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1

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

PubMed Central

Background Electronic documentation handling may facilitate information flows in health care settings to support better coordination of care among Health Care Providers (HCPs), but evidence is limited. Methods that accurately depict changes to the workflows of HCPs are needed to assess whether the introduction of a Critical Care clinical Information System (CCIS) to two Intensive Care Units (ICUs) represents a positive step for patient care. To evaluate a previously described method of quantifying amounts of time spent and interruptions encountered by HCPs working in two ICUs. Methods Observers used PDAs running the Work Observation Method By Activity Timing (WOMBAT) software to record the tasks performed by HCPs in advance of the introduction of a Critical Care clinical Information System (CCIS) to quantify amounts of time spent on tasks and interruptions encountered by HCPs in ICUs. Results We report the percentages of time spent on each task category, and the rates of interruptions observed for physicians, nurses, respiratory therapists, and unit clerks. Compared with previously published data from Australian hospital wards, interdisciplinary information sharing and communication in ICUs explain higher proportions of time spent on professional communication and documentation by nurses and physicians, as well as more frequent interruptions which are often followed by professional communication tasks. Conclusions Critical care workloads include requirements for timely information sharing and communication and explain the differences we observed between the two datasets. The data presented here further validate the WOMBAT method, and support plans to compare workflows before and after the introduction of electronic documentation methods in ICUs.

2011-01-01

2

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.

Chakraborty, Dev P.

2009-01-01

3

Selecting Observational Studies for Comparing Medical Interventions. Methods Guide for Comparative Effectiveness Reviews.  

National Technical Information Service (NTIS)

While systematic reviewers disagree about the role of observational studies in answering questions about the benefits or intended effects of interventions, there is widespread agreement that observational studies, particularly those derived from large cli...

D. Atkins E. Johnson G. Randhawa M. Oremus M. Ospina R. Kane S. Fox S. Norris S. C. Morton W. Bruening

2010-01-01

4

A Method for Detection of Residual Confounding in Time-Series and Other Observational Studies  

PubMed Central

Background A difficult issue in observational studies is assessment of whether important confounders are omitted or misspecified. Here, we present a method for assessing whether residual confounding is present. Our method depends on availability of an indicator with two key characteristics: first, it is conditionally independent (given measured exposures and covariates) of the outcome in the absence of confounding, misspecification and measurement errors; second, it is associated with the exposure and, like the exposure, with any unmeasured confounders. Methods We demonstrate the method using a time-series study of the effects of ozone on emergency department visits for asthma in Atlanta. We argue that future air pollution may have the characteristics appropriate for an indicator, in part because future ozone cannot have caused yesterday’s health events. Using directed acyclic graphs and specific causal relationships, we show that one can identify residual confounding using an indicator with the stated characteristics. We use simulations to assess the discriminatory ability of future ozone as an indicator of residual confounding in the association of ozone with asthma-related emergency department visits. Parameter choices are informed by observed data for ozone, meteorologic factors and asthma. Results In simulations, we found that ozone concentrations one day after the emergency department visits had excellent discriminatory ability to detect residual confounding by some factors that were intentionally omitted from the model, but weaker ability for others. Although not the primary goal, the indicator can also signal other forms of modeling errors, including substantial measurement error, and does not distinguish between them. Conclusion The simulations illustrate that the indicator based on future air pollution levels can have excellent discriminatory ability for residual confounding, although performance varied by situation. Application of the method should be evaluated by considering causal relationships for the intended application, and should be accompanied by other approaches, including evaluation of a priori knowledge.

Flanders, W. Dana; Klein, M.; Darrow, L.A.; Strickland, M.J.; Sarnat, S.E.; Sarnat, J.A.; Waller, L.A.; Winquist, A.; Tolbert, P.E.

2013-01-01

5

A study of the pointed observation methods and sensitivity of HXMT  

NASA Astrophysics Data System (ADS)

The Hard X-ray Modulation Telescope (HXMT) is an X-ray astronomy satellite consisting of three slat-collimated instruments, the High Energy X-ray Instrument (HE), the Medium Energy X-ray Instrument (ME), and the Low Energy X-ray Instrument (LE). HXMT will carry out an all sky survey and make pointed observations in the 1-250 keV energy band. In order to get the source and background fluxes simultaneously in the pointed observations, two methods, i.e., the combined field of view (FOV) method and the off-axis pointing method are proposed in this paper. Comprehensive analyses of the sensitivities of the three instruments by using these two methods are presented, respectively. It is found that the off-axis pointing method has a higher sensitivity for HE and ME but a lower sensitivity for LE. Since the axes of the three instruments are aligned along the same direction, the off-axis pointing method is recommended as the main method in the pointed observation for HXMT; the combined FOV method can be used when LE is the most relevant instrument in order to satisfy the scientific objective of the observation.

Jin, Jing; Chen, Yong; Zhang, Shuang-Nan; Zhang, Shu; Li, Xin-Qiao; Li, Gang

2010-01-01

6

Monitoring of earthquake processes by passive and active EM methods. An observational study  

NASA Astrophysics Data System (ADS)

Three experiments are carried out from the Institute of Geology, CEA research group to study earthquake process by using different electromagnetic (EM) methods in recent years. Several earthquakes did occur during the observational period and EM anomalies were recorded before the main shocks. Our observation at 20 km away from the epicenter of Zhangbei MS6.2 earthquake of January 10, 1998 shows that the apparent resistivity decreases in the strike direction before and/or during the earthquake. In the same time the resistivity increases in the decline direction. This anomalous variation in apparent resistivity reaches about 20%. The apparent resistivity at the epicentral area decrease in the strike and decline directions before and/or during the earthquake and increase after the shock. The experiments using active low frequency electromagnetic signals were carried out in 1999 and show that the resolution and stability of electric and magnetic spectra are improved. The spectra of electric and magnetic fields and apparent resistivity at the Baodi station began to anomalously change two days before the Qian’an MS4.2 earthquake of May 12 with 120 km distant to the station. The anomalous variation of electric and magnetic spectra is about twice as great as normal variation and the apparent resistivity changes is about 20%. The measurements in active seismic area of Yunnan province in the year 2005 indicate that the electric and magnetic spectra anomalously change by one order before the Taoyuan MS3.6 earthquake of September 21 in about 100 km away from the observatories. But the measurements at the sites in Beijing area, 2 000 km away from the epicenter did not show any anomalous behavior. Our observation experience show presence of EM anomalous variations in different frequencies detected near to the epicentral areas of several earthquakes. We are considering that these practical examples and many other reported, suggest that the ground electromagnetic methods could play an important role in the understanding the EM phenomena related to the earthquake process.

Zhao, G.; Yan, Z.; Lifeng, W.; Wang, J.; Tang, J.; Xiao, Q.; Chen, X.; Zhao, J.

2009-12-01

7

Consistency across Methods of Observation -- An In-Depth Study of the Cognitive Preference Test.  

ERIC Educational Resources Information Center

|Two response formats and request for reason-for-choice on a traditional cognitive preference test (CPT) and an open-ended CPT were used to test for consistency across methods of observation at individual/population levels. Results indicate that validation of CPT constructs has not reached state of unequivocality necessary for their application in…

Jungwirth, Ehud

1983-01-01

8

An Alternative Method of Acute Lung Injury Classification for Use in Observational Studies  

PubMed Central

Background: In observational studies using acute lung injury (ALI) as an outcome, a spectrum of lung injury and difficult-to-interpret chest radiographs (CXRs) may hamper efforts to uncover risk factor associations. We assessed the impact of excluding patients with difficult-to-classify or equivocal ALI diagnosis on clinical and genetic risk factor associations for ALI after trauma. Methods: This study was of a prospective cohort of 280 critically ill trauma patients. The primary outcome was the development of ALI. Patients were classified into one of three groups: (1) definite ALI (patients who fulfilled the American-European Consensus Conference [AECC] criteria for ALI), (2)equivocal ALI (patients who had difficult-to-interpret CXRs), and (3) definite non-ALI. We compared clinical and genetic ALI risk factor associations between two classification schemes: AECC classification (definite ALI vs rest) and alternative classification (definite ALI vs definite non-ALI, excluding equivocal ALI). Results: Ninety-three (35%) patients were classified as definite ALI, 67 (25%) as equivocal, and 104 (39%) as definite non-ALI. Estimates of clinical and genetic ALI risk factor associations were farther from the null using the alternative classification. In a multivariable risk factor model, the C statistic of the alternative classification was significantly higher than that derived from the AECC classification (0.82 vs 0.74; P < .01). Conclusions: The ability to detect ALI risk factors may be improved by excluding patients with equivocal or difficult-to-classify ALI. Such analyses may provide improved ability to detect clinical and genetic risk factor associations in future epidemiologic studies of ALI.

Shah, Chirag V.; Lanken, Paul N.; Localio, A. Russell; Gallop, Robert; Bellamy, Scarlett; Ma, Shwu-Fan; Flores, Carlos; Kahn, Jeremy M.; Finkel, Barbara; Fuchs, Barry D.; Garcia, Joe G. N.

2010-01-01

9

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

Microsoft Academic Search

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

R Scott McCain; Andrew R Harris; Kevin McCallion; W Jeffrey Campbell; Stephen J Kirk

2010-01-01

10

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

11

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

PubMed Central

Objective To evaluate the effectiveness of methods that control for confounding by indication, we compared breast cancer recurrence rates among women receiving adjuvant chemotherapy versus those who did not. Study Design and Setting In a medical record review-based study of breast cancer treatment in older women (n=1798) diagnosed 1990-1994, our crude analysis suggested adjuvant chemotherapy was positively associated with recurrence [hazard ratio (HR)=2.6 (95% confidence interval (CI)=1.9, 3.5)]. We expected a protective effect, so postulated that the crude association was confounded by indications for chemotherapy. We attempted to adjust for this confounding by restriction, multivariable regression, propensity scores [PS], and instrumental variable [IV] methods. Results After restricting to women at high-risk for recurrence (n=946), chemotherapy was not associated with recurrence [HR=1.1 (95% CI=0.7, 1.6)] using multivariable regression. PS adjustment yielded similar results [HR=1.3 (95% CI=0.8, 2.0)]. The IV-like method yielded a protective estimate [HR=0.9; (95% CI=0.2, 4.3)]; however imbalances of measured factors across levels of the IV suggested residual confounding. Conclusion Conventional methods do not control for unmeasured factors, which often remain important when addressing confounding by indication. PS and IV analysis methods can be useful under specific situations, but neither method adequately controlled confounding by indication in this study.

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

2009-01-01

12

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

Microsoft Academic Search

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

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

2004-01-01

13

A Method to Detect Residual Confounding in Spatial and Other Observational Studies  

PubMed Central

Background Residual confounding is challenging to detect. We recently described a method for detecting confounding and justified it primarily for time-series studies. The method depends on an indicator with two key characteristics: (1) it is conditionally independent (given measured exposures and covariates) of the outcome, in the absence of confounding, misspecification and measurement errors; and (2) like the exposure, it is associated with confounders, possibly unmeasured. We proposed using future exposure levels as the indicator to detect residual confounding. This choice seems natural for time-series studies because future exposure cannot have caused the event, yet they could be spuriously related to it. A related question – addressed here – is whether an analogous indicator can be used to identify residual confounding in a study based on spatial, rather than temporal, contrasts. Methods Using directed acyclic graphs, we show that future air pollution levels may have the characteristics appropriate for an indicator of residual confounding in spatial studies of environmental exposures. We empirically evaluate performance for spatial studies using simulations. Results In simulations based on a spatial study of ambient air pollution levels and birth weight in Atlanta, and using ambient air pollution one year after conception as the indicator, we were able to detect residual confounding. The discriminatory ability approached 100% for some factors intentionally omitted from the model, but was very weak for others. Conclusion The simulations illustrate that an indicator based on future exposures can have excellent ability to detect residual confounding in spatial studies, although performance varied by situation.

Flanders, W. Dana; Klein, M.; Darrow, L.A.; Strickland, M.J.; Sarnat, S.E.; Sarnat, J.A.; Waller, L.A.; Winquist, A.; Tolbert, P.E.

2011-01-01

14

OBSERVATIONAL STUDIES OF PATIENTS IN THE EMERGENCY DEPARTMENT: A COMPARISON OF FOUR SAMPLING METHODS  

PubMed Central

Objectives We evaluated the ability of four sampling methods to generate representative samples of the Emergency Department (ED) population. Methods We analyzed the electronic records of 21,662 consecutive patient visits at an urban, academic ED. From this population, we simulated different models of study recruitment in the ED by employing two sample sizes (n = 200, 400) and four sampling methods: 1) true random; 2) random 4-hour time blocks by exact sample size; 3) random 4-hour time blocks by a pre-determined number of blocks; and 4) convenience or “business hours.” For each method and sample size, we obtained 1,000 samples from the population. Using chi-square tests, we measured the number of statistically significant differences between the sample and the population for eight variables (age, gender, race/ethnicity, language, triage acuity, arrival mode, disposition and payer source). Then, for each variable, method and sample size, we compared the proportion of the 1,000 samples that differed from the overall ED population to the expected proportion (5%). Results Only the true random samples represented the population with respect to gender, race/ethnicity, triage acuity, mode of arrival, language and payer source in at least 95% of the samples. Patient samples obtained using random 4-hour time blocks and business hours sampling systematically differed from the overall ED patient population for several important demographic and clinical variables. However, the magnitude of these differences was not large. Conclusions Common sampling strategies selected for ED-based studies may affect parameter estimates for several representative population variables. However, the potential for bias for these variables appears small.

Valley, Morgan A.; Heard, Kennon J.; Ginde, Adit A.; Lezotte, Dennis C.; Lowenstein, Steven R.

2012-01-01

15

Are There Better Methods of Monitoring MRSA Control than Bacteraemia Surveillance? An Observational Database Study  

Microsoft Academic Search

BackgroundDespite a substantial burden of non-bacteraemic methicillin resistant Staphylococcus aureus (MRSA) disease, most MRSA surveillance schemes are based on bacteraemias. Using bacteraemia as an outcome, trends at hospital level are difficult to discern, due to random variation. We investigated rates of nosocomial bacteraemic and non-bacteraemic MRSA infection as surveillance outcomes.Methods and FindingsWe used microbiology and patient administration system data from

Sarah Walker; Tim E. A. Peto; Lily O'Connor; Derrick W. Crook; David Wyllie; Steven M. Opal

2008-01-01

16

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

Microsoft Academic Search

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

Graham A. Colditz

2010-01-01

17

Maternal Observations of Child Behaviours in the Course of Home Televiewing: A Method for Studying Small Children's Preferences for and Reactions to TV Programmes. Summary of the Method Used in Six Studies of Children.  

ERIC Educational Resources Information Center

|The findings of six studies based on in-home observations of children's television viewing behavior as recorded by mothers, fathers, or other adults caring for the child are summarized and compared. The object of this research method is to determine child interest in the programs, the variability of interest within programs, the amount of series…

Feilitzen, Cecilia

18

A review of methods used in assessing non-serious adverse drug events in observational studies among type 2 diabetes mellitus patients  

PubMed Central

Clinical drug trials are often conducted in selective patient populations, with relatively small numbers of patients, and a short duration of follow-up. Observational studies are therefore important for collecting additional information on adverse drug events (ADEs). Currently, there is no guidance regarding the methodology for measuring ADEs in such studies. Our aim was to evaluate whether the methodology used to assess non-serious ADEs in observational studies is adequate for detecting these ADEs, and for addressing limitations from clinical trials in patients with type 2 diabetes mellitus. We systematically searched MEDLINE and EMBASE for observational studies reporting non-serious ADEs (1999-2008). Methods to assess ADEs were classified as: 1) medical record review; 2) surveillance by health care professionals (HCP); 3) patient survey; 4) administrative data; 5) laboratory/clinical values; 6) not specified. We compared the range of ADEs identified, number and selection of patients included, and duration of follow-up. Out of 10,125 publications, 68 studies met our inclusion criteria. The most common methods were based on laboratory/clinical values (n = 25) and medical record review (n = 18). Solicited surveillance by HCP (n = 17) revealed the largest diversity of ADEs. Patient surveys (n = 15) focused mostly on hypoglycaemia and gastrointestinal ADEs, laboratory values based studies on hepatic and metabolic ADEs, and administrative database studies (n = 5) on cardiovascular ADEs. Four studies presented ADEs that were identified with the use of more than one method. The patient population was restricted to a lower risk population in 19% of the studies. Less than one third of the studies exceeded pre-approval regulatory requirements for sample size and duration of follow-up. We conclude that the current assessment of ADEs is hampered by the choice of methods. Many observational studies rely on methods that are inadequate for identifying all possible ADEs. Patient-reported outcomes and combinations of methods are underutilized. Furthermore, while observational studies often include unselective patient populations, many do not adequately address other limitations of pre-approval trials. This implies that these studies will not provide sufficient information about ADEs to clinicians and patients. Better protocols are needed on how to assess adverse drug events not only in clinical trials but also in observational studies.

2011-01-01

19

Parallax correction in collocating CloudSat and Moderate Resolution Imaging Spectroradiometer (MODIS) observations: Method and application to convection study  

Microsoft Academic Search

Parallax correction is important for spaceborne studies of convective cloudsParallax correction here improves the estimates of cloud top temperatureParallax correction affects relevant statistics in satellite data analysis

Chunpeng Wang; Zhengzhao Johnny Luo; Xianglei Huang

2011-01-01

20

Evaluation of the process observer method: Group leader, member, and observer perspectives  

Microsoft Academic Search

Previous research indicates that the presence of an observer my be disruptive for group members and leaders, whereas anecdotal reports suggest that the presence of a process observer is minimally disruptive. This study evaluated the process observer method of group training from the perspective of 20 leaders, 38 members, and 11 observers. Results indicated that process observers were not a

Kathleen J. Bieschke; Connie Matthews; John Wade; Paula Ann Pricken

1998-01-01

21

What Observational Studies Can Offer Decision Makers  

Microsoft Academic Search

Observational studies, for example cohort and case-control studies in which patients are allocated treatment on a non-random basis, are thought by some investigators to be flawed. This view results from the fact that, unlike experimental methods (randomized controlled trials; RCTs), the results of such observational studies are vulnerable to confounding. However, this view assumes that satisfactory adjustment of differences in

Nick Black

1999-01-01

22

Assessing observational studies of medical treatments  

PubMed Central

Background Previous studies have assessed the validity of the observational study design by comparing results of studies using this design to results from randomized controlled trials. The present study examined design features of observational studies that could have influenced these comparisons. Methods To find at least 4 observational studies that evaluated the same treatment, we reviewed meta-analyses comparing observational studies and randomized controlled trials for the assessment of medical treatments. Details critical for interpretation of these studies were abstracted and analyzed qualitatively. Results Individual articles reviewed included 61 observational studies that assessed 10 treatment comparisons evaluated in two studies comparing randomized controlled trials and observational studies. The majority of studies did not report the following information: details of primary and ancillary treatments, outcome definitions, length of follow-up, inclusion/exclusion criteria, patient characteristics relevant to prognosis or treatment response, or assessment of possible confounding. When information was reported, variations in treatment specifics, outcome definition or confounding were identified as possible causes of differences between observational studies and randomized controlled trials, and of heterogeneity in observational studies. Conclusion Reporting of observational studies of medical treatments was often inadequate to compare study designs or allow other meaningful interpretation of results. All observational studies should report details of treatment, outcome assessment, patient characteristics, and confounding assessment.

Hartz, Arthur; Bentler, Suzanne; Charlton, Mary; Lanska, Douglas; Butani, Yogita; Soomro, G Mustafa; Benson, Kjell

2005-01-01

23

Observational Studies and Experiments Activity  

NSDL National Science Digital Library

This activity will allow students to learn the difference between observational studies and experiments, with emphasis on the importance of cause-and-effect relationships. The activity will also familiarize students with key terms such as factors, treatments, retrospective and prospective studies, etc. This is an easy to follow lesson plan for those teaching a course in statistics.

2009-07-21

24

Importance of Observational Studies in Clinical Practice  

Microsoft Academic Search

Background: In this era of evidence-based medicine, clinicians require a comprehensive range of well-designed studies to support prescribing decisions and patient management. In recent years, data from observational studies have become an increasingly important source of evidence because of improvements in observational-study methods and advances in statistical analysis.Objective: This article reviews the current literature and reports some of the key

Robert J. Ligthelm; Vito Borzì; Janusz Gumprecht; Ryuzo Kawamori; Yang Wenying; Paul Valensi

2007-01-01

25

A Tutorial on Methods to Estimating Clinically and Policy-Meaningful Measures of Treatment Effects in Prospective Observational Studies: A Review  

PubMed Central

In randomized controlled trials (RCTs), treatment assignment is unconfounded with baseline covariates, allowing outcomes to be directly compared between treatment arms. When outcomes are binary, the effect of treatment can be summarized using relative risks, absolute risk reductions and the number needed to treat (NNT). When outcomes are time-to-event in nature, the effect of treatment on the absolute reduction of the risk of an event occurring within a specified duration of follow-up and the associated NNT can be estimated. In observational studies of the effect of treatments on health outcomes, treatment is frequently confounded with baseline covariates. Regression adjustment is commonly used to estimate the adjusted effect of treatment on outcomes. We highlight several limitations of measures of treatment effect that are directly obtained from regression models. We illustrate how both regression-based approaches and propensity-score based approaches allow one to estimate the same measures of treatment effect as those that are commonly reported in RCTs. The CONSORT statement recommends that both relative and absolute measures of treatment effects be reported for RCTs with dichotomous outcomes. The methods described in this paper will allow for similar reporting in observational studies.

Austin, Peter C; Laupacis, Andreas

2011-01-01

26

Ways of learning: Observational studies versus experiments  

USGS Publications Warehouse

Manipulative experimentation that features random assignment of treatments, replication, and controls is an effective way to determine causal relationships. Wildlife ecologists, however, often must take a more passive approach to investigating causality. Their observational studies lack one or more of the 3 cornerstones of experimentation: controls, randomization, and replication. Although an observational study can be analyzed similarly to an experiment, one is less certain that the presumed treatment actually caused the observed response. Because the investigator does not actively manipulate the system, the chance that something other than the treatment caused the observed results is increased. We reviewed observational studies and contrasted them with experiments and, to a lesser extent, sample surveys. We identified features that distinguish each method of learning and illustrate or discuss some complications that may arise when analyzing results of observational studies. Findings from observational studies are prone to bias. Investigators can reduce the chance of reaching erroneous conclusions by formulating a priori hypotheses that can be pursued multiple ways and by evaluating the sensitivity of study conclusions to biases of various magnitudes. In the end, however, professional judgment that considers all available evidence is necessary to render a decision regarding causality based on observational studies.

Shaffer, T. L.; Johnson, D. H.

2008-01-01

27

Observer evaluation of a method for producing simulated mammograms  

NASA Astrophysics Data System (ADS)

We have developed a method for producing simulated mammograms from high fidelity breast specimen radiographs. The method has the advantage of having access to all the truth information for the lesions. By modeling different parts of a screen-film system, we simulated the output of the system, and compared it to the real mammography images from the same samples. In this work we show how our simulation program produces realistic mammography images and also the observer study that tests how well the observers can distinguish the real and simulated images. Preliminary results from the ROC study show that the observers could not distinguish the two types of images very well.

Chinander, Michael R.; Nishikawa, Robert M.; Seifi, Payam

2007-03-01

28

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

29

Observational studies of stellar rotation  

NASA Astrophysics Data System (ADS)

This course reviews the rotational properties of non- degenerate stars as observed from the protostellar stage to the end of the main sequence. It includes an introduction to the various observational techniques used to measure stellar rotation. Angular momentum evolution models developed over the mass range from the substellar domain to high-mass stars are briefly discussed.

Bouvier, J.

2013-09-01

30

Science Studies from Archived Observations  

NASA Astrophysics Data System (ADS)

Goals for spaceflight investigations include the discovery and characterization of physical features of the in- situ and remote environment. Abundant successes of flight investigations are easily documented. Prudent scientific practice dictates that to the maximum extent possible, observations should be well-characterized, reliably catalogued, and knowledgeably interpreted. This is especially true of data sets used in the publication of results in the reviewed literature. Typical scientific standards include making primary data numbers available to other investigators for replicated study. While NASA's contracts with investigators have required that data be submitted to agency official archives, the details, completeness (especially of ancillary and metadata) and forms differ from investigation to investigation and project to project. After several generations of improvements and refinements, modern computing and communications technology makes it possible to link multiple data sets at multiple locations through a unified data model. Virtual Observatories provide the overall organizational structures and SPASE-compliant XML defines the data granules that can be located. Proofs of the feasibility and value of this latest approach remain to be seen, but its ultimate goal of improving archival research using flight-derived data sets appears to depend on user acceptance and efficient use of the VxO resources. Criteria based on the authors experience in science derived from archival sources follow: 1. Interfaces and tools must be easy to learn, easy to use, and reliable. 2. Data numbers must be promptly downloadable in plain text. 3. Data must be available in or readily converted to physical units using calibrations and algorithms easily traceable as part of the search. Knowledge about (or heritage of) specific data items present in the science literature must be associated with the search for that item. 4. Data items must be trustworthy, having quoted uncertainties and available history where versioning has occurred. While these are challenging criteria to meet-especially in succinct form-the use of archival data for valid science publication requires that these criteria are achieved. The full presentation will illustrate and expand on these criteria.

Armstrong, T. P.; Manweiler, J. W.; Patterson, J. D.

2008-12-01

31

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

Microsoft Academic Search

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

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

2004-01-01

32

Geometrical methods for the analysis of cosmological observations  

NASA Astrophysics Data System (ADS)

Methods were analyzed with which the cosmologically significant content of cosmological observations can be exploited for the establishment of cosmological models. The studies, based on the invariant calculus of differential geometry, were performed in the framework of the general relativity theory, with real shift, angular diameter, and apparent luminosity as observable quantities. The ascertainment procedure for the cosmological parameters (Hubble constant and deceleration parameter) are transferred from kinematical Robertson-Walker models to universal space-time models, leading to several generalizations of these parameters. Then idealized observation results are analyzed with a view to the circumscription of the world model to be constructed.

Hasse, Wolfgang

33

Primer: challenges in randomized and observational studies  

Microsoft Academic Search

Randomized controlled trials (RCTs) are considered superior to observational studies, and both clinicians and researchers believe that conclusions that stem from observational research are flawed. RCTs, however, have important methodological and interpretational limitations, and particular clinical questions can only be addressed by observational research. This Review compares RCTs and observational studies with regard to particular limitations, and explains how the

Désirée van der Heijde; Robert Landewé

2007-01-01

34

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.

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

2012-01-01

35

Micro cutting of tungsten carbides with sem direct observation method  

Microsoft Academic Search

This paper describes the micro cutting of wear resistant tungsten carbides using PCD (Poly-Crystalline Diamond) cutting tools\\u000a in performance with SEM (Scanning Electron Microscope) direct observation method. Turning experiments were also carried out\\u000a on this alloy (V50) using a PCD cutting tool. One of the purposes of this study is to describe clearly the cutting mechanism\\u000a of tungsten carbides and

Heo Sung-jung

2004-01-01

36

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

37

Classroom Observation: A Case Study in Obtrusiveness.  

National Technical Information Service (NTIS)

A case study is presented concerning an observation methodology that advocates an anthropological approach to such data collection, and, in particular, demonstrates the effectiveness of a highly interactive role for the classroom observer. Part I traces t...

T. H. Bikson

1977-01-01

38

Offering fragile X syndrome carrier screening: a prospective mixed-methods observational study comparing carrier screening of pregnant and non-pregnant women in the general population  

PubMed Central

Introduction Fragile X syndrome (FXS) is the leading cause of inherited intellectual and developmental disability. Policy development relating to carrier screening programmes for FXS requires input from large studies examining not only test uptake but also psychosocial aspects. This study will compare carrier screening in pregnant and non-pregnant populations, examining informed decision-making, psychosocial issues and health economics. Methods and Analysis Pregnant and non-pregnant women are being recruited from general practices and obstetric services. Women receive study information either in person or through clinic mail outs. Women are provided pretest counselling by a genetic counsellor and make a decision about testing in their own time. Data are being collected from two questionnaires: one completed at the time of making the decision about testing and the second 1?month later. Additional data are gathered through qualitative interviews conducted at several time points with a subset of participating women, including all women with a positive test result, and with staff from recruiting clinics. A minimum sample size of 500 women/group has been calculated to give us 88% power to detect a 10% difference in test uptake and 87% power to detect a 10% difference in informed choice between the pregnant and non-pregnant groups. Questionnaire data will be analysed using descriptive statistics and multivariate logistic regression models. Interview data will be thematically analysed. Willingness-to-pay and cost effectiveness analyses will also be performed. Recruitment started in July 2009 and data collection will be completed by December 2013. Ethics and Dissemination Ethics approval has been granted by the Universities of Melbourne and Western Australia and by recruiting clinics, where required. Results will be reported in peer-reviewed publications, conference presentations and through a website http://www.fragilexscreening.net.au. The results of this study will make a significant contribution to discussions about the wider introduction of population carrier screening for FXS.

Martyn, M; Anderson, V; Archibald, A; Carter, R; Cohen, J; Delatycki, M; Donath, S; Emery, J; Halliday, J; Hill, M; Sheffield, L; Slater, H; Tassone, F; Younie, S; Metcalfe, S

2013-01-01

39

A Method for Systematically Observing and Recording Collective Action  

Microsoft Academic Search

his article describes a method for systematically observing and recording collective action within temporary gather- ings. Our method uses trained observers, distributed across a gather- ing, who complete a code sheet during time interval samples. The data collected provide a rich record of collective action across space and time. This method has been used to collect data at three Washington,

DAVID SCHWEINGRUBER; CLARK MCPHAIL

1999-01-01

40

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.  

