the magnetic stray field energy.

Soffel, H. C.; Aumller, C.; Hoffmann, V.; Appel, E.

245

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

246

GPS based method of ionospheric study  

NASA Astrophysics Data System (ADS)

The GPS ionospheric sounding is a powerful tool for remote sensing of the ionosphere. The GPS signals have provided an unique opportunity to study the short scale length variations in TEC (Total Electron Content) along the signal path in the presence of ionospheric irregularities and scintillations caused by these irregularities. GPS based ionospheric measurement can measure TEC variations smaller than 10-2 TEC unit. This paper presents the observations of real time TEC and scintillation obtained with dual frequency GPS receiver GSV4004A at Bhopal. The receiver is specially configured to measure amplitude and phase scintillation from the L1 frequency GPS signals and ionospheric TEC from the L1 (1575 MHz) and L2 (1227 MHz) frequency GPS signals. The data for TEC and scintillation have been analyzed and the results for the crest of anomaly region (Bhopal) have been discussed.

Gwal, A. K.; Sarkar, S.; Malhotra, K.

247

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

248

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

249

Clinical observation and mechanism study on treatment of senile dementia with Naohuandan  

Microsoft Academic Search

Objective: To observe the therapeutic effect and mechanism of Naohuandan (NHD) in treating senile dementia (SD).Methods: Clinical study: Fifty-eight patients with SD, whose diagnosis conforms to the Diagnostic Standard of DSM-IV issued by American\\u000a Association of Psychiatry, were enrolled and randomly assigned into two groups. The 30 patients in the treated group were\\u000a treated with NHD, 4 capsules each time,

Meng Rong-sen; Li Qing-ming; Wei Chang-xiu; Chen Bo; Liao Hong-ying; Zhou Yu-tian

2005-01-01

250

Social media methods for studying rare diseases.  

PubMed

For pediatric rare diseases, the number of patients available to support traditional research methods is often inadequate. However, patients who have similar diseases cluster "virtually" online via social media. This study aimed to (1) determine whether patients who have the rare diseases Fontan-associated protein losing enteropathy (PLE) and plastic bronchitis (PB) would participate in online research, and (2) explore response patterns to examine social media's role in participation compared with other referral modalities. A novel, internet-based survey querying details of potential pathogenesis, course, and treatment of PLE and PB was created. The study was available online via web and Facebook portals for 1 year. Apart from 2 study-initiated posts on patient-run Facebook pages at the study initiation, all recruitment was driven by study respondents only. Response patterns and referral sources were tracked. A total of 671 respondents with a Fontan palliation completed a valid survey, including 76 who had PLE and 46 who had PB. Responses over time demonstrated periodic, marked increases as new online populations of Fontan patients were reached. Of the responses, 574 (86%) were from the United States and 97 (14%) were international. The leading referral sources were Facebook, internet forums, and traditional websites. Overall, social media outlets referred 84% of all responses, making it the dominant modality for recruiting the largest reported contemporary cohort of Fontan patients and patients who have PLE and PB. The methodology and response patterns from this study can be used to design research applications for other rare diseases. PMID:24733869

Schumacher, Kurt R; Stringer, Kathleen A; Donohue, Janet E; Yu, Sunkyung; Shaver, Ashley; Caruthers, Regine L; Zikmund-Fisher, Brian J; Fifer, Carlen; Goldberg, Caren; Russell, Mark W

2014-05-01

251

A New Method for Meteor Entry Dynamics Determination Based on Observations and Results of Calculations  

NASA Astrophysics Data System (ADS)

A great amount of photographic data of meteoroid trajectories in the Earth's atmosphere has been collected. Most images have been obtained by four fireball networks, which operated in USA, Canada, Europe, and Spain in different time periods. The approximation of the data by theoretical relations makes it possible to obtain additional estimates which do not directly follow from observations. In the present paper, I suggest the algorithm to find such parameters of theoretical relation between the height and the velocity of the bolide motion to fit observations along the luminous trajectories. The main difference to the previous works is that the given observations are approximated using the analytical solution of the equations of meteor physics. The model presented in this paper was applied here to a number of bright meteors observed by the Canadian MORP camera network and to the Benesov bolide, which is one of the the brightest well observed fireballs registered by the European network. The correct mathematical modelling of meteor events in the atmosphere is necessary for further estimates of key parameters, including the extra-atmospheric mass, the ablation coefficient, and the effective enthalpy of evaporation of entering bodies. This information is needed by some applications, namely those aimed to study the problems of asteroid and comet security, to develop measures of planetary defense, and to determine the bodies that can reach the Earth's surface.

Gritsevich, M. I.

2010-12-01

252

Coordination and management of multicenter clinical studies in trauma: Experience from the PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) Study  

PubMed Central

Aim Early death due to hemorrhage is a major consequence of traumatic injury. Transfusion practices differ among hospitals and it is unknown which transfusion practices improve survival. This report describes the experience of the PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) Study Data Coordination Center in designing and coordinating a study to examine transfusion practices at ten Level 1 trauma centers in the U.S. Methods PROMMTT was a multisite prospective observational study of severely injured transfused trauma patients. The clinical sites collected real-time information on the timing and amounts of blood product infusions as well as colloids and crystalloids, vital signs, initial diagnostic and clinical laboratory tests, life saving interventions and other clinical care data. Results Between July 2009 and October 2010, PROMMTT screened 12,561 trauma admissions and enrolled 1,245 patients who received one or more blood transfusions within 6 hours of ED admission. A total of 297 massive transfusions were observed over the course of the study at a combined rate of 5.0 massive transfusion patients/week. Conclusion PROMMTT is the first multisite study to collect real-time prospective data on trauma patients requiring transfusion. Support from the Department of Defense and collaborative expertise from the ten participating centers helped to demonstrate the feasibility of prospective trauma transfusion studies. The observational data collected from this study will be an invaluable resource for research in trauma surgery and it will guide the design and conduct of future randomized trials. PMID:22001613

Rahbar, Mohammad H.; Fox, Erin E.; del Junco, Deborah J.; Cotton, Bryan A.; Podbielski, Jeanette M.; Matijevic, Nena; Cohen, Mitchell J.; Schreiber, Martin A.; Zhang, Jiajie; Mirhaji, Parsa; Duran, Sarah; Reynolds, Robert J.; Benjamin-Garner, Ruby; Holcomb, John B.

2011-01-01

253

DIAGNOSTIC EVALUATION OF AIR QUALITY MODELS USING ADVANCED METHODS WITH SPECIALIZED OBSERVATIONS OF SELECTED AMBIENT SPECIES -PART II  

EPA Science Inventory

This is Part 2 of "Diagnostic Evaluation of Air Quality Models Using Advanced Methods with Specialized Observations of Selected Ambient Species". A limited field campaign to make specialized observations of selected ambient species using advanced and innovative instrumentation f...

254

Acoustic streaming in lithotripsy fields: preliminary observation using a particle image velocimetry method  

Microsoft Academic Search

This study considers the acoustic streaming in water produced by a lithotripsy pulse. Particle image velocimetry (PIV) method was employed to visualize the acoustic streaming produced by an electromagnetic shock wave generator using video images of the light scattering particles suspended in water. Visualized streaming features including several local peaks and vortexes around or at the beam focus were easily

Min Joo Choi; Doeg Hee Doh; Tae Gyu Hwang; Chu Hyun Cho; Dong Guk Paeng; Gun Hee Rim; A. J. Coleman

2006-01-01

255

Mass changes of microparticles in a plasma observed by a phase-resolved resonance method  

NASA Astrophysics Data System (ADS)

The influence of a plasma environment on melamine formaldehyde particles is studied. High-precision measurements of the vertical confinement frequency with a phase-resolved resonance method indicate that the particle mass is affected in two ways: the deposition of sputtered material at the particle leads to a mass gain, whereas the outgassing of water causes a mass loss.

Carstensen, Jan; Jung, Hendrik; Greiner, Franko; Piel, Alexander

2011-03-01

256

Comparative study of selected parallel tempering methods  

NASA Astrophysics Data System (ADS)

We review several parallel tempering schemes and examine their main ingredients for accuracy and efficiency. The present study covers two selection methods of temperatures and several choices for the exchange of replicas, including a recent novel all-pair exchange method. We compare the resulting schemes and measure specific heat errors and efficiency using the two-dimensional (2D) Ising model. Our tests suggest that an earlier proposal for using numbers of local moves related to the canonical correlation times is one of the key ingredients for increasing efficiency, and protocols using cluster algorithms are found to be very effective. Some of the protocols are also tested for efficiency and ground state production in 3D spin-glass models where we find that a simple nearest-neighbor approach using a local n-fold-way algorithm is the most effective. Finally, we present evidence that the asymptotic limits of the ground state energy for the isotropic case and for an anisotropic case of the 3D spin-glass model are very close and may even coincide.

Malakis, A.; Papakonstantinou, T.

2013-07-01

257

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

258

Observations on ion track structure in semiconductors : a phenomenological study  

NASA Technical Reports Server (NTRS)

An ion track structure model at the nanometer scale is presented. The model is based on electrostatic principles and is supported by observed experimental results conducted on power MOSFETs. The model predicts the existence of a transient induced electric field following the passage of an energetic heavy ion. There are two segments to the field (a radial and an axial component). It is the interaction of this transient electric field with the local environment that can trigger a catastrophic failure.

Selva, L. E.; Wallace, R. E.

2001-01-01

259

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

260

A simple and efficient method to observe internal structures of helminths by scanning electron microscopy.  

PubMed

Morphological studies of helminths by scanning electron microscopy are generally limited to the external topography of the organisms. In this work, we present a simple technique using ethanol as a cryoprotectant without postfixation in osmium tetroxide that allows for observation of the inner organization of helminths and preserves cellular structures. We tested the technique in three helminths: Echinostoma paraensei, Cruzia tentaculata, and Hassalstrongylus epsilon. The results show that this technique could potentially be applied to study the morphology, ultrastructure, and taxonomy of helminths. PMID:24148995

Adnet, Fernando Antnio de O; Gonalves, Jlia P; de Souza, Wanderley; Attias, Mrcia

2013-12-01

261

Observer assessment of multi-pinhole SPECT geometries for prostate cancer imaging: a simulation study  

NASA Astrophysics Data System (ADS)

SPECT imaging using In-111 ProstaScint is an FDA-approved method for diagnosing prostate cancer metastases within the pelvis. However, conventional medium-energy parallel-hole (MEPAR) collimators produce poor image quality and we are investigating the use of multipinhole (MPH) imaging as an alternative. This paper presents a method for evaluating MPH designs that makes use of sampling-sensitive (SS) mathematical model observers for tumor detectionlocalization tasks. Key to our approach is the redefinition of a normal (or background) reference image that is used with scanning model observers. We used this approach to compare different MPH configurations for the task of small-tumor detection in the prostate and surrounding lymph nodes. Four configurations used 10, 20, 30, and 60 pinholes evenly spaced over a complete circular orbit. A fixed-count acquisition protocol was assumed. Spherical tumors were placed within a digital anthropomorphic phantom having a realistic Prostascint biodistribution. Imaging data sets were generated with an analytical projector and reconstructed volumes were obtained with the OSEM algorithm. The MPH configurations were compared in a localization ROC (LROC) study with 2D pelvic images and both human and model observers. Regular and SS versions of the scanning channelized nonprewhitening (CNPW) and visual-search (VS) model observers were applied. The SS models demonstrated the highest correlations with the average human-observer results

Kalantari, Faraz; Sen, Anando; Gifford, Howard C.

2014-03-01

262

Study on short term prediction using observed water quality from 8-day intervals in Nakdong river  

NASA Astrophysics Data System (ADS)

There are lots of accidents on water quality, like green algal blooms, occurring in Nakdong river which is one of the largest river in Korea. This is because of climate change around the world. It is essential to develop scientific and quantitative assessment methods. In this study, artificial neural network based on back propagation algorithm, which is simple and flexible method, was used for forecasting the water quality on the purpose of water resources management. Especially, as used observed water quality data from 8-day intervals in Nakdong river, it makes to increase the accuracy of water quality forecast over short term. This was established for predicting the water quality factors 1, 3, and 7 days ahead. The best model, as evaluated by its performance functions with RMSE and R2, was selected and applied to established models of BOD, DO, COD, and Chl-a using artificial neural network. The results showed that the models were suitable for 1 and 3 days forecasts in particular. This method is strong and convenient to predict water quality factors over the short term easily based on observed data. It is possible to overcome and manage problems related to the water resources. In the future, this will be a powerful method because it is basically based on observed water quality data.

Kim, M.; Shon, T.; Joo, J.; Kim, J.; Shin, H.

2012-12-01

263

Cost-of-illness studies : a review of current methods.  

PubMed

The number of cost-of-illness (COI) studies has expanded considerably over time. One outcome of this growth is that the reported COI estimates are inconsistent across studies, thereby raising concerns over the validity of the estimates and methods. Several factors have been identified in the literature as reasons for the observed variation in COI estimates. To date, the variation in the methods used to calculate costs has not been examined in great detail even though the variations in methods are a major driver of variation in COI estimates. The objective of this review was to document the variation in the methodologies employed in COI studies and to highlight the benefits and limitations of these methods. The review of COI studies was implemented following a four-step procedure: (i) a structured literature search of MEDLINE, JSTOR and EconLit; (ii) a review of abstracts using pre-defined inclusion and exclusion criteria; (iii) a full-text review using pre-defined inclusion and exclusion criteria; and (iv) classification of articles according to the methods used to calculate costs. This review identified four COI estimation methods (Sum_All Medical, Sum_Diagnosis Specific, Matched Control and Regression) that were used in categorising articles. Also, six components of direct medical costs and five components of indirect/non-medical costs were identified and used in categorising articles.365 full-length articles were reflected in the current review following the structured literature search. The top five cost components were emergency room/inpatient hospital costs, outpatient physician costs, drug costs, productivity losses and laboratory costs. The dominant method, Sum_Diagnosis Specific, was a total costing approach that restricted the summation of medical expenditures to those related to a diagnosis of the disease of interest. There was considerable variation in the methods used within disease subcategories. In several disease subcategories (e.g. asthma, dementia, diabetes mellitus), all four estimation methods were represented, and in other cases (e.g. HIV/AIDS, obesity, stroke, urinary incontinence, schizophrenia), three of the four estimation methods were represented. There was also evidence to suggest that the strengths and weaknesses of each method were considered when applying a method to a specific illness. Comparisons and assessments of COI estimates should consider the method used to estimate costs both as an important source of variation in the reported COI estimates and as a marker of the reliability of the COI estimate. PMID:16942122

Akobundu, Ebere; Ju, Jing; Blatt, Lisa; Mullins, C Daniel

2006-01-01

264

Case Study of Ion Beams Observed By Cluster At Perigee  

NASA Astrophysics Data System (ADS)

During substorms the short beams of ions in the keV-to-tens keV energy range are injected into the auroral flux tubes from the magnetotail (sometimes extending up to >100 keV energy) carrying the information on the source distance, scale-size and temporal history of plasma acceleration. We present observations with the CLUSTER crossing inward the auroral zone flux tubes at ~4Re distance near its perigee during the substorm activity on February 14, 2001. The ion beams cover the same region (poleward half) of the auroral oval where the low-energy ions are extracted from the ionosphere, and where the small-scale transient transverse Alfven waves are observed which carry predominantly the downward parallel Poynting flux into the ionosphere. The multiple beams were basically confirmed to be the transient effects, although some effects including the (spatial) velocity filter and the parallel electric fields (im- posed by quasineutrality requirement) may complicate the interpretation. The gener- ation region of ion beams is not limited to most poleward, newly-reconnected flux tubes; the beam generation region could extend across magnetic field inward by as much as >100km (if mapped to the ionosphere). Surprising variety of injection dis- tances observed nearly simultaneously (ranging between >60 Re and ~10 Re) have been inferred when using the full available energy and time resolution, with shorter injection distances be possibly associated with the flow braking process. The beam multiplicity often displays the apparent ~3 min quasiperiodicity inherent to the basic dissipation process, it was not yet explained by any substorm theory.

Sergeev, V.; Sauvaud, J.-A.; Perigee Beam Team

265

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

266

Quantitative Study of Solar Farside Observations to Predict Active Regions  

NASA Astrophysics Data System (ADS)

Estimates of sunspots on the far side of the Sun have been obtained for several years with SOHO/MDI and recently with GONG observations. E.g. http://soi.stanford.edu/data/full_farside/. We have examined the predictive usefulness of far-side images of regions within a few days of the East limb by comparing the far-side images with subsequent magnetograms. We developed a quantitative measure of success based on the frequency of true positives and false alarms. We can detect about 75% of strong magnetic regions with a false alarm rate of less than 20%.

Buder, I.; Scherrer, P. H.

2006-12-01

267

Methods for environmental change; an exploratory study  

PubMed Central

Background While the interest of health promotion researchers in change methods directed at the target population has a long tradition, interest in change methods directed at the environment is still developing. In this survey, the focus is on methods for environmental change; especially about how these are composed of methods for individual change (Bundling) and how within one environmental level, organizations, methods differ when directed at the management (At) or applied by the management (From). Methods The first part of this online survey dealt with examining the bundling of individual level methods to methods at the environmental level. The question asked was to what extent the use of an environmental level method would involve the use of certain individual level methods. In the second part of the survey the question was whether there are differences between applying methods directed at an organization (for instance, by a health promoter) versus from within an organization itself. All of the 20 respondents are experts in the field of health promotion. Results Methods at the individual level are frequently bundled together as part of a method at a higher ecological level. A number of individual level methods are popular as part of most of the environmental level methods, while others are not chosen very often. Interventions directed at environmental agents often have a strong focus on the motivational part of behavior change. There are different approaches targeting a level or being targeted from a level. The health promoter will use combinations of motivation and facilitation. The manager will use individual level change methods focusing on self-efficacy and skills. Respondents think that any method may be used under the right circumstances, although few endorsed coercive methods. Conclusions Taxonomies of theoretical change methods for environmental change should include combinations of individual level methods that may be bundled and separate suggestions for methods targeting a level or being targeted from a level. Future research needs to cover more methods to rate and to be rated. Qualitative data may explain some of the surprising outcomes, such as the lack of large differences and the avoidance of coercion. Taxonomies should include the theoretical parameters that limit the effectiveness of the method. PMID:23190712

2012-01-01

268

Applying Agile Methods to the Development of a Community-Based Sea Ice Observations Database  

NASA Astrophysics Data System (ADS)

Local and traditional knowledge and community-based monitoring programs are increasingly being recognized as an important part of establishing an Arctic observing network, and understanding Arctic environmental change. The Seasonal Ice Zone Observing Network (SIZONet, http://www.sizonet.org) project has implemented an integrated program for observing seasonal ice in Alaska. Observation and analysis by local sea ice experts helps track seasonal and inter-annual variability of the ice cover and its use by coastal communities. The ELOKA project (http://eloka-arctic.org) is collaborating with SIZONet on the development of a community accessible, Web-based application for collecting and distributing local observations. The SIZONet project is dealing with complicated qualitative and quantitative data collected from a growing number of observers in different communities while concurrently working to design a system that will serve a wide range of different end users including Arctic residents, scientists, educators, and other stakeholders with a need for sea ice information. The benefits of linking and integrating knowledge from communities and university-based researchers are clear, however, development of an information system in this multidisciplinary, multi-participant context is challenging. Participants are geographically distributed, have different levels of technical expertise, and have varying goals for how the system will be used. As previously reported (Pulsifer et al. 2010), new technologies have been used to deal with some of the challenges presented in this complex development context. In this paper, we report on the challenges and innovations related to working as a multi-disciplinary software development team. Specifically, we discuss how Agile software development methods have been used in defining and refining user needs, developing prototypes, and releasing a production level application. We provide an overview of the production application that includes discussion of a hybrid architecture that combines a traditional relational database, schema-less database, advanced free text search, and the preliminary framework for Semantic Web support. The current version of the SIZONet web application is discussed in relation to the high-value features defined as part of the Agile approach. Preliminary feedback indicates a system that meets the needs of multiple user groups.

Pulsifer, P. L.; Collins, J. A.; Kaufman, M.; Eicken, H.; Parsons, M. A.; Gearheard, S.

2011-12-01

269

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

270

Recognising advancing nursing practice: evidence from two observational studies  

Microsoft Academic Search

Debates over title, grades and relationships across the profession has tended to dominate the literature in advancing nursing practice. Fewer research projects have attempted to study the activities of nurses who are designated as undertaking advancing nursing roles. One study evaluating Masters courses for Clinical Nursing Practice and a second addressing the impact of the Scope of Professional Practice (United

Jennifer Wilson-Barnett; K. Louise Barriball; Heidi Reynolds; Sandra Jowett; Iain Ryrie

2000-01-01

271

Studying Aerosol Properties with Astronomical Observations Using a Scattered Moonlight Model  

NASA Astrophysics Data System (ADS)

We are developing a new technique for monitoring the atmosphere with astronomical observations and our scattered moonlight model. This could be used to determine the size distributions and amounts of various aerosol particles. By taking the Moon as an illuminating source in sky observations, it is possible to iteratively find aerosol properties for a given time and location. There is a wealth of astronomical data over the last decade taken at Cerro Paranal in Chile where this technique can be applied. Our advanced scattered moonlight model is part of a sky radiance and transmission model developed for the Very Large Telescope of the European Southern Observatory. The moon model can calculate the amount of scattered moonlight present in a given astronomical observation based on the positions of the Moon and target, lunar phase, and atmospheric properties. This model is more physical than previous works in astronomy, which were almost completely empirical. For the original astronomical purpose, the model uses typical size distributions of remote continental tropospheric and stratospheric aerosols and the measured extinction curve from standard star observations to calculate the scattering and absorption of the moonlight to determine the amount of light that would eventually arrive to the telescope. Because the model incorporates the properties of the aerosols, in principle we can use this model with sky background observations to find the aerosol composition. The sky observations would first need to be analysed with our full sky model to calculate the other sky background components, and a derived extinction curve from standard star observations. Then with our moon model we could iteratively find the best aerosol composition for the data. This would require optical and near infrared spectra for an unique, optimized solution. This technique for studying aerosol properties would provide data from a new perspective. The investigated aerosols would be nocturnal, from a remote location in the Chilean desert, and this method could be extended into the past decade and other locations. Most current methods use the Sun as the illuminating source to study the aerosols and so with this new nocturnal data set one could compare the two types. Additionally, the aerosols near the observatory are not dominated by local pollution sources and the background aerosols can be better studied. Also, the observatory has been operational for over a decade, and the aerosol data set could be extended into the past, as well as the model can be modified so the technique could be applied to other observatories around the globe. This new method for determining aerosol properties from astronomical observations with our scattered moonlight model could be a promising tool for atmospheric science.

Jones, Amy; Noll, Stefan; Kausch, Wolfgang; Szyszka, Cezary; Kimeswenger, Stefan

2013-04-01

272

Study on method of bacteria image recognition  

Microsoft Academic Search

The thesis brings up a method to identify bacteria automatically. It analyzes the features of microscopy image, proposes a method to identify bacteria from microscope image according to these features. At last it proposes a method based on recursion that can rapidly label connected domain.

Hong-wei Shi; Yao-wu Shi; Yong-guang Yin

2011-01-01

273

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: 40914). 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

274

Herpes simplex virus type 2 and HIV disease progression: a systematic review of observational studies  

PubMed Central

Background Herpes simplex virus type 2 (HSV-2) is a common co-infection among HIV-infected adults that is hypothesized to accelerate HIV disease progression. Methods We searched Medline, EMBASE, relevant conference proceedings (200612) and bibliographies of identified studies without language restriction for cohort studies examining the impact of HSV-2 on highly active antiretroviral therapy-untreated HIV disease in adults. The exposure of interest was HSV-2 seropositivity or clinical/laboratory markers of HSV-2 activity. The primary outcome was HIV disease progression, defined as antiretroviral initiation, development of AIDS/opportunistic infection, or progression to CD4 count thresholds (?200 or ?350 cells/mm3). Secondary outcomes included HIV plasma viral load and CD4 count. Results Seven studies were included. No definitive relationship was observed between HSV-2 seropositivity and time to antiretroviral initiation (n=2 studies), CD4?350 (n=1), CD4?200 (n=1), death (n=1), viral load (n=6) or CD4 count (n=3). Although two studies each observed trends towards accelerated progression to clinical AIDS/opportunistic infection in HSV-2 seropositives, with pooled unadjusted hazard ratio=1.85 (95% CI=1.12,3.06; I2=2%), most OIs observed in the study for which data were available can occur at high CD4 counts and may not represent HIV progression. In contrast, a single study HSV-2 disease activity found that the presence of genital HSV-2 DNA was associated with a 0.4 log copies/mL increase in HIV viral load. Conclusions Despite an observation that HSV-2 activity is associated with increased HIV viral load, definitive evidence linking HSV-2 seropositivity to accelerated HIV disease progression is lacking. The attenuating effects of acyclovir on HIV disease progression observed in recent trials may result both from direct anti-HIV activity as well as from indirect benefits of HSV-2 suppression. PMID:24164861

2013-01-01

275

Theoretical and Observational Studies of the Central Engines of AGN  

NASA Technical Reports Server (NTRS)

In Active Galactic Nuclei (AGN) the luminosity is so intense that the effect of radiation pressure on a particle may exceed the gravitational attraction. It was shown that when such luminosities are reached, relatively cold (not completely ionized) thermal matter clouds may form in the central engines of AGN, where most of the luminosity originates. We show that the spectrum of emission from cold clouds embedded in hot relativistic matter is similar to the observed spectrum. We also show that within the hot relativistic matter, cold matter moves faster than the speed of sound or the Alfven speed, and shocks form. The shocks provide a mechanism by which a localized perturbation can propagate throughout the central engine. The shocked matter can emit the observed luminosity, and can explain the flux and spectral variability. It may also provide an efficient mechanism for the outward transfer of angular momentum and provide the outward flow of winds. With observations from X-ray satellites, emission features from the cold and hot matter may be revealed. Our analysis of X-ray data from the Seyfert 1 galaxy MCG - 6-30-15 over five years using detectors on the Ginga and Rosat satellites, revealed some interesting variable features. A source with hot matter emits non-thermal radiation which is Compton reflected from cold matter and then absorbed by warm (partially ionized) absorbing matter in the first model, which can be fit to the data if both the cold and warm absorbers are near the central engine. An alternative model in which the emission from the hot matter is partially covered by very warm matter (in which all elements except Iron are mostly ionized) is also successful. In this model the cold and warm matter may be at distances of up to 100 times the size of the central engine, well within the region where broad optical lines are produced. The flux variability is more naturally explained by the second model. Our results support the existence of cold matter in, or near, the central engine of MCG -6-30-15. Cold matter in the central engine, and evidence of the effects of shocks, is probably forthcoming with future X-ray satellites.

Sivron, Ran

1995-01-01

276

78 FR 32406 - Submission for OMB Review; 30-Day Comment Request: Women's Health Initiative Observational Study  

Federal Register 2010, 2011, 2012, 2013

...Review; 30-Day Comment Request: Women's Health Initiative Observational Study...Eason Ludlam, Project Officer, Women's Health Initiative Program Office, 6701...writing. Proposed Collection: Women's Health Initiative Observational...

2013-05-30

277

78 FR 24220 - Submission for OMB Review; 30-Day Comment Request: Women's Health Initiative Observational Study  

Federal Register 2010, 2011, 2012, 2013

...Review; 30-Day Comment Request: Women's Health Initiative Observational Study...Eason Ludlam, Project Officer, Women's Health Initiative Program Office, 6701...writing. Proposed Collection: Women's Health Initiative Observational...

2013-04-24

278

Effectiveness of Compounded Bioidentical Hormone Replacement Therapy: An Observational Cohort Study  

Microsoft Academic Search

BackgroundBioidentical Hormone Replacement Therapy (BHRT) is believed it to be a safer and equally effective alternative to Conventional\\u000a Hormone Therapy for the relief of menopausal symptoms; however, data are needed to support these claims. The objective of\\u000a this study is to evaluate the effectiveness of compounded BHRT provided in six community pharmacies.\\u000a \\u000a \\u000a \\u000a \\u000a MethodsThis was an observational cohort study of women

Andres D Ruiz; Kelly R Daniels; Jamie C Barner; John J Carson; Christopher R Frei

2011-01-01

279

Observational studies of early-type binary stars: VV Orionis  

E-print Network

New and previously published observations of the bright eclipsing binary VV Orionis are analyzed. We present new radial velocities and interstellar reddening measurements from high-resolution spectra of this detached, short-period (P=1.48 d) binary. We discuss the validity of prior claims for the existence of a third body and show that our new velocities and light curve solution cast doubt on them. The components of VV Ori are shown to be a B1 V primary with a mass $M{_1}=10.9 \\pm 0.1 M_{\\sun}$ and a radius $R_{1}=4.98 \\pm 0.02 R_{\\sun}$ and a B4.5 V secondary with a mass $M{_2}=4.09 \\pm 0.05 M_{\\sun}$ and a radius $R_{2}=2.41 \\pm 0.01 R_{\\sun}$.