PubMed

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. PMID:22516804

Chakraborty, Dev P

2012-04-20

41

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

42

[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; Gøtzsche, Peter C; Vandenbroucke, Jan P

43

[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; Gøtzsche, Peter C; Vandenbroucke, Jan P

44

New method for studying isostatic compensation of the earth from ground-based and satellite gravity observations with some numerical results  

Microsoft Academic Search

The problem of approximate determination of the characteristic density of the earth's crust and upper mantle from ground-based and satellite gravimetric observations is formulated. It is shown that the earth is isostatically uncompensated, and on the basis of experimental data, zones on the earth's surface with characteristic density larger and smaller than the density corresponding to isostatic equilibrium are identified.

Zh. Zhelev

1978-01-01

45

Systematic studies of global observables by PHENIX  

SciTech Connect

Systematic studies of global observables in different collision systems are indispensable for mapping the QCD phase diagram. Fluctuations in these quantities can provide fundamental information relevant for the phase transitions. The following global observables relevant to critical behavior are studied: the longitudinal density correlation, K to {pi} and p to {pi} fluctuations, and the constituent quark number scaling for elliptic flows.

Homma, Kensuke [Hiroshima University, Japan; Awes, Terry C [ORNL; Cianciolo, Vince [ORNL; Efremenko, Yuri V [ORNL; Enokizono, Akitomo [Lawrence Livermore National Laboratory (LLNL); Hornback, Donald [University of Tennessee, Knoxville (UTK); Read Jr, Kenneth F [ORNL; Silvermyr, David O [ORNL; Sorensen, Soren P [University of Tennessee, Knoxville (UTK); Stankus, Paul W [ORNL; Young, Glenn R [ORNL; PHENIX, Collaboration [The

2008-01-01

46

Methods of observations of pulsars and its data processing  

Microsoft Academic Search

Basic observational methods of pulsars and their data processing are introduced. Signal processing procedures in the experimental observation of PSR 1929+10 are reported. A method to get the best result by connecting the mid-results with different SNR is given at the end.

Jinlin Han

1992-01-01

47

A new method of ARGO buoys system observation data interpolation  

NASA Astrophysics Data System (ADS)

Study and solution of geophysical hydrodynamics problems are based on experimental and observation data from different sources. Despite large amount of observation data, availability of them often remains insufficient because data are provided on sets of irregular points and during the asynchronous moments of time. In this work a new method of temperature fields creation on regular grids according to observation data is offered taking into account a transfer by their currents. By means of this method it is possible to receive "pseudo-observations" for the required moment of time and, thereby, to solve a problem of an asynchronism of geophysical information. The results of numerical experiments on the World Ocean area within ARGO buoys system data are given. This study was supported by the Russian Foundation for Basic Research (project 11-01-12046, 12-05-00469) and by the Russian Federal target Program "Research and educational human resources for innovative Russia" (project 8219) for 2009-2013 and the Federal target program "Researches and development in priority fields of scientific and technological complex of Russia for 2007-2013" (project 11.519.11.1005) and the Ministry of education and science of Russia, project 14.A18.21.1901. References 1. Zakharova N.B., Agoshkov V.I., Parmuzin E.I., The new method of ARGO buoys system observation data interpolation. Russian Journal of Numerical Analysis and Mathematical Modelling. Vol. 28, Issue 1, 2013. 2. Agoshkov V.I., Zakharova N.B., The creation of piecewise - harmonic interpolation on spherical surfaces. Russian Journal of Numerical Analysis and Mathematical Modelling. Vol. 27, Issue 6, 2012. 3. Zakharova N.B., Lebedev S.A., Interpolation of on-line data of the ARGO buoys system for data assimilation in the World ocean circulation model. Actual problems in remote sensing of the Earth from space: Principal physics, physical methods and technologies for monitoring of environment, of potentially dangerous occurrences and objects. The proceedings. Vol. 7. No. 4. 2010. (In russian)

Zakharova, Natalia; Agoshkov, Valery; Parmuzin, Eugene

2013-04-01

48

Comparison of statistical methods for analysis of clustered binary observations.  

PubMed

When correlated observations are obtained in a randomized controlled trial, the assumption of independence among observations within cluster likely will not hold because the observations share the same cluster (e.g. clinic, physician, or subject). Further, the outcome measurements of interest are often binary. The objective of this paper is to compare the performance of four statistical methods for analysis of clustered binary observations: namely (1) full likelihood method; (2) penalized quasi-likelihood method; (3) generalized estimating equation method; (4) fixed-effects logistic regression method. The first three methods take correlations into account in inferential processes whereas the last method does not. Type I error rate, power, bias, and standard error are compared across the four statistical methods through computer simulations under varying effect sizes, intraclass correlation coefficients, number of clusters, and number of observations per cluster, including large numbers 20 and 100 of observations per cluster. The results show that the performance of the full likelihood and the penalized quasi-likelihood methods is superior for analysis of clustered binary observations, and is not necessarily inferior to that of the fixed-effects logistic regression fit even when within-cluster correlations are zero. PMID:15558576

Heo, Moonseong; Leon, Andrew C

2005-03-30

49

On "observation minus reanalysis" method: A view from multidecadal variability  

NASA Astrophysics Data System (ADS)

The observation minus reanalysis (OMR) method is widely used to investigate the impact of urbanization and land use change on climate. Here we present the OMR trends for the periods of 1979-1998 and 1989-2008 in eastern China, which appear inconsistent for the regions experiencing rapid urbanization during recent decades. Using Ensemble Empirical Mode Decomposition, we extract the secular trend and multidecadal variability (MDV) from the temperature observations at stations and the corresponding reanalysis data for the last century and find that, in general, MDV in the reanalysis data is weaker than that in the station observations. This systematic difference considerably modulates the magnitude of the OMR trends during different periods, leading to inconsistent estimates of the impact of urbanization. After MDV adjustment, the OMR trends for Beijing and Shanghai are consistent for the different periods, about 0.04°C-0.1°C/decade, much smaller than some previous estimates. We caution those using OMR methods to estimate the effect of urbanization and also for those using reanalysis data for a limited period in studies of this kind.

Wang, Jun; Yan, Zhongwei; Jones, Phil D.; Xia, Jiangjiang

2013-07-01

50

Methods for observational post-licensure medical product safety surveillance.  

PubMed

Post-licensure medical product safety surveillance is important for detecting adverse events potentially not identified pre-licensure. Historically, post-licensure safety monitoring has been accomplished using passive reporting systems and by conducting formal Phase IV randomized trials or large epidemiological studies, also known as safety surveillance or pharmacovigilance studies. However, crucial gaps in the safety evidence base provided by these approaches have led to high profile product withdrawals and growing public concern about unknown health risks associated with licensed products. To address the limitations of existing surveillance systems and to facilitate more accurate and rapid detection of safety problems, new systems involving active surveillance of large, population-based cohorts using observational health care utilization databases are being developed. In this article, we review common statistical methods that have been employed previously for post-licensure safety monitoring, including data mining and sequential hypothesis testing, and assess which methods may be promising for potential use within this newly proposed prospective observational cohort monitoring framework. We discuss gaps in existing approaches and identify areas where methodological development is needed to improve the success of safety surveillance efforts in this setting. PMID:22138688

Nelson, Jennifer C; Cook, Andrea J; Yu, Onchee; Zhao, Shanshan; Jackson, Lisa A; Psaty, Bruce M

2011-12-01

51

Interdisciplinary rehabilitation in morbidly obese subjects: an observational pilot study  

Microsoft Academic Search

Interdisciplinary rehabilitation in morbidly obese subjects: an observational pilot study. E. Clini, F. Prato, M. Nobile, M. Bondi, B. Serri, C. Cilione, D. Lugli. Background and aim. To assess the clinical effective- ness of a interdisciplinary rehabillitation programme (CR), in a population of morbidly obese subjects we have undertaken a observational study. Methods. The study included fifty-nine adult subjects (18

E. Clini; F. Prato; M. Nobile; M. Bondi; B. Serri; C. Cilione; D. Lugli

52

Community Engagement in Observational Human Exposure Studies  

EPA Science Inventory

Although observational human exposure studies do not deliberately expose participants to chemicals or environmental conditions, merely involving people as research participants and conducting research inside homes raises ethical issues. Community engagement offers a promising st...

53

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.

Chakraborty, Dev P.

2012-01-01

54

An observational method of assessing handedness in children and adults.  

PubMed

The current study was performed to assess the WatHand Cabinet Test (WHCT), a newly developed multidimensional observational test of handedness. Because the test is observational, it is ideal for assessing children, as it does not require a high degree of verbal comprehension on the part of the participants. 548 individuals participated in the present study on a voluntary basis. Individuals of varying ages were examined (including 3 to 5, 6, 7, 8, 9, 10, and 11-year-olds, and 19-to 24-year-olds). Each participant was asked to complete the WHCT, the Annett Pegboard (Annett, 1985), and the Waterloo Handedness Questionnaire (WHQ) (M.P. Bryden, 1977). Overall, the total score on the WHCT was significantly correlated with both the WHQ, r = .795, p < .01, and the Annett Pegboard, r = .542, p < .01. Sub-scores measuring skilled performance, bimanual performance, and internal consistency were also examined, as well as performance on the three tests as a function of age. Overall, findings indicate that that the WHCT is a valid test of hand preference in both children and adults. Its ease of use, quick administration, and built-in quantitative sub-scores offer a robust alternative method for measuring hand preference. PMID:17956184

Bryden, P J; Roy, E A; Spence, J

2007-01-01

55

Systematic observer variation in trachoma studies  

PubMed Central

There has been increasing awareness in recent years among trachomatologists, as well as among workers in other fields of medical research, of the frequency and importance of observer variation in epidemiological studies and clinical trials. In trachoma, the lack of simple definitive laboratory diagnostic procedures suitable for wide application has placed the onus largely, and usually exclusively, on clinical observation. The study reported is based on the recorded observations of two skilled ophthalmologists in an epidemiological survey covering more than 35 000 persons in Taiwan. Observer differences were found to lie not only in deciding whether a case is trachomatous or not but also in assigning cases diagnosed as trachoma to the appropriate evolutive stage of the WHO trachoma classification. The conclusions reached are that: (a) inter- and intra-observer variations of some degree are inevitable if dependence is placed on clinical examination alone; (b) it is possible by preliminary testing of observers' interpretation of clinical signs to determine the nature of these differences, to assess their importance, and to reduce them; also to set base-lines for the detection of subsequent divergences over time; and (c) it is better to have two observers than one in any trachoma survey or clinical trial.

Assaad, F. A.; Maxwell-Lyons, F.

1967-01-01

56

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

Microsoft Academic Search

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

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

2007-01-01

57

Observing Protein & Energy Nutrition (OPEN) Study  

Cancer.gov

Skip to Content Cancer Control and Population Sciences Home Applied Research Home Risk Factor Monitoring and Methods Home OPEN: What is the OPEN Study? Why assess measurement error? How did OPEN assess measurement error? What is the current status of

58

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

59

Freezing Rain: An Observational and Theoretical Study  

Microsoft Academic Search

Data from a Doppler radar, an instrumented aircraft, and several rawinsonde observations during freezing rain and ice pellet events have been analyzed for this study. From these data, 34 soundings were obtained that characterized the vertical structure of the atmosphere at the time of the freezing precipitation. These soundings were analyzed to determine the general nature of the vertical structure

Ryan J. Zerr

1997-01-01

60

Observational Equivalence? Regional Studies and Regional Science  

Microsoft Academic Search

McCann P. (2007) Observational equivalence? Regional studies and regional science, Regional Studies41, 1209–1221. This paper considers the methodological and empirical issues raised by the adoption of stylized constructs in the development of regional policy. Public policies invariably require funding, and the greater levels of public data availability and press scrutiny nowadays have led to increasing requirements for policy transparency driven

Philip Mccann

2007-01-01

61

The Implications of Observer Variation for Existing Macrophyte Recording Methods  

Microsoft Academic Search

\\u000a The scale of observer variation recorded during the Western Cleddau sampling trials has implications for all of the established\\u000a methods of river macrophyte recording, and in this chapter we look at the implications for two of the methods associated with\\u000a Water Framework Directive (WFD) monitoring in the UK, namely Common Standards Monitoring (CSM) and the LEAFPACS macrophyte\\u000a methodology. We also

Clive Hurford; Richard Lansdown

62

An Observational Study of Cataclysmic Variable Evolution  

NASA Astrophysics Data System (ADS)

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

Araujo-Betancor, Sofia

2004-03-01

63

Parent–child interactions and anxiety disorders: an observational study  

Microsoft Academic Search

Past research has indicated a potential link between anxiety and parenting styles that are characterised by control and rejection. However, few studies have utilised observational methods to support these findings. In the current study, mother–child interactions were observed while the child completed two difficult cognitive tasks. The sample consisted of clinically anxious children (n=43), oppositional defiant children (n=20) and non-clinical

Jennifer L Hudson; Ronald M Rapee

2001-01-01

64

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

65

Method Study 2: Nutrient Analyses, Manual Methods.  

National Technical Information Service (NTIS)

Interlaboratory studies were conducted on selected chemical methods of analysis for ammonia nitrogen, nitrate nitrogen, Kjeldahl nitrogen or organic nitrogen, orthophosphate and total phsophorus. Samples were prepared in pairs at similar yet different con...

1970-01-01

66

Methods Control Radioastronomy Observations and Processing of Cosmic Radio Sources  

NASA Astrophysics Data System (ADS)

In this paper the following methods represented: control of the radio astronomical observations using the estimation results, making decisions on the detection of cosmic sources, taking into account noise and interference, and recognizers classes of cosmic radio sources to the maximum of a posteriori probability (Bayesian approach). The problem researched is about storing and transferring large amounts of scientific information from cosmic radio sources to consumers.

Isaev, E. A.

67

LONGITUDINAL COHORT METHODS STUDIES  

EPA Science Inventory

Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Exposure classification for occupational studies is relatively easy compared to predicting residential childhood exposures. Recent NHEXAS (Maryland) study articl...

68

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

69

Disproportionality methods for pharmacovigilance in longitudinal observational databases.  

PubMed

Data mining disproportionality methods (PRR, ROR, EBGM, IC, etc.) are commonly used to identify drug safety signals in spontaneous report system (SRS) databases. Newer data sources such as longitudinal observational databases (LOD) provide time-stamped patient-level information and overcome some of the SRS limitations such as an absence of the denominator, total number of patients who consume a drug, and limited temporal information. Application of the disproportionality methods to LODs has not been widely explored. The scale of the LOD data provides an interesting computational challenge. Larger health claims databases contain information on more than 50 million patients and each patient has records for up to 10 years. In this article we systematically explore the application of commonly used disproportionality methods to simulated and real LOD data. PMID:21878461

Zorych, Ivan; Madigan, David; Ryan, Patrick; Bate, Andrew

2011-08-30

70

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

71

Techniques and methods in ground-based observation of Mercury  

NASA Astrophysics Data System (ADS)

Modern telescopes and equipments have permitted excellent ground-based observations of Mercury, despite its proximity to the Sun. This is one of the main reasons why it has been observed using different techniques from high-resolution spectroscopy to high-resolution imaging from visible to infrared up to radio wavelengths. Because there is no obscuration from a thick atmosphere, the surface and exosphere have been imaged and the surface studied by infrared spectroscopy. This manuscript describes the techniques used to obtain information and new data of Mercury giving an overview of advantages and difficulties, and describes important scientific discoveries made with specific telescopic instrumentation.

Cremonese, G.; Warell, J.; Harmon, J. K.; Leblanc, F.; Mendillo, M.; Sprague, A. L.

2010-01-01

72

Applying an Automatic Image-Processing Method to Synoptic Observations  

NASA Astrophysics Data System (ADS)

We used an automatic image-processing method to detect solar-activity features observed in white light at the Kislovodsk Solar Station. This technique was applied to automatically or semi-automatically detect sunspots and active regions. The results of this automated recognition were verified with statistical data available from other observatories and revealed a high detection accuracy. We also provide parameters of sunspot areas, of the umbra, and of faculae as observed in Solar Cycle 23 as well as the magnetic flux of these active elements, calculated at the Kislovodsk Solar Station, together with white-light images and magnetograms from the Michaelson Doppler Imager onboard the Solar and Heliospheric Observatory (SOHO/MDI). The ratio of umbral and total sunspot areas during Solar Cycle 23 is ? 0.19. The area of sunspots of the leading polarity was approximately 2.5 times the area of sunspots of the trailing polarity.

Tlatov, Andrey G.; Vasil'eva, Valeria V.; Makarova, Valentina V.; Otkidychev, Pavel A.

2013-10-01

73

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 Alzheimer’s 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 Förstl

2007-01-01

74

Why Rudolph's nose is red: observational study  

PubMed Central

Objective To characterise the functional morphology of the nasal microcirculation in humans in comparison with reindeer as a means of testing the hypothesis that the luminous red nose of Rudolph, one of the most well known reindeer pulling Santa Claus’s sleigh, is due to the presence of a highly dense and rich nasal microcirculation. Design Observational study. Setting Tromsø, Norway (near the North Pole), and Amsterdam, the Netherlands. Participants Five healthy human volunteers, two adult reindeer, and a patient with grade 3 nasal polyposis. Main outcome measures Architecture of the microvasculature of the nasal septal mucosa and head of the inferior turbinates, kinetics of red blood cells, and real time reactivity of the microcirculation to topical medicines. Results Similarities between human and reindeer nasal microcirculation were uncovered. Hairpin-like capillaries in the reindeers’ nasal septal mucosa were rich in red blood cells, with a perfused vessel density of 20 (SD 0.7) mm/mm2. Scattered crypt or gland-like structures surrounded by capillaries containing flowing red blood cells were found in human and reindeer noses. In a healthy volunteer, nasal microvascular reactivity was demonstrated by the application of a local anaesthetic with vasoconstrictor activity, which resulted in direct cessation of capillary blood flow. Abnormal microvasculature was observed in the patient with nasal polyposis. Conclusions The nasal microcirculation of reindeer is richly vascularised, with a vascular density 25% higher than that in humans. These results highlight the intrinsic physiological properties of Rudolph’s legendary luminous red nose, which help to protect it from freezing during sleigh rides and to regulate the temperature of the reindeer’s brain, factors essential for flying reindeer pulling Santa Claus’s sleigh under extreme temperatures.

2012-01-01

75

Advanced Rain\\/No-Rain Classification Methods for Microwave Radiometer Observations over Land  

Microsoft Academic Search

Seto et al. developed rain\\/no-rain classification (RNC) methods over land for the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). In this study, the methods are modified for appli- cation to other microwave radiometers. The previous methods match TMI observations with TRMM precipitation radar (PR) observations, classify the TMI pixels into rain pixels and no-rain pixels, and then statistically summarize

Shinta Seto; Takuji Kubota; Nobuhiro Takahashi; Toshio Iguchi; Taikan Oki

2008-01-01

76

The Effects of Integrating Technology, Observation and Writing into a Teacher Education Method Course  

ERIC Educational Resources Information Center

|The purpose of this study was to integrate asynchronous learning technology with teaching strategies on observation and writing into a teacher education method course. The research questions were to explore the effects of the innovative teaching method and to compare it with the traditional teaching method. There were 134 preservice teachers…

Jang, Syh-Jong

2008-01-01

77

A novel method for the observation of membrane transporter dynamics.  

PubMed Central

A new method is proposed for measuring the dynamic properties of a membrane transporter by means of steady-state fluxes. Any voltage-sensitive transporter will give a flow of substrate in the presence of a steady-state periodic membrane potential. The periodic steady-state flow, averaged over one period, is a flux that can be measured by traditional steady-state techniques, such as the radioactive tracer method. The average flux, solely due to the periodic field, is described by a set of Lorentzian functions that depend on the applied periodic field amplitude and frequency. The normal mode amplitudes and frequencies of these Lorentzians are model-independent parameters of the transport mechanism. Measurement of the average flux as a function of the applied periodic frequency permits determination of system relaxation times as the reciprocals of the midpoints of the Lorentzian curves, which in turn can be used to estimate individual rate constants of specific models. It was found by simulation of a six-state model of the electrogenic Na+/glucose cotransporter, using published estimates of the model rate constants, that the periodic field effects can be large and rich with measurable details that can be used to study the mechanism thoroughly. The new method serves in this case to complement and expand on the information obtainable by means of the voltage clamp method. It was also found by means of simulations of a nonelectrogenic six-state cotransporter model that experimentally measurable effects are expected and that results can be used to distinguished among alternative kinetic models as well as to estimate individual rate constants. The range of dynamic information available with this method is not accessible by voltage clamp or other pre-steady-state methods presently in use.

Horn, L. W.

1993-01-01

78

Air quality: from observation to applied studies  

NASA Astrophysics Data System (ADS)

Air qualities studies in urban areas embrace several directions that are strongly associated with urban complexity. In the last centuries cities evolution implied changes in urbanization trends: urban sprawl has modified the relationship between cities and surroundings settlements. The existence and protection of urban green and open areas is promoted as a mean to improve the quality of life of their citizens and increase the satisfactory level of the inhabitants against pollution and noise adverse effects. This paper outlines the methods and approaches used in the EU research project Benefits of Urban Green Space (BUGS). The main target of BUGS is to assess the role of urban green spaces in alleviating the adverse effects of urbanization trends by developing an integrative methodology, ranging from participatory planning tools to numerical simulation models. The influence of urban structures on atmospheric pollutants distribution is investigated as a multi-scale problem ranging from micro to macro/regional scale. Traditionally, air quality models are applied on a single scale, seldom considering the joint effects of traffic network and urban development together. In BUGS, several numerical models are applied to cope with urban complexity and to provide quantitative and qualitative results. The differing input data requirements for the various models demanded a methodology which ensures a coherent data extraction and application procedure. In this paper, the stepwise procedure used for BUGS is presented after a general presentation of the research project and the models implied. A discussion part will highlight the statements induced by the choices made and a conclusive part bring to the stage some insights for future investigations.

Weber, Christiane H.; Wania, Annett; Hirsch, Jacky; Bruse, Michael

2004-10-01

79

SCIENTIFIC OBJECTIVES AND OBSERVING METHODS FOR A MINIMUM ARTIFICIAL EARTH SATELLITE  

Microsoft Academic Search

The problems of systematic and accurate observations of a proposed ; minlmum earth satellite were studied. Limitations imposed by scientific ; objectives of a satellite vehicle, size of the vehicle, kinds of orbits possible, ; existing instrumentation technology and the suitability of instrumentation sites ; were considered. lt is concluded that a combination of optical and electronic ; observing methods

L. G. deBey; W. W. Berning; D. Reuyl; H. M. Cobb

1955-01-01

80

Experimental Land Observing Data System Feasibility Study.  

National Technical Information Service (NTIS)

An end-to-end data system to support a Shuttle-based Multispectral Linear Array (MLA) mission in the mid-1980's was defined. The experimental Land Observing System (ELOS) is discussed. A ground system that exploits extensive assets from the LANDSAT-D Prog...

J. L. Buckley H. Kraiman

1982-01-01

81

Anesthesia Alarms in Context: An Observational Study  

Microsoft Academic Search

This paper surveys current work on the design of alarms for anesthesia environments and notes some of the problems arising from the need to interpret alarms in context. Anesthetists' responses to audible alarms in the operating room were observed across four types of surgical procedure (laparoscopic, arthroscopic, cardiac, and intracranial) and across three phases of a procedure (induction, maintenance, and

F. Jacob Seagull; Penelope M. Sanderson

2001-01-01

82

Observations on a Laboratory Method for Submerged Acetic Fermentation  

PubMed Central

Submerged acetic fermentation experiments were performed for the purpose of determining the conditions under which this type of fermentation should be conducted under laboratory conditions. The apparatus used consisted of a set of glass tubes provided with air spargers. Acetobacter acetigenum was found to be the most suitable bacterium among six Acetobacter compared under submerged acetic fermentation conditions in a synthetic medium. Statistically significant different rates of fermentation were observed in acetators that were identical in construction, fermentation medium, and aeration characteristics. Extremely long growth lag periods and complete absence of growth were often observed when starting fermentations. The causes of this behavior were investigated. It was found that it was not produced by lack of nutrients or by presence of a bacteriophage. Different kinds of bacterial starters were studied and compared. Cultures maintained in a liquid medium were reliable starters with a short growth lag period. Liquid medium cultures maintained their good starter characteristics after periods of storage of up to 11 weeks at 40 F (4 C).

Lopez, Anthony; Johnson, L. W.; Wood, C. B.

1961-01-01

83

Rapid evaluation methods (REM) of health services performance: methodological observations.  

PubMed

The rapid evaluation method (REM) was developed by WHO in order to assess the performance and quality of health care services, identify operational problems, and assist in taking managerial action. It was tested in five developing countries (Botswana, Madagascar, Papua New Guinea, Uganda and Zambia) between 1988 and 1991. REM consists of a set of observation- and survey-based diagnostic activities, carried out mainly in health care facilities. The article describes the various steps of REM, methodological issues such as setting objectives and using an issue-information matrix, preparation of survey instruments, use of computer software (Epi Info), data quality control, fieldwork, and the use of data to produce useful information for decision-makers. REM aims at bringing prompt and relevant information to planners and decision-makers who need it for a specific purpose. In the present examples, REM provided information for preparing a programme proposal for external funding, for establishing baseline data for a situation analysis, and for assessing staff performance after extensive training in order to improve the curriculum. PMID:8440033

Anker, M; Guidotti, R J; Orzeszyna, S; Sapirie, S A; Thuriaux, M C

1993-01-01

84

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

85

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

86

An observational study of patients receiving homeopathic treatment  

Microsoft Academic Search

Background. Observational studies have recently contributed useful information to the debate about the utility of homeopathic treatment in everyday practice.Aim. To gather data about routine homeopathic general practice.Setting. Eighty general medical practices in Belgium where physicians were members of the Unio Homoeopathica Belgica.Methods. All patients and their physicians visiting the practices on a specified day completed a questionnaire.Results. A total

M Van Wassenhoven; G Ives

2004-01-01

87

Observational database for studies of nearby universe  

NASA Astrophysics Data System (ADS)

We present the description of a database of galaxies of the Local Volume (LVG), located within 10 Mpc around the Milky Way. It contains more than 800 objects. Based on an analysis of functional capabilities, we used the PostgreSQL DBMS as a management system for our LVG database. Applying semantic modelling methods, we developed a physical ER-model of the database. We describe the developed architecture of the database table structure, and the implemented web-access, available at http://www.sao.ru/lv/lvgdb.

Kaisina, E. I.; Makarov, D. I.; Karachentsev, I. D.; Kaisin, S. S.

2012-01-01

88

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.

89

Air quality: from observation to applied studies  

Microsoft Academic Search

Air qualities studies in urban areas embrace several directions that are strongly associated with urban complexity. In the last centuries cities evolution implied changes in urbanization trends: urban sprawl has modified the relationship between cities and surroundings settlements. The existence and protection of urban green and open areas is promoted as a mean to improve the quality of life of

Christiane H. Weber; Annett Wania; Jacky Hirsch; Michael Bruse

2004-01-01

90

Social Studies: Issues and Methods.  

ERIC Educational Resources Information Center

This competency based workbook in social studies education provides information on developing teaching strategies and instructional materials. Designed for undergraduate students in social studies, student teachers, and methods instructors, it serves as a source of assignments for students, a guide in testing student competencies in social studies

Dynneson, Thomas L.

91

The application of physiological observation methods to emotion research  

Microsoft Academic Search

Purpose – The purpose of this paper is to examine consumer emotions and the social science and observation measures that can be utilised to capture the emotional experiences of consumers. The paper is not setting out to solve the theoretical debate surrounding emotion research, rather to provide an assessment of methodological options available to researchers to aid their investigation into

Laura Chamberlain; Amanda J. Broderick

2007-01-01

92

Multinational, observational study of procalcitonin in ICU patients with pneumonia requiring mechanical ventilation: a multicenter observational study  

Microsoft Academic Search

Introduction  The intent of this study was to determine whether serum procalcitonin (PCT) levels are associated with prognosis, measured\\u000a as organ dysfunctions and 28-day mortality, in patients with severe pneumonia.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  This was a multicenter, observational study of critically ill adult patients with pneumonia requiring mechanical ventilation\\u000a conducted in 10 academic hospitals in Canada, the United States, and Central Europe. PCT was

Frank Bloos; John C Marshall; Richard P Dellinger; Jean-Louis Vincent; Guillermo Gutierrez; Emanuel Rivers; Robert A Balk; Pierre-Francois Laterre; Derek C Angus; Konrad Reinhart; Frank M Brunkhorst

2011-01-01

93

Are Observational Studies ‘Just as Effective’ as Randomized Clinical Trials?  

Microsoft Academic Search

The question of whether observational studies are ‘just as effective’ as randomized clinical trials appears to presume a competition between the two. However, from a methodological perspective, the two types of studies are complementary. Observational studies and randomized clinical trials can be viewed as expressions in the setting of modern clinical research of the steps of observation and experimentation that

Tom Greene

2000-01-01

94

Observed migration of a controlled DNAPL release by geophysical methods  

Microsoft Academic Search

Seven hundred seventy liters of a dense nonaqueous phase liquid (DNAPL), tetrachloroethylene (PCE), were released into an isolated volume of a completely saturated natural sandy aquifer. The release was monitored over a period of 984 hours with a variety of geophysical methods including ground penetrating radar, time domain reflectometry, in situ resistivity, and a neutron soil moisture probe. The PCE

M. L. Brewster; A. P. Annan; J. P. Greenhouse; J. D. Redman; B. H. Kueper; G. R. Olhoeft; K. A. Sander

1995-01-01

95

Spectral meteor observations by the method of instantaneous exposure  

NASA Astrophysics Data System (ADS)

An analysis of a meteor spectrum with dispersion 67 A/mm, photographed with exposures of 0.003 sec, is presented. Spectral line wavelengths are determined to plus or minus 2 A. The Na I doublet lines of Mg I, and 42 various FE I multiplets stand out among the brightest lines. Lines of Ca I, Ni I, Cr I, Mn I, and Co I are identifiable, and the first positive system of molecular nitrogen bands (N2) is visible also. A very weak continuous spectrum is observed in the wavelength region 5898-6900 A.

Babadzhanov, P. B.; Getman, V. S.; Zolova, O. F.; Konovalova, N. A.