Dirk Terrell; Ulisse Munari; Alessandro Siviero

2006-10-06

280

Disciplinary Culture, Bibliometrics, and Historical Studies: Preliminary Observations.  

ERIC Educational Resources Information Center

Discusses bibliometrics and its relationship to historical studies in order to examine community formation of scientific and scholarly communication through institutional affiliation. A history journal is investigated and reveals an institutional and geographical mapping of the contributors. (Author/LRW)

Buchanan, Anne L.; Herubel, Jean-Pierre V. M.

1997-01-01

281

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

282

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

283

Changes in smoking behaviours following a smokefree legislation in parks and on beaches: an observational study  

PubMed Central

Objective To examine the effect of an outdoor smokefree law in parks and on beaches on observed smoking in selected venues. Methods The study involved repeated observations in selected parks and beaches in Vancouver, British Columbia, Canada. The main outcome measure was changes in observed smoking rates in selected venues from prelaw to 12 months postlaw. Results No venue was 100% smokefree at the 12-month postlaw observation time point. There was a significant decrease in observed smoking rates in all venues from prelaw to 12-month postlaw (prelaw mean smoking rate=20.5 vs 12-month mean smoking rate=4.7, p=0.04). In stratified analysis by venue, the differences between the prelaw and 12-month smoking rates decreased significantly in parks (prelaw mean smoking rate=37.1 vs 12-month mean smoking rate=6.5, p=0.01) but not in beaches (prelaw mean smoking rate=2.9 vs 12-month mean smoking rate=1.0, p=0.1). Conclusions Smokefree policies in outdoor recreational venues have the potential to decrease smoking in these venues. The effectiveness of such policies may differ by the type and usage of the venue; for instance, compliance may be better in venues that are used more often and have enforcement. Future studies may further explore factors that limit and foster the enforcement of such policies in parks and beaches. PMID:23794560

Okoli, Chizimuzo; Johnson, Andrew; Pederson, Ann; Adkins, Sarah; Rice, Wendy

2013-01-01

284

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

285

Comparison of direct observational methods for measuring stereotypic behavior in children with autism spectrum disorders.  

PubMed

We compared partial-interval recording (PIR) and momentary time sampling (MTS) estimates against continuous measures of the actual durations of stereotypic behavior in young children with autism or pervasive developmental disorder-not otherwise specified. Twenty-two videotaped samples of stereotypy were scored using a low-tech duration recording method, and relative durations (i.e., proportions of observation periods consumed by stereotypy) were calculated. Then 10, 20, and 30s MTS and 10s PIR estimates of relative durations were derived from the raw duration data. Across all samples, PIR was found to grossly overestimate the relative duration of stereotypy. Momentary time sampling both over- and under-estimated the relative duration of stereotypy, but with much smaller errors than PIR (Experiment 1). These results were replicated across 27 samples of low, moderate and high levels of stereotypy (Experiment 2). PMID:15026089

Gardenier, Nicole Ciotti; MacDonald, Rebecca; Green, Gina

2004-01-01

286

A dynamic scheduling method of Earth-observing satellites by employing rolling horizon strategy.  

PubMed

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

287

Method for calculating and observing microwave absorption by a sphere in a single mode rectangular cavity  

NASA Technical Reports Server (NTRS)

A new theory of microwave absorption by a lossy dielectric sphere in a single mode rectangular cavity has been recently developed. The absorption was treated in the framework of an electromagnetic scattering problem. That theory is summarized here and calculated results that bear on optimizing the processing of materials are illustrated. Methods for observing power absorption and other results predicted by the scattering model are discussed. Cavity perturbation theory provides a bridge between theoretical calculations and experimental observations, and a special problem that arises when an established version of cavity perturbation theory is applied to spheres is identified, analyzed, and resolved. The direct problem of predicting shifts in frequency and Q from model calculations is discussed for a sphere in a cavity when the sphere's complex dielectric constant is known. Also, the inverse problem of determining the complex dielectric constants from measured values of those shifts is considered. The small sphere limit, where an electrostatic or quasistatic model is valid, is treated in detail, and planned work on parallel problems for larger spheres is described.

Jackson, H. W.; Barmatz, M.

1991-01-01

288

Computational methods for inverse problems in geophysics: inversion of travel time observations  

USGS Publications Warehouse

General ways of solving various inverse problems are studied for given travel time observations between sources and receivers. These problems are separated into three components: (a) the representation of the unknown quantities appearing in the model; (b) the nonlinear least-squares problem; (c) the direct, two-point ray-tracing problem used to compute travel time once the model parameters are given. Novel software is described for (b) and (c), and some ideas given on (a). Numerical results obtained with artificial data and an implementation of the algorithm are also presented. ?? 1980.

Pereyra, V.; Keller, H. B.; Lee, W. H. K.

1980-01-01

289

Complicated intra-abdominal infections in a worldwide context: an observational prospective study (CIAOW Study)  

PubMed Central

Despite advances in diagnosis, surgery, and antimicrobial therapy, mortality rates associated with complicated intra-abdominal infections remain exceedingly high. The World Society of Emergency Surgery (WSES) has designed the CIAOW study in order to describe the clinical, microbiological, and management-related profiles of both community- and healthcare-acquired complicated intra-abdominal infections in a worldwide context. The CIAOW study (Complicated Intra-Abdominal infection Observational Worldwide Study) is a multicenter observational study currently underway in 57 medical institutions worldwide. The study includes patients undergoing surgery or interventional drainage to address complicated intra-abdominal infections. This preliminary report includes all data from almost the first two months of the six-month study period. Patients who met inclusion criteria with either community-acquired or healthcare-associated complicated intra-abdominal infections (IAIs) were included in the study. 702 patients with a mean age of 49.2 years (range 1898) were enrolled in the study. 272 patients (38.7%) were women and 430 (62.3%) were men. Among these patients, 615 (87.6%) were affected by community-acquired IAIs while the remaining 87 (12.4%) suffered from healthcare-associated infections. Generalized peritonitis was observed in 304 patients (43.3%), whereas localized peritonitis or abscesses was registered in 398 (57.7%) patients. The overall mortality rate was 10.1% (71/702). The final results of the CIAOW Study will be published following the conclusion of the study period in March 2013. PMID:23286785

2013-01-01

290

Observational Studies of Early-type Overcontact Binaries: TU Muscae  

E-print Network

We present new spectroscopic and photometric data on the early-type overcontact binary TU Muscae. The analysis of the spectroscopic data shows that the line of sight to the system crosses three kinematically sharp and well-separated interstellar reddening sources and that the stars rotate synchronously. We present new radial velocities that are in good agreement with earlier optical velocities and, thus, do not confirm the systematically smaller velocities obtained from IUE spectra. The optical velocities are analyzed simultaneously with the photometric data to derive accurate absolute dimesions for the binary components.The results show that TU Mus consists of an O7.5 primary with M_1=23.5 +/- 0.8 M_sun, R_1=7.48 +/- 0.08 R_sun and an O9.5 secondary with M_2=15.3 +/- 0.4 M_sun, R_2=6.15 +/- 0.07 R_sun in an overcontact configuration and that the orbital period has remained constant over the three decades covered by the observations. These results might imply that the mass transfer seen in late-type overcontact binaries does not occur in their early-type counterparts.

Dirk Terrell; Ulisse Munari; Tomaz Zwitter; Robert Nelson

2003-09-12

291

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

292

ORD BEST PRACTICES FOR OBSERVATIONAL HUMAN EXPOSURE MEASUREMENT STUDIES  

EPA Science Inventory

This abstract describes a presentation for the 2007 Society of Toxicology Annual Meeting in Charlotte, NC on March 27, 2007. It will be included in a special Issues Session titled "Scientific and Ethical Considerations in Human Exposure Studies." The presentation desc...

293

Amplification of Sensitivity Analysis in Matched Observational Studies  

E-print Network

. The study asked whether greater intensity of chemotherapy for ovarian cancer was beneficial to patients in terms of survival, or whether it simply increased toxicity. Outside of clinical trials, where treatments of randomized clinical trials. Is there a source of variation in the intensity of chemotherapy

Rosenbaum, Paul R.

294

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

295

Predicting Three Dimensions of Residential Curbside Recycling: An Observational Study.  

ERIC Educational Resources Information Center

Three dependent variables of household recycling behavior were studied in a suburban community over eight weeks, 10 independent variables serving as predictors. Results indicate that many of the independent variables that predicted recycling behavior in past research have weaker relationships in current, more convenient curbside programs.

Oskamp, Stuart; Burkhardt, Rachel L.; Schultz, P. Wesley; Hurin, Sharrilyn; Zelezny, Lynnette

1998-01-01

296

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...

297

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

298

Motorcycle Helmet Use in Southern China: An Observational Study  

Microsoft Academic Search

Objective. In China, despite national motorcycle helmet legislation and the known safety benefits of helmets, helmet use remains low. The aim of this study was to determine the rate of motorcycle helmet use and attitudes towards helmet use among drivers and passengers in two cities in Southern China to provide baseline data and scientific evidence for the formulation of an

Gong-li Li; Li-ping Li; Qi-en Cai

2008-01-01

299

Comparison of Pooled Risk Estimates for Adverse Effects from Different Observational Study Designs: Methodological Overview  

PubMed Central

Background A diverse range of study designs (e.g. case-control or cohort) are used in the evaluation of adverse effects. We aimed to ascertain whether the risk estimates from meta-analyses of case-control studies differ from that of other study designs. Methods Searches were carried out in 10 databases in addition to reference checking, contacting experts, and handsearching key journals and conference proceedings. Studies were included where a pooled relative measure of an adverse effect (odds ratio or risk ratio) from case-control studies could be directly compared with the pooled estimate for the same adverse effect arising from other types of observational studies. Results We included 82 meta-analyses. Pooled estimates of harm from the different study designs had 95% confidence intervals that overlapped in 78/82 instances (95%). Of the 23 cases of discrepant findings (significant harm identified in meta-analysis of one type of study design, but not with the other study design), 16 (70%) stemmed from significantly elevated pooled estimates from case-control studies. There was associated evidence of funnel plot asymmetry consistent with higher risk estimates from case-control studies. On average, cohort or cross-sectional studies yielded pooled odds ratios 0.94 (95% CI 0.881.00) times lower than that from case-control studies. Interpretation Empirical evidence from this overview indicates that meta-analysis of case-control studies tend to give slightly higher estimates of harm as compared to meta-analyses of other observational studies. However it is impossible to rule out potential confounding from differences in drug dose, duration and populations when comparing between study designs. PMID:23977151

Golder, Su; Loke, Yoon K.; Bland, Martin

2013-01-01

300

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

301

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

302

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

303

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

SciTech Connect

Kohn-Sham density functional theory (DFT) is a powerful, well-established tool for the study of condensed phase electronic structure. However, there are still a number of situations where its applicability is limited. The basic theme of our research is the development of first principles electronic structure approaches for condensed matter that goes beyond what can currently be done with standard implementations ofKohn-Sham DFT. Our efforts to this end have focused on two classes or' methods. The first addresses the well-lmown inability of DFT to handle strong, many-body electron correlation effects. Our approach is a DFT -based embedding theory, to treat localized features (e.g. impurity, adsorbate, vacancy, etc.) embedded in a periodic, metallic crystal. A description for the embedded region is provided by explicitly correlated, ab initio wave function methods. DFT, as a fo1n1ally ground state theory, does not give a good description of excited states; an additional feature of our approach is the ability to obtain excitations localized in this region. We apply our method to a first-principles study of the adsorption of a single magnetic Co ada tom on non-magnetic Cu( 111 ), a known Kondo system whose behavior is governed by strong electron correlation. ? The second class of methods that we are developing is an orbital-free density functional theory (OFDFT), which addresses the speed limitations ofKohn-Sham DFT. OFDFT is a powerful, O(N) scaling method for electronic structure calculations. Unlike Kohn-Sham DFT, OFDFT goes back to the original Hohenberg-Kohn idea of directly optimizing an energy functional which is an explicit functional of the density, without invoking an orbital description. This eliminates the need to manipulate orbitals, which leads to O(N{sup 3}) scaling in the Kahn-Sham approach. The speed of OFDFT allows direct electronic structure calculations on large systems on the order of thousands to tens of thousands of atoms, an expensive feat within Kohn-Sham. Due to our incomplete knowledge of the exact, universal energy density functional, this speedup comes at the cost of some accuracy with respect to Kohn-Sham methods. However, OFDFT has been shown to be remarkably accurate with respect to Kohn-Sham when used in the study of nearly-free-electron-like metals, e.g., AI, for which good density functionals have been derived. Examples of past applications of OFDFT include the prediction of properties of bulk crystals, surfaces, vacancies, vacancy clusters, nanoclusters, and dislocations, as well as OFDFT -based multiscale simulations of nanoindentation in AI and Al-Mg alloys.

Carter, Emily A

2013-02-02

304

Physical and dynamical studies of meteors. [radar observation of fragmentation  

NASA Technical Reports Server (NTRS)

Distribution of meteors in streams detected in the synoptic-year meteor sample plus a study of the fragmentation characteristics of the synoptic-year meteor sample are presented. Population coefficients and dispersion coefficients were determined for each meteor stream. These two parameters serve to determine the number of definite members of the stream in the sample used, and to estimate the actual space density of meteor streams. From results of the fragmentation study, it appears that the main body of most radar meteors does not ablate fragments layer by layer, but collapses rather suddenly under dynamic pressures on the order of 0,0002 dynes/cm. Furthermore, it is believed that fragmentation does not cause a serious selection effect in the radar meteor data.

Southworth, R. B.; Sekanina, Z.

1974-01-01

305

Study of parity violating observables in few-nucleon systems  

SciTech Connect

Parity violation in few-nucleon systems is studied using a nucleon-nucleon parity-violating (PV) potential derived within an effective field theory framework at next-to-next-to-leading order. The potential includes one- and two-pion exchanges, contact interactions and relativistic corrections and depends on six low-energy constants: the pion-nucleon coupling constant h{sup 1}{sub {pi}} and five parameters multiplying the independent contact interaction terms (with one four-gradient). This potential is used to study the {vec p}-p longitudinal asymmetry, the neutron spin rotation in {vec n}-d scattering, and the longitudinal asymmetry in the {sup 3}He({vec n},p){sup 3}H reaction.