1980-04-01

96

The value of site-based observations complementary to naturalistic driving observations: a pilot study on the right turn manoeuvre.  

PubMed

Naturalistic driving studies are increasingly applied in different shapes and sizes. The European project PROLOGUE has investigated the value and feasibility of a large-scale naturalistic driving study in Europe. Within PROLOGUE several pilot studies have been conducted in different countries. The Dutch field trial investigated the value and feasibility of adding site-based observations to in-vehicle observations. In this trial, one intersection was equipped with cameras for site-based observation. Additionally eight cars were equipped of drivers crossing this intersection regularly. On this small scale, combining the two observation methods turned out to be technically feasible. It was possible to recognise the instrumented vehicles in the site-based video data, to match cases from the different observations and the speed measures from the separate studies appeared to be similar. The value of combining these two observation methods lies in the possibility to enrich the data from one study with complementary data from the other study. The study illustrated that each type of observation has its unique values. From in-vehicle data it is possible to look in detail at the driving behaviour of the participants over time and in different situations. The site-based study offers information about the position and speed of other road users surrounding the participant's vehicle, including vulnerable road users such as cyclists and pedestrians. Two values of adding site-based observations to in-vehicle observations were identified: to obtain more in depth understanding and to relate the behaviour of participants of the naturalistic driving study to behaviour of the full population of drivers (non-participants). For a future (large-scale) naturalistic driving study two research topics are identified that could benefit from these complementary observations: driving behaviour in relation to specific infrastructure and the interaction between drivers and vulnerable road users. PMID:23915473

van Nes, Nicole; Christoph, Michiel; Hoedemaeker, Marika; van der Horst, Richard A

2013-07-13

97

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) Eligibility—did the patient fulfil the study entry criteria? (2) Accessibility—was it possible to access the patient to be able to inform them about the study? (3) Consent—did 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.

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

2013-01-01

98

Studying trilinear gauge couplings at LEP2 using optimal observables  

NASA Astrophysics Data System (ADS)

We study the sensitivity of the processes e+e- ->L?L qq' at LEP2 energies on the non-standard trilinear gauge couplings (TGC), using the optimal observables method. All relevant leading logarithmic corrections to the three-order cross section, as well as experimental resolution effects have been studied. Taking into account correlations among the different TGC parameters we show that the limits on the TGC can reach the level of 0.15 (ld) at 161 GeV with 100 pb-1, a challenge for the first LEP2 phase. At higher energies this can be improved drastically, reaching for the level of 0.02 (1sd).

Papadopoulos, Costas G.

1996-02-01

99

CNODES: the Canadian Network for Observational Drug Effect Studies  

PubMed Central

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

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

2012-01-01

100

Guidelines to Evaluate Human Observational Studies for Quantitative Risk Assessment  

PubMed Central

Background Careful evaluation of the quality of human observational studies (HOS) is required to assess the suitability of HOS for quantitative risk assessment (QRA). In particular, the quality of quantitative exposure assessment is a crucial aspect of HOS to be considered for QRA. Objective We aimed to develop guidelines for the evaluation of HOS for QRA and to apply these guidelines to case–control and cohort studies on the relation between exposure to benzene and acute myeloid leukemia (AML). Methods We developed a three-tiered framework specific for the evaluation of HOS for QRA and used it to evaluate HOS on the relation between exposure to benzene and AML. Results The developed framework consists of 20 evaluation criteria. A specific focus of the framework was on the quality of exposure assessment applied in HOS. Seven HOS on the relation of benzene and AML were eligible for evaluation. Of these studies, five were suitable for QRA and were ranked based on the quality of the study design, conduct, and reporting on the study. Conclusion The developed guidelines facilitate a structured evaluation that is transparent in its application and harmonizes the evaluation of HOS for QRA. With the application of the guidelines, it was possible to identify studies suitable for QRA of benzene and AML and rank these studies based on their quality. Application of the guidelines in QRA will be a valuable addition to the assessment of the weight of evidence of HOS for QRA.

Vlaanderen, Jelle; Vermeulen, Roel; Heederik, Dick; Kromhout, Hans

2008-01-01

101

Force requirements of observed object lifting are encoded by the observer's motor system: a TMS study.  

PubMed

Several transcranial magnetic stimulation (TMS) studies have reported facilitation of the primary motor cortex (M1) during the mere observation of actions. This facilitation was shown to be highly congruent, in terms of somatotopy, with the observed action, even at the level of single muscles. With the present study, we investigated whether this muscle-specific facilitation of the observer's motor system reflects the degree of muscular force that is exerted in an observed action. Two separate TMS experiments are reported in which corticospinal excitability was measured in the hand area of M1 while subjects observed the lifting of objects of different weights. The type of action 'grasping-and-lifting-the-object' was always identical, but the grip force varied according to the object's weight. In accordance to previous findings, excitability of M1 was shown to modulate in a muscle-specific way, such that only the cortical representation areas in M1 that control the specific muscles used in the observed lifting action became increasingly facilitated. Moreover, muscle-specific M1 facilitation was shown to modulate to the force requirements of the observed actions, such that M1 excitability was considerably higher when observing heavy object lifting compared with light object lifting. Overall, these results indicate that different levels of observed grip force are mirrored onto the observer's motor system in a highly muscle-specific manner. The measured force-dependent modulations of corticospinal excitability in M1 are hypothesized to be functionally relevant for scaling the observed grip force in the observer's own motor system. In turn, this mechanism may contribute, at least partly, to the observer's ability to infer the weight of the lifted object. PMID:20377627

Alaerts, Kaat; Senot, Patrice; Swinnen, Stephan P; Craighero, Laila; Wenderoth, Nicole; Fadiga, Luciano

2010-03-01

102

Action observation and speech production: study on children and adults  

Microsoft Academic Search

The present study aimed to determine whether observation of upper limb actions selectively influences speech production. We compared the effects on children with those on adults, hypothesizing that action observation is used by children for speech learning. Children and adults observed an actor either grasping a cherry or an apple, or bringing the same fruits to his mouth. They pronounced

Maurizio Gentilucci; Silvia Stefanini; Alice C Roy; Paola Santunione

2004-01-01

103

WHAT OBSERVATIONAL LEARNING ENTAILS: A MULTIPLE CASE STUDY  

Microsoft Academic Search

Observational learning has proved to be effective with learners of various ages and in various school subjects, including writing. However, little is known about the actual behavior of learners while carrying out observation tasks. In this case study, students' learning activities when processing observa- tion tasks are closely analyzed: six students thought aloud while observing sets of writers as peer

MARTINE A. H. BRAAKSMA; GERT RIJLAARSDAM

104

Observed smoking in cars: a method and differences by socioeconomic area  

PubMed Central

Objectives To establish a reproducible method to estimate he point prevalence of smoking and second?hand smoke (SHS) exposure in cars, and to compare this prevalence between two areas of contrasting socioeconomic status. Method A method involving two teams of observers was developed and evaluated. It involved observing 16?055 cars in Wellington, New Zealand. Two of the observation sites represented a high and a low area of deprivation (based on a neighbourhood deprivation index) and three were in the central city. Results A 4.1% point prevalence of smoking in cars was observed (95% confidence interval (CI) 3.8% to 4.4%). There was a higher prevalence of smoking in cars in the high deprivation area relative to the other sites, and particularly compared to the low deprivation area (rate ratio relative to the latter 3.2, 95% CI 2.6 to 4.0). Of cars with smoking, 23.7% had other occupants being exposed to SHS. Cars with smoking and other occupants were significantly more likely to have a window open (especially if the smoker was not the driver). The observation method developed was practical, and inter?observer agreement was high (? value for the “smoking seen in car” category 0.95). Conclusions Observational studies can be an effective way of investigating smoking in cars. The data from this survey suggest that smoking in cars occurs at a higher rate in relatively deprived populations and hence may contribute to health inequalities. Fortunately, there are a number of policy options for reducing SHS exposure in cars including mass media campaigns and laws for smoke?free cars.

Martin, Josh; George, Robert; Andrews, Kirsty; Barr, Peter; Bicknell, Derryn; Insull, Elizabeth; Knox, Carl; Liu, Jessie; Naqshband, Mumraiz; Romeril, Kate; Wong, Donny; Thomson, George; Wilson, Nick

2006-01-01

105

Communication behaviours in a hospital setting: an observational study  

PubMed Central

Objective: An exploratory study to identify patterns of communication behaviour among hospital based healthcare workers. Design: Non-participatory, qualitative observational study. Setting: British district general hospital. Subjects: Eight doctors and two nurses. Results: Communication behaviours resulted in an interruptive workplace, which seemed to contribute to inefficiency in work practice. Medical staff generated twice as many interruptions via telephone and paging systems as they received. Hypothesised causes for this level of interruption include a bias by staff to interruptive communication methods, a tendency to seek information from colleagues in preference to printed materials, and poor provision of information in support of contacting individuals in specific roles. Staff were observed to infer the intention of messages based on insufficient information, and clinical teams demonstrated complex communication patterns, which could lead to inefficiency. Conclusion: The results suggest a number of improvements to processes or technologies. Staff may need instruction in appropriate use of communication facilities. Further, excessive emphasis on information technology may be misguided since much may be gained by supporting information exchange through communication technology. Voicemail and email with acknowledgment, mobile communication, improved support for role based contact, and message screening may be beneficial in the hospital environment. Key messages We observed communication behaviour among 10 hospital based healthcare workers Communication behaviours resulted in an interruptive work place, which seemed to contribute to inefficiency in work practice Medical staff generated twice as many interruptions via telephone and paging systems as they received, and possible causes for this included a bias by staff to interruptive communication methods, a tendency to seek information from colleagues in preference to printed materials, and poor provision of information in support of contacting individuals in specific roles Staff were observed to infer the intention of messages based on insufficient information, and clinical teams showed complex communication patterns, which could lead to inefficiency We conclude that hospital staff may need instruction in appropriate use of communication facilities and that some communication technology—voicemail and email with acknowledgment, cellular telephones for mobile communication, improved support for role based contact, and message screening—may be beneficial

Coiera, Enrico; Tombs, Vanessa

1998-01-01

106

Comparative study of methods for WHPA delineation.  

PubMed

Human activities, whether agricultural, industrial, commercial, or domestic, can contribute to ground water quality deterioration. In order to protect the ground water exploited by a production well, it is essential to develop a good knowledge of the flow system and to adequately delineate the area surrounding the well within which potential contamination sources should be managed. Many methods have been developed to delineate such a wellhead protection area (WHPA). The integration of more information on the geologic and hydrogeologic characteristics of the study area increases the precision of any given WHPA delineation method. From a practical point of view, the WHPA delineation methods allowing the simplest and least expensive integration of the available information should be favored. This paper presents a comparative study in which nine different WHPA delineation methods were applied to a well and a spring in an unconfined granular aquifer and to a well in a confined highly fractured rock aquifer. These methods range from simple approaches to complex computer models. Hydrogeological mapping and numerical modeling with MODFLOW-MODPATH were used as reference methods to respectively compare the delineation of the zone of contribution and the zone of travel obtained from the various WHPA methods. Although applied to simple ground water flow systems, these methods provided a relatively wide range of results. To allow a realistic delineation of the WHPA in aquifers of variable geometry, a WHPA delineation method should ensure a water balance and include observed or calculated regional flow characteristics. PMID:17335480

Paradis, Daniel; Martel, Richard; Karanta, Gilbert; Lefebvre, René; Michaud, Yves; Therrien, René; Nastev, Miroslav

107

The impact of consent on observational research: a comparison of outcomes from consenters and non consenters to an observational study  

Microsoft Academic Search

BACKGROUND: Public health benefits from research often rely on the use of data from personal medical records. When neither patient consent nor anonymisation is possible, the case for accessing such records for research purposes depends on an assessment of the probabilities of public benefit and individual harm. METHODS: In the late 1990s, we carried out an observational study which compared

Una Macleod; Graham CM Watt

2008-01-01

108

FISH Methods in Cytogenetic Studies.  

PubMed

This chapter describes the various methods derived from the protocol of standard fluorescent in situ hybridization (FISH) that are used in human, animal, plant, and microbial studies. These powerful techniques allow us to detect and physically map on interphase nuclei, chromatin fibers, or metaphase chromosomes probes derived from single-copy genes to repetitive DNA sequences. Other variants of the technique enable the co-localization of genes and the overall comparison of the genome among individuals of the same species or of different taxa. A further variant detects and localizes bacteria on tissues and cells. Overall, this offers a remarkable multiplicity of possible applications ranging from strict physical mapping, to clinical and evolutionary studies, making it a powerful and informative complement to other molecular, functional, or genomic approaches. PMID:24162984

Pita, Miguel; Orellana, Juan; Martínez-Rodríguez, Paloma; Martínez-Ramírez, Angel; Fernández-Calvín, Begoña; Bella, José L

2014-01-01

109

Observational study of suspected maltreatment in Italian paediatric emergency departments  

PubMed Central

Aims: To evaluate how often children seen in paediatric accident & emergency (A&E) departments were suspected of abuse or neglect, and to explore some of the correlates of suspected child maltreatment. Methods: Multicentre, cross-sectional study of 15 randomised census days during a six month period. Trained research assistants working with local paediatric staff completed a purpose made anonymised checklist covering sociodemographic and medical information. A six point suspicion index was used to rate compatibility with child maltreatment based on the occurrence of observable harm. Statistical analysis was carried out on the basis that a score of 4 or more was suspicious of child maltreatment. Nineteen hospitals provided standardised paediatric A&E consultation data on 0–14 year olds presenting between 10 am and 10 pm. Results: Of 10 175 assessed children, 204 aroused suspicion of child maltreatment (95% CI 163 to 214 per 10 000). In a logistic regression model of suspected maltreatment statistically significant associations were found with socioeconomic disadvantage, children living in single parent families, and developmental delay. There was no correlation with pre-school age, male gender, foreign origin, or living in urban areas. Conclusions: Child maltreatment based on immediate scoring of suspicion, focused on observable harm, occurred in 2% of a representative sample of paediatric emergency consultations in Italy. This was more common if there were associated social and developmental vulnerabilities. True prevalence of child maltreatment in emergency departments remains elusive because of changing definitions and forensic validation problems.

Palazzi, S; de Girolamo, G; Liverani, T; on, b

2005-01-01

110

In-Hospital Recruitment to Observational Studies of Stroke  

ERIC Educational Resources Information Center

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

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

2010-01-01

111

Rainfall Observed Over Bangladesh 2000-2008: A Comparison of Spatial Interpolation Methods  

NASA Astrophysics Data System (ADS)

In preparation for a hydrometeorological study of freshwater resources in the greater Ganges-Brahmaputra region, we compared the results of four methods of spatial interpolation applied to point measurements of daily rainfall over Bangladesh during a seven year period (2000-2008). Two univariate (inverse distance weighted and spline-regularized and tension) and two multivariate geostatistical (ordinary kriging and kriging with external drift) methods were used to interpolate daily observations from a network of 221 rain gauges across Bangladesh spanning an area of 143,000 sq km. Elevation and topographic index were used as the covariates in the geostatistical methods. The validity of the interpolated maps was analyzed through cross-validation. The quality of the methods was assessed through the Pearson and Spearman correlations and root mean square error measurements of accuracy in cross-validation. Preliminary results indicated that the univariate methods performed better than the geostatistical methods at daily scales, likely due to the relatively dense sampled point measurements and a weak correlation between the rainfall and covariates at daily scales in this region. Inverse distance weighted produced the better results than the spline. For the days with extreme or high rainfall—spatially and quantitatively—the correlation between observed and interpolated estimates appeared to be high (r2 ~ 0.6 RMSE ~ 10mm), although for low rainfall days the correlations were poor (r2 ~ 0.1 RMSE ~ 3mm). The performance quality of these methods was influenced by the density of the sample point measurements, the quantity of the observed rainfall along with spatial extent, and an appropriate search radius defining the neighboring points. Results indicated that interpolated rainfall estimates at daily scales may introduce uncertainties in the successive hydrometeorological analysis. Interpolations at 5-day, 10-day, 15-day, and monthly time scales are currently under investigation.

Pervez, M.; Henebry, G. M.

2010-12-01

112

A passive acoustic monitoring method applied to observation and group size estimation of finless porpoises.  

PubMed

The present study aimed at determining the detection capabilities of an acoustic observation system to recognize porpoises under local riverine conditions and compare the results with sighting observations. Arrays of three to five acoustic data loggers were stationed across the main channel of the Tian-e-zhou Oxbow of China's Yangtze River at intervals of 100-150 m to record sonar signals of free-ranging finless porpoises (Neophocaena phocaenoides). Acoustic observations, concurrent with visual observations, were conducted at two occasions on 20-22 October 2003 and 17-19 October 2004. During a total of 42 h of observation, 316 finless porpoises were sighted and 7041 sonar signals were recorded by loggers. The acoustic data loggers recorded ultrasonic signals of porpoises clearly, and detected the presence of porpoises with a correct detection level of 77.6% and a false alarm level of 5.8% within an effective distance of 150 m. Results indicated that the stationed passive acoustic observation method was effective in detecting the presence of porpoises and showed potential in estimating the group size. A positive linear correlation between the number of recorded signals and the group size of sighted porpoises was indicated, although it is faced with some uncertainty and requires further investigation. PMID:16158672

Wang, Kexiong; Wang, Ding; Akamatsu, Tomonari; Li, Songhai; Xiao, Jianqiang

2005-08-01

113

A passive acoustic monitoring method applied to observation and group size estimation of finless porpoises  

NASA Astrophysics Data System (ADS)

The present study aimed at determining the detection capabilities of an acoustic observation system to recognize porpoises under local riverine conditions and compare the results with sighting observations. Arrays of three to five acoustic data loggers were stationed across the main channel of the Tian-e-zhou Oxbow of China's Yangtze River at intervals of 100-150 m to record sonar signals of free-ranging finless porpoises (Neophocaena phocaenoides). Acoustic observations, concurrent with visual observations, were conducted at two occasions on 20-22 October 2003 and 17-19 October 2004. During a total of 42 h of observation, 316 finless porpoises were sighted and 7041 sonar signals were recorded by loggers. The acoustic data loggers recorded ultrasonic signals of porpoises clearly, and detected the presence of porpoises with a correct detection level of 77.6% and a false alarm level of 5.8% within an effective distance of 150 m. Results indicated that the stationed passive acoustic observation method was effective in detecting the presence of porpoises and showed potential in estimating the group size. A positive linear correlation between the number of recorded signals and the group size of sighted porpoises was indicated, although it is faced with some uncertainty and requires further investigation.

Wang, Kexiong; Wang, Ding; Akamatsu, Tomonari; Li, Songhai; Xiao, Jianqiang

2005-08-01

114

Design Method of ZMP Disturbance Observer for Walking Stabilization of Biped Robot  

NASA Astrophysics Data System (ADS)

This paper proposes a design method of zero-moment point (ZMP) disturbance observer for walking stabilization of biped robots. A parameter design method for the filter required in the ZMP disturbance observer is proposed for performance improvement, and a variable compliance controller is introduced for impact reduction during landing. The validity of the proposed method was confirmed by simulations and experiments.

Sato, Tomoya; Sakaino, Sho; Ohnishi, Kouhei

115

The application of error quaternion and PID control method in Earth observation satellite's attitude control system  

Microsoft Academic Search

Because of its payload's work characteristic, it requires much higher precision in Earth observation satellite's attitude control systems than others. Most Earth observation satellites use zero-momentum three-axis stabilization control method. This paper investigates this control method in satellite control system, deducing the dynamics and kinematics of satellite attitude's model expressed by attitude error quaternion, applying PID control method in this

Qiyu Wang; Jianping Yuan; Zhanxia Zhu

2006-01-01

116

Effective population management practices in diabetes care - an observational study  

PubMed Central

Background Ensuring that evidence based medicine reaches patients with diabetes in the US and internationally is challenging. The chronic care model includes evidence based management practices which support evidence based care. However, despite numerous studies, it is unclear which practices are most effective. Few studies assess the effect of simultaneous practices implemented to varying degrees. The present study evaluates the effect of fifteen practices applied concurrently and takes variation in implementation levels into account while assessing the impact of diabetes care management practices on glycemic and lipid monitoring. Methods Fifteen management practices were identified. Implementation levels of the practices in 41 medical centres caring for 553,556 adults with diabetes were assessed from structured interviews with key informants. Stepwise logistic regression models with management practices as explanatory variables and glycemic and lipid monitoring as outcome variables were used to identify the diabetes care practices most associated with high performance. Results Of the 15 practices studied, only provider alerts were significantly associated with higher glycemic and lipid monitoring rates. The odds ratio for glycemic monitoring was 4.07 (p < 0.00001); the odds ratio for lipid monitoring was 1.63 (p < 0.006). Weaker associations were found between action plans and glycemic monitoring (odds ratio = 1.44; p < 0.03) and between guideline distribution and training and lipid monitoring (odds ratio = 1.46; p < 0.03). The covariates of gender, age, cardiac disease and depression significantly affected monitoring rates. Conclusions Of fifteen diabetes care management practices, our data indicate that high performance is most associated with provider alerts and more weakly associated with action plans and with guideline distribution and training. Lack of convergence in the literature on effective care management practices suggests that factors contributing to high performance may be highly context-dependent or that the factors involved may be too numerous or their implementation too nuanced to be reliably identified in observational studies.

2010-01-01

117

Randomized trials versus observational studies in adolescent pregnancy prevention.  

PubMed

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; and contact with content experts. We included randomized trials and observational studies that evaluated the impact of primary prevention interventions including sex education classes, school-based clinics, free-standing clinics, physician/nurse practitioner practice-based service, improved access, and community-based programs on four outcomes: sexual intercourse, birth control use, responsible sexual behavior, or pregnancy in adolescents. One investigator abstracted the data and a second conducted a detailed review of the abstraction. We identified 13 randomized trials and 17 observational studies. We generated estimates of the impact of the interventions separately for males and females for all four outcomes for both observational studies and randomized trials. For six of the eight outcomes the summary odds ratios for the observational studies showed a significant intervention benefit (P<0.05) while the randomized trials did not show a benefit for any outcome in either females or males. The difference between the results of the observational studies and randomized trials was statistically significant in two of the eight outcomes (P<0.05 for initiation of intercourse and pregnancy in females). Observational studies yield systematically greater estimates of treatment effects than randomized trials of adolescent pregnancy prevention interventions. Public policy or individual patient treatment decisions should be based on observational studies only when randomized trials are unavailable and only with careful consideration of possible biases. PMID:10729689

Guyatt, G H; DiCenso, A; Farewell, V; Willan, A; Griffith, L

2000-02-01

118

Linking Indigenous Knowledge and Observed Climate Change Studies.  

National Technical Information Service (NTIS)

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 o...

B. Weeks C. Rosenzweig C. Sakakibara C. C. Alexander C. V. Shadrin J. Waterhouse L. Johnson M. Vicarelli N. Bynum N. Oettle P. Neofotis T. Mustonen U. King

2010-01-01

119

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

120

Study on Bridge of Violin by Photoelastic Observation  

Microsoft Academic Search

The stress of the bridge of a violin was observed by means of the photoelastic method, and a frequency analysis of the tones of two violins was performed. It was found that the stress of the bridge and the tone of the violin depended on the shape and the tilt of the bridge, the direction of force applied by bowing

Akihiro Matsutani

2002-01-01

121

Smoking Behaviors Among Cancer Survivors: An Observational Clinical Study  

PubMed Central

Purpose: Smoking is a well-recognized risk factor for several cancers including cancers of the lung, bladder, and head and neck. Studies have shown that smoking can adversely affect the outcomes of different modalities of cancer treatment. This study examines smoking behaviors among cancer survivors to collect information necessary to create successful smoking cessation interventions. Methods: For this observational clinical study, questionnaires were sent to 1,000 randomly selected patients diagnosed with cancer between 2003 and 2007 in one cancer center. Data were statistically analyzed to determine the likelihood of a patient quitting smoking after being diagnosed with cancer. Results: We received 187 responses from the 1,000 surveys sent (18.7%). Of these, 166 were usable for analysis. The mean age of respondents was 64 (± 13) years. Men were more likely than women to be past smokers (55% of men and 32% of women respectively, P = .003). Fifty-two percent of respondents reported having a history of smoking. However, only 20% of patients reported having been active smokers at the time they were diagnosed with cancer. Furthermore, only 44% of these reported having quit smoking after their diagnosis with cancer. Only 62% of all respondents reported that they had been informed of the dangers of smoking by their health care provider during cancer treatment. Conclusion: In our study sample, less than one half (44%) of smoking cancer patients quit smoking after their cancer diagnosis, and only 62% of smoking cancer patients received smoking cessation counseling from their physicians. Intervention programs are needed to help cancer survivors to quit smoking. Prospective clinical trials may help identify the ideal intervention for smoking cessation.

Burke, Lola; Miller, Lesley-Ann; Saad, Ayman; Abraham, Jame

2009-01-01

122

Observation of swelling behavior of ArF resist during development by using QCM method  

NASA Astrophysics Data System (ADS)

Many reports have discussed the swelling behavior of photoresists during development, as observed by the QCM method. Previously, we reported on the development of development analysis equipment based on the QCM method. In this paper, we report on a high-precision resist development analyzer also based on the QCM method. This equipment incorporates a high-precision developing solution temperature controller and features a high-precision air conditioning function for the measurement chamber. We also measured swelling behavior during development using a TBAH developer solution, which features larger molecules than TMAH, comparing these results with those obtained with TMAH. The results of this measurement indicate that the extent of resist swelling during development is less with TBAH developer solution than with TMAH developer solution. This result is consistent with results of a study by Itani et al. using high-speed AFM, suggesting the suitability of the measurement equipment used in our experiments.

Sekiguchi, Atsushi; Konishi, Hiroko; Isono, Mariko

2012-03-01

123

Comparing Simulations and Observations of Galaxy Evolution: Methods for Constraining the Nature of Stellar Feedback  

NASA Astrophysics Data System (ADS)

Computational hydrodynamical simulations are a very useful tool for understanding how galaxies form and evolve over cosmological timescales not easily revealed through observations. However, they are only useful if they reproduce the sorts of galaxies that we see in the real universe. One of the ways in which simulations of this sort tend to fail is in the prescription of stellar feedback, the process by which nascent stars return material and energy to their immediate environments. Careful treatment of this interaction in subgrid models, so-called because they operate on scales below the resolution of the simulation, is crucial for the development of realistic galaxy models. Equally important is developing effective methods for comparing simulation data against observations to ensure galaxy models which mimic reality and inform us about natural phenomena. This thesis examines the formation and evolution of galaxies and the observable characteristics of the resulting systems. We employ extensive use of cosmological hydrodynamical simulations in order to simulate and interpret the evolution of massive spiral galaxies like our own Milky Way. First, we create a method for producing synthetic photometric images of grid-based hydrodynamical models for use in a direct comparison against observations in a variety of filter bands. We apply this method to a simulation of a cluster of galaxies to investigate the nature of the red-sequence/blue-cloud dichotomy in the galaxy color-magnitude diagram. Second, we implement several subgrid models governing the complex behavior of gas and stars on small scales in our galaxy models. Several numerical simulations are conducted with similar initial conditions, where we systematically vary the subgrid models, afterward assessing their efficacy through comparisons of their internal kinematics with observed systems. Third, we generate an additional method to compare observations with simulations, focusing on the tenuous circumgalactic medium. Informed by our previous studies, we investigate the sensitivity of this new mode of comparison to hydrodynamical subgrid prescription. Finally, we synthesize the results of these studies and identify future avenues of research.

Hummels, Cameron

124

Observational study of prehospital delays in patients with chest pain  

PubMed Central

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

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

2003-01-01

125

Observational study of potential risk factors of medication administration errors  

Microsoft Academic Search

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

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

2003-01-01

126

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

127

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

128

Language Interaction in a Bilingual Classroom: An Observational Study.  

ERIC Educational Resources Information Center

|Designed by the Ilinois Bilingual Evaluation Center as a pilot project, the purpose of this study was to explore the process or nature of events in a bilingual classroom and to investigate the feasibility of using observational techniques to examine this process in an evaluation context. The subjects for the study were three children of Spanish…

Rodriguez-Brown, Flora V.; And Others

129

An observational study on information flow during nurses' shift change  

Microsoft Academic Search

We present an observational study that was conducted to guide the design and development of technologies to support information flow during nurses' shift change in a hospital ward. Our goal is to find out how the complex information sharing processes during nurses' brief shift change unfold in a hospital setting. Our study shows the multitude of information media that nurses

Charlotte Tang; M. Sheelagh T. Carpendale

2007-01-01

130

Seeing Isn't Believing? Neither Is Hearing! In Defense of Observational Studies.  

ERIC Educational Resources Information Center

Rejects Peter C. Gronn's criticisms of structured observation as a method for studying administrators, arguing that these criticisms grow from a limited conception of administration and an overzealous promotion of alternative research techniques. (PGD)

Thomas, A. Ross

1986-01-01

131

Vascular Surgery, ICU and HDU: A 14-Year Observational Study  

PubMed Central

INTRODUCTION Over the course of the past decade, numerous changes have occurred in the management of patients undergoing vascular surgical operations. The introduction of high dependency units (HDUs) has meant that many patients previously requiring observation in intensive care units (ICUs) are now managed in this new environment. In addition, many vascular patients may now be suitable for management on a vascular ward immediately following their surgery. This study reports the chronological changes in resource utilisation of patients undergoing major vascular surgery in a district general hospital over a 14-year period. PATIENTS AND METHODS Details of all patients admitted to either the ICU or HDU under the care of a single vascular surgeon during the period 1991–2004 were extracted from a prospectively maintained anaesthetic department database. Details of the age and gender of the patients were obtained together with source of admission, place of discharge and need for re-admission. Operative details for each patient were extracted from a prospectively maintained vascular surgery database including type of procedure undertaken and degree of urgency. RESULTS During the 14-year period under study, there was a dramatic decrease in the use of ICU facilities for the management of vascular patients from 100% in 1991 to 36% in 2004. There was a corresponding increase in the use of HDU for major vascular cases during the same period from 0% to 66%. However, despite a significant increase in the total number of major vascular operations performed, from 67 in 1991 to 185 in 2004 as a result of sub-specialisation, overall use of all high-care facilities fell as the number of patients returned directly to the vascular ward increased from 34% in 1991 to 64% in 2004. The efficacy of the choice of management venue was confirmed by the observation that only 7.7% of those managed on ICU had been initially managed at a lower level of care. In addition, only 1.8% of patients managed on HDU had been admitted after initially being managed on the vascular ward. CONCLUSIONS Sub-specialisation over the past decade has meant a significantly increased major vascular work-load. Since the introduction of the HDU, there has been a significant fall in the use of ICU facilities for routine cases. These changes in resource utilisation have significant implications in terms of budget allocation. It would appear that finances, in relation to vascular surgery, should be concentrated on expanding HDU facilities and ensuring vascular surgery expertise amongst ward nursing staff.

Teli, Mary; Morris-Stiff, Gareth; Rees, John R; Woodsford, Paul V; Lewis, Michael H

2008-01-01

132

Primary care funding, contract status, and outcomes: an observational study  

PubMed Central

Background The introduction of the Quality and Outcomes Framework (QOF) provides a quantitative way of assessing quality of care in general practice. We explore the achievements of general practice in the first year of the QOF, with specific reference to practice funding and contract status. Aim To determine the extent to which differences in funding and contract status affect quality in primary care. Design of study Cross-sectional observational study using practice data obtained under the Freedom of Information Act 2000. Setting One hundred and sixty-four practices from six primary care trusts (PCTs) in England. Method Practice data for all 164 practices were collated for income and contract status. The outcome measure was QOF score for the year 2004–2005. All data were analysed statistically. Results Contract status has an impact on practice funding, with Employed Medical Services (EMS) and Personal Medical Services (PMS) practices receiving higher levels of funding than General Medical Services (GMS) practices (P<0.001). QOF scores also vary according to contract status. Higher funding levels in EMS practices are associated with lower QOF scores (P=0.04); while GMS practices exhibited the opposite trend, with higher-funded practices achieving better quality scores (P<0.001). Conclusion GMS practices are the most efficient contract status, achieving high quality scores for an average of £62.51 per patient per year. By contrast, EMS practices are underperforming, achieving low quality scores for an average of £105.37 per patient per year. Funding and contract status are therefore important factors in determining achievement in the QOF.

Morgan, Claire L; Beerstecher, Hendrik J

2006-01-01

133

Giant cell arteritis: a multicenter observational study in Brazil  

PubMed Central

OBJECTIVE: To describe demographic features, disease manifestations and therapy in patients with giant cell arteritis from referral centers in Brazil. METHODS: A retrospective cohort study was performed on 45 giant cell arteritis patients from three university hospitals in Brazil. Diagnoses were based on the American College of Rheumatology classification criteria for giant cell arteritis or temporal artery biopsy findings. RESULTS: Most patients were Caucasian, and females were slightly more predominant. The frequencies of disease manifestations were as follows: temporal headache in 82.2%, neuro-ophthalmologic manifestations in 68.9%, jaw claudication in 48.9%, systemic symptoms in 44.4%, polymyalgia rheumatica in 35.6% and extra-cranial vessel involvement in 17.8% of cases. Aortic aneurysms were observed in 6.6% of patients. A comparison between patients with biopsy-proven giant cell arteritis and those without temporal artery biopsies did not yield significant differences in disease manifestations. All patients were treated with oral prednisone, and intravenous methylprednisolone was administered to nearly half of the patients. Methotrexate was the most commonly used immunosuppressive agent, and low-dose aspirin was prescribed to the majority of patients. Relapses occurred in 28.9% of patients, and aspirin had a protective effect against relapses. Females had higher prevalences of polymyalgia rheumatica, systemic manifestations and jaw claudication, while permanent visual loss was more prevalent in men. CONCLUSIONS: Most of the clinical features of Brazilian giant cell arteritis patients were similar to those found in other studies, except for the high prevalence of neuro-ophthalmic manifestations and permanent blindness in the Brazilian patients. Aspirin had a protective effect on relapses.

de Souza, Alexandre Wagner Silva; Okamoto, Karine Yoshiye Kajiyama; Abrantes, Fabiano; Schau, Bruno; Bacchiega, Ana Beatriz Santos; Shinjo, Samuel Katsuyuki

2013-01-01

134

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.

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

2012-01-01

135

Food intake patterns and body mass index in observational studies  

Microsoft Academic Search

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

P Togo; M Osler; TIA Sørensen; BL Heitmann

2001-01-01

136

Study on Bridge of Violin by Photoelastic Observation  

NASA Astrophysics Data System (ADS)

The stress of the bridge of a violin was observed by means of the photoelastic method, and a frequency analysis of the tones of two violins was performed. It was found that the stress of the bridge and the tone of the violin depended on the shape and the tilt of the bridge, the direction of force applied by bowing and so on. In addition, it was demonstrated scientifically that adjustment of the instrument is very important and that players should maintain the instrument properly. The proposed visualization method may be helpful for violin teaching and for practice of bowing skills of amateur violinists.

Matsutani, Akihiro

2002-10-01

137

Statistical study of the Earth's distant magnetotail: Wind observations  

NASA Astrophysics Data System (ADS)

We present a statistical study of the distant Earth's magnetotail observations between November 2003 and January 2004. During this time, the Wind spacecraft voyaged behind -200 RE to the L2 point and recorded magnetotail dynamics as a response of solar wind activities. The main goal of this study is to compare the magnetotail dynamics with the solar wind monitor data near the L1 point (ACE spacecraft), identifying some distant magnetotail regions (magnetosheath, tail lobes, plasmasheet, etc) and evaluating a probability of their observations along the Wind spacecraft orbit. We also correlate the plasma parameters in these regions with the parameters of the solar wind in front of the Earth.

Grygorov, K.; Prech, L.; Safrankova, J.; Nemecek, Z.

2012-04-01

138

Adverse drug events in surgical patients: an observational multicentre study.  

PubMed

Background Errors occurring during different steps of the medication process can lead to adverse drug events (ADEs). Surgical patients are expected to have an increased risk for ADEs during hospitalization. However, detailed information about ADEs in the surgical patient is lacking. Objective In this study, we aim to measure the incidence and nature of (preventable) ADEs, potential risk factors for and outcome parameters of (preventable) ADEs in surgical patients. Setting Observational multicentre cohort study in which eight surgical wards participated from three Dutch hospitals, all using computerized physician order entry (CPOE) systems with clinical decision support. Methods Electively admitted surgical patients of the participating wards were included from March until June 2009. ADEs were measured using a standardized method with expert judgment. Incidence, severity, preventability and accountable medication were assessed. Poisson regression analysis was applied to determine the associations between possible risk factors and the occurrence of ADEs, expressed as incidence rate ratio (IRR). Also outcomes of ADEs in surgical patients were measured. Main outcome measure The incidence and nature of (preventable) ADEs in surgical patients. Results A total of 567 surgical patients were included. We found an incidence of 27.5 ADEs and 4.2 preventable ADEs (pADEs) per 100 admissions (15.4 %). A quarter of the pADEs were severe or life-threatening. Opioids and anti-coagulation medication play a major role in the occurrence of ADEs and pADEs respectively. Univariate analysis revealed an American Society of Anesthesiologists classification of III or more as a risk factor for ADEs. Patients older than 65 years [IRR 2.77 (1.14-6.72)], with cardiovascular comorbidity [IRR 2.87 (1.13-7.28)], or undergoing vascular surgery [IRR 2.32 (1.01-5.32)] were at risk for pADEs. Patients experiencing an ADE had a significant longer duration of admission than patients without an ADE. Conclusions Surgical patients are at considerable risk of experiencing one or more ADEs during their admission, also in CPOE-hospitals. Risk factors for pADEs are age older than 65 years, cardiovascular comorbidity, and vascular surgery. Intensified monitoring may be needed in patients with a higher than average risk for pADEs. PMID:23722455

de Boer, Monica; Boeker, Eveline B; Ramrattan, Maya A; Kiewiet, Jordy J S; Dijkgraaf, Marcel G W; Boermeester, Marja A; Lie-A-Huen, Loraine

2013-05-31

139

Methods for Estimating the Efficiency of Human and Computational Observers in Ultrasonography  

Microsoft Academic Search

Experimental methods for estimating detection efficiencies of human and computational observers viewing low-contrast targets in acoustic noise are described. Sonographic image simulations were generated with signal and noise properties specified exactly. These images were presented to observers in a two-alternative forced-choice experiment. Relative to the ideal observer, human observers were less than 50% efficient for detecting targets of various energies.

Michael F. Insana; Timothy J. Hall

1993-01-01

140

Fatal poisonings in Oslo: a one-year observational study  

PubMed Central

Background Acute poisonings are common and are treated at different levels of the health care system. Since most fatal poisonings occur outside hospital, these must be included when studying characteristics of such deaths. The pattern of toxic agents differs between fatal and non-fatal poisonings. By including all poisoning episodes, cause-fatality rates can be calculated. Methods Fatal and non-fatal acute poisonings in subjects aged ?16 years in Oslo (428 198 inhabitants) were included consecutively in an observational multi-centre study including the ambulance services, the Oslo Emergency Ward (outpatient clinic), and hospitals, as well as medico-legal autopsies from 1st April 2003 to 31st March 2004. Characteristics of fatal poisonings were examined, and a comparison of toxic agents was made between fatal and non-fatal acute poisoning. Results In Oslo, during the one-year period studied, 103 subjects aged ?16 years died of acute poisoning. The annual mortality rate was 24 per 100 000. The male-female ratio was 2:1, and the mean age was 44 years (range 19-86 years). In 92 cases (89%), death occurred outside hospital. The main toxic agents were opiates or opioids (65% of cases), followed by ethanol (9%), tricyclic anti-depressants (TCAs) (4%), benzodiazepines (4%), and zopiclone (4%). Seventy-one (69%) were evaluated as accidental deaths and 32 (31%) as suicides. In 70% of all cases, and in 34% of suicides, the deceased was classified as drug or alcohol dependent. When compared with the 2981 non-fatal acute poisonings registered during the study period, the case fatality rate was 3% (95% C.I., 0.03-0.04). Methanol, TCAs, and antihistamines had the highest case fatality rates; 33% (95% C.I., 0.008-0.91), 14% (95% C.I., 0.04-0.33), and 10% (95% C.I., 0.02-0.27), respectively. Conclusions Three per cent of all acute poisonings were fatal, and nine out of ten deaths by acute poisonings occurred outside hospital. Two-thirds were evaluated as accidental deaths. Although case fatality rates were highest for methanol, TCAs, and antihistamines, most deaths were caused by opiates or opioids.

2010-01-01

141

Nonlesional skin in atopic dermatitis is seemingly healthy skin - observations using noninvasive methods  

PubMed Central

Introduction Atopic dermatitis (AD) is a chronic and relapsing skin disorder, which is characterized by abnormal skin barrier function within the entire skin surface. Several noninvasive bioengineering methods have been commonly used to quantify disease severity. High-frequency ultrasonography (HF-USG) is an important contribution to this field. Aim To evaluate noninvolved skin during the external treatment in relation to involved regions in patients with AD skin using noninvasive methods. Material and methods Transepidermal water loss (TEWL), capacitance and erythema assessment and HF-USG were performed in 55 AD patients within 2 regions (involved and uninvolved skin) before and after therapy. The clinical severity of the disease process was based on the eczema area and severity index (EASI) score. A control group consisting of 15 subjects was also included. Results On the basis of 4 bioengineering methods our study revealed that uninvolved skin in AD presents subclinical disturbances and significantly changes during therapy. The HF-USG detects inflammation in the upper dermis in AD patients in the form of a hypoechoic band, which may also be observed to a lesser extent within normal-appearing skin. Conclusions Nonlesional skin differs significantly from lesional skin in AD and from skin of healthy subjects. Noninvasive methods are able to measure subclinical skin disturbances within normal-appearing skin, which are not evaluated using standard clinical scores. They are objective and may facilitate communication between different research groups.

Danczak-Pazdrowska, Aleksandra; Silny, Wojciech; Jenerowicz, Dorota; Olek-Hrab, Karolina; Osmola-Mankowska, Agnieszka

2013-01-01

142

SABRE observations of Pi2 pulsations: case studies  

NASA Astrophysics Data System (ADS)

The characteristics of substorm-associated Pi2 pulsations observed by the SABRE coherent radar system during three separate case studies are presented. The SABRE field of view is well positioned to observe the differences between the auroral zone pulsation signature and that observed at mid-latitudes. During the first case study the SABRE field of view is initially in the eastward electrojet, equatorward and to the west of the substorm-enhanced electrojet current. As the interval progresses, the western, upward field-aligned current of the substorm current wedge moves westward across the longitudes of the radar field of view. The westward motion of the wedge is apparent in the spatial and temporal signatures of the associated Pi2 pulsation spectra and polarisation sense. During the second case study, the complex field-aligned and ionospheric currents associated with the pulsation generation region move equatorward into the SABRE field of view and then poleward out of it again after the third pulsation in the series. The spectral content of the four pulsations during the interval indicate different auroral zone and mid-latitude signatures. The final case study is from a period of low magnetic activity when SABRE observes a Pi2 pulsation signature from regions equatorward of the enhanced substorm currents. There is an apparent mode change between the signature observed by SABRE in the ionosphere and that on the ground by magnetometers at latitudes slightly equatorward of the radar field of view. The observations are discussed in terms of published theories of the generation mechanisms for this type of pulsation. Different signatures are observed by SABRE depending on the level of magnetic activity and the position of the SABRE field of view relative to the pulsation generation region. A twin source model for Pi2 pulsation generation provides the clearest explanation of the signatures observed Acknowledgements. The authors are grateful to Prof. D. J. Southwood (Imperial College, London), J. C. Samson (University of Alberta, Edmonton), L. J. Lanzerotti (AT&T Bell Laboratories), A. Wolfe (New York City Technical College) and to Dr. M. Vellante (University of LÁquila) for helpful discussions. They also thank Dr. A. Meloni (Istituto Nazionale di Geofisica, Roma) who made available geomagnetic field observations from LÁquila Geomagnetic Observatory. This research activity at LÁquila is supported by MURST (40% and 60% contracts) and by GIFCO/CNR. Topical Editor K.-H. Glaßmeier thanks C. Waters and S. Fujita for their help in evaluating this paper.-> Correspondence to :P. Francia->

Bradshaw, E. G.; Lester, M.

1997-01-01

143

Observer performance using monitors with different phosphors: an ROC study  

Microsoft Academic Search

The goal of the study was to compare observer performance using a P104 vs P45 CRT monitor for display of radiographic images. Different types of phosphor in a CRT monitor can affect the SNR, which in turn could affect the visibility of certain structures of lesions in an image. A series of portable CR chest images with subtle pulmonary nodules

Elizabeth A. Krupinski; Hans Roehrig

2001-01-01

144

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...

145

Bayesian sensitivity analysis for unmeasured confounding in observational studies  

Microsoft Academic Search

SUMMARY We consider Bayesian sensitivity analysis for unmeasured confounding in observational studies where the association between a binary exposure, binary response, measured confounders and a single binary unmeasured confounder can be formulated using logistic regression models. A model for unmeasured confounding is presented along with a family of prior distributions that model beliefs about a possible unknown unmeasured confounder. Simulation

Lawrence C. McCandless; Paul Gustafson; Adrian Levy

2007-01-01

146

A statistical study of ion frictional heating observed by EISCAT  

Microsoft Academic Search

Results of a statistical survey of F-region ion frictional heating are presented, a survey which is based on over 4000 h of common programme observations taken by the European incoherent scatter (EISCAT) UHF radar facility. The criterion adopted in this study for the identification of ion frictional heating was that defined by McCrea et al., requiring an enhancement in the

J. A. Davies; M. Lester; I. W. McCrea

1997-01-01

147

Observational Analysis of the Hand and Wrist: A Pilot Study  

Microsoft Academic Search

A system for quantitative analysis of risk factors associated with cumulative trauma disorders of the hand and wrist was developed and tested in a pilot study. To use the system, analysts observed the worker and counted the total number of hand exertions per work cycle and the number of exertions associated with specific risk factors such as high force or

Diana S. Stetson; William M. Keyserling; Barbara A. Silverstein; Juli A. Leonard

1991-01-01

148

An Observational Study of a Thermal Belt on Hillsides  

Microsoft Academic Search

A thermal belt or a warm zone on a hillside, developing under calm weather conditions during the night, is one of the well-known local climatic phenomena. Although many models describing its fundamental concept have been constructed, very little observational data exists to support the models directly. The difficulty in studying local climatic phenomena lies mainly in collecting data. In the

Tetsuo Kobayashi; Makito MORI; Kenji Wakimizu; Kazuhiro Takeshita

1994-01-01

149

The New Worlds Observer: the astrophysics strategic mission concept study  

Microsoft Academic Search

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

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

2009-01-01

150

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...

151

Chromosomal methods in population studies.  

PubMed Central

A brief description of chromosome aberrations and sister chromatid exchange (SCE) as cytogenetic endpoints for evaluation of DNA damaging agents is presented. Problems associated with the use of cytogenetic assays as population monitors of radiation and chemical exposures are discussed. Adequate cell sample size requirements and accurate assessment of cummulative exposure effects with increasing age are stressed as important considerations for reliable cost-benefit analysis of population studies involving low level exposures. Examples of population studies using SCE as an indicator of specific chemical exposures are cited, and factors contributing to variations in control baseline SCE levels are discussed. Possible implications of population cytogenetic data on general public health are suggested.

Conner, M K; Wald, N

1981-01-01

152

Method to observe hemodynamic and metabolic changes during hemodiafiltration therapy with exercise.  

PubMed

Intradyalitic exercise programas are important to improve patient's hemodynamic stability. Blood pressure and metabolic changes are correlated when heat accumulation is due to increment of the body core temperature (+1.0 °C). However, increase in temperature could be controlled by lowering dialysate's temperature using two main modalities techniques (isothermic and thermoneural) with different patient's thermal balance consequences, not yet well studied. In this work, a new method to observe the main physiological parameters (hearth rate variability (HRV), blood pressure, BTM dialysate temperature control and substrate utilization by indirect calorimtery) which are involved in hemodiafitration (HDF), are displayd. An experiment was carried out in a group of 5 patients waiting kidney transplant. In each patient, EE was assessed as well as the HRV during isothermic and thermoneutral modalities as a manner of cross and prospective study (a) at before therapy, (b) during therapy and (c) at the end of the HDF therapy. Power extraction was also measured by a BTM (Blood Temperature Monitor from Fresenius Inc), in order to determine how the dialysate temperature was controlled. The results showed important method's advantages which place the BTM performance as unstable control system with the possibility to produce undesirable HRV changes as the vagotonical response. However more patient cases are needed in order to identify the real advantage of this new method. PMID:21095679

Cadena, Miguel; Pérez-Grovas, Héctor; Flores, Pedro; Azpiroz, Joaquín; Borja, Gisella; Medel, Humberto; Rodriguez, Fausto; Flores, Francisco

2010-01-01

153

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

SciTech Connect

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

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

2010-11-01

154

Neiderlaendische Konfliktbeobachtungstechnik 'DOCTOR' (Dutch Conflict Observation Method 'DOCTOR' (Dutch Objective Conflict Technique for Operation and Research)).  

National Technical Information Service (NTIS)

Based on information and experience the SWOV and IZF-TNO developed the conflict observation method 'DOCTOR' (Dutch Objective Conflict Technique for Operation and Research). 'DOCTOR' defines a conflict as a critical traffic situation in which two (or more)...

J. H. Kraay

1987-01-01

155

Study on Calibration Methods for Earth Observation Optical Imaging Instruments.  

National Technical Information Service (NTIS)

The properties and calibration of lamps diffusors, and detectors are considered. Measurements of solar irradiance from ground level are illustrated and the NASA solar spectral irradiance experiments are discussed with respect to the possibility of image s...

E. O. Mongain

1980-01-01

156

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

157

Terminal sliding mode observer based parameter estimation method for permanent magnet synchronous motor control system  

Microsoft Academic Search

This paper proposes an observer based method for estimating the mechanical parameters of permanent magnet synchronous motor (PMSM) used for complex mechanical systems. A terminal sliding mode observer is designed and the equivalent control principle is utilized to estimate the mechanical parameters of a motor system. The robustness of the estimation can be guaranteed using the sliding mode control technique.

Yong Feng; Liuping Wang

2010-01-01

158

Observer-based direct field orientation: analysis and comparison of alternative methods  

Microsoft Academic Search

This paper focuses on methods of achieving direct field orientation (DFO) of induction machines based on closed-loop, stator, and rotor flux observers which are well suited to both zero and very high-speed operation. Both observer topologies are dominated by a current model at zero and low speeds, and a voltage model at high speeds. Application of such rotor and stator

Patrick L. Jansen; Robert D. Lorenz; Donald W. Novotny

1994-01-01

159

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

160

Observational studies of depression in primary care: what do we know?  

Microsoft Academic Search

BACKGROUND: We undertook a systematic review of observational studies of depression in primary care to determine 1) the nature and scope of the published studies 2) the methodological quality of the studies; 3) the identified recovery and risk factors for persistent depression and 3) the treatment and health service use patterns among patients. METHODS: Searches were conducted in MEDLINE, CINAHL

Gail Gilchrist; Jane Gunn

2007-01-01

161

Nontraditional method for determining unperturbed orbits of unknown space objects using incomplete optical observational data  

NASA Astrophysics Data System (ADS)

A physical-geometrical method for computing the orbits of earth satellites on the basis of an inadequate number of angular observations (N3) was developed. Specifically, a new method has been developed for calculating the elements of Keplerian orbits of unidentified artificial satellites using two angular observations (alpha sub k, S sub k, k = 1). The first section gives procedures for determining the topocentric distance to AES on the basis of one optical observation. This is followed by description of a very simple method for determining unperturbed orbits using two satellite position vectors and a time interval which is applicable even in the case of antiparallel AED position vectors, a method designated the R sub 2 iterations method.

Perov, N. I.

1985-02-01

162

COMPUTATIONAL BEAM DYNAMICS STUDIES OF COLLECTIVE INSTABILITIES OBSERVED IN SNS  

SciTech Connect

During the commissioning and early operation of the Spallation Neutron Source, some physics shifts were set aside for high intensity stability studies. Under certain, especially contrived conditions, a number of beam instabilities were induced. These included both electron cloud and ring impedance driven phenomena. We are now applying both simple analytic models and the ORBIT Code to the description and simulation of these observed instabilities.

Holmes, Jeffrey A [ORNL; Cousineau, Sarah M [ORNL; Danilov, Viatcheslav V [ORNL; Shishlo, Andrei P [ORNL; Jain, Lalit K [University of Waterloo, Canada

2008-01-01

163

Manchester triage system in paediatric emergency care: prospective observational study  

Microsoft Academic Search

Objective To validate use of the Manchester triage system in paediatric emergency care.Design Prospective observational study.Setting Emergency departments of a university hospital and a teaching hospital in the Netherlands, 2006-7.Participants 17 600 children (aged <16) visiting an emergency department over 13 months (university hospital) and seven months (teaching hospital).Intervention Nurses triaged 16 735\\/17 600 patients (95%) using a computerised Manchester

M van Veen; Ewout W Steyerberg; Madelon Ruige; Alfred H J van Meurs; Jolt Roukema; Johan van der Lei; Henriette A Moll

2008-01-01

164

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

165

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.

2012-01-01

166

Gender differences in young children's temperament traits: comparisons across observational and parent-report methods.  

PubMed

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

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

2013-01-11

167

A direct method for the construction of nonlinear discrete-time observer with linearizable error dynamics  

Microsoft Academic Search

We provide a direct method for the design of nonlinear discrete-time observers by a construction of a change of variables. An explicit expression of the change of variables is given. Some simulations for chaotic systems, such as Lozi system and He´non system, are provided to illustrate the proposed method.

MingQing Xiao

2006-01-01

168

EPA (Environmental Protection Agency) Method Study 29, Method 624--Purgeables.  

National Technical Information Service (NTIS)

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 vari...

1984-01-01

169

EPA (Environmental Protection Agency) Method Study 14, Method 604-Phenols.  

National Technical Information Service (NTIS)

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

D. L. Strother J. R. Florance J. R. Hall M. N. Wass

1984-01-01

170

EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 15, METHOD 605--BENZIDINES  

EPA Science Inventory

Seventeen laboratories participated in an interlaboratory study conducted to provide precision and accuracy statements for the proposed EPA Method 605 for measuring concentrations of the Category 7 chemicals benzidine and 3,3'dichlorobenzidine (DCB) in municipal and industrial aq...

171

Markov chain Monte Carlo methods for state-space models with point process observations.  

PubMed

This letter considers how a number of modern Markov chain Monte Carlo (MCMC) methods can be applied for parameter estimation and inference in state-space models with point process observations. We quantified the efficiencies of these MCMC methods on synthetic data, and our results suggest that the Reimannian manifold Hamiltonian Monte Carlo method offers the best performance. We further compared such a method with a previously tested variational Bayes method on two experimental data sets. Results indicate similar performance on the large data sets and superior performance on small ones. The work offers an extensive suite of MCMC algorithms evaluated on an important class of models for physiological signal analysis. PMID:22364499

Yuan, Ke; Girolami, Mark; Niranjan, Mahesan

2012-02-24

172

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

173

Applying Analytical Methods to Study Terrorism  

Microsoft Academic Search

This paper presents a perspective on the application of theoretical and empirical methods to the study of domestic and transnational terrorism. The use of such methods can lead to informed policy making. On the theoretical side, both choice-theoretic and game-theoretic methods are examined. For empirical applications, the paper focuses on the study of trend, cycles, and forecasting. Additionally, the use

Todd Sandler; Walter Enders

2007-01-01

174

Evaluation of autoimmune safety signal in observational vaccine safety studies  

PubMed Central

Autoimmune safety evaluation is an important component of post-licensure vaccine safety evaluation. Recently, we published the findings from a large observational safety study of the quadrivalent human papillomavirus vaccine in females. From this study, based on two large managed care organizations, we have obtained some empirical data that may prove useful for the design of future vaccine safety studies within a managed care environment. For autoimmune conditions, a major challenge in vaccine safety study is to determine true incident cases in relation to the timing of vaccination. We found expert case review of medical records an indispensable component for autoimmune safety studies based on electronic health records. Case identification should also be expanded to include the use of laboratory test results or other relevant measures in addition to the disease specific ICD-9 diagnosis codes, when applicable. Furthermore, we recommend the parallel use of both safety signal evaluation that involves pattern evaluation for conditions that are more common, and statistical comparisons for conditions that are rather rare. Finally, we recommend an accompanying vaccine uptake study to understand the potential selection bias and confounding in a given study population that should be addressed with data collection and analytical techniques.

Chao, Chun; Jacobsen, Steven

2012-01-01

175

Microbiota and healthy ageing: observational and nutritional intervention studies.  

PubMed

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

Brüssow, Harald

2013-03-26

176

GPS TEC observation of substorm particle injection: a case study  

NASA Astrophysics Data System (ADS)

One of the signatures of magnetospheric substorms is the dispersionless injection of high en-ergy particles into the ionosphere. Low spatial coverage of ground and satellite instruments has limited observations of how this substorm injection region evolves. Using GPS TEC measure-ments from several GPS receivers, we examined electron injection signatures associated with an October 4, 2008 substorm event and monitored the expansion of the injection region with a higher temporal and spatial resolution than previously available. Along with corresponding dispersionless injection signatures observed in Cluster satellite and ground-based riometer data, we have found TEC signatures associated with the particle injection along 30 separate GPS ray paths from 6 GPS receivers located in the Canadian Arctic. Signature timing on different ray paths from different stations indicates a mainly northward (tailward) expansion of the injection region with a smaller westward (azimuthal) component. By applying a triangulation method, we also calculated propagation velocity of the injection boundary in regions covered by our GPS receivers. Velocities ranged from 0.5 -3 km/s northward and 0.5 -1 km/s westward and tend to decrease in magnitude at higher latitudes. Implications of the results will be discussed.

Watson, Chris; Jayachandran, Thayyil; Spanswick, Emma; Donovan, Eric; Danskin, Donald

177

Fatal poisonings in Oslo: a one-year observational study  

Microsoft Academic Search

BACKGROUND: Acute poisonings are common and are treated at different levels of the health care system. Since most fatal poisonings occur outside hospital, these must be included when studying characteristics of such deaths. The pattern of toxic agents differs between fatal and non-fatal poisonings. By including all poisoning episodes, cause-fatality rates can be calculated. METHODS: Fatal and non-fatal acute poisonings

Mari A Bjornaas; Brita Teige; Knut E Hovda; Oivind Ekeberg; Fridtjof Heyerdahl; Dag Jacobsen

2010-01-01

178

IVF conversion to IUI in poor responders: an observational study  

Microsoft Academic Search

Purpose  The purpose of this study was to evaluate the significance of converting an IVF stimulation cycle with poor ovarian response\\u000a to an IUI cycle.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Between January and December 2007, 47 cycles of IVF conversion to IUI were retrospectively studied in 44 infertile women who\\u000a had a low response to ovarian hyperstimulation for IVF. Patients’ characteristics, ovarian stimulation, and ovarian response

Thomas Freour; Sophie Dubourdieu; Sophie Mirallie; Marie Laure Langlois; Miguel Jean; Paul Barrière

2010-01-01

179

Multimedia measurements and activity patterns in an observational pilot study of nine young children  

Microsoft Academic Search

A pilot observational exposure study was performed to evaluate methods for collecting multimedia measurements (air, dust, food, urine) and activity patterns to assess potential exposures of young children to pesticides in their homes. Nine children (mean age=5 years) and their caregivers participated in this study, performed in the Duval County, Florida, in collaboration with the Centers for Disease Control and

Nicolle S Tulve; Peter P Egeghy; Roy C Fortmann; Donald A Whitaker; Marcia G Nishioka; Luke P Naeher; Aaron Hilliard

2008-01-01

180

Classical homeopathy in the treatment of cancer patients - a prospective observational study of two independent cohorts  

Microsoft Academic Search

BACKGROUND: Many cancer patients seek homeopathy as a complementary therapy. It has rarely been studied systematically, whether homeopathic care is of benefit for cancer patients. METHODS: We conducted a prospective observational study with cancer patients in two differently treated cohorts: one cohort with patients under complementary homeopathic treatment (HG; n = 259), and one cohort with conventionally treated cancer patients

Matthias Rostock; Johannes Naumann; Corina Guethlin; Lars Guenther; Hans H Bartsch; Harald Walach

2011-01-01

181

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

PubMed Central

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

2012-01-01

182

General approach to the sign problem: Factorization method with multiple observables  

SciTech Connect

The sign problem is a notorious problem, which occurs in Monte Carlo simulations of a system with the partition function whose integrand is not real positive. The basic idea of the factorization method applied on such a system is to control some observables in order to determine and sample efficiently the region of configuration space which gives important contribution to the partition function. We argue that it is crucial to choose appropriately the set of the observables to be controlled in order for the method to work successfully in a general system. This is demonstrated by an explicit example, in which it turns out to be necessary to control more than one observable. Extrapolation to large system size is possible due to the nice scaling properties of the factorized functions, and known results obtained by an analytic method are shown to be consistently reproduced.