M. Viviani, A. Baroni, R. Schiavilla, L. Girlanda, A. Kievsky, L. E. Marcucci

2011-12-01

306

Statistical study of EMIC waves using Cluster observations  

NASA Astrophysics Data System (ADS)

The Electromagnetic Ion Cyclotron (EMIC) wave is an important instability in magnetospheric dynamics. It is responsible for efficiently scattering high-energy electrons into the loss cone. The minimum energy for effective scattering depends on the wavenumber, which can be determined from the EMIC dispersion relation using the phase differencing technique. This study analyses EMIC waves in Cluster data to statistically determine the minimum resonant energy for a range of magnetospheric conditions.

Pakhotin, Ivan; Balikhin, Michael A.; Silin, Illia

307

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

308

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...

309

Using action observation to study superior motor performance: a pilot fMRI study  

PubMed Central

The most efficient way to acquire motor skills may be through physical practice. Nevertheless, it has also been shown that action observation may improve motor performance. The aim of the present pilot study was to examine a potential action observation paradigm used to (1) capture the superior performance of expert athletes and (2) capture the underlying neural mechanisms of successful action observation in relation to task experience. We used functional magnetic resonance imaging to measure regional blood flow while presenting videos of a hockey player shooting a puck toward a hockey goal. The videos (a total of 120) where stopped at different time frames with different amount of information provided, creating a paradigm with three different levels of difficulty to decide the fate of a shot. Since this was only a pilot study, we first tested the paradigm behaviorally on six elite expert hockey players, five intermediate players, and six non-hockey playing controls. The results showed that expert hockey players were significantly (p < 0.05) more accurate on deciding the fate of the action compared to the others. Thus, it appears as if the paradigm can capture superior performance of expert athletes (aim 1). We then tested three of the hockey players and three of the controls on the same paradigm in the MRI scanner to investigate the underlying neural mechanisms of successful action anticipation. The imaging results showed that when expert hockey players observed and correctly anticipated situations, they recruited motor and temporal regions of the brain. Novices, on the other hand, relied on visual regions during observation and prefrontal regions during action decision. Thus, the results from the imaging data suggest that different networks of the brain are recruited depending on task experience (aim 2). In conclusion, depending on the level of motor skill of the observer, when correctly anticipating actions different neural systems will be recruited. PMID:24348365

Olsson, Carl-Johan; Lundstrom, Peter

2013-01-01

310

On a method of extended observations of the spectrum of plasma instabilities in the electrojet  

NASA Astrophysics Data System (ADS)

Because past investigations of the equatorial electrojet with backscatter radars have limited K spectrum studies to oblique angles at different locations and relatively short wavelengths, a method has been devised which employs only one station but takes advantage of the radio rays' reflections from the F-layer and the ground surface. Different wave vectors K can be detected at the same location in the instability layer, using backscatter and forwardscatter propagations, and the K spectrum investigation can be extended to horizontal and long wavelength instabilities. The wavenumber spectrum can be explored even at very long wavelengths, to about 100 m, using only one HF radar frequency through forwardscatter mode exploration. Experimental results obtained in Ethiopia at 7.25 and 14.2 MHz are presented, and several modes are identified in agreement with the method's predictions.

Crochet, M.; Hanuise, C.

1981-08-01

311

Primary reperfusion in acute right ventricular infarction: An observational study  

PubMed Central

AIM: To investigate the impact of primary reperfusion therapy (RT) on early and late mortality in acute right ventricular infarction (RVI). METHODS: RVI patients (n = 679) were prospectively classified as without right ventricular failure (RVF) (class A, n = 425, 64%), with RVF (class B, n = 158, 24%) or with cardiogenic shock (CS) (class C, n = 96, 12%). Of the 679 patients, 148 (21.7%) were considered to be eligible for thrombolytic therapy (TT) and 351 (51.6%) for primary percutaneous coronary intervention (PPCI). TIMI 3-flow by TT was achieved for A, B and C RVI class in 65%, 64% and 0%, respectively and with PPCI in 93%, 91% and 87%, respectively. RESULTS: For class A without RT, the mortality rate was 7.9%, with TT was reduced to 4.4% (P < 0.01) and with PPCI to 3.2% (P < 0.01). Considering TT vs PPCI, PPCI was superior (P < 0.05). For class B without RT the mortality was 27%, decreased to 13% with TT (P < 0.01) and to 8.3% with PPCI (P < 0.01). In a TT and PPCI comparison, PPCI was superior (P < 0.01). For class C without RT the in-hospital mortality was 80%, with TT was 100% and with PPCI, the rate decreased to 44% (P < 0.01). At 8 years, the mortality rate without RT for class A was 32%, for class B was 48% and for class C was 85%. When PPCI was successful, the long-term mortality was lower than previously reported for the 3 RVI classes (A: 21%, B: 38%, C: 70%; P < 0.001). CONCLUSION: PPCI is superior to TT and reduces short/long-term mortality for all RVI categories. RVI CS patients should be encouraged to undergo PPCI at a specialized center. PMID:24527184

Lupi-Herrera, Eulo; Gonzlez-Pacheco, Hctor; Jurez-Herrera, rsulo; Espinola-Zavaleta, Nilda; Chuquiure-Valenzuela, Eduardo; Villavicencio-Fernndez, Ramn; Pea-Duque, Marco Antonio; Ban-Hayashi, Ernesto; Frez-Santander, Sergio

2014-01-01

312

In Vitro Cercariae Transformation: Comparison of Mechanical and Nonmechanical Methods and Observation of Morphological Changes of Detached Cercariae Tails  

PubMed Central

Schistosomula, the larval stage of schistosomes in vertebrate hosts, are highly vulnerable and considered an ideal target for vaccine and drug development. Although the schistosomule stage is essential for biological studies, collecting sufficient numbers of schistosomula from their definitive hosts in vivo is difficult to accomplish. However, in vitro collection via cercariae transformation can effectively yield high numbers of schistosomula. We compared a current and widely used double-endedneedle mechanical transformation method to a culture medium based on a nonmechanical method. We found the rates of transformed cercariae, i.e., separated cercariae heads from tails, differed by only 27% at 0.5, 1, and 2 days in culture and that there was no significant difference in the number of transformed cercariae between the transformation methods at 3 and 4 days in culture. Notably, the mechanical and nonmechanical cercariae transformation methods both yielded significantly large and similar quantities of viable schistosomula. Given that the nonmechanical method is simpler and less damaging to the parasites, we recommend the use of it as an alternative way for in vitro cercariae transformation. In addition, we also observed morphological changes of the detached cercariae tails in culture medium. Interestingly, the tails are able to regenerate head-like organs/tissues and survive for at least 4 days. This intriguing change suggests unique biological features of the cells in the tails. PMID:22519732

Coultas, Kristen A.; Zhang, Si-Ming

2013-01-01

313

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

314

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

315

Observational Studies of Protoplanetary Disks at Mid-Infrared Wavelengths  

NASA Astrophysics Data System (ADS)

We have used mid-infrared cameras on 8-to-10 m class telescopes to study the properties of young circumstellar disks. During the initial phases of this program we examined a large sample of mid-IR images of standard stars delivered by T-ReCS at Gemini South to evaluate its on-sky performance as characterized by, for example the angular resolution, the PSF shape, and the PSF temporal stability, properties that are most relevant to our high-angular resolution study of disks. With this information we developed an Interactive Data Language (IDL) package of routines optimized for reducing the data and correcting for image defects commonly seen in ground-based mid-IR data. We obtained, reduced, and analyzed mid-IR images and spectra of several Herbig Ae/Be disks (including HD 259431, MWC 1080, VV Ser) and the debris disk (? Pic), and derived their physical properties by means of radiative transfer modeling or spectroscopic decomposition and analyses. These results are highlighted here. During this study, we also helped commission CanariCam, a new mid-IR facility instrument built by the University of Florida for the 10.4 m Gran Telescopio Canarias (GTC) on La Palma, Canary Islands, Spain. CanariCam is an imager with spectroscopic, polarimetric, and coronagraphic capabilities, with the dual-beam polarimetry being a unique mode introduced with CanariCam for the first time to a 10 m telescope at mid-IR wavelengths. It is well known that measurements of polarization, originating from aligned dust grains in the disks and their environments, have the potential to shed light on the morphologies of the magnetic fields in these regions, information that is critical to understanding how stars and planets form. We have obtained polarimetric data of several Herbig Ae/Be disks and YSOs, and the data reduction and analyses are in process. We present preliminary results here. This poster is based upon work supported by the NSF under grant AST-0903672 and AST-0908624 awarded to C.M.T.

Li, Dan; Telesco, Charles; Wright, Christopher; Packham, Christopher; Marinas, Naibi

2013-07-01

316

Multi-component power spectra estimation method for multi-detector observations of the Cosmic Microwave Background  

E-print Network

We present a new method for multi-component power spectra estimation in multi-frequency observations of the CMB. Our method is based on matching a model to the cross and auto power spectra of observed maps. All the component power spectra are estimated, as well as their mixing matrix. Noise power spectra are also estimated. The method has been applied to full-sky Planck simulations containing five astrophysical components and white noise. The beam smoothing effect is taken into account.

Guillaume Patanchon

2003-11-13

317

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

318

Offshore observations of eastern red bats (Lasiurus borealis) in the Mid-Atlantic United States using multiple survey methods.  

PubMed

Little is known about the migration and movements of migratory tree-roosting bat species in North America, though anecdotal observations of migrating bats over the Atlantic Ocean have been reported since at least the 1890s. Aerial surveys and boat-based surveys of wildlife off the Atlantic Seaboard detected a possible diurnal migration event of eastern red bats (Lasiurus borealis) in September 2012. One bat was sighted approximately 44 km east of Rehoboth Beach, Delaware during a boat-based survey. Eleven additional bats were observed between 16.9 and 41.8 km east of New Jersey, Delaware, and Virginia in high definition video footage collected during digital aerial surveys. Observations were collected incidentally as part of a large baseline study of seabird, marine mammal, and sea turtle distributions and movements in the offshore environment. Digital survey methods also allowed for altitude estimation for several of these bats at >100 m above sea level. These observations provide new evidence of bat movements offshore, and offer insight into their flight heights above sea level and the times of day at which such migrations may occur. PMID:24367614

Hatch, Shaylyn K; Connelly, Emily E; Divoll, Timothy J; Stenhouse, Iain J; Williams, Kathryn A

2013-01-01

319

Cruciferous vegetables intake and the risk of colorectal cancer: a meta-analysis of observational studies  

PubMed Central

Background Epidemiological studies have reported inconsistent associations between cruciferous vegetable (CV) intake and colorectal cancer (CRC) risk. To our knowledge, a comprehensive and quantitative assessment of the association between CV intake and CRC has not been reported. Methods Relevant articles were identified by searching MEDLINE. We pooled the relative risks (RR) from individual studies using a random-effect model and carried out heterogeneity and publication bias analyses. Results Twenty-four casecontrol and 11 prospective studies were included in our analysis. When all studies were pooled, we yielded a significantly inverse association between CV (RR: 0.82; 95% confidence interval 0.750.90) intake and CRC risk. Specific analysis for cabbage and broccoli yielded similar result. When separately analyzed, casecontrol studies of CV intake yield similar results, and the results from the prospective studies showed borderline statistical significance. Moreover, significant inverse associations were also observed in colon cancer and its distal subsite both among prospective and casecontrol studies. Conclusions Findings from this meta-analysis provide evidence that high intake of CV was inversely associated with the risk of CRC and colon cancer in humans. Further analysis on other specific CV, food preparation methods, stratified results by anatomic cancer site, and subsite of colon cancer should be extended in future study. PMID:23211939

Wu, Q. J.; Yang, Y.; Vogtmann, E.; Wang, J.; Han, L. H.; Li, H. L.; Xiang, Y. B.

2013-01-01

320

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

321

Comparative study of two commercially pure titanium casting methods  

PubMed Central

The interest in using titanium to fabricate removable partial denture (RPD) frameworks has increased, but there are few studies evaluating the effects of casting methods on clasp behavior. Objective This study compared the occurrence of porosities and the retentive force of commercially pure titanium (CP Ti) and cobalt-chromium (Co-Cr) removable partial denture circumferential clasps cast by induction/centrifugation and plasma/vacuum-pressure. Material and Methods 72 frameworks were cast from CP Ti (n=36) and Co-Cr alloy (n=36; control group). For each material, 18 frameworks were casted by electromagnetic induction and injected by centrifugation, whereas the other 18 were casted by plasma and injected by vacuum-pressure. For each casting method, three subgroups (n=6) were formed: 0.25 mm, 0.50 mm, and 0.75 mm undercuts. The specimens were radiographed and subjected to an insertion/removal test simulating 5 years of framework use. Data were analyzed by ANOVA and Tukey's to compare materials and cast methods (?=0.05). Results Three of 18 specimens of the induction/centrifugation group and 9 of 18 specimens of plasma/vacuum-pressure cast presented porosities, but only 1 and 7 specimens, respectively, were rejected for simulation test. For Co-Cr alloy, no defects were found. Comparing the casting methods, statistically significant differences (p<0.05) were observed only for the Co-Cr alloy with 0.25 mm and 0.50 mm undercuts. Significant differences were found for the 0.25 mm and 0.75 mm undercuts dependent on the material used. For the 0.50 mm undercut, significant differences were found when the materials were induction casted. Conclusion Although both casting methods produced satisfactory CP Ti RPD frameworks, the occurrence of porosities was greater in the plasma/vacuum-pressure than in the induction/centrifugation method, the latter resulting in higher clasp rigidity, generating higher retention force values. PMID:21085805

RODRIGUES, Renata Cristina Silveira; FARIA, Adriana Claudia Lapria; ORSI, Iara Augusta; de MATTOS, Maria da Gloria Chiarello; MACEDO, Ana Paula; RIBEIRO, Ricardo Faria

2010-01-01

322

The young stellar population of NGC 4214 as observed with HST. I. Data and methods  

E-print Network

We present the data and methods that we have used to perform a detailed UV-optical study of the nearby dwarf starburst galaxy NGC 4214 using multifilter HST/WFPC2+STIS photometry. We explain the process followed to obtain high-quality photometry and astrometry of the stellar and cluster populations of this galaxy. We describe the procedure used to transform magnitudes and colors into physical parameters using spectral energy distributions. The data show the existence of both young and old stellar populations that can be resolved at the distance of NGC 4214 (2.94 Mpc) and we perform a general description of those populations.

Leonardo beda; J. Maz-Apellniz; John MacKenty

2007-08-26

323

Heavy metals and neurodegenerative diseases: an observational study.  

PubMed

In this study, we evaluated the levels of some of the most investigated metals (Cu, Se, Zn, Pb, and Hg) in the blood of patients affected by the most common chronic neurodegenerative diseases like Alzheimer's disease (AD) and multiple sclerosis (MS), in order to better clarify their involvement. For the first time, we investigated a Sicilian population living in an area exposed to a potentially contaminated environment from dust and fumes of volcano Etna and consumer of a considerable quantity of fish in their diet, so that this represents a good cohort to demonstrate a possible link between metals levels and development of neurodegenerative disorders. More specifically, 15 patients affected by AD, 41 patients affected by MS, 23 healthy controls, and 10 healthy elderly controls were recruited and subjected to a venous blood sampling. Quantification of heavy metals was performed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). This technique has allowed us to establish that there is a concomitance of heavy metal unbalance associated with AD more than in other neurodegenerative pathologies, such as MS. Also, we can assess that the concentration of these elements is independent from the diet, especially from occasional or habitual consumption of fruits and vegetables, prevalence in the diet of meat or fish, possible exposure to contaminated environment due both to the occupation and place of residence. PMID:25107328

Giacoppo, Sabrina; Galuppo, Maria; Calabr, Rocco Salvatore; D'Aleo, Giangaetano; Marra, Angela; Sessa, Edoardo; Bua, Daniel Giuseppe; Potort, Angela Giorgia; Dugo, Giacomo; Bramanti, Placido; Mazzon, Emanuela

2014-11-01

324

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

325

A Observational Study of Mixing in the Arctic Winter Stratosphere.  

NASA Astrophysics Data System (ADS)

Dynamic isolation of the winter Arctic circumpolar vortex is studied using analyzed winds derived from geopotential height fields. Isentropic trajectories are calculated for assemblages of particles initialized on uniform latitude -longitude grids. Transport across isolines of Ertel potential vorticity (PV) is used to characterize the mixing processes of ejection of vortex air and entrainment of midlatitude air into the vortex. During January and February a barrier to mixing, where exchange of air is inhibited, typically forms near the vortex boundary. At 450 K, transport across the barrier is predominantly in the form of thin filaments of particles ejected from the vortex. These filaments tend to wrap around the vortex, creating a layered structure of vortex and midlatitude air at the vortex edge. Near or total splits of the vortex into two or more distinct vortex fragments are quite common based on these trajectory calculations. Significant entrainment deep into the vortex is rare and results from only a limited number of the splitting events. During December and March the mixing barrier is less evident due to nonconservative factors during the spin-up and breakdown of the vortex, respectively. In December both ejection and entrainment are only weakly inhibited by the mixing barrier. Exchange in March is dominated by ejection of air from the vortex. Isolation of the vortex during 1991-1992 through 1993-1994 (the first three northern hemisphere winters of the UARS mission) is compared to the climatological values obtained from the analysis of 16 Arctic winters. A number of unusual features of both winters are discussed. The most notable features are the anomalous isolation experienced by the vortex during December 1992 and the unusual degree of isolation and persistence of the vortex during February and March of both years. The 1992-1993 winter season is the most consistently isolated vortex on record. Only during January 1993, when entrainment is large, is this pattern of extreme isolation broken.

Dahlberg, Steven Paul

1995-01-01

326

Comparative study of the geostatistical ore reserve estimation method over the conventional methods  

Microsoft Academic Search

Part I contains a comprehensive treatment of the comparative study of ; the geostatistical ore reserve estimation method over the conventional methods. ; The conventional methods chosen for comparison were: (a) the polygon method, (b) ; the inverse of the distance squared method, and (c) a method similar to (b) but ; allowing different weights in different directions. Briefly, the

Y. C. Kim; H. P. Knudsen

1975-01-01

327

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

328

75 FR 3237 - Proposed Collection; Comment Request; Women's Health Initiative Observational Study  

Federal Register 2010, 2011, 2012, 2013

...addition, the observational study will complement the clinical...Individuals or households and health care providers. Type...Observational Study Participants...941 1 .083 79 Health Care Providers \\1...appropriate automated, electronic, mechanical, or...

2010-01-20

329

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

330

Postoperative cognitive deficit after cardiopulmonary bypass with preserved cerebral oxygenation: a prospective observational pilot study  

Microsoft Academic Search

BackgroundNeurologic deficits after cardiac surgery are common complications. Aim of this prospective observational pilot study was\\u000a to investigate the incidence of postoperative cognitive deficit (POCD) after cardiac surgery, provided that relevant decrease\\u000a of cerebral oxygen saturation (cSO2) is avoided during cardiopulmonary bypass.\\u000a \\u000a \\u000a \\u000a \\u000a MethodscSO2 was measured by near infrared spectroscopy in 35 patients during cardiopulmonary bypass. cSO2 was kept above 80%

Axel Fudickar; Snke Peters; Claudia Stapelfeldt; Gtz Serocki; Jrn Leiendecker; Patrick Meybohm; Markus Steinfath; Berthold Bein

2011-01-01

331

Fibrin sealant in inguinal hernioplasty: an observational multicentre study in 1,201 patients  

Microsoft Academic Search

PurposeA prospective, multicentre, observational study was undertaken to assess Tisseel fibrin sealant for atraumatic mesh fixation in inguinal hernia repair throughout France.\\u000a \\u000a \\u000a \\u000a MethodsSurgeons recorded data on patients undergoing tension-free inguinal hernioplasty with mesh fixation with Tisseel, regardless of the hernioplasty technique used. Assessments were made at 2days and 1month after surgery. Data on local\\u000a complications, operation times and ease of

B. Descottes; M. Bagot dArc

2009-01-01

332

Effects of anorexia on mortality among older adults receiving home care: An observational study  

Microsoft Academic Search

PurposeWe describe the prevalence of secondary anorexia in a population of older people living in community and receiving home care.\\u000a In addition, we examined the relationship between secondary anorexia and mortality.\\u000a \\u000a \\u000a \\u000a \\u000a MethodsWe analyzed data from a large collaborative observational study group, the Italian Silver Network Home Care project, that\\u000a collected data on patients admitted to home care programs. A total

Francesco Landi; R. Liperoti; F. Lattanzio; A. Russo; M. Tosato; C. Barillaro; R. Bernabei; G. Onder

333

Seismic Study of The Solar Interior: Inferences from SOI/MDI Observations during Solar Activity  

NASA Technical Reports Server (NTRS)

The principal investigator describes several types of solar research conducted during the reporting period and gives a statement of work to be performed in the following year. Research conducted during the reporting period includes: exhaustive analysis of observational and instrumental effects that might cause systematic errors in the characterization of high-degree p-modes; study of the structure, asphericity and dynamics of the solar interior from p-mode frequencies and frequency splittings; characterizing the solar rotation; Time-Distance inversion; and developing and using a new peak-fitting method for very long MDI time series at low degrees.

Korzennik, Sylvain G.

2003-01-01

334

A Method to Simulate the Observed Surface Properties of Proton Irradiated Silicon Strip Sensors  

E-print Network

During the scheduled high luminosity upgrade of LHC, the world's largest particle physics accelerator at CERN, the position sensitive silicon detectors installed in the vertex and tracking part of the CMS experiment will face more intense radiation environment than the present system was designed for. To upgrade the tracker to required performance level, extensive measurements and simulations studies have already been carried out. A defect model of Synopsys Sentaurus TCAD simulation package for the bulk properties of proton irradiated devices has been producing simulations closely matching with measurements of silicon strip detectors. However, the model does not provide expected behavior due to the fluence increased surface damage. The solution requires an approach that does not affect the accurate bulk properties produced by the proton model, but only adds to it the required radiation induced properties close to the surface. These include the observed position dependency of the strip detector's charge collec...

Peltola, Timo; Dalal, Ranjeet; Eber, Robert; Eichhorn, Thomas; Lalwani, Kavita; Messineo, Alberto; Printz, Martin; Ranjan, Kirti

2014-01-01

335

Methods for Composing Tradeoff Studies under Uncertainty  

E-print Network

subsystem-level tradeoff studies under uncertainty into mathematically valid system-level tradeoff studies and efficiently eliminate inferior alternatives through intelligent sampling. The approaches are based on three key ideas: the use of stochastic...

Bily, Christopher

2012-10-19

336

Periodontal Disease and Risk of Chronic Obstructive Pulmonary Disease: A Meta-Analysis of Observational Studies  

PubMed Central

Background Many epidemiological studies have found a positive association between periodontal disease (PD) and risk of chronic obstructive pulmonary disease (COPD), but this association is varied and even contradictory among studies. We performed a meta-analysis to ascertain the relationship between PD and COPD. Methods PubMed and Embase database were searched up to January 10, 2012, for relevant observational studies on the association between PD and risk of COPD. Data from the studies selected were extracted and analyzed independently by two authors. The meta-analysis was performed using the Comprehensive Meta-Analysis software. Results Fourteen observational studies (one nested case-control, eight case-control, and five cross-sectional) involving 3,988 COPD patients were yielded. Based on random-effects meta-analysis, a significant association between PD and COPD was identified (odds ratio?=?2.08, 95% confidence interval?=?1.482.91; P<0.001), with sensitivity analysis showing that the result was robust. Subgroups analyses according to study design, ethnicity, assessment of PD/COPD, and adjusted/unadjusted odds ratios also revealed a significant association. Publication bias was detected. Conclusions Based on current evidence, PD is a significant and independent risk factor of COPD. However, whether a causal relationships exists remains unclear. Morever, we suggest performing randomized controlled trails to explore whether periodontal interventions are beneficial in regulating COPD pathogenesis and progression. PMID:23094025

Zeng, Xian-Tao; Tu, Ming-Li; Liu, Dong-Yan; Zheng, Dong; Zhang, Jing; Leng, WeiDong

2012-01-01

337

Periodontal Disease and Risk of Head and Neck Cancer: A Meta-Analysis of Observational Studies  

PubMed Central

Background Many epidemiological studies have found a positive association of periodontal disease (PD) with risk of head and neck cancer (HNC), but the findings are varied or even contradictory. In this work, we performed a meta-analysis to ascertain the relationship between PD and HNC risk. Methods We searched the PubMed, Embase, and Cochrane Library databases for relevant observational studies on the association between PD and HNC risk published up to March 23, 2013. Data from the included studies were extracted and analyzed independently by two authors. Meta-analysis was performed using RevMan 5.2 software. Results We obtained seven observational studies involving two cohort and six case-control studies. Random-effects meta-analysis indicated a significant association between PD and HNC risk (odds ratio = 2.63, 95% confidence interval = 1.1.68 - 4.14; p < 0.001), with sensitivity analysis showing that the result was robust. Subgroup analyses based on adjustment for covariates, study design, PD assessment, tumor site, and ethnicity also revealed a significant association. Conclusions Based on currently evidence, PD is probably a significant and independent risk factor of HNC. PMID:24194957

Zeng, Xian-Tao; Deng, Ai-Ping; Li, Cheng; Xia, Ling-Yun; Niu, Yu-Ming; Leng, Wei-Dong

2013-01-01

338

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

339

Stable hemoglobin in hemodialysis patients: forest for the trees - a 12-week pilot observational study  

PubMed Central

Background Hemoglobin (Hb) variability is a common occurrence in hemodialysis patients treated with erythropoiesis-stimulating agents. High amplitude fluctuations have been associated with greater risk of morbidity and mortality. Methods This prospective, single centre pilot observational study was conducted over a 3-month period in daily practice patterns, to assess per-dialysis events and inter-dialysis complications that could interfere with erythropoiesis in patients undergoing hemodialysis. Results Mean Hb levels remained stable in the 78 evaluable patients, as did darbepoetin alfa (DA) doses, including in patients suffering from diabetes or cardiac affections. In total, an average of 7.7 events / patient / month occurred, but no significant relationship with Hb excursions was shown. Conclusion The observation of 7.7 events per patient per month suggests a careful monitoring of Hb and DA dosing every other week, in order to maintain Hb level within the target. PMID:24180578

2013-01-01

340

A Method for Naturalistic Observation of the Childbirth Environment: With Application to Theory Building and Research.  

ERIC Educational Resources Information Center

An instrument for naturalistic observation in the childbirth environment is presented. Observable features of the parturient woman's physical state, stimulus contact she experiences, and themes of conversations with the woman are recorded using a system of categories to time-sample in cycles of 30 seconds for observing followed by 30 seconds for

Nicholson, Joanne; Standley, Kay

341

Lack of benefits for prevention of cardiovascular disease with aspirin therapy in type 2 diabetic patients - a longitudinal observational study  

Microsoft Academic Search

BACKGROUND: The risk-benefit ratio of aspirin therapy in prevention of cardiovascular disease (CVD) remains contentious, especially in type 2 diabetes. This study examined the benefit and harm of low-dose aspirin (daily dose < 300 mg) in patients with type 2 diabetes. METHODS: This is a longitudinal observational study with primary and secondary prevention cohorts based on history of CVD at

Wilson Y Leung; Wing-yee So; Derek Stewart; Augustine Lui; Peter C Tong; Gary T Ko; Alice P Kong; Ronald C Ma; Francis K Chan; Xilin Yang; Sau-chu Chiang; Juliana C Chan

2009-01-01

342

Task based assessment of cardiac function in Monte Carlo simulated gated Tl201 perfusion SPECT: A human observer study  

Microsoft Academic Search

Different implementations of the receiver operator characteristic (ROC) method in cardiac perfusion SPECT have been described. However, none has attempted to independently assess cardiac function. The aim of this study was, therefore, to design and execute a human observer ROC study that includes the evaluation of cardiac function and perfusion. Due to the lack of a gold standard, our initial

P. Hendrik Pretorius; J. Michael O'Connor; Robert Licho; Jovan G. Brankov

2010-01-01

343

Assessing agile methods: An empirical study  

Microsoft Academic Search

Agile software processes emerged to address the issue of building software on time and within the planned budget. To adopt\\u000a an agile process, it is imperative to analyze and evaluate its effectiveness in supporting high quality software development\\u000a while complying with stringent time constraints. In this paper we describe an agile method for Web-based application development\\u000a (XWebProcess) and an experiment

Amrico Sampaio; Alexandre Vasconcelos; Pedro R. Falcone Sampaio

2004-01-01

344

The SILC study by PDO method  

NASA Astrophysics Data System (ADS)

Stress induced leakage current (SILC) has been discussed for a long time by many researchers. The oxide traps are believed to be the cause of SILC, but characterization of these traps is still not clear. In this paper, we demonstrate that the SILC related oxide traps can be distinguished into two kinds with different characterization parameter by PDO method. Linear fitting also shows that double oxide trap model is better than single oxide trap model.