Anagnostopoulos, Konstantinos N. [Physics Department, National Technical University of Athens, Zografou Campus, GR-15780 Athens (Greece); Azuma, Takehiro [Institute for Fundamental Sciences, Setsunan University, 17-8 Ikeda Nakamachi, Neyagawa, Osaka, 572-8508 (Japan); Nishimura, Jun [KEK Theory Center, High Energy Accelerator Research Organization, Tsukuba 305-0801 (Japan); Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, Graduate University for Advanced Studies (SOKENDAI), Tsukuba 305-0801 (Japan)

2011-03-01

183

Observer performance using monitors with different phosphors: an ROC study  

NASA Astrophysics Data System (ADS)

The goal of the study was to compare observer performance using a P104 vs P45 CRT monitor for display of radiographic images. Different types of phosphor in a CRT monitor can affect the SNR, which in turn could affect the visibility of certain structures of lesions in an image. A series of portable CR chest images with subtle pulmonary nodules were presented to radiologists. They were instructed to search the images while their eye position was recorded. They reported on the presence or absence of a nodule, rate their confidence and reported on image quality. Physical measurements were also taken for both monitors (e.g., dynamic range, MTF, veiling glare). Observer performance was slightly better with the P45 than with the P104 monitor, although the difference was not statistically significant. Physical characterization of the two monitors also revealed advantages for the P45 monitor. P104 monitors are typically used in Asia while P45 monitors are typically used in the US. This study shows that choice of monitor phosphor may influence diagnostic and/or visual search performance and thus should be taken into account when selecting a monitor for clinical use.

Krupinski, Elizabeth A.; Roehrig, Hans

2001-06-01

184

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

185

Observation and control for air-breathing hypersonic aircrafts based on sliding mode method  

Microsoft Academic Search

In this paper, the state observation and control problems are studied for air-breathing cruise hypersonic aircrafts. As many variables in flight cannot be measurable, a sliding mode observer is firstly introduced to derive all unmeasurable states. Secondly the feedback linearization is executed on the longitudinal model of air-breathing hypersonic aircrafts using all states, then a sliding mode controller is designed

Chaoxu Mu; Changyin Sun; Xinghuo Yu

2011-01-01

186

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.

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

187

Mathematical methods of studying physical phenomena  

NASA Astrophysics Data System (ADS)

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

Man'ko, Margarita A.

2013-03-01

188

Mucocutaneous manifestations of acquired hypoparathyroidism: An observational study.  

PubMed

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

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

2012-09-01

189

Mucocutaneous manifestations of acquired hypoparathyroidism: An observational study  

PubMed Central

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

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

2012-01-01

190

Study of pulsar evolution through timing and single pulse observations  

SciTech Connect

In order to investigate the phenomena associated with the evolution of pulsars, two observing programs were undertaken. Beginning in 1978 October, pulse arrival time measurements were made at roughly two month intervals with the 92 meter telescope for a sample of ninety-eight pulsars. Sixty-three of these pulsars had been discovered in surveys at the NRAO and the Molonglo Observatory in 1978. A second program using the 305 meter telescope of the Arecibo Observatory, studied the single pulse behavior of twenty of the recently discovered pulsars. The results of these programs are discussed. The timing program has resulted in the measurement of accurate periods, period derivatives, and positions for fifty-one of the recently discovered pulsars, and improved periods and/or positions for seven others. Data for the other thirty-five pulsars in the program were combined with data from previous timing programs. Improved parameters were obtained for nine of these pulsars. One pulsar, PSR2224 + 65, was found to have undergone a large glitch comparable in magnitude to those exhibited by the Vela pulsar. It is only the third middle aged pulsar observed to have undergone an unambiguous glitch. The results of this timing program are combined with measurements of period derivatives from other observers. The resulting P-P diagram for 295 pulsars is examined in terms of current models of pulsar evolution. The basic wedge-shaped distribution of points is unchanged. However, a few pulsars are found outside of the wedge. Two of these pulsars may have evolved in binary systems which were subsequently disrupted.

Backus, P.R.

1981-01-01

191

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 ...

192

Theory, Method, and Triangulation in the Study of Street Children.  

ERIC Educational Resources Information Center

Describes how a comparative study of street children in Montevideo (Uruguay), Rio de Janeiro, and Mexico City contributes to a synergism between theory and method. Notes how theoretical approaches of symbolic interactionism, genetic structuralism, and habitus theory complement interview, participant observation, and content analysis methods;…

Lucchini, Riccardo

1996-01-01

193

Qualitative Evaluation of Courses Intended for Patients Suffering from Chronic Diseases: New Observation Method for the Continuous Training of the Healthcare Team.  

ERIC Educational Resources Information Center

Proposes "analytical observation" as a method of training evaluation for health-care providers. The method, which utilizes observation charts, has been validated through a study that examined the impact of supervision of health-care providers in the domain of therapeutic education of patients. Results show that this method has a definite impact on…

Jacquemet, S.; Lacroix, A.; Perrolini, M.; Golay, A.; Assal, J-Ph.

1998-01-01

194

Chunking Method of Teaching and Studying: II.  

ERIC Educational Resources Information Center

Data from three general psychology classes were used in a study of the chunking method of teaching and studying. Two classes participated in a study on chunking study outline (CSO) length, and one in a study on retention rates. Results of students with high and low cognitive processing capacities (CPC) were also compared. It was found that a CSO…

Furukawa, James M.; And Others

195

Methods to study degradation of ruminant feeds.  

PubMed

Ruman degradation is crucial in the supply of dietary nutrients to meet the nutrient demands of the anaerobic microbes and body tissues of ruminant animals. Therefore, it is essential to study the dynamics of rumen degradation of various feeds before their potential use to formulate nutritious diets for ruminant animals. Amongst many methods that have been used in the past, the in sacco method has been the most effective method to study rumen degradation. However, this method is undesirable due to its implications for animal welfare and costs. While many in vitro methods have been tested as possible alternatives to the in sacco method to study rumen degradation of feeds, they were unable to remove the need to use fistulated animals to obtain rumen fluid. Although solubility, enzyme- and faeces-based in vitro methods do not require rumen fluid, they still need data from either the in sacco method or the rumen fluid-based in vitro methods for comparison and validation. Therefore, there is a need to develop in vitro methods that do not require the need to surgically modify ruminants to obtain rumen fluid to study rumen degradation. We review the potentials and problems associated with the existing methods to study rumen degradation and their implications for the animal industry in different situations. PMID:19079855

Mohamed, Ruba; Chaudhry, Abdul Shakoor

2008-06-01

196

Observational methods to measure behaviors of captive cotton-top tamarins (Saguinus oedipus).  

PubMed

The purpose of this study was to identify efficient sampling methods for establishing accurate activity budgets for zoo animals. Seven cotton-top tamarins (Saguinus oedipus) from two zoos were videotaped for multiple 90 min sessions, 3 to 4 days per week for 12 weeks. An activity budget was constructed for each animal using a continuous sampling method to analyze 30 hr of video recording of each animal. These master datasets, reflecting actual behavior, were re-sampled using interval sampling lengths of 0.25, 0.5, 1, 2, 4, 5, 7, 10, 15 and 20 min, and cluster sampling protocols (periodic sessions of continuous sampling) of 10 min x 3, 15 min x 2, 20 min x 1, 15 min x 1 and 10 min x 1 (min x repetitions/90 min sample period) to construct additional activity budgets for each animal. The Canberra similarity index was used to determine the statistical relationship between these activity budgets and those based on the master datasets. As interval length increased, there was a consequent decrease in the accuracy of the associated activity budgets as compared with the master dataset. No cluster sampling protocols yielded activity budgets as accurate as the four shortest interval lengths, but all cluster sampling protocols were more accurate than the three longest interval lengths. All the tested protocols varied in ability to accurately portray animal behavior. Overall, interval sampling provided superior behavioral representations at lower observer input. Results from this study will potentially facilitate the standardization of behavior monitoring protocols at zoos. PMID:19653282

Edwards, Lily N; Sorkin, Andrew E; Rhodes, Richard C; Petersson, Katherine H

197

TV Observations of Meteors in INASAN: Equipment, Methods and First Results  

NASA Astrophysics Data System (ADS)

For the analysis the risk from particles of meteor streams, we must have proved information about masses and densities of meteors. The prime task is to select minor streams from sporadic meteors. Very few astronomers tried to do it, when others only mark observed meteor “Sporadic” without registering its track. So very few previous observations cannot be used for streams detection, and we had to do it from special observations. As a width of meteoroid stream may be very narrow, the Earth will cross it in few hours and it is necessary to observe meteor events 24 hour a day. This is why we provide meteor monitoring and catch every ray of light in night skies and ask other observers to join our program. The current goal of our investigation is continuous monitoring of meteor events by two ways: from nearby sites (about 20-60 km distance) for triangle observations and simultaneously from some observation sites separated by approximately thousand kilometers for detection of minor streams. The last one will reveal spatial heterogeneity's of strong meteor showers also. Since July 2002 at the Arkhyz Space Tracking Station (North Caucasus) and near Moscow hybrid TV-cameras with CCD (“PatrolCa”) are used for meteor observations. Limiting magnitude of the first camera is about +5 magn in the 52-degrees field under frame rate 25 f/sec, the second camera has limiting magnitude 11,5m in field 18x22 degrees with rate 7,5 f/sec. Since June 2006 four extra PatrolCa begin stereo (basis) TV-observation near Moscow with the aims of determination of individual orbits of observed meteors and their physical densities. Observed by meteor monitoring data show that at least 40% of sporadic meteors may be referred to catalogued weak meteor streams. In this paper we present the method of definition of celestial coordinates of objects in the single frame of the wide-angle system. The method allows definition of celestial coordinates of a meteor at the restrictions of absents of enough stars in the frame during the observations, for example at partially cloudy weather, or when there are few stars in the frame, or at large distortions of a coordinate grid in the frame. These restrictions can forbid direct using of other methods. We objectively registered 38 meteors with wide-angle camera “PatrolCA” during 9 nights from 2002 to 2007 years and 2000 meteors with highly sensitive camera FAVOR during 1000 nights at the same period. The work is supplied by RFBI grants 06-02-08313 and 06-02-16365.

Kartashova, Anna P.; Bagrov, A. V.; Leonov, V. A.

2007-08-01

198

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

199

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

200

A novel “sandwich” method for observation of the keyhole in deep penetration laser welding  

Microsoft Academic Search

A sandwich method was used to observe the keyhole in deep penetration laser welding, which provided an effective way to analyze both the Fresnel and inverse Bremsstrahlung absorption. In the transparent metal-analog system, different densities of metal vapor, ionized atoms, and free electrons in the keyhole can be simulated by changing the thickness of aluminum films. The research results show

Yi Zhang; Genyu Chen; Haiying Wei; Jun Zhang

2008-01-01

201

A Comparison of Heuristic Methods for Scheduling Earth Observing Satellites Fleet  

Microsoft Academic Search

This paper addressed the planning and scheduling problem for earth observing satellites fleet of China. The author first described the problem scope naturally, then proposed a mixed-integer programming model for a simplified version of the problem, which only considered the data-take activities of the satellites. Then the author gave two heuristic methods for it and made experimental comparisons based on

Pei Wang; Yuejin Tan; Gerhard Reinelt

2009-01-01

202

Observation of Charge Distribution in Electron Beam Irradiated Polymers using Pulsed Electroacoustic Method  

Microsoft Academic Search

Charge distributions in electron beam irradiated polymers are observed using the pulsed electro-acoustic (PEA) method. In space environment, bulk charge accumulation in insulating materials of a spacecraft, which is exposed in the radiation of cosmic rays, is one of remarkable problems because the accumulation may sometimes cause of the unexpected accidents followed by the static discharge. Therefore, the interaction between

W. Dang; M. Tahara; J. Taima; Y. Tanaka; R. Watanabe; T. Takada

2006-01-01

203

Coordinated Regional Benefit Studies of Coastal Ocean Observing Systems.  

National Technical Information Service (NTIS)

The long-term goal supported by this project is the development and sustained support of coastal ocean observing systems for the waters of the United States. The authors will first produce regional 'inventories' of ocean observation user sectors, includin...

A. Pulsipher C. S. Colgan H. L. Kite-Powell K. Wieand M. Luger

2003-01-01

204

New Methods of Studying Nuclear Reactor Thermohydraulics  

SciTech Connect

New methods of studying reactor thermohydraulic problematic such as CHF, DNBR, boiling and instability etc. were introduced briefly in this paper. Some of these methods have been successfully applied in the reactor thermohydraulic analysis. And the others have not yet been applied in this field. The further study work must be done to show that these new methods can be successfully applied in this field with high accuracy because they are interdisciplinary fields. (authors)

Su, Guanghui; Fukuda, K. [Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

2002-07-01

205

Determination of miscibility pressure by direct observation method. Quarterly report, January 1-March 31, 1982  

SciTech Connect

The objective of the project is to conduct laboratory tests to: (1) develop a method for determining MMP through direct observation using a high pressure cell; (2) determine feasibility of in-situ foam generation by visual observation and microphotographic technique. The project is presently organized and carried out in three major fronts: (1) MMP test; (2) high pressure sampling and chemical analysis; and (3) foam study and displacement test. The technical progress in each of these areas is discussed. The effects of temperature on MMP and appearance of CO/sub 2/-rich phase for four crude oils tested are plotted. The MMP is the pressure at which the CO/sub 2/-rich phase becomes miscible with CO/sub 2/ vapor. The results of gas chromatographic analysis for the four crude oils tested are presented. As previously stated the richness of C/sub 5/ to C/sub 20/ components is the key factor for determining the quality and stability of the miscible transition zone. The surfactant/CO/sub 2/ ratio relative to foam quality and foam quantity are presented in a table and also plotted. The plotted figures show: (1) the foam qualities increased as the surfactant rates are decreased; (2) at 75/sup 0/F, the foam quality increases as the pressure is decreased whereas the reverse is true for temperature at 120/sup 0/F; (3) foam generating rate increased with increasing surfactant/CO/sub 2/ ratio; (4) high temperatures tend to lower the rate and high pressures tend to increase the rate at 120/sup 0/F but to decrease at 75/sup 0/F; (5) foam quality was found to be affected more by surfactant/CO/sub 2/ ratio, and to a lesser degree by pressure and temperature. (ATT)

Wang, G. C.

1982-01-01

206

Observation of Adsorption Phenomena of Dibutyl Phthalate Molecules on Si Surface Using Quartz Crystal Microbalance Method  

NASA Astrophysics Data System (ADS)

The adsorption phenomena of dibutyl phthalate (DBP) molecules on the Si surface were observed in detail using a highly sensitive quartz crystal microbalance (QCM) and a new method involving a sliding chamber system. As a result of the precise observation of the adsorption phenomena and an accurate decomposition analysis, the typical Langmuir adsorption phenomenon with a time constant of 350 s was observed following the rapid adsorption phenomenon that occurs within the first 10 s and the next adsorption phenomenon of increasing linearly. After almost reaching the adsorption equilibrium amount, another Langmuir adsorption phenomena for a time constant of 3000 s was also observed; the Langmuir adsorption phenomenon for a time constant of 350 s seems to be that of an isolated admolecule whereas that for 3000 s seems to be one where admolecule cohere by mutual migration on a surface.

Okamura, Shigeru; Shimada, Manabu; Okuyama, Kikuo

2004-08-01

207

Gravity Wave Observations using the GRIPS Spectrometers: A Case Study  

NASA Astrophysics Data System (ADS)

Gravity waves play a prominent role in our understanding of atmospheric dynamics through carrying energy and momentum. There are numerous sources in the upper and lower atmosphere generating gravity waves. The waves often propagate vertically through the atmosphere and can affect the OH* emission layer in the mesopause region (around 87 km). Measurements of the OH*-airglow are therefore well suited to study gravity waves. Two case studies illustrating the potential of the GRIPS (Ground-based Infrared P-branch Spectrometer) system to quantify gravity wave parameters are presented. Observations of the GRIPS 1 instrument located at the Meteorological Observatory Hohenpeissenberg, Germany (48°N/11°E) and the GRIPS 3 instrument at the German Environmental Research Station Schneefernerhaus, Zugspitze (47.4°N/11°E) are used to study gravity waves in the alpine region. A case study estimating the gravity wave parameters is presented. The mobile spectrometer GRIPS 4 recorded a gravity wave event in the Bay of Biscay during the night of 15/16 October 2005 on its trip with the German research vessel ‘Polarstern' during the expedition ANTXXIII/1 from Bremerhaven (54°N/9°E) to Cape Town (34°S/19°E). At the same time period AVHRR composites indicate gravity wave structures in the water vapour in the troposphere. Additionally, vertical profiles of temperature, wind and ozone derived by radio- and ozonesondes during the ‘Polarstern' cruise show similar wave signals. A convective cloud cluster centred south-western of Iceland could be identified as the most likely source of these waves.

Höppner, K.; Bittner, M.; Koppmann, R.; Steinbrecht, W.

2009-04-01

208

Analyzing Interstellar Gas Flow Distributions Observed with IBEX Using a Maximum Likelihood Method  

NASA Astrophysics Data System (ADS)

The Interstellar Boundary Explorer (IBEX) observes interstellar neutral gas flow distributions of species that remain neutral to a large part in the interstellar gas, such as He and O. In order to fit model distributions to the data a maximum likelihood method is used to extract more information even with low counting statistics, compared with using a least chi square fit. Parameters, such as peak position, distribution height, width, and skewness may be obtained with the maximum likelihood method to characterize, for example, flow velocity, density, and temperature of the interstellar source as well as ionization rates. We will give an introduction to the application of the maximum likelihood method to the IBEX observations.

Leonard, Trevor

2009-10-01

209

2D vs. 3D mammography observer study  

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

210

An observational study of the formation and evolution of sunspots  

NASA Astrophysics Data System (ADS)

This dissertation focuses on the problem of molecules and the horizontal balance of forces in sunspots. Sunspots are quasi-static features on the solar surface and can be considered to be in a state of equilibrium. The weaker gas pressure of the cool sunspot interior is horizontally supported against the higher pressure of the hotter quiet-Sun by a strong vertical magnetic field. However, some sunspots show a rapid increase in magnetic pressure relative to the temperature of the gas in the coolest regions of the sunspot, implying that an isothermal decrease in the gas pressure must have occurred. The current model of sunspots is unable to describe this deviation from the assumed equilibrium state of the magnetic field and thermal gas pressure observed in these sunspots. Another method of altering the pressure of the gas must be occurring. The formation of molecules in sunspots may be the key to solving this puzzle. The sunspot interior provides a cool environment where molecules can form in abundance. As atoms become bound into molecules the total particle number of the gas is decreased. A sufficiently large molecular fraction could significantly alter the properties of the sunspot plasma, and specifically provide a mechanism for concentrating the magnetic field by non-thermally lowering the gas pressure. I have investigated the equilibrium condition of sunspots of different sizes and in a variety of evolutionary phases through a Milne-Eddington inversion of spectropolarimetric observations of the Zeeman-split Fe I lines at 6302 and 15650 A to obtain their thermal and magnetic topology. I carried out a calculation of the detailed radiative transfer and chemical equilibrium of model sunspot atmospheres to determine the molecular gas fraction. Several sunspots show unambiguous cases of isothermal magnetic field intensification, which can only be explained by the formation or destruction of a large molecular population. All sunspots with magnetic fields stronger than 2500 G and temperatures cooler than 5800 K consistently show a signature of magnetic field over-concentration, consistent with molecular hydrogen formation of a few percent of the total gas fraction. The formation of this large molecular population has widespread implications for sunspot physics.

Jaeggli, Sarah A.

211

Food worker hand washing practices: an observation study.  

PubMed

Improvement of food worker hand washing practices is critical to the reduction of foodborne illness and is dependent upon a clear understanding of current hand washing practices. To that end, this study collected detailed observational data on food worker hand washing practices. Food workers (n = 321) were observed preparing food, and data were recorded on specific work activities for which hand washing is recommended (e.g., food preparation, handling dirty equipment). Data were also recorded on hand washing behaviors that occurred in conjunction with these work activities. Results indicated that workers engaged in approximately 8.6 work activities per hour for which hand washing is recommended. However, workers made hand washing attempts (i.e., removed gloves, if worn, and placed hands in running water) in only 32% of these activities and washed their hands appropriately (i.e., removed gloves, if worn, placed hands in running water, used soap, and dried hands) in only 27% of these work activities. Attempted and appropriate hand washing rates varied by work activity--they were significantly higher in conjunction with food preparation than other work activities (46 versus < or = 37% for attempted hand washing; 41 versus < or = 30% for appropriate hand washing) and were significantly lower in conjunction with touching the body than other work activities (13 versus > or = 27% for attempted hand washing; 10 versus > or = 23% for appropriate hand washing). Attempted and appropriate hand washing rates were significantly lower when gloves were worn (18 and 16%) than when gloves were not worn (37 and 30%). These findings suggest that the hand washing practices of food workers need to be improved, glove use may reduce hand washing, and restaurants should consider reorganizing their food preparation activities to reduce the frequency with which hand washing is needed. PMID:17066921

Green, Laura R; Selman, Carol A; Radke, Vincent; Ripley, Danny; Mack, James C; Reimann, David W; Stigger, Tammi; Motsinger, Michelle; Bushnell, Lisa

2006-10-01

212

Clinicians' gut feeling about serious infections in children: observational study  

PubMed Central

Objective To investigate the basis and added value of clinicians’ “gut feeling” that infections in children are more serious than suggested by clinical assessment. Design Observational study. Setting Primary care setting, Flanders, Belgium. Participants Consecutive series of 3890 children and young people aged 0-16 years presenting in primary care. Main outcome measures Presenting features, clinical assessment, doctors’ intuitive response at first contact with children in primary care, and any subsequent diagnosis of serious infection determined from hospital records. Results Of the 3369 children and young people assessed clinically as having a non-severe illness, six (0.2%) were subsequently admitted to hospital with a serious infection. Intuition that something was wrong despite the clinical assessment of non-severe illness substantially increased the risk of serious illness (likelihood ratio 25.5, 95% confidence interval 7.9 to 82.0) and acting on this gut feeling had the potential to prevent two of the six cases being missed (33%, 95% confidence interval 4.0% to 100%) at a cost of 44 false alarms (1.3%, 95% confidence interval 0.95% to 1.75%). The clinical features most strongly associated with gut feeling were the children’s overall response (drowsiness, no laughing), abnormal breathing, weight loss, and convulsions. The strongest contextual factor was the parents’ concern that the illness was different from their previous experience (odds ratio 36.3, 95% confidence interval 12.3 to 107). Conclusions A gut feeling about the seriousness of illness in children is an instinctive response by clinicians to the concerns of the parents and the appearance of the children. It should trigger action such as seeking a second opinion or further investigations. The observed association between intuition and clinical markers of serious infection means that by reflecting on the genesis of their gut feeling, clinicians should be able to hone their clinical skills.

2012-01-01

213

Estimating effectiveness in an observational study: A case study of dornase alfa in cystic fibrosis  

Microsoft Academic Search

Patients with cystic fibrosis (CF) receiving dornase-alfa had improved pulmonary function relative to a control group in a large randomized phase III controlled study. We reviewed data from a large observational phase IV study to estimate the observed drug effect in patients receiving dornase alfa as part of their routine care. Patients 6 years or older and with a baseline

Charles A. Johnson; Steven M. Butler; Michael W. Konstan; Timothy J. Breen; Wayne J. Morgan

1999-01-01

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.

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

2013-01-01

215

Energy intakes of ultraendurance cyclists during competition, an observational study.  

PubMed

Endurance events>10 hr are becoming increasingly popular but provide numerous physiological challenges, several of which can be attenuated with optimal nutritional intakes. Previous studies in ultraendurance races have reported large energy deficits during events. The authors therefore aimed to assess nutritional intakes in relation to performance among ultraendurance cyclists. This observational study included 18 cyclists in a 384-km cycle race. At race registration each cyclist's support crew was provided with a food diary for their cyclist. On completion of the race, cyclists were asked to recall their race food and drink intakes. All food and fluids were analyzed using a computer software package. Mean (SD) time to complete the race was 16 hr 21 min (2 hr 2 min). Mean (SD) energy intake was 18.7 (8.6) MJ, compared with an estimated energy requirement for the race of 25.5 (7.4) MJ. There was a significant negative relationship between energy intake and time taken to complete the race (p=.023, r²=-.283). Mean (SD) carbohydrate, fat, and protein intakes were 52 (27), 15.84 (56.43), and 2.94 (7.25) g/hr, respectively. Only carbohydrate (p=.015, r²=-.563) and fat intake (p=.037, r²=-.494) were associated with time taken to complete the race. This study demonstrates the difficulties in meeting the high energy demands of ultraendurance cycling. The relationship between energy intake and performance suggests that reducing the energy deficit may be advantageous. Given the high carbohydrate intakes of these athletes, increasing energy intake from fat should be investigated as a means of decreasing energy deficits. PMID:22248496

Black, Katherine E; Skidmore, Paula M L; Brown, Rachel C

2012-02-01

216

Non-parametric method for measuring gas inhomogeneities from X-ray observations of galaxy clusters  

NASA Astrophysics Data System (ADS)

We present a non-parametric method to measure inhomogeneities in the intracluster medium (ICM) from X-ray observations of galaxy clusters. Analysing mock Chandra X-ray observations of simulated clusters, we show that our new method enables the accurate recovery of the 3D gas density and gas clumping factor profiles out to large radii of galaxy clusters. We then apply this method to Chandra X-ray observations of Abell 1835 and present the first determination of the gas clumping factor from the X-ray cluster data. We find that the gas clumping factor in Abell 1835 increases with radius and reaches ˜2-3 at r = R200. This is in good agreement with the predictions of hydrodynamical simulations, but it is significantly below the values inferred from recent Suzaku observations. We further show that the radially increasing gas clumping factor causes flattening of the derived entropy profile of the ICM and affects physical interpretation of the cluster gas structure, especially at the large cluster-centric radii. Our new technique should be useful for improving our understanding of the cluster structure and to advance the use of galaxy clusters as cosmological probes, by helping to exploit rich data sets provided by Chandra and XMM-Newton X-ray space telescopes.

Morandi, Andrea; Nagai, Daisuke; Cui, Wei

2013-09-01

217

Recovery of visual field defects: A large clinical observational study using vision restoration therapy  

Microsoft Academic Search

Abstract. Purpose: In small experimental trials, vision restoration therapy (VRT), a home-based rehabilitation method, has shown,to enlarge the visual field and improve,reaction times in patients with lesion involving the CNS. We now,evaluated the outcome,of VRT in a large sample,of clinical patients and studied factors contributing to subjective and objective measures,of visual field alterations. Methods: Clinical observational analysis of visual fields

Iris Mueller; Henning Mast; Bernhard A. Sabel

218

Observational and numerical study of Atlantic tropical instability waves  

NASA Astrophysics Data System (ADS)

This study uses high resolution satellite measurements from the Tropical Rainfall Measuring Mission (TRMM), Quick Scatterometer (QuikSCAT) and Special Sensor Microwave Imager (SSM/I) to investigate the variability of sea surface temperature (SST), surface wind velocity, water vapor, cloud liquid water and precipitation associated with westward moving tropical instability waves (TIWs) in the Atlantic Ocean from 1998 to 2005. On interannual scales, TIWs in the Pacific Ocean are strongest during the cold phase of El Ni¨no Southern Oscillation (ENSO), when the cold tongue is most pronounced. The waves are weak during the warm phase of ENSO. A low-frequency Atlantic air-sea coupled mode influences the TIW activity in the Atlantic Ocean as ENSO does in the Pacific Ocean. The characteristics of TIWs are largely associated with the background oceano-graphic states. Coherent ocean-atmosphere patterns are shown in the Atlantic Ocean during eight years. Southeasterly trades strengthen and water vapor increases over warm SST anomalies associated with TIWs. The opposite is true over cold TIW SST anomalies. The cloud liquid water and rain response to the SST follows a very similar pattern, appearing to be roughly in phase with wind convergence and divergence in the central tropical Atlantic. The atmospheric response to the TIW SST anomalies extends north of the TIW active region, suggesting a remote response to the TIWs. The atmospheric response to the Atlantic TIWs shows interannual variability. In 1999, the rainfall response to the TIW SST anomalies is much larger than in other years, which is due to the southward movement of Atlantic ITCZ (Intertropical Convergence Zone). When the Atlantic ITCZ moves south, it is more susceptible to TIW influence. One regional climate model and one global climate model are applied to study the mechanism of atmospheric response to the Atlantic TIWs with daily TMI satellite SST forcing. Both models successfully simulated the wind velocity, wind convergence and precipitation as observed. While the satellite observations support the vertical mixing mechanism for the surface wind response to TIWs, both models show the pressure gradient mechanism is dominant in the Atlantic.

Wu, Qiaoyan

219

Integrating patient teaching into bedside patient care: a participant-observation study of hospital nurses  

Microsoft Academic Search

Today’s patients are quickly discharged from hospitals and often continue complex treatments at home. Patient teaching is critical and hospital nurses are encouraged to use “every teachable moment.” This study explored and described the nature of integrating patient teaching into daily patient care and the factors influencing the delivery of teaching. A fieldwork method, conducted over 12 months, used participant-observation

Elaine D Barber-Parker

2002-01-01

220

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.

221

Patients’ assessments of the effectiveness of homeopathic care in Norway: A prospective observational multicentre outcome study  

Microsoft Academic Search

Objective: To evaluate the patient reported effects of homeopathic care 6 months after first consultations. Methods: Prospective uncontrolled observational multicentre outcome study. All patients visiting 80 homeopaths all over Norway for the first time in eight different time periods from 1996 to 1998 were approached. Patients wrote down their main complaint and scored its impact on daily living on a

A Steinsbekk; R Lüdtke

2005-01-01

222

Professional quality of life and organizational changes: a five-year observational study in Primary Care  

Microsoft Academic Search

BACKGROUND: The satisfaction and the quality of life perceived by professionals have implications for the performance of health organizations. We have assessed the variations in professional quality of life (PQL) and their explanatory factors during a services management decentralization process. METHODS: It was designed as a longitudinal analytical observational study in a Health Area in Madrid, Spain. Three surveys were

Jesus Martin-Fernandez; Tomas Gomez-Gascon; Milagros Beamud-Lagos; Jose Alfonso Cortes-Rubio; Angel Alberquilla-Menendez-Asenjo

2007-01-01

223

Observation of Psychoactive Substance Consumption: Methods and Results of the French OPPIDUM Programme  

Microsoft Academic Search

This study presents a French programme designed to observe and evaluate psychoactive substance dependence and abuse. Annual surveys lasting 4 weeks are performed with drug users in drug centres. Its usefulness is discussed using examples from the study: potential for antidepressant dependence (amineptine), monitoring benzodiazepine use and consumption associated with maintenance treatments. Flunitrazepam is the most consumed benzodiazepine and often

Xavier Thirion; Joelle Micallef; Karine Barrau; Samira Djezzar; Jean Louis Sanmarco; Georges Lagier

2001-01-01

224

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

225

The IPCS Collaborative Study on Neurobehavioral Screening Methods  

Microsoft Academic Search

The International Programme on Chemical Safety sponsored a collaborative study to evaluate the utility of neurobehavioral test methods for identifying neurotoxic chemicals. The protocol consisted of a functional observational battery and automated assessment of motor activity. The study involved four laboratories in the United States and four in Europe, each of which evaluated the dose- and time-related effects of seven

Virginia C. Moser; George C. Becking; Robert C. MacPhail; Beverly M. Kulig

1997-01-01

226

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

227

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 ethics—respect for persons/autonomy; beneficence/nonmaleficence; and distributive justice—as 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.

Norris, Alison; Jackson, Ashley; Khoshnood, Kaveh

2013-01-01

228

Dental injury after conventional direct laryngoscopy: a prospective observational study.  

PubMed

This observational study assessed the frequency and risk factors of dental damage after classic direct laryngoscopy for tracheal intubation in 536 adult patients. The patients' sex, age, height, weight, dental condition, dental mobility, Mallampati class, interincisor gap, thyromental distance, neck circumference, and head and neck extension were recorded. From anaesthesia records, the difficulty of intubation, the number of attempts, type of neuromuscular blocking agent used and duration of anaesthesia were recorded. After anaesthesia, examination revealed that 134 patients (25.0%) had dental damage affecting 162 teeth (147 maxillary; 15 mandibular). Enamel fracture was the commonest injury. In tooth number 21, the interincisor gap (OR 2.5 (95% CI 1.0-5.9)) and in tooth number 22, the number of intubation attempts (OR 5.3 (95% CI 1.3-22.0)) were considered a risk factor for dental injury. Conventional direct laryngoscopy is associated with a strikingly high incidence of dental damage, although specific risk factors remain unclear. PMID:24047290

Mourão, J; Neto, J; Luís, C; Moreno, C; Barbosa, J; Carvalho, J; Tavares, J

2013-10-01

229

Severe malaria in children in Yemen: two site observational study  

PubMed Central

Objectives To assess the burden of malaria on health services, describe the clinical presentation of severe malaria in children, and identify factors associated with mortality by means of a prospective observational study. Setting Two public hospitals in Taiz (mountain hinterland) and Hodeidah (coastal plain), Yemen. Participants Children aged 6 months to 10 years. Results Of 12 301 paediatric admissions, 2071 (17%) were for suspected severe malaria. The proportion of such admissions varied according to the season (from 1% to 40%). Falciparum malaria was confirmed in 1332 children; 808 had severe disease as defined by the World Health Organization. Main presentations were respiratory distress (322/808, 40%), severe anaemia (291/800, 37%), and cerebral malaria (60/808, 8%). Twenty two of 26 children who died had a neurological presentation. No deaths occurred in children with severe anaemia but no other signs of severity. In multivariate analysis, a Blantyre coma score ? 2, history of fits, female sex, and hyperlactataemia predicted mortality; severe anaemia, respiratory distress, and hyperparasitaemia were not significant predictors of mortality. Conclusions Severe malaria puts a high burden on health services in Yemen. Although presentation is similar to African series, some important differences exist. Case fatality is higher in girls.

Al-Taiar, Abdullah; Jaffar, Shabbar; Assabri, Ali; Al-Habori, Molham; Azazy, Ahmed; Al-Mahdi, Nagiba; Ameen, Khaled; Greenwood, Brian M; Whitty, Christopher J M

2006-01-01

230

[Prevalence of biological exposure among nursing students: an observational study].  

PubMed

Blood-transmitted infections such as viral hepatitis B, or human immunodeficiency virus , are a real danger to health workers. Student nurses are also exposed to biological risks during their clinical training. This study was carried out to assess the incidence and nature of such risks in student nurses in Italy, evaluating all the cases of biological exposure in the G. D'Annunzio University Hospital of Chieti from 2002 to 2006. Student nurses were monitored for 6 months after exposure. A total number of 2047 students was observed; 665 first -year (32.49%), 691 second-year (33.76%) and 691 third-year (33.76%). During training a total of 135 (6.6%) instances of biological exposure occurred, average age 24.94 (R.19-45; SD 5.52), 99 females (73.3%). Although there was a lower incidence in third-year students (-27%), most of them occurred in the Medical Department (86 =63.7%). Needle pricks were the primary cause of exposure while the tabs used for measuring blood-sugar levels also represented a high risk. Although risks were lower in last-year students, it is clear that more attention should be paid to prevention , increasing awareness of infection control and monitoring biological exposure throughout the entire training period. PMID:19250618

Cicolini, Giancarlo; Di Labio, Luisa; Lancia, Loreto

231

Observed wave characteristics during growth and decay: a case study  

NASA Astrophysics Data System (ADS)

Observed 1-h time series data on sea surface waves in the shelf waters off Goa, west coast of India (depth 80 m), during 17 24 March 1986, are analyzed with reference to the prevailing synoptic winds to understand wave growth and decay aspects. Wind speeds (U10) ranged from 0 to 11.5 m s-1, whereas significant wave height (Hs) varied between 0.6 and 2.3 m. Cross-correlation analysis betweenU10 andHs revealed a time-lag of 4 h. A relationship is obtained between wave steepness (Hs/L) and wave age (C/U10) viz. Log10(Hs/L= -0.53 Log10(C/U10) - 1.385. Phillips' hypothesis off-5 formula for equilibrium range of wave spectrum and relationship between non-dimensional energy (E* = Eg2/U*4) and non-dimensional peak frequency (v* = U*fm/g) are studied. Correlation of non-dimensional wave parameters (E* andv*) using the present data showed a better aereement with Hasselmannet al. (1976) when comnared to Toba (1978).

Prasada Rao, C. V. K.; Baba, M.

1996-10-01

232

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

PubMed Central

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

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

2012-01-01

233

Motor facilitation during action observation: a magnetic stimulation study.  

PubMed

1. We stimulated the motor cortex of normal subjects (transcranial magnetic stimulation) while they 1) observed an experimenter grasping 3D-objects, 2) looked at the same 3D-objects, 3) observed an experimenter tracing geometrical figures in the air with his arm, and 4) detected the dimming of a light. Motor evoked potentials (MEPs) were recorded from hand muscles. 2. We found that MEPs significantly increased during the conditions in which subjects observed movements. The MEP pattern reflected the pattern of muscle activity recorded when the subjects executed the observed actions. 3. We conclude that in humans there is a system matching action observation and execution. This system resembles the one recently described in the monkey. PMID:7666169

Fadiga, L; Fogassi, L; Pavesi, G; Rizzolatti, G

1995-06-01

234

Retrospective analysis showing the water method increased adenoma detection rate -- a hypothesis generating observation  

PubMed Central

Background A water method developed to attenuate discomfort during colonoscopy enhanced cecal intubation in unsedated patients. Serendipitously a numerically increased adenoma detection rate (ADR) was noted. Objective To explore databases of sedated patients examined by the air and water methods to identify hypothesis-generating findings. Design: Retrospective analysis. Setting: VA endoscopy center. Patients: creening colonoscopy. Interventions: From 1/2000–6/2006 the air method was used - judicious air insufflation to permit visualization of the lumen to aid colonoscope insertion and water spray for washing mucosal surfaces. From 6/2006–11/2009 the water method was adopted - warm water infusion in lieu of air insufflation and suction removal of residual air to aid colonoscope insertion. During colonoscope withdrawal adequate air was insufflated to distend the colonic lumen for inspection, biopsy and polypectomy in a similar fashion in both periods. Main outcome measurements: ADR. Results The air (n=683) vs. water (n=495) method comparisons revealed significant differences in overall ADR 26.8% (183 of 683) vs. 34.9% (173 of 495) and ADR of adenomas >9 mm, 7.2% vs. 13.7%, respectively (both P<0.05, Fisher's exact test). Limitations: Non-randomized data susceptible to bias by unmeasured parameters unrelated to the methods. Conclusion Confirmation of the serendipitous observation of an impact of the water method on ADR provides impetus to call for randomized controlled trials to test hypotheses related to the water method as an approach to improving adenoma detection. Because of recent concerns over missed lesions during colonoscopy, the provocative hypothesis-generating observations warrant presentation.

Leung, Joseph W; Do, Lynne D; Siao-Salera, Rodelei M; Ngo, Catherine; Parikh, Dhavan A; Mann, Surinder K

2011-01-01

235

Can headache impair intellectual abilities in children? An observational study  

PubMed Central

Background The purpose of this study was to assess the cognitive functioning of children affected by headache, pinpointing the differences in intelligence style between subjects affected by migraine without aura and subjects with tension-type headache. Methods The study population consisted of 147 children (mean age 10.82 ± 2.17 years) with headache, recruited from the Headache Center for Developmental Age, Child and Adolescent Neuropsychiatry Clinic, Second University of Naples. Cognitive profiling was performed using Weschler Intelligence Scale for Children Third Edition throughout the sample. According to the International Classification of Headache Disorders II criteria for pediatric age, subjects were divided into a migraine without aura group (n = 75; 43 boys, 32 girls) and a tension-type headache group (n = 72; 49 boys, 23 girls). The results were compared with the findings obtained from a sample of 137 healthy control subjects recruited from schools in the Campania region, matched for age and gender. Results No difference in full intelligence quotient was found between the groups, but the children with tension-type headache had a lower verbal intelligence quotient and a higher performance intelligence quotient than the healthy controls and children with migraine. Factor analysis data showed that the children with migraine seemed to have lower perceptual organization than the children affected by tension-type headache. Conclusion To our knowledge, studies on cognitive functioning in children affected by headache in the interictal phase are scarce, and our results suggest a new perspective in understanding of the neuropsychological aspects of young patients affected by headaches.

Esposito, Maria; Pascotto, Antonio; Gallai, Beatrice; Parisi, Lucia; Roccella, Michele; Marotta, Rosa; Lavano, Serena Marianna; Gritti, Antonella; Mazzotta, Giovanni; Carotenuto, Marco

2012-01-01

236

A helicopter observation platform for atmospheric boundary layer studies  

NASA Astrophysics Data System (ADS)

Spatial variability of the Earth's surface has a considerable impact on the atmosphere at all scales and understanding the mechanisms involved in land-atmosphere interactions is hindered by the scarcity of appropriate observations. A measurement gap exists between traditional point sensors and large aircraft and satellite-based sensors in collecting measurements of atmospheric quantities. Point sensors are capable of making long time series of measurements, but cannot make measurements of spatial variability. Large aircraft and satellites make measurements over large spatial areas, but with poor spatial and temporal resolution. A helicopter-based platform can make measurements on scales relevant for towers, especially close to the Earth's surface, and can extend these measurements to account for spatial variability. Thus, the Duke University Helicopter Observation Platform (HOP) is designed to fill the existing measurement gap. Because measurements must be made in such a way that they are as uncontaminated by the platform itself as much as is possible, it is necessary to quantify the aerodynamic envelope of the HOP. The results of an analytical analysis of the location of the main rotor wake at various airspeeds are shown. Similarly, the results of a numerical analysis using the commercial Computational Fluid Dynamics software Fluent are shown. The optimal flight speed for the sampling of turbulent fluxes is found to be around 30 m/s. At this airspeed, the sensors located in front of the nose of the HOP are in advance of the wake generated by the main rotor. This airspeed is also low enough that the region of high pressure due to the stagnation point on the nose of the HOP does not protrude far enough forward to affect the sensors. Measurements of differential pressures, variables and turbulent fluxes made while flying the HOP at different airspeeds support these results. No systematic effects of the platform are seen at airspeeds above about 10 m/s. Processing of HOP data collected using the current set of sensors is discussed, including the novel use of the Empirical Mode Decomposition (EMD) to detrend and filter the data. The EMD separates the data into a finite number of Intrinsic Mode Functions (IMFs), each of which is unique and orthogonal. The basis is determined by the data itself, so that it need not be known a priori, and it is adaptive. The EMD is shown to be an ideal tool for the filtering and detrending of the HOP data gathered during the Cloud and Land Surface Interaction Campaign (CLASIC). The ability of the HOP to accurately measure atmospheric profiles of atmospheric variables is demonstrated. During experiments conducted in the marine boundary layer (MBL) and the convective boundary layer (CBL), HOP profiles of potential temperature are evaluated using an elastic backscatter lidar. The HOP and the lidar agree on the height of the boundary layer in both cases, and the HOP effectively locates other atmospheric structures. Atmospheric sensible and latent heat fluxes, turbulence kinetic energy (TKE) and horizontal momentum fluxes are also measured, and the resulting information is used to provide context to tower-based data collected concurrently. A brief comparison made over homogeneous ocean conditions yields good results. A more exhaustive evaluation is made using short HOP flights performed above an orchard during the Canopy Horizontal Turbulence Study (CHATS). Randomly selected one-minute sections of tower data are used to calculate fluxes to which the HOP fluxes can be more directly compared, with good results. Profiles of atmospheric fluxes are used to provide context to tower-based measurements. In conclusion, the research conducted here demonstrates unambiguously that the HOP is a unique platform that fills an important gap in observation facilities for the atmospheric boundary layer. It is now available to the scientific community for performing research, which is likely to help bridging existing knowledge gaps in various aspects of Earth surface (continental and maritime) -- atmosphere interactio

Holder, Heidi Eichinger

237

Trigeminocardiac reflex in neurosurgical practice: An observational prospective study  

PubMed Central

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

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

2013-01-01

238

Bayesian statistical methods for genetic association studies  

Microsoft Academic Search

Bayesian statistical methods have recently made great inroads into many areas of science, and this advance is now extending to the assessment of association between genetic variants and disease or other phenotypes. We review these methods, focusing on single-SNP tests in genome-wide association studies. We discuss the advantages of the Bayesian approach over classical (frequentist) approaches in this setting and

Matthew Stephens; David J. Balding

2009-01-01

239

Methods for household waste composition studies  

Microsoft Academic Search

The question is how to conduct household waste composition studies. The review is divided into three parts: overview of known methods, sampling theory, and the waste components. Twenty methods are listed and commented on. There is no adopted, working international standard. In accordance with Pierre Gy’s Theory of Sampling, the seven types of sampling errors, when collecting and splitting solid

Lisa Dahlén; Anders Lagerkvist

2008-01-01

240

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

241

Observations of pulsed discharge phenomena in supercritical carbon dioxide by means of shadowgraph method  

Microsoft Academic Search

This paper describes the temporal development of pulsed discharg es in supercritical carbon dioxide (SCCO2). A magnetic pulsed compression generator with a step-up transformer was used to deliver high voltage pulses to a 5 mm-gap needle-to-plate electrode in SCCO2 (9.4 MPa and 313 K). A time-resolved shadowgraph method was employed to observe pre- and post- breakdown phenomena. A continuous wave

Takeshi Ihara; Tsuyoshi Kiyan; Sunao Katsuki; Takashi Sakugawa; Masanori Hara; Hidenori Akiyama

2010-01-01

242

A Re-estimation Method for Stochastic Language Modeling from Ambiguous Observations  

Microsoft Academic Search

This paper describes a reestimation method for stochastic language models such as the N-gram model and the Hidden Maxkov Model(HMM) from ambiguous observations. It is applied to model estimation for a tagger from a~ untagged corpus. We make extensions to a previous algorithm that reestimates the N-gram model from an untagged segmented language (e.g., English) text as training data. The

Mikio Yamamoto

1996-01-01

243

The Work Activity of School Principals: An Observational Study.  

ERIC Educational Resources Information Center

The content and characteristics of the work of three Australian principals who were observed for three weeks are described with the findings expressed in a set of propositions about the principalship. (Author/IRT)

Willis, Quentin

1980-01-01

244

An observational study of cometary globules near the Rosette nebula  

Microsoft Academic Search

Molecular line observations are reported of two regions containing small cometary globules at the edge of the Rosette Nebula. Observations of the CO, 3CO and C^18^O J=21,-and CO J=43-molecular lines towards Globule 1, the most prominent of the group, show it has a well-developed head-tail structure, with a head diameter ~0.4pc, and a tail extending ~1.3pc behind it. The major

G. J. White; B. Lefloch; C. V. M. Fridlund; C. A. Aspin; G. Dahmen; N. R. Minchin; M. Huldtgren

1997-01-01

245

Correlation studies on surface particle detection methods  

NASA Astrophysics Data System (ADS)

The accurate determination of dust levels on optical surfaces is necessary to assess sensor system performance. A comparison study was made on several particle measurement methods including those based on direct imaging and light scattering. The effectiveness of removing the particles from the surface prior to determining partice size distributions was also assessed. These studies revealed that some methods, especially those requiring particle removal before analysis, are subject to large systematic errors affecting particle size distributions. Thus, an understanding of the particle measurement methods employed is necessary before any surface cleanliness or obstruction value assignments are accepted as a true representation of an optical surface contamination condition.

Peterson, Ronald V.; White, James C., II

1990-04-01

246

Lateralization in motor facilitation during action observation: a TMS study  

Microsoft Academic Search

Action observation facilitates corticospinal excitability. This is presumably due to a premotor neural system that is active\\u000a when we perform actions and when we observe actions performed by others. It has been speculated that this neural system is\\u000a a precursor of neural systems subserving language. If this theory is true, we may expect hemispheric differences in the motor\\u000a facilitation produced

Lisa Aziz-Zadeh; Fumiko Maeda; Eran Zaidel; John Mazziotta; Marco Iacoboni

2002-01-01

247

Correlation methods in fingerprint detection studies  

Microsoft Academic Search

This investigation addresses two general issues regarding the role of pattern similarity statistics in greenhouse warming detection studies: normalization, and the relative merits of centered versus uncentered statistics. A pattern correlation statistic is used to search for the greenhouse warming signals predicted by five different models in the observed records of land and ocean surface temperature changes. Two forms of

B. D. Santer; T. M. L. Wigley; P. D. Jones

1993-01-01

248

Enhancement of force after action observation: behavioural and neurophysiological studies.  

PubMed

We tested here the hypothesis that observing others' actions can facilitate basic aspects of motor performance, such as force production, even if subjects are not required to immediately reproduce the observed actions and if they are not aware that observation can form the basis for procedural training. To this end, we compared in healthy volunteers the effects of repeated actual execution (MOV) or observation (OBS) of a simple intransitive movement (abduction of the right index and middle fingers). In a first experiment, we found that both actual and observational training significantly increased the finger abduction force of both hands. In the MOV group, force increases over pre-training values were significantly higher in the trained than in the untrained hand (50% versus 33%), whereas they were similar for the two hands in the OBS group (32% versus 30%). No force change was found in the control, untrained group. In a second experiment, we found that both training conditions significantly increased the isometric force exerted during right index finger abduction, whereas no post-training change in isometric force was found during abduction of the right little finger. Actual performance, imagination and, to a lower extent, observation of fingers movement enhanced the excitability of the corticospinal system targeting the first dorsal interosseus muscle, as tested by transcranial magnetic stimulation; pre- and post-training effects were of similar magnitude. These results show a powerful, specific role of action observation in motor training, likely exerted through premotor areas, which may prove useful in physiological and rehabilitative conditions. PMID:17681358

Porro, Carlo A; Facchin, Patrizia; Fusi, Simonetta; Dri, Guanita; Fadiga, Luciano

2007-06-30

249

Advances in Doppler Weather Radar Observing Methods and Data Processing Techniques.  

National Technical Information Service (NTIS)

A continuing objective of the Navy-sponsored, Doppler radar studies has been to develop the operational utility of the radar, both as a weather research tool and as an observing instrument useful for specialized, short-term forecasting. To fill this role ...

C. C. Easterbrook

1971-01-01

250

A Conceptual Study of Visual Training Methods.  

ERIC Educational Resources Information Center

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

Aik, Chong-Tek

2003-01-01

251

First application of the radioholographic method to wave observations in the upper atmosphere  

Microsoft Academic Search

Wave phenomena in the upper atmosphere can be studied using the high-precision Global Positioning System (GPS) radio navigational field. In this paper, basic principles, accuracy, and vertical resolution of the radioholographic technique for studies of ionospheric wave phenomena are presented for the general case when the orbits of the satellites are arbitrary. Results of testing of the radioholographic method are

A. Pavelyev; K. Igarashi; C. Reigber; K. Hocke; J. Wickert; G. Beyerle; S. Matyugov; A. Kucherjavenkov; D. Pavelyev; O. Yakovlev

2002-01-01

252

Method for repair of defects in range data observed with a laser range scanner  

NASA Astrophysics Data System (ADS)

Some types of laser range scanner can measure both range data and color texture data simultaneously from the same viewpoint, and are often used to acquire 3D structure of outdoor scenery. However, for outdoor scenery, unfortunately a laser range scanner cannot give us perfect range information about the target objects such as buildings, and various factors incur critical defects of range data. We present a defect detection method based on region segmentation using observed range and color data, and employ a nonlinear PDE (Partial Differential Equation)-based method to repair detected defect regions of range data. As to the defect detection, performing range-and-color segmentation, we divide observed data into several regions that correspond to buildings, trees, the sky, the ground, persons, street furniture, etc. Using the segmentation results, we extract occlusion regions of buildings as defects regions. Once the defect regions are extracted, 3D position data or range data will be repaired from the observed data in their neighborhoods. For that purpose, we adapt the digital inpainting algorithm, originally developed for the color image repair problem, for this 3D range data repair problem. This algorithm is formulated as the nonlinear time-evolution procedure based on the geometrical nonlinear PDE.

Saito, Takahiro; Komatsu, Takashi; Sunaga, Shin-ichi

2003-05-01

253

Economic thought and numerical observations : studies in 'political arithmetic'  

Microsoft Academic Search

This thesis investigates the epistemologieal status of 'raw' numerical observations, and to a lesser extent, more formal statistical constructs in economic thought. The definition of 'economic thought' used throughout this work follows Joseph Schumpeter's broad conception in that it includes two interrelated aspects: formal economic analysis and more everyday, commonsense thought. A central question is the issue of justifying numerical

Anthony M Endres

1982-01-01

254

Experimental determination of subjective similarity for pairs of clustered microcalcifications on mammograms: Observer study results  

SciTech Connect

Presentation of images of lesions similar to that of an unknown lesion might be useful to radiologists in distinguishing between benign and malignant clustered microcalcifications on mammograms. Investigators have been developing computerized schemes to select similar images from large databases. However, whether selected images are really similar in appearance is not examined for most of the schemes. In order to retrieve images that are useful to radiologists, the selected images must be similar from radiologists' diagnostic points of view. Therefore, in this study, the data of radiologists' subjective similarity for pairs of clustered microcalcification images were obtained from a number of observers, and the intra- and inter-observer variations and the intergroup correlations were determined to investigate whether reliable similarity ratings by human observers can be determined. Nineteen images of clustered microcalcifications, each of which was paired with six other images, were selected for the observer study. Thus, subjective similarity ratings for 114 pairs of clustered microcalcifications were determined by each observer. Thirteen breast, ten general, and ten nonradiologists participated in the observer study; some of them completed the study multiple times. Although the intraobserver variations for the individual readings and the interobserver variations for pairs of observers were not small, the interobserver agreements were improved by taking the average of readings by the same observers. When the similarity ratings by a number of observers were averaged among the groups of breast, general, and nonradiologists, the mean differences of the ratings between the groups decreased, and good concordance correlations (0.846, 0.817, and 0.785) between the groups were obtained. The result indicates that reliable similarity ratings can be determined by use of this method, and the average similarity ratings by breast radiologists can be considered meaningful and useful for the development and evaluation of a computerized scheme for selection of similar images.

Muramatsu, Chisako; Li, Qiang; Schmidt, Robert; Suzuki, Kenji; Shiraishi, Junji; Newstead, Gillian; Doi, Kunio [Department of Radiology, University of Chicago, Chicago, Illinois 60637 (United States)

2006-09-15

255

Review: FDA/AHRQ-sponsored observational studies of ...  

Center for Drug Evaluation (CDER)

Text Version... A Cox proportional hazards method was used, so that the ... ie, Medicaid), private health insurance, and health maintenance organization). ... Obesity ... More results from www.fda.gov/downloads/drugs/drugsafety

256

Observing using sound and light - a short review of underwater acoustic and video-based methods  

NASA Astrophysics Data System (ADS)

This paper is a review which briefly describes a selection of acoustic observation techniques and certain aspects of underwater video technology suitable for observations in an underwater environment. The review is divided into two sections, one for each subject, where each section concludes with a discussion of the current challenges within the respective fields. The acoustic section of the review covers bathymetric and geometrical measurements, imaging sonars, subsurface penetrating profilers, positioning methods, acoustic underwater communication and sensor networks, and water speed measurements. The section ends by considering temperature measurements by ocean acoustic tomography and passive acoustic monitoring. The underwater video section initially deals with questions of acquisition including underwater visibility, the type of platform, and video formats, image sensors and specialized cameras. This is followed by notes on processing techniques including mosaicking, stereo video, structured light, recording and transmission, image enhancement techniques and ends with a short discussion of underwater holographic cameras.

Jonsson, P.; Sillitoe, I.; Dushaw, B.; Nystuen, J.; Heltne, J.

2009-04-01

257

Shaping the Future: Writing up the Method on Qualitative Studies.  

ERIC Educational Resources Information Center

|Observations on qualitative manuscripts submitted for publication identified problem areas: organization and format, relationship of concept and method, methodological issues (study type, conceptual framework, sample, data collection/analysis, integrity, data management), discussion, and data presentation. Recommendations for improving quality of…

Rocco, Tonette S.

2003-01-01

258

Creation of an ensemble of simulated cardiac cases and a human observer study: tools for the development of numerical observers for SPECT myocardial perfusion imaging  

NASA Astrophysics Data System (ADS)

Our previous Single Photon Emission Computed Tomography (SPECT) myocardial perfusion imaging (MPI) research explored the utility of numerical observers. We recently created two hundred and eighty simulated SPECT cardiac cases using Dynamic MCAT (DMCAT) and SIMIND Monte Carlo tools. All simulated cases were then processed with two reconstruction methods: iterative ordered subset expectation maximization (OSEM) and filtered back-projection (FBP). Observer study sets were assembled for both OSEM and FBP methods. Five physicians performed an observer study on one hundred and seventy-nine images from the simulated cases. The observer task was to indicate detection of any myocardial perfusion defect using the American Society of Nuclear Cardiology (ASNC) 17-segment cardiac model and the ASNC five-scale rating guidelines. Human observer Receiver Operating Characteristic (ROC) studies established the guidelines for the subsequent evaluation of numerical model observer (NO) performance. Several NOs were formulated and their performance was compared with the human observer performance. One type of NO was based on evaluation of a cardiac polar map that had been pre-processed using a gradient-magnitude watershed segmentation algorithm. The second type of NO was also based on analysis of a cardiac polar map but with use of a priori calculated average image derived from an ensemble of normal cases.

O'Connor, J. Michael; Pretorius, P. Hendrik; Gifford, Howard C.; Licho, Robert; Joffe, Samuel; McGuiness, Matthew; Mehurg, Shannon; Zacharias, Michael; Brankov, Jovan G.

2012-02-01

259

The Saturn Ring Observer: In situ studies of planetary rings  

Microsoft Academic Search

As part of the Planetary Science Decadal Survey recently undertaken by the NRC's Space Studies Board for the National Academy of Sciences, studies were commissioned for a number of potential missions to outer planet targets. One of these studies examined the technological feasibility of a mission to carry out in situ studies of Saturn's rings, from a spacecraft placed in

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

2010-01-01

260

Complications of continuous renal replacement therapy in critically ill children: a prospective observational evaluation study  

Microsoft Academic Search

Introduction  Continuous renal replacement therapy (CRRT) frequently gives rise to complications in critically ill children. However, no\\u000a studies have analyzed these complications prospectively. The purpose of this study was to analyze the complications of CRRT\\u000a in children and to study the associated risk factors.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  A prospective, single-centre, observational study was performed in all critically ill children treated using CRRT in order

Maria J Santiago; Jesús López-Herce; Javier Urbano; María José Solana; Jimena del Castillo; Yolanda Ballestero; Marta Botrán; Jose María Bellón

2009-01-01

261

Robotic system and method for observing, learning, and supporting human activities  

US Patent & Trademark Office Database

An example method for allowing a robot to assist with a task, the task being carried out in an environment including one or more non-human objects each having associated object locations, comprises detecting one or more changes in object locations within the environment, predicting a task requirement (such as a future object location change, or task goal) by comparing the change in the object location with stored data, the stored data including object location changes associated with previously observed tasks; and providing robotic assistance to achieve the task requirement. Example apparatus are also disclosed.