Wang, Z.(i.)ou; Zhang, Heqiu; Xu, Mingzhen; Tan, Changhua

2004-12-01

345

Estimation of Measurement Uncertainty of kinematic TLS Observation Process by means of Monte-Carlo Methods  

NASA Astrophysics Data System (ADS)

In many cases, the uncertainty of output quantities may be computed by assuming that the distribution represented by the result of measurement and its associated standard uncertainty is a Gaussian. This assumption may be unjustified and the uncertainty of the output quantities determined in this way may be incorrect. One tool to deal with different distribution functions of the input parameters and the resulting mixed-distribution of the output quantities is given through the Monte Carlo techniques. The resulting empirical distribution can be used to approximate the theoretical distribution of the output quantities. All required moments of different orders can then be numerically determined. To evaluate the procedure of derivation and evaluation of output parameter uncertainties outlined in this paper, a case study of kinematic terrestrial laserscanning (k-TLS) will be discussed. This study deals with two main topics: the refined simulation of different configurations by taking different input parameters with diverse probability functions for the uncertainty model into account, and the statistical analysis of the real data in order to improve the physical observation models in case of k-TLS. The solution of both problems is essential for the highly sensitive and physically meaningful application of k-TLS techniques for monitoring of, e. g., large structures such as bridges.

Alkhatib, Hamza; Kutterer, Hansjrg

2013-05-01

346

Empathy levels among first year Malaysian medical students: an observational study  

PubMed Central

Background The literature indicates that medical practitioners experience declining empathy levels in clinical practice. This highlights the need to educate medical students about empathy as an attribute early in the academic curriculum. The objective of this study was to evaluate year one students self-reported empathy levels following a 2-hour empathy workshop at a large medical school in Malaysia. Methods Changes in empathy scores were examined using a paired repeated-measures t-test in this prospective before and after study. Results Analyzing the matched data, there was a statistically significant difference and moderate effect size between mean empathy scores before and 5 weeks after the workshop (112.0810.67 versus 117.9313.13, P<0.0001, d=0.48) using the Jefferson Scale Physician Empathy (Student Version). Conclusion The results of this observational study indicate improved mean self-reported empathy scores following an empathy workshop. PMID:24876799

Williams, Brett; Sadasivan, Sivalal; Kadirvelu, Amudha; Olaussen, Alexander

2014-01-01

347

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 graphite/epoxies, graphite/cyanide-ester, graphite/silicon-carbide, graphite phenolic and Kevlar/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

348

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

349

Direct observation of solute location in solutions frozen using various methods  

NASA Astrophysics Data System (ADS)

Photochemical reactions in snow and ice impact the transport and fate of organic and inorganic compounds in the snowpack, particularly in polar regions. While photodegradation rate constants have been determined for relatively few reactions on ice, in some cases different studies give significantly different results for the same reaction. Compounds in snow and ice can be located in several different compartments in the frozen matrix, including in bulk ice, at the ice-air interface in quasi-liquid layers (QLLs), or in liquid-like layers (LLLs) or micropockets within the ice matrix. Reaction rate differences may be due to changes in chemical kinetics in the various compartments, or variation in the photochemical reaction environment, such as photon flux. Here we examine various methods to segregate chemical compounds into different ice compartments by visualizing solute locations in the frozen samples. We preferentially segregate solutes into the various ice compartments by varying sample geometry, freezing speed (how quickly heat is removed from the liquid solution), and freezing direction (whether heat is removed from the solution from all sides equally, or preferentially in a single direction). We examine the results of our freezing methods by preparing ice samples containing a fluorescent solute, then using an imaging cryomicrotome to remove thin slices of the sample and image the remaining ice surface. By measuring the fluorescence from the ice surface as a function of depth, we can determine the location and concentration of the solute in various ice compartments.

Hullar, T.; Anastasio, C.

2012-12-01

350

Acoustic streaming in lithotripsy fields: preliminary observation using a particle image velocimetry method.  

PubMed

This study considers the acoustic streaming in water produced by a lithotripsy pulse. Particle image velocimetry (PIV) method was employed to visualize the acoustic streaming produced by an electromagnetic shock wave generator using video images of the light scattering particles suspended in water. Visualized streaming features including several local peaks and vortexes around or at the beam focus were easily seen with naked eyes over all settings of the lithotripter from 10 to 18 kV. Magnitudes of the peak streaming velocity measured vary in the range of 10-40 mm s(-1) with charging voltage settings. Since the streaming velocity was estimated on the basis of a series of the video images of particles averaged over 1/60s, the time resolution limited by the video frame rate which is 1-2 orders of magnitude larger than driving acoustic activities, measured velocities are expected to be underestimated and were shown a similar order of magnitude lower than those calculated from a simple theoretical consideration. Despite such an underestimation, it was shown that, as predicted by theory, the magnitude of the streaming velocity measured by the present PIV method was proportional to acoustic intensity. In particular it has almost a linear correlation with peak negative pressures (r=0.98683, p=0.0018). PMID:16376400

Choi, Min Joo; Doh, Doeg Hee; Hwang, Tae Gyu; Cho, Chu Hyun; Paeng, Dong Guk; Rim, Gun Hee; Coleman, A J

2006-02-01

351

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

352

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

353

Observations of Fabric Development in Polycrystalline Ice at Basal Pressures: Methods and Initial Results  

NASA Astrophysics Data System (ADS)

Understanding and predicting the flow of polycrystalline ice is crucial to ice sheet modeling and paleoclimate reconstruction from ice cores. Ice flow rates depend strongly on the fabric (i.e. the distribution of grain sizes and crystallographic orientations) which evolves over time and enhances the flow rate in the direction of applied stress. The mechanisms for fabric evolution in ice have been extensively studied at atmospheric pressures, but little work has been done to observe these processes at the high pressures experienced deep within ice sheets where long-term changes in ice rheology are expected to have significance. We conducted compressive creep tests on a 917 kg m-3 polycrystalline ice specimen at 20 MPa hydrostatic pressure, thus simulating ~2,000 m depth. Initial specimen grain orientations were random, typical grain diameters were 1.2 mm, and the applied creep stress was 0.3 MPa. Subsequent microstructural analyses on the deformed specimen and a similarly prepared, undeformed specimen allowed characterization of crystal fabric evolution under pressure. Our microstructural analysis technique simultaneously collected grain shape and size data from Scanning Electron Microscope (SEM) micrographs and obtained crystallographic orientation data via Electron BackScatter Diffraction (EBSD). Combining these measurements allows rapid analysis of the ice fabric over large numbers of grains, yielding statistically useful numbers of grain size and full c- and a-axis grain orientation data. The combined creep and microstructural data demonstrate pressure-dependent effects on the mechanical and microstructural evolution of polycrystalline ice. We discuss possible mechanisms for the observed phenomena, and future directions for hydrostatic creep testing.

Breton, D. J.; Baker, I.; Cole, D. M.

2012-12-01

354

Tropospheric CO Observations Using IASI datasets and an Optimal Estimation Retrieval Method  

NASA Astrophysics Data System (ADS)

Carbon monoxide (CO) in the troposphere acts as a marker of large-scale influences of pollution on both the regional and global scale, whilst acting as a reference source for incomplete combustion. Through its reactions with the hydroxyl radical OH, the concentration of CO is also related to the oxidizing capacity of the troposphere, hence providing a chemical marker for the "local" chemical environment and its state. Investigations into perturbations of the sources, sinks and net surface fluxes of CO are therefore of increasing importance. CO exhibits strong locally elevated concentrations in the vicinity of sources due to its relatively short life time of weeks to months. Global measurements of CO from satellites will therefore allow to identify the main source regions and to quantify their source strength. The Infrared Atmospheric Sounding Interferometer (IASI) is a high-resolution (0.25 cm-1 unapodized) Michelson interferometer which was launched in 2007 on the European polar Meteorological Operational Platform (METEOP-1) satellite. The IASI instrument has a swath of about 2200 km, ensuring 99% global coverage twice a day, and is the first of a series of three instruments launched every five years, ensuring a continuity of data for a planned period of 15 years. The IASI instrument thus offers the possibility of high-spectral resolution infrared monitoring of CO over a very long time period. This work presents a new Optimal Estimation Method (OEM) retrieval of CO profiles in the mid-troposphere from observations of the IASI instrument. First retrieval results, as well as a validation of these results with ground-based sites and other satellites are included, and error characterization as well as the effects of noise in the retrievals is also discussed.

Illingworth, S. M.

2009-04-01

355

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

356

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 600mg linezolid intravenously twice a day. Over 4days, 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 24hours (AUC24) 50.1 to 453.9mg/L, median 143.3mg*h/L; range of trough concentrations (Cmin)?observed for 63% and 50% of the patients, respectively. Finally, potentially toxic levels (defined as AUC24?>?400mg*h/L and Cmin?>?10mg/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

357

Microfabrication methods for the study of chemotaxis  

E-print Network

We have developed a system for studying chemotaxis in a microfabricated system. The goal was to develop a system capable of generating spatially and temporally stable concentration gradients of a chemotactic molecule while ...

Shur, Maiya, 1980-

2004-01-01

358

Preliminary Study of Advanced Diagnostic Prescreening Methods  

E-print Network

and maintenance opportunities (O&Ms). This report then compares those ECRMs against annual, monthly, daily, and hourly indices to determine how well such indicators can guide the energy audit process. Eleven schools in Texas were identified for case studies... discusses how data were collected, how indices were created, and presents comparative results across sites. Additional school specific data for the eleven case study schools may be found in Development of Prescreening Indices to Improve Energy Analysis...

Landman, D. S.; Haberl, J. S.

1996-01-01

359

Study on Marine Boundary Layer Structure and Clouds over Southern Oceans with Satellite Observations  

NASA Astrophysics Data System (ADS)

Marine boundary layer (MBL) clouds contribute significantly to the energy and moisture budgets of the earth due to their high occurrence and albedo. However, in current weather and climate models, the cloud cover and MBL structure are still poorly represented, especially in regions of persistent marine stratocumulus and Southern oceans. Due to complex interactions of MBL clouds with the vertical structure and turbulence of the MBL, the representation of convective and boundary layer processes are critical to successful simulations of climate. However, these interactions are poorly understood due to the lack of observations over ocean. In this study, 4-year A-train satellite observations over Southern Oceans were used to study the MBL structure, aerosol and cloud. With vertical structure of aerosols from CALIPSO lidar measurements, reliable methods are developed to determine MBL height and the mixing layer height. The characteristics of MBL decoupling structure were further analyzed and its controlling factors were examined. Results showed that the surface wind speed has the major influence on MBL decoupling structure in terms of aerosol loading. And the cloud-aerosol interaction especially the effects of biological aerosol on MBL mixed-phase clouds were also explored. These results highlighted that satellite multi-sensor observations offer an effective way to understand the MBL processes and clouds over the Southern Oceans.

Luo, T.; Wang, Z.

2013-12-01

360

Temporal Artery versus Bladder Thermometry during Adult Medical-Surgical Intensive Care Monitoring: An Observational Study  

Microsoft Academic Search

BACKGROUND: We sought to evaluate agreement between a new and widely implemented method of temperature measurement in critical care, temporal artery thermometry and an established method of core temperature measurement, bladder thermometry as performed in clinical practice. METHODS: Temperatures were simultaneously recorded hourly (n = 736 observations) using both devices as part of routine clinical monitoring in 14 critically ill

Henry T Stelfox; Sharon E Straus; William A Ghali; John Conly; Kevin Laupland; Adriane Lewin

2010-01-01

361

A unified Hinfinity adaptive observer synthesis method for a class of systems with both Lipschitz and monotone nonlinearities  

Microsoft Academic Search

This paper investigates the problem of the H? adaptive observer design for a class of nonlinear dynamical systems. The main contribution consists in providing a unified synthesis method for systems with both Lipschitz and monotone nonlinearities (not necessarily Lipschitz). Thanks to the innovation terms into the nonlinear functions [M. Arcak, P. Kokotovic, Observer-based control of systems with slope-restricted nonlinearities, IEEE

Ali Zemouche; Mohamed Boutayeb

2009-01-01

362

Horizontal flow fields observed in Hinode G-band images. I. Methods  

E-print Network

Context: The interaction of plasma motions and magnetic fields is an important mechanism, which drives solar activity in all its facets. For example, photospheric flows are responsible for the advection of magnetic flux, the redistribution of flux during the decay of sunspots, and the built-up of magnetic shear in flaring active regions. Aims: Systematic studies based on G-band data from the Japanese Hinode mission provide the means to gather statistical properties of horizontal flow fields. This facilitates comparative studies of solar features, e.g., G-band bright points, magnetic knots, pores, and sunspots at various stages of evolution and in distinct magnetic environments, thus, enhancing our understanding of the dynamic Sun. Methods: We adapted Local Correlation Tracking (LCT) to measure horizontal flow fields based on G-band images obtained with the Solar Optical Telescope on board Hinode. In total about 200 time-series with a duration between 1-16 h and a cadence between 15-90 s were analyzed. Selecti...