2012-03-20

262

Method for observation of deembedded sections of fish gonad by scanning electron microscopy  

NASA Astrophysics Data System (ADS)

This article reports a method for examining the intracellular structure of fish gonads using a scanning electron microscope(SEM). The specimen preparation procedure is similar to that for transmission electron microscopy wherein samples cut into semi-thin sections are fixed and embedded in plastic. The embedment matrix was removed by solvents. Risen-free specimens could be observed by SEM. The morphology of matured sperms in the gonad was very clear, and the oocyte internal structures appeared in three-dimensional images. Spheroidal nucleoli and yolk vesicles and several bundles of filaments adhered on the nucleoli could be viewed by SEM for the first time.

Mao, Lian-Ju

2000-09-01

263

A distribution-based method to resolve single-molecule Förster resonance energy transfer observations  

NASA Astrophysics Data System (ADS)

We introduce a new approach to analyze single-molecule Förster resonance energy transfer (FRET) data. The method recognizes that FRET efficiencies assumed by traditional ensemble methods are unobservable for single molecules. We propose instead a method to predict distributions of FRET parameters obtained directly from the data. Distributions of FRET rates, given the data, are precisely defined using Bayesian methods and increase the information derived from the data. Benchmark comparisons find that the response time of the new method outperforms traditional methods of averaging. Our approach makes no assumption about the number or distribution of underlying FRET states. The new method also yields information about joint parameter distributions going beyond the standard framework of FRET analysis. For example, the running distribution of FRET means contains more information than any conceivable single measure of FRET efficiency. The method is tested against simulated data and then applied to a pilot-study sample of calmodulin molecules immobilized in lipid vesicles, revealing evidence for multiple dynamical states.

Backovi?, Mihailo; Price, E. Shane; Johnson, Carey K.; Ralston, John P.

2011-04-01

264

Observational and theoretical studies of the nova outburst  

SciTech Connect

A nova outburst is one consequence of the accretion of hydrogen rich material onto a white dwarf in a close binary system. The strong electron degeneracy of a massive white dwarf drives the temperatures in the nuclear burning region to values exceeding 108K under all circumstances. As a result, a major fraction of the CNO nuclei in the envelope are transformed into e{sup +}-decay nuclei, which constrains the nuclear energy generation and yields non-solar CNO isotopic abundance ratios. In addition, the observations demonstrate that white dwarf core material is dredged up into the accreted layers and these nuclei are the catalysts for producing peak rates of energy generation that can exceed 10{sup 16} erg gm{sup -1}s{sup -1}. Observations show that there are two compositional classes of novae, one that occurs on a carbon-oxygen white dwarf and the other that occurs on an oxygen-neon-magnesium white dwarf.

Starrfield, S.; Vanlandingham, K.; Schwarz, G. [Arizona State Univ., Tempe, AZ (United States). Dept. of Physics and Astronomy] [and others

1998-04-01

265

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

266

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, Pisa; Norris, Jay; /Denver U.

2007-10-22

267

Global scale observation of the earth for climate studies  

NASA Astrophysics Data System (ADS)

Developed since 1983 at LMD, the 3I (Improved Initialization Inversion) physical retrieval algorithm has been recently extended to the processing of NOAA (TIROS-N Operational Vertical Sounder) observations at global scale. Starting from the version implemented at ECMWF in Reading, this global scheme has been recently improved and installed on a CRAY-2. One month of observations (Feb. 1989) of NOAA-10 and 11 has recently been processed, at a spatial resolution of 100 × 100 km2. A two years period should now be processed, in conjunction with the PathFinder and GEWEX-GVaP programmes. Results expected are: weekly to monthly averages of quantities like temperature structure, cloud parameters or the vertical distribution and total content of water vapor analysed in relationship to pertinent meteorological or other parameters, especially with respect to quantifying the fundamental characteristics and origines of water vapor variability.

Chedin, A.; Scott, N. A.; Claud, C.; Bonnet, B.; Escobar, J.; Dardaillon, S.; Cheruy, F.; Husson, N.

1994-01-01

268

Observing social gestures: an fMRI study  

Microsoft Academic Search

We investigated the effects of social content of gestures on brain activation patterns. We used a 3 × 3 × 3 factorial design\\u000a in an event-related functional magnetic resonance imaging experiment with participants observing gestures varied by type (fascist\\u000a salute, wave, or arm lift), number of images shown at a time, and face frequency. We sought to determine whether increasing\\u000a the social content of

Kristine M. Knutson; Erin M. McClellan; Jordan Grafman

2008-01-01

269

Observed wave characteristics during growth and decay: a case study  

Microsoft Academic Search

Observed 1-h time series data on sea surface waves in the shelf waters off Goa, west coast of India (depth 80 m), during 17–24 March 1986, are analyzed with reference to the prevailing synoptic winds to understand wave growth and decay aspects. Wind speeds (U10) ranged from 0 to 11.5 m s?1, whereas significant wave height (Hs) varied between 0.6

C. V. K. Prasada Rao; M. Baba

1996-01-01

270

Studying Rain Rate from Space and Ground Observations  

NASA Astrophysics Data System (ADS)

The distribution of rain rates (R) is of great interest in many fields. For example, hydrological applications such as flood forecasting depend on an accurate representation of the excess rainfall-driven by R-that does not infiltrate the soil. It is also of great concern to radio wave propagation-the theme of this symposium. Probability distribution functions (pdf) of R can now be obtained from spaceborne radar observations. Effort to evaluate these pdfs using ground observations is presented. The evaluation of instantaneous rainfall products and rain rate estimates from space is quite a challenge. Scatter plots of pixel-by-pixel comparisons of space-based R estimates with ground-based radar R estimates are extremely noisy because of sample volume discrepancies, timing and navigation mismatches, and uncertainties in the observed-radar reflectivity rain-rate Ze-R relations. Furthermore, comparisons of rainfall over daily, weekly or even monthly time scales suffer from the temporal sampling errors of the satellite where the revisit time is on the order of hours or days (e.g., the Tropical Rainfall Measuring Mission [TRMM] satellite, the future Global Precipitation Measurement [GPM] mission satellite). Consequently, an alternative approach of comparing space-based radar pdfs with pdfs derived from co-located ground-based radar observations is attractive for evaluating satellite-based precipitation products, such as those from TRMM precipitation radar (PR). We will present comparisons of R estimates from the TRMM PR and co-located data from gauge-adjusted ground-based radar (WSR-88D) estimates obtained during nine years of observations. These results provide an overview of how well the satellite retrieved estimates-based on the new NASA TRMM radar rainfall products-compare to the ground-based estimates. These comparisons are part of a new framework for global verification of space-borne radar estimates of precipitation based on comparing pdfs of R. The framework demonstrates how a hydrologic approach that uses statistical properties of precipitation to estimate the uncertainties can be combined with a meteorological approach that uses physical properties of rainfall. The presentation provides insights into the uncertainties in space-based and ground-based radar estimates of rain rate distributions, and a discussion of opportunities and challenges to determine and reduce these uncertainties. This presentation combines results which are summarized in [1], [2], and [3]. Examples of comparison are provided in the following figures.

Amitai, Eyal

2007-07-01

271

Arctic stratospheric dehydration - Unprecedented observations and microphysical modeling study  

NASA Astrophysics Data System (ADS)

Polar stratospheric clouds (PSCs) may form in the lower stratosphere above the winter poles at sufficiently low temperatures. Ice PSCs require the coldest conditions, with temperatures some degrees below the frost point to nucleate ice particles. When the particles grow to sizes large enough to sediment, they may result in dehydration, i.e. irreversible redistribution of water vapor, as it frequently occurs above the Antarctic. Conversely, there are no observations above the Arctic that would have provided clear evidence for vertical redistribution of water vapor. Here we report on unequivocal in situ observations in January 2010 above Sodankylä, Finland, which mesh with vortex-wide satellite measurements. Within the LABPIAT-II field campaign, a series of balloon-borne aerosol backscatter and water vapor measurements has been performed. The balloon payload comprised the backscatter sonde COBALD in combination with the cryogenic frost point hygrometer CFH and the fluorescent Lyman-Alpha stratospheric hygrometer FLASH-B. Together with satellite measurements from the Aura microwave limb sounder MLS and the cloud-aerosol lidar CALIOP, a unique and coherent picture of de- and rehydration in the Arctic vortex will be presented within this paper. An extensive coverage of synoptic scale ice PSCs has been observed by CALIOP and COBALD by mid-January due to exceptionally low temperatures in the Arctic vortex. This observation goes along with a simultaneously measured strong reduction in water vapor by 1.6 ppmv relative to background conditions. Subsequent sedimentation and sublimation of ice particles led to a vertical redistribution of water inside the vortex, which was tracked remotely and could be quantified again by in situ measurements some five days later. By means of a microphysical column model, we are able to connect the individual balloon soundings by trajectories and simulate the formation, evolution and sedimentation of the ice particles. Simulated water vapor profiles are verified by CFH, FLASH-B and MLS measurements. Optical T-Matrix calculations enable us to additionally compare the simulations with COBALD and CALIOP backscatter measurements. We examine the effect of different PSC formation pathways - in particular homogeneous vs. heterogeneous ice formation - and changing temperatures and finally show that synoptic scale ice PSCs and concurrent reduction in water vapor are tightly linked with the observed de- and rehydration signatures.

Engel, Ines; Luo, Beiping P.; Khaykin, Sergey; Wienhold, Frank G.; Vömel, Holger; Kivi, Rigel; Pitts, Michael C.; Poole, Lamont R.; Santee, Michelle L.; Grooß, Jens-Uwe; Peter, Thomas

2013-04-01

272

Effective population management practices in diabetes care - an observational study  

Microsoft Academic Search

BACKGROUND: Ensuring that evidence based medicine reaches patients with diabetes in the US and internationally is challenging. The chronic care model includes evidence based management practices which support evidence based care. However, despite numerous studies, it is unclear which practices are most effective. Few studies assess the effect of simultaneous practices implemented to varying degrees. The present study evaluates the

Anne Frølich; Jim Bellows; Bo Friis Nielsen; Per Bruun Brockhoff; Martin Hefford

2010-01-01

273

Observations on studies useful to asbestos operations and management activities  

SciTech Connect

Asbestos-containing materials found in buildings may release asbestos fibers into the air. Some of these fibers will eventually settle and attach to room surfaces (walls, furnishings, equipment, floors, and carpet) as part of normal dust. Activities like dusting, sweeping and vacuuming are likely to re-entrain the dust causing exposure to airborne asbestos. The paper discusses data that are largely observational in nature, but are illustrative of general trends of interest to those individuals dealing with the day-to-day problems of asbestos in buildings.

Wilmoth, R.C.; Powers, T.J.; Millette, J.R.

1991-01-01

274

A comparative method based on ROC analysis for the quantitation of observer performance in scintigraphy.  

PubMed

A method is proposed for the evaluation of observer performance based on the concept of count density: it provides a description of the effects of different display or processing techniques that is easily graphed. A set of ROC curves is produced for use as a calibration for other ROC graphs. Each curve is obtained experimentally using the same series of images and varying only the count density. The effect of an image processing operation is evaluated by comparison with the calibration curves, and is expressed as the change in count density in unprocessed images that produces the same effect on an observer as the processing. The relative change in count density is defined as the gain of the processing operation. The method is used to quantitate the effects of three linear filters, and of their respective noise textures, on the detectability of spheres 3 cm in diameter immersed in a uniform background. The smoothing filters gave the largest gain (2.5) of the three. When stimulated image data were manipulated so that filtering changed the noise texture only, with spatial resolution and noise variance held constant, the smoothing filter provided a gain of about 0.25 for the targets considered; this corresponds to a loss of about 75% of the counts in an unprocessed image. PMID:7134266

Guignard, P A

1982-09-01

275

Personality, Study Methods and Academic Performance  

ERIC Educational Resources Information Center

|A questionnaire measuring four student personality types--stable introvert, unstable introvert, stable extrovert and unstable extrovert--along with the Eysenck Personality Inventory (Form A) were give to 72 graduate students at Aberdeen University and the results showed recognizable interaction between study methods, motivation and personality…

Entwistle, N. J.; Wilson, J. D.

1970-01-01

276

Microhardness method of studying intracrystalline liquation  

Microsoft Academic Search

Conclusion 1.Intra-crystalline liquation of alloys of aluminum and magnesium and of bismuth and antimony has been studied by the micro-hardness method.2.The hardness of the alloys varies in accordance with the theoretical consideration previously advanced.

D. A. Patrov; L. A. Raikovskaya

1952-01-01

277

Study of underground power cable installation methods  

Microsoft Academic Search

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

J. Nicol

1977-01-01

278

A Study of Rapid Photointerpretation Methods.  

National Technical Information Service (NTIS)

The study was designed to assess the value of single-phase and two-phase methods of quick-time image interpretation. Accuracy and completeness data were compared for single-phase (one viewing of each photo frame) and two-phase (first and second viewings o...

R. L. Beechler S. H. Winterstein R. M. Kamper T. E. Jeffrey

1969-01-01

279

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

280

Integration in an Integrated Learning System: Does it Make a Difference? An Observational Research Study  

Microsoft Academic Search

The purpose of the research was to determine examine and describe teacher use of integrated and non-integrated methods employing CompassLearning software on the classroom environment, system management, and the perceptions of the teachers and students in an elementary school. CompassLearning use was examined over a four week period. Fifty-two participants completed all activities. This qualitative study included observation, surveys, and

Cassia C. Milhollin

281

An Observational Study on Outgrowing Food Allergy during Non-Birch Pollen-Specific, Subcutaneous Immunotherapy  

Microsoft Academic Search

Background: Birch pollen-specific immunotherapy (SIT) decreases allergy to foods containing birch pollen-homologous allergens. Cross-reactivity was also observed between plane tree pollen and some vegetable foods. Objective: The aim of this study was to evaluate the outgrowing of food allergy by patients suffering from vegetable food allergy associated with plane tree pollinosis (rhinoconjunctivitis and\\/or asthma) during plane tree pollen SIT. Methods:

R. Alonso; E. Enrique; F. Pineda; M. Basagaña; M. M. San Miguel-Moncín; J. Bartra; R. Palacios; A. Cisteró-Bahíma

2007-01-01

282

Magnetic Fields in the Milky Way, Derived from Radio Continuum Observations and Faraday Rotation Studies  

Microsoft Academic Search

Magnetic fields are found everywhere in our Universe. We know that our Earth possesses a dipolar magnetic field. Magnetic\\u000a fields have been observed on the Sun either as optical streamers during solar eclipses and by using remote sensing methods.\\u000a Magnetic fields of the solar planets have been studied in situ by measurements made by magnetometers on various spacecraft.\\u000a Stars, supernova

Richard Wielebinski

283

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

284

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

SciTech Connect

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 [IEAP, Christian-Albrechts-Universitaet, D-24098 Kiel (Germany)

2011-03-15

285

Amateur boxing and risk of chronic traumatic brain injury: systematic review of observational studies  

PubMed Central

Objective To evaluate the risk of chronic traumatic brain injury from amateur boxing. Setting Secondary research performed by combination of sport physicians and clinical academics. Design, data sources, and methods Systematic review of observational studies in which chronic traumatic brain injury was defined as any abnormality on clinical neurological examination, psychometric testing, neuroimaging studies, and electroencephalography. Studies were identified through database (1950 to date) and bibliographic searches without language restrictions. Two reviewers extracted study characteristics, quality, and data, with adherence to a protocol developed from a widely recommended method for systematic review of observational studies (MOOSE). Results 36 papers had relevant extractable data (from a detailed evaluation of 93 studies of 943 identified from the initial search). Quality of evidence was generally poor. The best quality studies were those with a cohort design and those that used psychometric tests. These yielded the most negative results: only four of 17 (24%) better quality studies found any indication of chronic traumatic brain injury in a minority of boxers studied. Conclusion There is no strong evidence to associate chronic traumatic brain injury with amateur boxing.

Knowles, Charles H; Whyte, Greg P

2007-01-01

286

“Minnesota slots”: An observational study of pull tab gambling  

Microsoft Academic Search

A study of pull tab gambling in Minnesota was undertaken to describe the state's most popular form of gambling. The study also focused on the detection of any abuses or addictive problems that might be associated with it. Pull tab gambling is similar to slot machine gambling. The game, fundamentals of play, and some of the behaviors of pull tab

Mikal J. Aasved; James M. Schaefer

1995-01-01

287

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

288

Comparative study of brain deformation estimation methods  

NASA Astrophysics Data System (ADS)

Shift of brain tissues during surgical procedures affects the precision of image-guided neurosurgery (IGNS). To improve the accuracy of the alignment between the patient and images, finite element model-based non-rigid registration methods have been investigated. The best prior estimate (BPE), the forced displacement method (FDM), the weighted basis solutions (WBS), and the adjoint equations method (AEM) are versions of this approach that have appeared in the literature. In this paper, we present a quantitative comparison study on a set of three patient cases. Three-dimensional displacement data from the surface and subsurface was extracted using the intra-operative ultrasound (iUS) and intraoperative stereovision (iSV). These data are then used as the "ground truth" in a quantitative study to evaluate the accuracy of estimates produced by the finite element models. Different types of clinical cases are presented, including distension and combination of sagging and distension. In each case, a comparison of the performance is made with the four methods. The AEM method which recovered 26-62% of surface brain motion and 20-43% of the subsurface deformation, produced the best fit between the measured data and the model estimates.

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

2006-03-01

289

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

290

Observations of a potential Mars analog at the microscale using rover-inspired methods: A 10-sol observation of Fort Rock tuff ring  

NASA Astrophysics Data System (ADS)

The terrestrial geologist's hand lens is a fundamental tool for identifying and correlating rocks and minerals. We used rover-inspired methods of remote hand lens-scale data acquisition to conduct reconnaissance of a well-characterized Martian analog field site. The objective was to determine if the current methodologies associated with the use of remote hand lens-scale imagers maximizes science return. Field geologists provided with hand lens-scale images of targets in geologic context could correctly identify many important characteristics of those targets. However, they could not fully confirm or rule out any formation hypothesis using the data provided solely through rover-driven observational strategies. This was due to (1) a lack of “intermediate-scale,” or millimeter- to centimeter-scale images providing important contextual information for the targets studied and (2) the limited number of hand lens-scale images that were taken using rover-driven methodology. We conclude that the benefits of the hand lens as an effective triage tool and discriminator of microtexture are limited using current rover-driven methodology because the hand lens-type imager is not deployed frequently, and resulting data cannot be used to fully support geochemical observations. We recommend pursuing ways to increase the number of images that can reasonably be acquired at the hand lens scale. In order for hand lens-scale imaging to be fully effective, textural characteristics diagnostic of the nature of a geologic site need to be identifiable at a number of different resolutions; rover microscale observational strategies must include more contextual imaging.

Yingst, R. A.; Schmidt, M. E.; Lentz, R. C. F.

2009-06-01

291

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.

Tang, Jin-Ling; Wang, Jung-Der

2013-01-01

292

Catalyst performance study using Taguchi methods  

SciTech Connect

A study was conducted to determine the effects of various factors on the performance characteristics of aged monolithic catalytic converters. The factors that were evaluated were catalyst volume, converter configuration (number of elements), catalyst supplier washcoat technology, rhodium loading, platinum loading, and palladium loading. This study was also designed to evaluate the interactions among the various factors. To improve the efficiency of the study a 2-level fractional experiment was designed using the Taguchi method. That made it possible to study the effects of the seven main factors and six interactions by evaluating only 16 different samples. The study helped sort the factors that had significant effects and helped quantify their effect on catalyst performance. This paper details there methodology used to design the experiment and analyze the results.

Sims, G.S.; Johri, S.

1988-01-01

293

Xenon consumption during general surgery: a retrospective observational study  

PubMed Central

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

2013-01-01

294

Experimental and Observational Data in the Study of Interlanguage Pragmatics.  

ERIC Educational Resources Information Center

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

Hartford, Beverly S.; Bardovi-Harlig, Kathleen

1992-01-01

295

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

296

Managing Alaska's Information Systems: A Participant-Observer Study.  

ERIC Educational Resources Information Center

|This paper describes Alaska's state-managed telecommunications system, and details state efforts to increase the value of the state's information system to users within state government and in the private sector. The results of two studies conducted in 1986 at the request of the State Legislature are discussed, i.e., a statewide survey of Alaskan…

Pearson, Larry

297

Musical Expression: An Observational Study of Instrumental Teaching  

ERIC Educational Resources Information Center

Research has shown that both music students and teachers think that expression is important. Yet, we know little about how expression is taught to students. Such knowledge is needed in order to enhance teaching of expression. The aim of this study was thus to explore the nature of instrumental music teaching in its natural context, with a focus on…

Karlsson, Jessika; Juslin, Patrik N.

2008-01-01

298

On the Treatment of Grouped Observations in Life Studies.  

National Technical Information Service (NTIS)

Cox (Regression models and life tables, J. Roy. Statist. Soc. 34B, 1972) presents a systematic study of the use of covariates in the analysis of life time. Cox's basic model is that of proportional failure rates. A particularly thorny point in theory and ...

W. A. Thompson

1976-01-01

299

Placental Pathology in Patients Using Cocaine: An Observational Study  

Microsoft Academic Search

Objective: Although retroplacental hemorrhage is a major cause of fetal death, its etiology often remains obscure. In some reports, cocaine use by pregnant women has been associated with retroplacental hemorrhage and clinical abruptio placentae. This study was designed to assess the occurrence of chorionic villus hemorrhage, an entity shown recently to be associated with retroplacental hemorrhage, in the placentas of

Eoghan E. Mooney; Kim A. Boggess; William N. P. Herbert; Lester J. Layfield

1998-01-01

300

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

EPA Science Inventory

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

301

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

2013-04-18

302

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.

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

2013-01-01

303

A study on the characteristics of retrospective optimal interpolation using an Observing System Simulation Experiment  

NASA Astrophysics Data System (ADS)

This study presents the introduction of retrospective optimal interpolation (ROI) and its application with Weather Research and Forecasting model (WRF). Song et al. (2009) suggested ROI method which is an optimal interpolation (OI) that gradually assimilates observations over the analysis window for variance-minimum estimate of an atmospheric state at the initial time of the analysis window. The assimilation window of ROI algorithm is gradually increased, similar with that of the quasi-static variational assimilation (QSVA; Pires et al., 1996). Unlike QSVA method, however, ROI method assimilates the data at post analysis time using perturbation method (Verlaan and Heemink, 1997) without adjoint model. Song and Lim (2011) improved this method by incorporating eigen-decomposition and covariance inflation. The computational costs for ROI can be reduced due to the eigen-decomposition of background error covariance which can concentrate ROI analyses on the error variances of governing eigenmodes by transforming the control variables into eigenspace. A total energy norm is used for the normalization of each control variables. In this study, ROI method is applied to WRF model with Observing System Simulation Experiment (OSSE) to validate the algorithm and to investigate the capability. Horizontal wind, pressure, potential temperature, and water vapor mixing ratio are used for control variables and observations. Firstly, 1-profile assimilation experiment is performed. Subsequently, OSSE's are performed using the virtual observing system which consists of synop, ship, and sonde data. The difference between forecast errors with assimilation and without assimilation is obviously increased as time passed, which means the improvement of forecast error with the assimilation by ROI. The characteristics and strength/weakness of ROI method are also investigated by conducting the experiments with 3D-Var (3-dimensional variational) method and 4D-Var (4-dimensional variational) method. In the initial time, ROI produces a larger forecast error than that of 4D-Var. However, the difference between the two experimental results is decreased gradually with time, and the ROI shows apparently better result (i.e., smaller forecast error) than that of 4D-Var after 9-hour forecast.

Kim, Shin-Woo; Noh, Nam-Kyu; Lim, Gyu-Ho

2013-04-01

304

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

305

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

SciTech Connect

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

Emily A. Carter

2009-01-23

306

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

307

Monitoring and analysis of ocean swell fields from space: New methods for routine observations  

NASA Astrophysics Data System (ADS)

Satellite synthetic aperture radar (SAR) observations can provide a global view of ocean swell fields when using a specific "wave mode" sampling. A methodology is presented to routinely derive integral properties of the longer-wavelength (swell) portion of the wave spectrum from SAR level 2 products and both monitor and predict their evolution across ocean basins. SAR-derived estimates of swell height and energy-weighted peak period and direction are validated against buoy observations, and the peak directions are used to project the peak periods in one dimension along the corresponding great circle route, both forward and back in time, using the peak period group velocity. The resulting real-time data set of great circle-projected peak periods produces two-dimensional maps that can be used to monitor and predict the spatial extent and temporal evolution of individual ocean swell fields as they propagate from their source region to distant coastlines. The result is found to be consistent with the dispersive arrival of peak swell periods at a midocean buoy. The simple great circle propagation method cannot project the swell heights in space like the peak periods, because energy evolution along a great circle is a function of the source storm characteristics and the unknown swell dissipation rate. A more general geometric optics model is thus proposed for the far field of the storms. This model is applied here to determine the attenuation over long distances. For one of the largest recorded storms, observations of 15 s period swells are consistent with a constant dissipation rate that corresponds to a 3300 km e-folding scale for the energy. In this case, swell dissipation is a significant term in the wave energy balance at global scales.

Collard, Fabrice; Ardhuin, Fabrice; Chapron, Bertrand

2009-07-01

308

Modelling non-Gaussianity of background and observational errors by the Maximum Entropy method  

NASA Astrophysics Data System (ADS)

The Best Linear Unbiased Estimator (BLUE) has widely been used in atmospheric-oceanic data assimilation. However, when data errors have non-Gaussian pdfs, the BLUE differs from the absolute Minimum Variance Unbiased Estimator (MVUE), minimizing the mean square analysis error. The non-Gaussianity of errors can be due to the statistical skewness and positiveness of some physical observables (e.g. moisture, chemical species) or due to the nonlinearity of the data assimilation models and observation operators acting on Gaussian errors. Non-Gaussianity of assimilated data errors can be justified from a priori hypotheses or inferred from statistical diagnostics of innovations (observation minus background). Following this rationale, we compute measures of innovation non-Gaussianity, namely its skewness and kurtosis, relating it to: a) the non-Gaussianity of the individual error themselves, b) the correlation between nonlinear functions of errors, and c) the heteroscedasticity of errors within diagnostic samples. Those relationships impose bounds for skewness and kurtosis of errors which are critically dependent on the error variances, thus leading to a necessary tuning of error variances in order to accomplish consistency with innovations. We evaluate the sub-optimality of the BLUE as compared to the MVUE, in terms of excess of error variance, under the presence of non-Gaussian errors. The error pdfs are obtained by the maximum entropy method constrained by error moments up to fourth order, from which the Bayesian probability density function and the MVUE are computed. The impact is higher for skewed extreme innovations and grows in average with the skewness of data errors, especially if those skewnesses have the same sign. Application has been performed to the quality-accepted ECMWF innovations of brightness temperatures of a set of High Resolution Infrared Sounder channels. In this context, the MVUE has led in some extreme cases to a potential reduction of 20-60% error variance as compared to the BLUE.

Pires, Carlos; Talagrand, Olivier; Bocquet, Marc

2010-05-01

309

Geodetic methods for monitoring water overexploitation: Results from geometric and gravimetric observation techniques  

NASA Astrophysics Data System (ADS)

Growth of population and urbanisation place increasing demands on groundwater resources for irrigation, drinking water supply and industrialisation. In semiarid and arid regions, decades of unrestrained extraction of groundwater has resulted in severe depletion of this valuable resource, leaving in turn its fingerprints in the time series of different space geodetic observing systems. On the one hand, the loss of water is accompanied by local and regional scale surface deformations that can be monitored by InSAR and permanent GPS networks with an accuracy of few millimeters. On the other hand, the mass loss is associated with changes of the Earth’s gravity field, being reflected by the observations of dedicated satellite missions. This paper analyses observation time series of InSAR and GRACE and quantifies the loss of water mass due to overexploitation of groundwater in selected regions over a period of several years. The results are subsequently compared with the output of the numerical hydrological models LaD and WGHM. Surface deformations are derived from InSAR time-series analysis using Envisat data. Mass variations are deduced from spherical harmonic expansions as well as from regional analyses of the GRACE gravity field as provided by various processing centers. Our case-studies are performed for regions in Central Iran where groundwater overdrafting is widespread.

Seitz, F.; Motagh, M.

2009-12-01

310

Holographic interferometric observation of float glass plate fractured by shock tube method  

NASA Astrophysics Data System (ADS)

In order to study the fracture and deformation in float glass loaded in a shock tube test for analyzing explosion resistance, high-speed photography with holographic interferometry was utilized. Ordinary float glass (soda-lime- silica glass) plate of size 300 mm X 300 mm and in two thickness was used for these specimens for this experiment. By using single and double exposure holographic interferometry, crack propagation and deformation in float glass loaded by a shock tube was photographically observed, and the value of stress generation was measured.

Aratani, Shin'ichi; Ojima, Hidenori; Takayama, Kazuyoshi

2001-04-01

311

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

312

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

313

Methods for studying habitual behavior in mice  

PubMed Central

Habit formation refers to the process by which goal-directed behavior becomes automatized and less sensitive to changes in the value of the goal. It has clear relevance for our understanding of skill learning and addiction. Recent studies have begun to reveal the neural substrates underlying this process. This article summarizes what is known about the experimental methods used, and provides a protocol for generating and assessing habit formation in mice.

Rossi, Mark A.; Yin, Henry H.

2012-01-01

314

Methods for household waste composition studies.  