Verma, M

2011-01-01

363

The neural correlates of Fitts's law in action observation: An fMRI study  

Microsoft Academic Search

Previous neuroimaging studies support the assumption of a strong link between perception and action, demonstrating that the motor system is involved when others' actions are observed. One question that is still open to debate is which aspects of observed actions engage the motor system. The present study tested whether motor activation corresponds to the difficulty of the observed action, using

Terry Eskenazi; Pia Rotshtein; Marc Grosjean; Guenther Knoblich

2012-01-01

364

The neural correlates of Fitts's law in action observation: An fMRI study  

Microsoft Academic Search

Previous neuroimaging studies support the assumption of a strong link between perception and action, demonstrating that the motor system is involved when others actions are observed. One question that is still open to debate is which aspects of observed actions engage the motor system. The present study tested whether motor activation corresponds to the difficulty of the observed action, using

Terry Eskenazi; Pia Rotshtein; Marc Grosjean; Guenther Knoblich

2011-01-01

365

Outdoor play among children in relation to neighborhood characteristics: a cross-sectional neighborhood observation study  

PubMed Central

Background Although environmental characteristics as perceived by parents are known to be related to childrens outdoor play behavior, less is known about the relation between independently measured neighborhood characteristics and outdoor play among children. The purpose of this study was to identify quantitative as well as qualitative neighborhood characteristics related to outdoor play by means of neighborhood observations. Methods Questionnaires including questions on outdoor play behavior of the child were distributed among 3,651 parents of primary school children (aged 412?years). Furthermore, neighborhood observations were conducted in 33 Dutch neighborhoods to map neighborhood characteristics such as buildings, formal outdoor play facilities, public space, street pattern, traffic safety, social neighborhood characteristics, and general impression. Data of the questionnaires and the neighborhood observations were coupled via postal code of the respondents. Multilevel GEE analyses were performed to quantify the correlation between outdoor play and independently measured neighborhood characteristics. Results Parental education was negatively associated with outdoor play among children. Neither the presence nor the overall quality of formal outdoor play facilities were (positively) related to outdoor play among children in this study. Rather, informal play areas such as the presence of sidewalks were related to childrens outdoor play. Also, traffic safety was an important characteristic associated with outdoor play. Conclusions This study showed that, apart from individual factors such as parental education level, certain modifiable characteristics in the neighborhood environment (as measured by neighborhood observations) were associated with outdoor play among boys and girls of different age groups in The Netherlands. Local policy makers from different sectors can use these research findings in creating more activity-friendly neighborhoods for children. PMID:22901102

2012-01-01

366

A cross-sectional observational study of helmet use among motorcyclists in Wa, Ghana.  

PubMed

Motorcyclists' injuries and fatalities are a major public health concern in many developing countries including Ghana. This study therefore aimed to investigate the prevalence of helmet use among motorcyclists in Wa, Ghana. The method used involved a cross-sectional roadside observation at 12 randomly selected sites within and outside the CBD of Wa. A total of 14,467 motorcyclists made up of 11,360 riders and 3107 pillion riders were observed during the study period. Most observed riders (86.5%) and pillion riders (61.7%) were males. The overall prevalence of helmet use among the observed motorcyclists was 36.9% (95% CI: 36.1-37.7). Helmet use for riders was 45.8% (95% CI: 44.8-46.7) whilst that for pillion riders was 3.7% (95 CI: 3.0-4.4). Based on logistic regression analysis, higher helmet wearing rates were found to be significantly associated with female gender, weekdays, morning periods and at locations within the CBD. Riders at locations outside the CBD were about 7 times less likely to wear a helmet than riders within the CBD (48.9% compared to 42.3%; ?(2)(1)=49.526; p<0.001). The study concluded that despite the existence of a national helmet legislation that mandates the use of helmets by both riders and pillion riders on all roads in Ghana, helmet use is generally low in Wa. This suggests that all stakeholders in road safety should jointly intensify education on helmet use and pursue rigorous enforcement on all road types especially at locations outside the CBD to improve helmet use in Wa. PMID:24316503

Akaateba, Millicent Awialie; Amoh-Gyimah, Richard; Yakubu, Ibrahim

2014-03-01

367

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

368

The Maximum Similarity Shape Matching (MSSM) method applied to oil spill feature tracking observed in SAR imagery  

SciTech Connect

In this study, the Maximum Similarity in Shape Matching (MSSM) method was applied to a pair of airborne SAR images and two pairs of spaceborne SAR images in order to observe the small scale features of oil spill. The Gulf Stream front and the coast of Wales, UK, were chosen as the test sites. For the coast of Wales, spaceborne RADARSAT, ERS-1 and ERS-2 SAR images detected the persistence of slick features associated with the Sea Empress tanker massive oil spill, and showed the evolution of these features from February 22 to February 26, 1996. Drift speeds calculated using SAR images and MSSM method were as high as 11 cm/s. Deformation of the slick features was also evident throughout the five day period. The result of the investigation revealed the trajectory of this particular oil spill, and also demonstrated the possible future application of this method to analysis of SAR imagery, in general, and to oil spill monitoring, in particular.

Yan, Xiao-Hai; Clemente-Colon, P. [Univ. of Delaware, Newark, DE (United States)

1997-06-01

369

A Two-Air-Stream Observation Chamber for Studying Responses of Flying Insects.  

National Technical Information Service (NTIS)

The paper describes an observation chamber and airconditioning system designed for studying the responses of flying insects at the boundary between two microclimates. Two vertical air streams each fill one half of the rectangular observation chamber. Turb...

P. N. Daykin, F. E. Kellogg

1964-01-01

370

HEALTHY study rationale, design and methods  

PubMed Central

The HEALTHY primary prevention trial was designed and implemented in response to the growing numbers of children and adolescents being diagnosed with type 2 diabetes. The objective was to moderate risk factors for type 2 diabetes. Modifiable risk factors measured were indicators of adiposity and glycemic dysregulation: body mass index ?85th percentile, fasting glucose ?5.55 mmol l-1 (100 mg per 100 ml) and fasting insulin ?180 pmol l-1 (30 ?U ml-1). A series of pilot studies established the feasibility of performing data collection procedures and tested the development of an intervention consisting of four integrated components: (1) changes in the quantity and nutritional quality of food and beverage offerings throughout the total school food environment; (2) physical education class lesson plans and accompanying equipment to increase both participation and number of minutes spent in moderate-to-vigorous physical activity; (3) brief classroom activities and family outreach vehicles to increase knowledge, enhance decision-making skills and support and reinforce youth in accomplishing goals; and (4) communications and social marketing strategies to enhance and promote changes through messages, images, events and activities. Expert study staff provided training, assistance, materials and guidance for school faculty and staff to implement the intervention components. A cohort of students were enrolled in sixth grade and followed to end of eighth grade. They attended a health screening data collection at baseline and end of study that involved measurement of height, weight, blood pressure, waist circumference and a fasting blood draw. Height and weight were also collected at the end of the seventh grade. The study was conducted in 42 middle schools, six at each of seven locations across the country, with 21 schools randomized to receive the intervention and 21 to act as controls (data collection activities only). Middle school was the unit of sample size and power computation, randomization, intervention and primary analysis. PMID:19623188

2009-01-01

371

Antidepressant treatment patterns in a novel methadone maintenance clinic targeting young adults an observational study.  

PubMed

This observational study examined the antidepressant treatment patterns of a novel New York City methadone maintenance treatment program (MMTP), founded for the treatment of adolescents and now targeting young adults and older patients with special problems. The goal of the study was to investigate demographic or clinical characteristics that were associated with prescribing patterns, as well as whether antidepressant use was associated with sobriety. The method of data collection was a thorough chart review. Antidepressant treatment was significantly associated with gender, education, marital status, and relapse. However, after controlling for demographic and clinical characteristics, antidepressant treatment was not significantly associated with a reduction in relapse risk. Further research is needed to explore these relationships, as well as their generalizability to adult methadone clinics, and to examine the underlying factors that lead to similarities and distinctions in antidepressant prescribing practices between various types of clinics (i.e., general outpatient vs. methadone maintenance). PMID:16785219

Galarneau, David W; Teres, Jedediah J; Leon, Andrew C; Melia, Dorothy; Lilly, Charles; Kellogg, Scott; Khuri, Elizabeth; Kreek, Mary Jeanne

2006-01-01

372

METHODS USED TO STUDY RESPIRATORY VIRUS INFECTION  

PubMed Central

This unit describes protocols for infecting the mouse respiratory tract, and assaying virus replication and host response in the lung. Respiratory infections are the leading cause of acute illness worldwide, affecting mostly infants and children in developing countries. The purpose of this unit is to provide the readers with a basic strategy and protocols to study the pathogenesis and immunology of respiratory virus infection using the mouse as an animal model. The procedures include: (i) basic techniques for mouse infection, tissue sampling and preservation, (ii) determination of viral titers, isolation and analysis of lymphocytes and dendritic cells using flow-cytometry, and (iii) lung histology, immunohistochemistry and in situ hybridization. PMID:19499505

Flano, Emilio; Jewell, Nancy A.; Durbin, Russell K.; Durbin, Joan E.

2009-01-01

373

C2 emission features in the Red Rectangle. A combined observational laboratory study  

NASA Astrophysics Data System (ADS)

Context. The Red Rectangle proto-planetary nebula (HD 44179) is known for a number of rather narrow emission features superimposed on a broad extended red emission (ERE) covering the 5000-7500 regime. The origin of these emission features is unknown. Aims: The aim of the present work is to search for potential carriers by combining new observational and laboratory data. This also allows to interpret spectral emission features in terms of actual physical conditions like temperature and density constraints and to trace chemical processes in the outflows of the Red Rectangle. Methods: Observational spectra have been obtained with the EMMI-NTT at offsets of 3'', 6'', 7'', 11'', 16'' and 20'' distance to the central star HD 44179. The spectra are compared to the outcome of a time-gated laser induced fluorescence laboratory study of an expanding acetylene plasma using a special supersonic pin-hole discharge source. With this set-up the hydrocarbon chemistry in the Red Rectangle nebula is simulated under laboratory controlled conditions. The plasma source has the unique feature to generate electronically and vibrationally excited species at low rotational temperatures. The comparison is facilitated by a simple model for fluorescent emission in the nebula. Results: Two of the astronomically observed narrow emission bands can be assigned as originating from unresolved rovibronic progressions within the d3?_g ? a3?_u Swan system of the C2 radical. The band appearance corresponds to a rotational temperature between 200 and 1000 K. The emission is driven by absorption in the C2 Phillips bands followed by intersystem crossing from the singlet to the triplet state and pumping in the Swan bands. Conclusions: These observations imply an active (photo)chemistry in the ejecta of the Red Rectangle. Based on observations collected at the European Southern Observatory, Chile. Program ID: 080.C-0814(A).

Wehres, N.; Romanzin, C.; Linnartz, H.; van Winckel, H.; Tielens, A. G. G. M.

2010-07-01

374

Methods to Estimate Surface Fluxes of Momentum and Heat from Routine Weather Observations for Dispersion Applications under Stable Stratification  

Microsoft Academic Search

We examine the efficacy of two methods commonly used to estimate the vertical turbulent fluxes of momentum and sensible heat\\u000a from routinely observed mean quantities in the surface layer under stable stratification. The single-level method uses mean\\u000a wind speed and temperature measurements at a single height, whereas the two-level method uses mean wind speed measurements\\u000a at a single height and

Ashok K. Luhar; Ken N. Rayner

2009-01-01

375

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

376

A prospective observational study of skin to subarachnoid space depth in the Indian population  

PubMed Central

Background and Aims: A pre-puncture estimate of skin to subarachnoid space depth (SSD) may guide spinal needle placement and reduce complications associated with lumbar puncture. Our aim was to determine (1) The SSD in Indian males, females, parturients and the overall population; (2) To derive formulae for predicting SSD and (3) To determine which previously suggested formula best suited our population. Methods: In this prospective, observational study, 800 adult Indian patients undergoing surgery under spinal anaesthesia were divided into three groups: Males (Group M), females (Group F) and parturients (Group PF). SSD was measured after lumbar puncture. The relationship between SSD and patient characteristics was studied and statistical models were used to derive formula for predicting SSD. Statistical analysis included One-way ANOVA with post hoc analysis, forward stepwise multivariate regression analysis and paired t-tests. Results: Mean SSD was 4.71 0.70 cm in the overall population. SSD in adult males (4.81 0.68 cm) was significantly longer than that observed in females (4.55 0.66 cm) but was comparable with SSD in parturients (4.73 0.73 cm). Formula for predicting SSD in the overall population was 2.71 + 0.09 Body Mass Index (BMI). Stocker's formula when applied correlated best with the observed SSD. Formulae were derived for the three groups. Conclusions: We found gender-based differences in SSD, with SSD in males being significantly greater than that observed in the female population. SSD correlated with BMI in the parturient and the overall population. Amongst the previously proposed formulae, Stocker's formula was most accurate in predicting SSD in our population. PMID:24963181

Prakash, Smita; Mullick, Parul; Chopra, Pooja; Kumar, Santosh; Singh, Rajvir; Gogia, Anoop R

2014-01-01

377

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 (0.874.37; 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

378

Impact of Inherited Thrombophilia on Venous Thromboembolism in Children A Systematic Review and Meta-Analysis of Observational Studies  

Microsoft Academic Search

BackgroundThe aim of the present study was to estimate the impact of inherited thrombophilia (IT) on the risk of venous thromboembolism (VTE) onset and recurrence in children by a meta-analysis of published observational studies. Methods and ResultsA systematic search of electronic databases (Medline, EMBASE, OVID, Web of Science, The Cochrane Library) for studies published from 1970 to 2007 was conducted

Guy Young; Manuela Albisetti; Mariana Bonduel; Leonardo Brandao; Anthony Chan; Frauke Friedrichs; Neil A. Goldenberg; Eric Grabowski; Christine Heller; Janna Journeycake; Gili Kenet; Anne Krmpel; Karin Kurnik; Aaron Lubetsky; Christoph Male; Marilyn Manco-Johnson; Prasad Mathew; Paul Monagle; Heleen van Ommen; Paolo Simioni; Pavel Svirin; Daniela Tormene; Ulrike Nowak-Gttl

2011-01-01

379

Qualitative Methods for Studying Distributed Software Development: Issues and Challenges  

E-print Network

the begin- ning stages of my doctoral studies via a formal course on qualitative research methods as well. Subsequently, I have applied the knowl- edge and insights by incorporating qualitative methods in my researchQualitative Methods for Studying Distributed Software Development: Issues and Challenges Sameer

Patil, Sameer

380

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

381

An Observational Study of the Interactions of Socially Withdrawn/Anxious Early Adolescents and Their Friends  

ERIC Educational Resources Information Center

Background: The friendships of socially withdrawn/anxious children and early adolescents have been found to lack critical rewarding qualities. Observational research may help elucidate the obstacles they face in forming and maintaining high-quality friendships with sociable peers. Method: We observed the interactions of 38 socially withdrawn early

Schneider, Barry H.

2009-01-01

382

Direct observation of biting for studying grazing behavior of goats and llamas on garrigue rangelands  

Microsoft Academic Search

In any heterogeneous environment, classical methods used to estimate daily DMI and daily diets of grazing animals are difficult to implement. To investigate the grazing behavior of a goat and a llama, feeding on the garrigue in their respective flock, we therefore used a technique based on direct observation of biting. The observations were carried out in spring and early

B. Dumont; M. Meuret; M. Prud'hon

1995-01-01

383

Crop management based on field observations: Case studies in sugarcane and coffee  

Microsoft Academic Search

For millennia farmers have continually improved their crop management and production practices through their observations and experience. More recently modern science and research methods based on controlled experiments became the most visible instrument of technological change in agriculture, nevertheless farmers continued to develop and implement new technologies based on their own observations made under commercial conditions. Modern information technology and

James Cock; Thomas Oberthr; Camilo Isaacs; Peter Roman Lderach; Alberto Palma; Javier Carbonell; Jorge Victoria; Geoff Watts; Alvaro Amaya; Laure Collet; Einar Anderson

2011-01-01

384

Arachidonic acid and cancer risk: a systematic review of observational studies  

PubMed Central

Background An n-6 essential fatty acid, arachidonic acid (ARA) is converted into prostaglandin E2, which is involved in tumour extension. However, it is unclear whether dietary ARA intake leads to cancer in humans. We thus systematically evaluated available observational studies on the relationship between ARA exposure and the risk of colorectal, skin, breast, prostate, lung, and stomach cancers. Methods We searched the PubMed database for articles published up to May 17, 2010. 126 potentially relevant articles from the initial search and 49,670 bibliographies were scrutinised to identify eligible publications by using predefined inclusion criteria. A comprehensive literature search yielded 52 eligible articles, and their reporting quality and methodological quality was assessed. Information on the strength of the association between ARA exposure and cancer risk, the dose-response relationship, and methodological limitations was collected and evaluated with respect to consistency and study design. Results For colorectal, skin, breast, and prostate cancer, 17, 3, 18, and 16 studies, respectively, were identified. We could not obtain eligible reports for lung and stomach cancer. Studies used cohort (n?=?4), nested case-control (n?=?12), case-control (n?=?26), and cross-sectional (n?=?12) designs. The number of subjects (n = 15 - 88,795), ARA exposure assessment method (dietary intake or biomarker), cancer diagnosis and patient recruitment procedure (histological diagnosis, cancer registries, or self-reported information) varied among studies. The relationship between ARA exposure and colorectal cancer was inconsistent based on ARA exposure assessment methodology (dietary intake or biomarker). Conversely, there was no strong positive association or dose-response relationship for breast or prostate cancer. There were limited numbers of studies on skin cancer to draw any conclusions from the results. Conclusions The available epidemiologic evidence is weak because of the limited number of studies and their methodological limitations, but nonetheless, the results suggest that ARA exposure is not associated with increased breast and prostate cancer risk. Further evidence from well-designed observational studies is required to confirm or refute the association between ARA exposure and risk of cancer. PMID:23249186

2012-01-01

385

The Future of Research Methods in Africana Studies Graduate Curriculum  

Microsoft Academic Search

This study examines the state of research methods in Africana studies. In addition, the role that courses on research methods\\u000a play in Africana Studies departments is also explored. Content analysis of departmental course offerings and descriptions\\u000a reveal that half of graduate level degrees granting Africana Studies programs offer departmental courses on research methods.\\u000a Moreover, the majority of the programs that

Serie Mcdougal

386

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

387

Synchronous Motor Observability Study and an Improved Zero-speed Position Estimation Design  

E-print Network

with the Permanent Magnet Synchronous Motor (PMSM) observability analysis for sensor- less control design here for the surface Permanent Magnet Synchronous Motor (PMSM) to overcome position observabilitySynchronous Motor Observability Study and an Improved Zero-speed Position Estimation Design Dalila

Boyer, Edmond

388

An Assessment of AKIN Criteria for Hospital-Acquired Acute Kidney Injury: A Prospective Observational Cohort Study  

Microsoft Academic Search

Background and Aims: The Acute Kidney Injury Network (AKIN) criteria assert a new definition for acute kidney injury (AKI). We investigated the incidence of hospital-acquired AKI, along with the clinical characteristics and outcomes in hospitalized patients according to AKIN stage. Methods: We performed a prospective, observational, single-center study. We monitored serum creatinine everyday for all patients using a hospital data

Soon Hyo Kwon; Hyunjin Noh; Jin Seok Jeon; Yongbae Kim; Dong Cheol Han

2010-01-01

389

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

390

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=45.54months old, SD=9.07). Multiple informants and methods including observational methods (i.e., 160min 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

391

Pseudo interface waves observed at the fluid/porous-medium interface. A comparison of two methods.  

PubMed

At the fluid/porous-medium interface the pseudo-Rayleigh (pR) and pseudo-Stoneley (pSt) waves exist. The relation with the corresponding poles in the slowness plane is not unambiguous, depending on the choice of branch cuts. For a point-force excitation, the far-field Green's functions are computed using vertical branch cuts (method I) implying that the pR- and pSt-poles obey the radiation condition. Then, a separate pseudo interface wave is entirely captured by the corresponding pole residue because the loop integral along a branch cut contributes to a body wave only. When hyperbolic branch cuts are used (method II) the poles lie on the "principal" Riemann sheet. Then, also the loop integrals necessarily contribute to the pR-wave because the pR-pole is different from that in method I. They do not contribute to the pSt-wave when the pSt-pole lies on the principal Riemann sheet because the pole is identical to that in method I. When the pSt-pole has migrated to another Riemann sheet, however, the pSt-wave is fully captured by the loop integrals. In conclusion, the phase velocity and attenuation of a separate pseudo interface wave can be computed from the pole location in method I, but should be extracted from the full response in method II. PMID:21568394

van Dalen, K N; Drijkoningen, G G; Smeulders, D M J

2011-05-01

392

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; Kaa, Glin; Koyuncu, Mehmet; Turkan, B Nilay

2014-02-01

393

An observational study of intravenous medication errors in the United Kingdom and in Germany  

Microsoft Academic Search

Objectives: To investigate the incidence and the severity of intravenous (i.v.) drug preparation and administration errors in two countries and three pharmacy services. Method: A disguised observational method was used to record details of the preparation and administration of prescribed i.v. drugs on two wards in each of three teaching hospitals: one with a traditional British ward pharmacy service (TBP)

V. Wirtz; Nick D. Barber; K. taxis

2003-01-01

394

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

E-print Network

Observed Soil Moisture Feifei Pan1 ; Christa D. Peters-Lidard2 ; and Anthony W. King3 Abstract: Soil.g., drainage, runoff, soil moisture, evaporation, and evapo- transpiration. With information about soil PSD, we can estimate almost all soil hydraulic properties e.g., saturated soil moisture, field capacity

Pan, Feifei

395

An Instrumented Observability Coverage Method for System Validation Peter Lisherness, Kwang-Ting (Tim) Cheng  

E-print Network

each expression in a system model. Coverage is measured in simulation by tracking tags alongside be adequately analyzed or modeled in pre-silicon verification [1]. Higher levels of integration and complexity validation while considering this limited observability, we have developed a tool that models hypothetical

396

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

397

A study on the development of a compensation method for humidity effect in QCM sensor responses  

Microsoft Academic Search

In this study, humidity influence on quartz crystal microbalance (QCM) sensor responses during gas applications is investigated. The goal is to search a compensation method to remove humidity influence over the QCM sensor array at the data processing stage. Some experiments have been conducted to observe sensors behavior with the industrial gas of toluene under changing humidity conditions. The observed

Bekir Mumyakmaz; Ahmet zmen; Mehmet A. Ebeo?lu; Cihat Ta?alt?n; ?lke Grol

2010-01-01

398

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

399

Unsafe riding practice among electric bikers in Suzhou, China: an observational study  

PubMed Central

Background Electric bike (E-bike)-related deaths have been increasing rapidly in China and such injuries may be partly attributable to unsafe riding practice. Objectives To describe potentially unsafe riding behaviours among electric bikers (E-bikers) and to investigate factors influencing these practices in China. Methods In September 2012, a cross-sectional observation study including a speed measurement component was conducted in Wuzhong (an urban district) and Zhangjiagang (a rural district) of Suzhou, Jiangsu Province, China. Hand-held radar speed metres were used to read travelling speeds of E-bikes and a pro forma observation checklist was used to collect data on road riding practice. Mixed-effect logistic regressions were used to calculate adjusted ORs and 95% CIs for the association between speeding, road rule violations and helmet use and their influencing factors. Results Among 800 E-bikes with a speed reading, 70.9% exceeded the designed speed limit of 20?km/h. Among a further 20?647 E-bikers observed, 38.3% did not comply with the road rules when entering intersections; and only 2.2% wore helmets. No regional variation was identified between urban and rural areas. Male E-bikers were associated with more speeding and road rule violations, whereas riding a pedal-equipped E-bike was associated with less road rule violations and less helmet use. Conclusions Unsafe riding practices such as speeding, road rule violations and lack of helmet use were commonplace among E-bikers, especially among men. The study findings indicate that measures aimed at improving E-bike safety are required in China. PMID:24435891

Yang, Jie; Hu, Yihe; Du, Wei; Powis, Brent; Ozanne-Smith, Joan; Liao, Yilan; Li, Ning; Wu, Ming

2014-01-01

400

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

401

Comparison of midwifery students' satisfaction with direct observation of procedural skills and current methods in evaluation of procedural skills in Mashhad Nursing and Midwifery School  

PubMed Central

Background: The clinical evaluation, as one of the most important elements in medical education, must measure students competencies and abilities. The implementation of any assessment tool is basically dependent on the acceptance of students. This study tried to assess midwifery students satisfaction with Direct Observation of Procedural Skills (DOPS) and current clinical evaluation methods. Materials and Methods: This quasi-experimental study was conducted in the university hospitals affiliated to Mashhad University of Medical Sciences. The subjects comprised 67 undergraduate midwifery students selected by convenience sampling and allocated to control and intervention groups according to the training transposition. Current method was performed in the control group, and DOPS was conducted in the intervention group. The applied tools included DOPS rating scales, logbook, and satisfaction questionnaires with clinical evaluation methods. Validity and reliability of these tools were approved. At the end of training, students satisfaction with the evaluation methods was assessed by the mentioned tools. The data were analyzed by descriptive and analytical statistics. Results: Satisfaction mean scores of midwifery students with DOPS and current methods were 76.7 12.9 and 62.6 14.7 (out of 100), respectively. DOPS students satisfaction mean score was significantly higher than the score obtained in current method (P < 0.000). The most satisfactory domains in the current method were consistence with learning objectives (71.2 14.9) and objectiveness in DOPS (87.9 15.0). In contrast, the least satisfactory domains in the current method were interested in applying the method (57.8 26.5) and number of assessments for each skill (58.8 25.9) in DOPS method. Conclusions: This study showed that DOPS method is associated with greater students satisfaction. Since the students satisfaction with the current method was also acceptable, we recommend combining this new clinical evaluation method with the current method, which covers its weaknesses, to promote the students satisfaction with clinical evaluation methods in a perfect manner. PMID:23983736

Hoseini, BiBi Leila; Mazloum, Seyed Reza; Jafarnejad, Farzaneh; Foroughipour, Mohsen

2013-01-01

402

Expanded Clinical Observations in Toxicity Studies: Historical Perspectives and Contemporary Issues  

Microsoft Academic Search

Recent or proposed changes in major testing guidelines require expanded clinical observations (ECOs) for a wide variety of toxicity studies in animals. ECOs supplement the simple cageside and hand-held observations traditionally employed during such studies. The new guidelines specify out-of-cage observations [e.g., posture, gait, and reactivity to various stimuli (e.g., auditory, tactile, noxious)] using defined scales and are intended as

Joseph F. Ross; Joel L. Mattsson; Andrew S. Fix

1998-01-01

403

A Residual Kriging method for the reconstruction of 3D high-resolution meteorological fields from airborne and surface observations  

NASA Astrophysics Data System (ADS)

Manned light aircrafts and remotely piloted aircrafts represent very valuable and flexible measurement platforms for atmospheric research, as they are able to provide high temporal and spatial resolution observations of the atmosphere above the ground surface. In the present study the application of a geostatistical interpolation technique called Residual Kriging (RK) is proposed for the mapping of airborne measurements of scalar quantities over regularly spaced 3D grids. In RK the dominant (vertical) trend component underlying the original data is first extracted to filter out local anomalies, then the residual field is separately interpolated and finally added back to the trend; the determination of the interpolation weights relies on the estimate of the characteristic covariance function of the residuals, through the computation and modelling of their semivariogram function. RK implementation also allows for the inference of the characteristic spatial scales of variability of the target field and its isotropization, and for an estimate of the interpolation error. The adopted test-bed database consists in a series of flights of an instrumented motorglider exploring the atmosphere of two valleys near the city of Trento (in the southeastern Italian Alps), performed on fair-weather summer days. RK method is used to reconstruct fully 3D high-resolution fields of potential temperature and mixing ratio for specific vertical slices of the valley atmosphere, integrating also ground-based measurements from the nearest surface weather stations. From RK-interpolated meteorological fields, fine-scale features of the atmospheric boundary layer developing over the complex valley topography in connection with the occurrence of thermally-driven slope and valley winds, are detected. The performance of RK mapping is also tested against two other commonly adopted interpolation methods, i.e. the Inverse Distance Weighting and the Delaunay triangulation methods, comparing the results of a cross-validation procedure.

Laiti, Lavinia; Zardi, Dino; de Franceschi, Massimiliano; Rampanelli, Gabriele

2013-04-01

404

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 casecontrol 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

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A prospective observational study of the outcome of central venous catheterization in 100 patients  

PubMed Central

Context: To Study the outcome following central vein catheterization in patients receiving chemotherapy. Aims: To Study the outcome of central venous catheterization in terms of difficulty during insertion, duration, incidence of infections and other complications and reasons for removal. Settings and Designs: Prospective observational study conducted in 100 patients attending to Gujarat Cancer and Research Institute. Materials and Methods: Both onco-medical and onco-surgical patients who required insertion of central venous catheters were enrolled after ethical approval from June 2008 to November 2010. The study comprised 100 patients. Statistical Analysis Used: Mean and percentage. Results: Mean duration of the indwelling catheter was 109 days for Hickman catheter, 39 days for cavafix and 59 days for certofix. Difficulty in insertion and arrhythmias were common complications. There were no incidences of major life threatening complications. Catheter related infection was 30%. The commonest reason for catheter removal was treatment completion 72%. The next frequent cause was catheter infection 14% and patient death 6%. Conclusions: Even though central venous catheterization is associated with acceptable complications, they serve a useful aid in management of patients on chemotherapy.