PubMed

The question is how to conduct household waste composition studies. The review is divided into three parts: overview of known methods, sampling theory, and the waste components. Twenty methods are listed and commented on. There is no adopted, working international standard. In accordance with Pierre Gy's Theory of Sampling, the seven types of sampling errors, when collecting and splitting solid samples, are described and commented on in relation to sampling of household solid waste. It is concluded that the most crucial choices in household waste composition studies are: to divide the investigation into relevant number and types of strata; to decide the required sample size and number of samples; to choose the sampling location, i.e., sampling at household level or sampling from loads of waste collection vehicles; and to choose the type and number of waste component categories to be investigated. Various classifications of household waste components used in composition studies are listed and discussed. Difficulties and weaknesses of the reviewed methods are discussed and concluded in suggested questions for further research. PMID:17920857

Dahlén, Lisa; Lagerkvist, Anders

2007-10-24

315

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; Réjean Hébert; Peter McCracken; Alain Robillard; Doanh Luong; Amanda Yu

2004-01-01

316

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...

317

Experimental human influenza: observations from studies of influenza antivirals.  

PubMed

Randomized, placebo-controlled trials have been conducted for nearly five decades in experimentally induced human influenza infections to assess the effectiveness, tolerability and pharmacological properties of influenza antivirals. The results of such studies have not only provided key proof-of-concept data to facilitate drug development but also contributed to our understanding of influenza pathogenesis and transmission. The lack of availability of contemporary, safety-tested virus inoculation pools in recent years needs to be resolved in order to avoid hindering the development of new drugs and vaccines. PMID:22311616

Hayden, Frederick G

2012-02-03

318

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

319

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.; Romilly, A. P.; Scmidt, Phyllis

2001-06-01

320

Class III Nerve-sparing Radical Hysterectomy Versus Standard Class III Radical Hysterectomy: An Observational Study  

Microsoft Academic Search

Background  The purpose of this observational study was to evaluate disease-free survival, overall survival, local recurrence rate, and\\u000a morbidities in patients submitted to class III nerve-sparing radical hysterectomy (NSRH) compared with standard radical hysterectomy\\u000a (RH) in cervical cancer (CC). This was a comparative study in the context of multimodal therapies.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and Methods  We investigated patients with CC admitted to the National

Antonino Ditto; Fabio Martinelli; Flavia Mattana; Claudio Reato; Eugenio Solima; Marialuisa Carcangiu; Edward Haeusler; Luigi Mariani; Francesco Raspagliesi

321

Cerebral perfusion pressure and risk of brain hypoxia in severe head injury: a prospective observational study  

Microsoft Academic Search

Introduction  Higher and lower cerebral perfusion pressure (CPP) thresholds have been proposed to improve brain tissue oxygen pressure (PtiO2) and outcome. We study the distribution of hypoxic PtiO2 samples at different CPP thresholds, using prospective multimodality monitoring in patients with severe traumatic brain injury.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  This is a prospective observational study of 22 severely head injured patients admitted to a neurosurgical critical

Antonio J Marín-Caballos; Francisco Murillo-Cabezas; Aurelio Cayuela-Domínguez; Jose M Domínguez-Roldán; M Dolores Rincón-Ferrari; Julio Valencia-Anguita; Juan M Flores-Cordero; M Angeles Muñoz-Sánchez

2005-01-01

322

Increased creatinine clearance in polytrauma patients with normal serum creatinine: a retrospective observational study  

Microsoft Academic Search

Introduction  The aim of this study, performed in an intensive care unit (ICU) population with a normal serum creatinine, was to estimate\\u000a urinary creatinine clearance (CLCR) in a population of polytrauma patients (PT) through a comparison with a population of non trauma patients (NPT).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  This was a retrospective, observational study in a medical and surgical ICU in a university hospital. A

Vincent Minville; Karim Asehnoune; Stephanie Ruiz; Audrey Breden; Bernard Georges; Thierry Seguin; Ivan Tack; Acil Jaafar; Sylvie Saivin; Olivier Fourcade; Kamran Samii; Jean Marie Conil

2011-01-01

323

An observationally centred method to quantify local climate change as a distribution  

NASA Astrophysics Data System (ADS)

For planning and adaptation, guidance on trends in local climate is needed at the specific thresholds relevant to particular impact or policy endeavours. This requires quantifying trends at specific quantiles in distributions of variables such as daily temperature or precipitation. These non-normal distributions vary both geographically and in time. The trends in the relevant quantiles may not simply follow the trend in the distribution mean. We present a method[1] for analysing local climatic timeseries data to assess which quantiles of the local climatic distribution show the greatest and most robust trends. We demonstrate this approach using E-OBS gridded data[2] timeseries of local daily temperature from specific locations across Europe over the last 60 years. Our method extracts the changing cumulative distribution function over time and uses a simple mathematical deconstruction of how the difference between two observations from two different time periods can be assigned to the combination of natural statistical variability and/or the consequences of secular climate change. This deconstruction facilitates an assessment of the sensitivity of different quantiles of the distributions to changing climate. Geographical location and temperature are treated as independent variables, we thus obtain as outputs how the trend or sensitivity varies with temperature (or occurrence likelihood), and with geographical location. These sensitivities are found to be geographically varying across Europe; as one would expect given the different influences on local climate between, say, Western Scotland and central Italy. We find as an output many regionally consistent patterns of response of potential value in adaptation planning. We discuss methods to quantify the robustness of these observed sensitivities and their statistical likelihood. This also quantifies the level of detail needed from climate models if they are to be used as tools to assess climate change impact. [1] S C Chapman, D A Stainforth, N W Watkins, 2013, On Estimating Local Long Term Climate Trends, Phil. Trans. R. Soc. A, in press [2] Haylock, M.R., N. Hofstra, A.M.G. Klein Tank, E.J. Klok, P.D. Jones and M. New. 2008: A European daily high-resolution gridded dataset of surface temperature and precipitation. J. Geophys. Res (Atmospheres), 113, D20119, doi:10.1029/2008JD10201

Stainforth, David; Chapman, Sandra; Watkins, Nicholas

2013-04-01

324

Gravity wave propagation studies using the Indian MST radar observations  

NASA Astrophysics Data System (ADS)

The Indian MST radar facility at Gadanki (13.5°N, 79.2°E) has been utilised to study the propagation of gravity waves from the troposphere/lower stratosphere to the mesosphere and their interaction with the radar backscattered signal variations. The main objective is to correlate vertically propagating gravity waves derived from the tropospheric velocity fields with the dynamics of mesospheric scattering centres. The tropospheric wind velocities and signal strengths over the entire height range have been subjected to power spectral and wavelet analysis to determine the predominant wave periods/amplitudes and the coupling between the lower atmosphere and mesosphere. Results show that (a) the gravity waves are clearly detectable near tropopause heights, (b) while relatively higher period gravity waves (20-50 min) interact with mesospheric scattering centres, the lower period waves (<20 min) are absorbed in the troposphere itself, (c) the mesospheric scattering layers are affected by gravity waves of complementary periods.

Chakravarty, S. C.

2012-02-01

325

Weight versus volume in breast surgery: an observational study  

PubMed Central

Objectives The study hypothesis is to assess correlation of breast specimen weight versus volume. Design Consecutive patients undergoing breast surgery at a single tertiary referral centre during a 6-month period were included. Specimen weight was measured in grams. Direct volume measurements were performed using water displacement. Data including side of the breast, age and menstrual status of the patient were noted. Setting Knowledge of breast volume provides an objective guide in facilitating the achievements of balance in reconstructive operations. Surgeons use intraoperative weight measurements from individual breasts to calculate the breast volume assuming that weight is equal to the volume of the specimen. However, it is unclear whether weight accurately reveals the true volume of resection. Participants Forty-one patients were included in the study with 28 having bilateral surgeries, 13 having unilateral procedures giving a total of 69 breast specimens. Main outcome measures Breast specimen weight correlation to breast specimen volume. Results The mean age of the group was 42.4 years. Fifty-two specimens were from premenopausal patients and 17 were of postmenopausal. Thirty-five were left-sided. Twenty-six patients had bilateral breast reduction, two had bilateral mastectomy, nine had a unilateral mastectomy and four patients had a unilateral breast reduction. The difference between weight and volume of these breasts was 36.4 units (6.6% difference). The difference in measurement of weight and volume in premenopausal was 37.6 units compared to 32.6 units in postmenopausal women. The density was 1.07 and 1.06, respectively. This was statistically not significant. Conclusions No significant difference between volume and weight was seen in this series. Furthermore, we are unable to support the notion that premenopausal patients have a significant difference in the proportion of fatty and glandular tissue as there was little difference between the weight and the volume. An easy, clinically proper formula for the quantification of actual breast volume has yet to be derived.

Parmar, Chetan; West, Malcolm; Pathak, Samir; Nelson, J; Martin, Lee

2011-01-01

326

Observational and modeling studies of aerosol indirect effects  

NASA Astrophysics Data System (ADS)

The effects of aerosols on climate have drawn a great deal of research attention. Aerosols scatter and absorb both solar radiation and terrestrial thermal emission (i.e., aerosol direct effect). Additionally, aerosols indirectly influence climate by affecting cloud properties and precipitation. This study investigates the potential connections between aerosols and cloud properties through statistical analysis of satellite remote sensing data and numerical modeling. Empirical orthogonal function analysis and regression analysis are used to identify the leading modes of variability and to identify relationships between different variables. The datasets used include MODIS Aqua aerosol and cloud products, TOMS OMI aerosol index, and TRMM precipitation rate data. Moreover, numerical simulations are carried out with the latest version of the Community Atmospheric Model (CAM5), which includes parameterizations for aerosol-cloud indirect effects. The results of the present analysis show that signals corresponding to the first and second aerosol indirect effects found in the statistical analysis and the model output are similar in several regions. Several other areas, however, show no or even contradictory correlations between aerosol and cloud properties (precipitation). Errors in satellite data and uncertainties in the model (such as the use of simple physical parameterizations instead of an actual aerosol indirect mechanism) could be among the reasons for the differences in the results.

Yi, B.; Yang, P.; Bowman, K. P.

2010-12-01

327

Case studies: Soil mapping using multiple methods  

NASA Astrophysics Data System (ADS)

Soil is a non-renewable resource with fundamental functions like filtering (e.g. water), storing (e.g. carbon), transforming (e.g. nutrients) and buffering (e.g. contamination). Degradation of soils is meanwhile not only to scientists a well known fact, also decision makers in politics have accepted this as a serious problem for several environmental aspects. National and international authorities have already worked out preservation and restoration strategies for soil degradation, though it is still work of active research how to put these strategies into real practice. But common to all strategies the description of soil state and dynamics is required as a base step. This includes collecting information from soils with methods ranging from direct soil sampling to remote applications. In an intermediate scale mobile geophysical methods are applied with the advantage of fast working progress but disadvantage of site specific calibration and interpretation issues. In the framework of the iSOIL project we present here some case studies for soil mapping performed using multiple geophysical methods. We will present examples of combined field measurements with EMI-, GPR-, magnetic and gammaspectrometric techniques carried out with the mobile multi-sensor-system of Kiel University (GER). Depending on soil type and actual environmental conditions, different methods show a different quality of information. With application of diverse methods we want to figure out, which methods or combination of methods will give the most reliable information concerning soil state and properties. To investigate the influence of varying material we performed mapping campaigns on field sites with sandy, loamy and loessy soils. Classification of measured or derived attributes show not only the lateral variability but also gives hints to a variation in the vertical distribution of soil material. For all soils of course soil water content can be a critical factor concerning a succesful application of geophysical methods, e.g. GPR on wet loessy soils will result in a high attenuation of signals. Furthermore, with this knowledge we support the development of geophysical pedo-transfer-functions, i.e. the link between geophysical to soil parameters, which is active researched in another work package of the iSOIL project. Acknowledgement: iSOIL-Interactions between soil related sciences - Linking geophysics, soil science and digital soil mapping is a Collaborative Project (Grant Agreement number 211386) co-funded by the Research DG of the European Commission within the RTD activities of the FP7 Thematic Priority Environment.

Petersen, Hauke; Wunderlich, Tina; Hagrey, Said A. Al; Rabbel, Wolfgang; Stümpel, Harald

2010-05-01

328

Occasions and the Reliability of Classroom Observations: Alternative Conceptualizations and Methods of Analysis  

Microsoft Academic Search

Student–teacher interactions are dynamic relationships that change and evolve over the course of a school year. Measuring classroom quality through observations that focus on these interactions presents challenges when observations are conducted throughout the school year. Variability in observed scores could reflect true changes in the quality of student–teacher interaction or simply reflect measurement error. Classroom observation protocols should be

J. Patrick Meyer; Anne H. Cash; Andrew Mashburn

2011-01-01

329

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

330

Environmental and Social Correlates of Physical Activity in Neighborhood Parks: An Observational Study in Tampa and Chicago  

Microsoft Academic Search

This study used observational methods to examine physical activity (PA) and selected correlates in 28 parks in Tampa, Florida, and Chicago, Illinois. We observed 9,454 park users within predetermined activity zones and coded their activity as sedentary, walking (i.e., moderate intensity), or vigorous PA. In Tampa, higher temperature, unorganized activity, lower amounts of shade, lower neighborhood income, Hispanic neighborhood ethnicity,

Myron F. Floyd; J. O. Spengler; Jay E. Maddock; Paul H. Gobster; Luis Suau

2008-01-01

331

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

332

Designing A Mixed Methods Study In Primary Care  

PubMed Central

BACKGROUND Mixed methods or multimethod research holds potential for rigorous, methodologically sound investigations in primary care. The objective of this study was to use criteria from the literature to evaluate 5 mixed methods studies in primary care and to advance 3 models useful for designing such investigations. METHODS We first identified criteria from the social and behavioral sciences to analyze mixed methods studies in primary care research. We then used the criteria to evaluate 5 mixed methods investigations published in primary care research journals. RESULTS Of the 5 studies analyzed, 3 included a rationale for mixing based on the need to develop a quantitative instrument from qualitative data or to converge information to best understand the research topic. Quantitative data collection involved structured interviews, observational checklists, and chart audits that were analyzed using descriptive and inferential statistical procedures. Qualitative data consisted of semistructured interviews and field observations that were analyzed using coding to develop themes and categories. The studies showed diverse forms of priority: equal priority, qualitative priority, and quantitative priority. Data collection involved quantitative and qualitative data gathered both concurrently and sequentially. The integration of the quantitative and qualitative data in these studies occurred between data analysis from one phase and data collection from a subsequent phase, while analyzing the data, and when reporting the results. DISCUSSION We recommend instrument-building, triangulation, and data transformation models for mixed methods designs as useful frameworks to add rigor to investigations in primary care. We also discuss the limitations of our study and the need for future research.

Creswell, John W.; Fetters, Michael D.; Ivankova, Nataliya V.

2004-01-01

333

Ethics and observational studies in medical research: various rules in a common framework  

PubMed Central

Background Research ethics have become universal in their principles through international agreements. The standardization of regulations facilitates the internationalization of research concerning drugs. However, in so-called observational studies (i.e. from data collected retrospectively or prospectively, obtained without any additional therapy or monitoring procedure), the modalities used for applying the main principles vary from one country to the other. This situation may entail problems for the conduct of multi-centric international studies, as well as for the publication of results if the authors and editors come from countries governed by different regulations. In particular, several French observational studies were rejected or retracted by United States peer reviewed journals, because their protocols have not been submitted to an Institutional Review Board/Independent Ethics Committee (IRB/IEC). Methods national legislation case analysis Results In accordance with European regulation, French observational studies from data obtained without any additional therapy or monitoring procedure, do not need the approval of an IRB/IEC. Nevertheless, these researches are neither exempt from scientific opinion nor from ethical and legal authorization. Conclusion We wish to demonstrate through the study of this example that different bodies of law can provide equivalent levels of protection that respect the same ethical principles. Our purpose in writing this paper was to encourage public bodies, scientific journals, and researchers to gain a better understanding of the various sets of specific national regulations and to speak a common language.

Claudot, Frederique; Alla, Francois; Fresson, Jeanne; Calvez, Thierry; Coudane, Henry; Bonaiti-Pellie, Catherine

2009-01-01

334

Development of observation method for hydrothermal flows with acoustic video camera  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

335

Forced Ignition Study Based on Wavelet Method  

NASA Astrophysics Data System (ADS)

The control of ignition in a rocket engine is a critical problem for combustion chamber design. Therefore it is essential to fully understand the mechanism of ignition during its earliest stages. In this paper the characteristics of flame kernel formation and initial propagation in a hydrogen-argon-oxygen mixing layer are studied using 2D direct numerical simulations with detailed chemistry and transport properties. The flame kernel is initiated by adding an energy deposition source term in the energy equation. The effect of unsteady strain rate is studied by imposing a 2D turbulence velocity field, which is initialized by means of a synthetic field. An adaptive wavelet method, based on interpolating wavelets is used in this study to solve the compressible reactive Navier- Stokes equations. This method provides an alternative means to refine the computational grid points according to local demands of the physical solution. The present simulations show that in the very early instants the kernel perturbed by the turbulent field is characterized by an increased burning area and a slightly increased radical formation. In addition, the calculations show that the wavelet technique yields a significant reduction in the number of degrees of freedom necessary to achieve a prescribed solution accuracy.

Martelli, E.; Valorani, M.; Paolucci, S.; Zikoski, Z.

2011-08-01

336

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

Microsoft Academic Search

AbstractObjective: To investigate the association between birth weight of offspring and mortality among fathers and mothers in the west of Scotland.Design: Prospective observational study.Participants: 794 married couples in Renfrew district of the west of Scotland.Main outcome measures: Mortality from all causes and from cardiovascular disease over 15 year follow up.Results: Women who had heavier babies were taller, had higher body

George Davey Smith; Carole Hart; Catherine Ferrell; Mark Upton; David Hole; Victor Hawthorne; Graham Watt

1997-01-01

337

Terrestrial gamma-ray flashes in the Fermi era: Improved observations and analysis methods  

NASA Astrophysics Data System (ADS)

A new data mode and new analysis methods are used to detect Terrestrial Gamma-ray Flashes (TGFs) with the Fermi Gamma-ray Burst Monitor (GBM) 10 times more frequently than previously. In 1037 h of observations at times and over regions for which TGFs are expected, 384 new TGFs were found in addition to the 39 TGFs and two Terrestrial Electron Beam events already detected without the new data mode and methodology. Cosmic ray showers were found to be an important background; they show characteristic signatures in the data of both GBM and the Fermi Large Area Telescope Calorimeter that enable their removal, leaving a sample estimated to consist of ?98% TGFs. The sample includes shorter TGFs than previously found with GBM. The true duration distribution likely contains additional short TGFs because their detection by GBM is limited by detector dead time. One-third of this sample has matches with locations from the World Wide Lightning Location Network (WWLLN)—maps of these locations show the geographic and meteorological features more clearly than maps of spacecraft locations. The intrinsic TGF rate is evaluated using the lightning rate maps of the Lightning Imaging Sensor, accounting for the detection efficiency of GBM as a function of spacecraft-source offset, from which we estimate a global TGF rate of ?400,000 per year. With continuous production of data in the new mode we estimate that GBM will detect ?850 TGFs per year.

Briggs, Michael S.; Xiong, Shaolin; Connaughton, Valerie; Tierney, Dave; Fitzpatrick, Gerard; Foley, Suzanne; Grove, J. Eric; Chekhtman, Alexandre; Gibby, Melissa; Fishman, Gerald J.; McBreen, Shelia; Chaplin, Vandiver L.; Guiriec, Sylvain; Layden, Emily; Bhat, P. N.; Hughes, Maximilian; Greiner, Jochen; Kienlin, Andreas; Kippen, R. Marc; Meegan, Charles A.; Paciesas, William S.; Preece, Robert D.; Wilson-Hodge, Colleen; Holzworth, Robert H.; Hutchins, Michael L.

2013-06-01

338

a Study of the Fracture Impedance Method  

NASA Astrophysics Data System (ADS)

The hydraulic impedance method is a method for estimating the dimension of a downhole fracture by using the reflected waves measured at the wellhead. The existence of a fracture on the hole surface changes the wave impedance in the hole and it causes a reflection of the wave at the location of the fracture. Thus, the dimension of the fracture may be estimated by analyzing the reflected waves measured at the wellhead. The wave motions in a fluid-filled a fractured wellbore are analyzed by coupling the wave motions in the borehole and the wave motions in the fracture. By modeling the fracture as a Helmholtz resonator, expressions for the fracture impedance and the reflection coefficient for a fluid-filled a fractured borehole are derived. The reflected waveforms at the wellhead are calculated numerically by multiplying the spectrum of the input signal by the wellhead reflection coefficient and carrying out the inverse Fourier transform of the product. The calculated results are found to be in good agreement with the results from an experimental study by Paige. Furthermore, the results from the numerical simulation study have demonstrated that the sought-after information on fracture dimension will appear clearly in the reflected wave at the wellhead when the hydraulic fracture is excited at its resonant frequency.

Shaaban Ashour, Ahmed-Aly Ibrahim

339

Chemical equilibria studies using multivariate analysis methods.  

PubMed

Chemical multiequilibria systems can be monitored efficiently with the aid of spectroscopic techniques. Both hard- and soft-modeling are effective and powerful tools to extract chemical information from spectroscopic data. Recently, hybrid approaches that combine the flexibility of soft-modeling with the precise solutions provided by hard-modeling have been proposed. Here, we tested the performance of these three chemometric approaches for the analysis of several simulated data sets. In addition, experimental data recorded during the study of the acid-base equilibria of two DNA structures (G-quadruplex and i-motif) corresponding to two short sequences of the k-ras oncogene were studied. Finally, we also analyzed the interaction of the two DNA sequences with the model ligand TMPyP4. The results obtained from the analysis of these data sets may be useful to determine the most appropriate use of each approach. Whenever the presence of optically active interferences or unknown drifts can be neglected and a chemical model can easily be proposed and fitted, the hard-modeling method shows the best performance. If any of these conditions is not fulfilled, a hybrid-modeling approach may be a better option because all the contributions (chemical and unknown) can be modeled and the ambiguities inherent to soft-modeling methods show minor effects. PMID:21046087

Jaumot, Joaquim; Eritja, Ramon; Gargallo, Raimundo

2010-10-28

340

The acute impact of a hematopoietic allograft on lung function and inflammation: a prospective observational study  

PubMed Central

Background No studies have investigated the immediate impact of receiving an allogeneic hematopoietic stem cell transplant (HSCT) on pulmonary inflammation or lung function. Methods Using a prospective study design, we quantified the changes in these outcome measures in eligible adult individuals in the first six months after receiving an allogeneic hematopoietic stem cell transplant. Results Between January 2007 and December 2008, 72 patients were eligible to participate in the cohort, and of these 68 (94%) were included in the study. Compared to baseline, pulmonary inflammation as measured by exhaled nitric oxide increased after receiving a HSCT with the largest increment seen at three months (+6.0ppb, 95%CI: +0.4 to +11.5), and this was sustained at six months. Percent predicted forced expiratory volume in one second decreased over the same period, with the largest decrease observed at six weeks (?5.9%, 95% CI: -8.9 to ?2.9), and this was also sustained over a six month period. Similar associations were observed for FVC. A larger increase in exhaled nitric oxide from baseline at six weeks and three months may be associated with decreased mortality (p=0.06, p=0.04 respectively). Conclusion Our data demonstrate that recipients of an allogeneic HSCT experience an increase in biomarkers of pulmonary inflammation and a decrease in lung function in the first six months after the procedure. If independently validated in other study populations, these observations could have potential as a prognostic biomarker for this patient group.

2013-01-01

341

Structural methods for studying IRES function.  

PubMed

Internal ribosome entry sites (IRESs) substitute RNA sequences for some or all of the canonical translation initiation protein factors. Therefore, an important component of understanding IRES function is a description of the three-dimensional structure of the IRES RNA underlying this mechanism. This includes determining the degree to which the RNA folds, the global RNA architecture, and higher resolution information when warranted. Knowledge of the RNA structural features guides ongoing mechanistic and functional studies. In this chapter, we present a roadmap to structurally characterize a folded RNA, beginning from initial studies to define the overall architecture and leading to high-resolution structural studies. The experimental strategy presented here is not unique to IRES RNAs but is adaptable to virtually any RNA of interest, although characterization of RNA-protein interactions requires additional methods. Because IRES RNAs have a specific function, we present specific ways in which the data are interpreted to gain insight into that function. We provide protocols for key experiments that are particularly useful for studying IRES RNA structure and that provide a framework onto which additional approaches are integrated. The protocols we present are solution hydroxyl radical probing, RNase T1 probing, native gel electrophoresis, sedimentation velocity analytical ultracentrifugation, and strategies to engineer RNA for crystallization and to obtain initial crystals. PMID:17913644

Kieft, Jeffrey S; Costantino, David A; Filbin, Megan E; Hammond, John; Pfingsten, Jennifer S

2007-01-01

342

Hertfordshire sarcopenia study: design and methods  

PubMed Central

Background Sarcopenia is defined as the loss of muscle mass and strength with age. Although a number of adult influences are recognised, there remains considerable unexplained variation in muscle mass and strength between older individuals. This has focused attention on influences operating earlier in life. Our objective for this study was to identify life course influences on muscle mass and strength in an established birth cohort and develop methodology for collection of muscle tissue suitable to investigate underlying cellular and molecular mechanisms. Methods One hundred and five men from the Hertfordshire Cohort Study (HCS), born between 1931 and 1939 who have historical records of birth weight and weight at one year took part in the Hertfordshire Sarcopenia Study (HSS). Each participant consented for detailed characterisation of muscle mass, muscle function and aerobic capacity. In addition, a muscle biopsy of the vastus lateralis using a Weil-Blakesley conchotome was performed. Data on muscle mass, function and aerobic capacity was collected on all 105 participants. Muscle biopsy was successfully carried out in 102 participants with high rates of acceptability. No adverse incidents occurred during the study. Discussion The novel approach of combining epidemiological and basic science characterisation of muscle in a well established birth cohort will allow the investigation of cellular and molecular mechanisms underlying life course influences on sarcopenia.

2010-01-01

343

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

ERIC Educational Resources Information Center

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

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

2009-01-01

344

Failure of non-invasive ventilation in patients with acute lung injury: observational cohort study  

Microsoft Academic Search

Introduction  The role of non-invasive positive pressure ventilation (NIPPV) in the treatment of acute lung injury (ALI) is controversial.\\u000a We sought to assess the outcome of ALI that was initially treated with NIPPV and to identify specific risk factors for NIPPV\\u000a failure.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  In this observational cohort study at the two intensive care units of a tertiary center, we identified consecutive patients

Sameer Rana; Hussam Jenad; Peter C Gay; Curtis F Buck; Rolf D Hubmayr; Ognjen Gajic

2006-01-01

345

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

Microsoft Academic Search

Purpose  We 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 Methods  We 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

346

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

Microsoft Academic Search

Background  Neurologic 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 Methods  cSO2 was measured by near infrared spectroscopy in 35 patients during cardiopulmonary bypass. cSO2 was kept above 80%

Axel Fudickar; Sönke Peters; Claudia Stapelfeldt; Götz Serocki; Jörn Leiendecker; Patrick Meybohm; Markus Steinfath; Berthold Bein

2011-01-01

347

Fireball observations in central Europe and western Australia: instruments, methods, and results  

NASA Astrophysics Data System (ADS)

Penetration of larger meteoroids through the atmosphere which gives rise to spectacular luminous events - fireballs or even superbolides - is of the greatest interest. Their registrations, especially photographic and newly also photoelectric recordings, provide excellent means to examine physical properties as well as the temporal and spatial distribution of extraterrestrial matter in near-Earth space. The most efficient tools for registration of these very scarce events are the fireball networks: systems covering large areas of the Earth's surface, with multiple camera stations designed to image a large fraction of the night sky. Such camera networks for fireball observations have been set up in several nations at various times in the past (European Fireball Network (EN) in the Czech Republic, Germany, Austria, and Slovakia; the Prairie Network in the USA; and the Meteorite Observation and Recovery Project (MORP) in Canada). Of these networks, only the European fireball network is still in operation, and this continuously since it was started up, but recently new networks were established in South-West Australia and in Ontario, Canada. The two main scientific aims of all these programs remain the same as in the very beginning - first, to constrain the flux of extraterrestrial material to the Earth over a range of masses, and second, to provide a statistically significant group of meteorites with accurate orbits. This contribution was focused on the current work and some particular recent results from the European Fireball Network, especially from its Czech part (current status is described, for example, by Spurny et al., 2006) and from the Desert Fireball Network in the Nullarbor Plains of South-West Australia (Bland, 2004; Spurny et al., 2012; and Bland et al., 2012). The mode of operation of both networks and the analysis methods used were described in detail and illustrated by some examples. Similarly, the most important recent results, especially from the Desert Fireball Network, such as the Bunburra Rockhole and Mason Gully meteorite falls, were presented in detail. These results are already published by Spurny et al. (2011, Mason Gully; 2012, Bunburra Rockhole) and Bland et al. (2009, Bunburra Rockhole).

Spurny, P.

2012-01-01

348

Comparative study of selected parallel tempering methods.  

PubMed

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. PMID:23944588

Malakis, A; Papakonstantinou, T

2013-07-30

349

OBSERVATIONAL STUDIES VS. RANDOMIZED CONTROLLED TRIALS: AVENUES TO CAUSAL INFERENCE IN NEPHROLOGY  

PubMed Central

A common frustration for practicing Nephrologists is the adage that the lack of randomized controlled trials (RCTs) does not allow us to establish causality, but merely associations. The field of Nephrology, like many other disciplines, has been suffering from a lack of RCTs. The view that short of RCTs there is no reliable evidence has hampered our ability to ascertain the best course of action for our patients. However, many clinically important questions in medicine and public health such as the association of smoking and lung cancer are not amenable to RCTs due to ethical or other considerations. Whereas RCTs unquestionably hold many advantages over observational studies, it should be recognized that they also have many flaws that render them fallible under certain circumstances. We provide a description of the various pros and cons of RCTs and of observational studies using examples from the Nephrology literature, and argue that it is simplistic to rank them solely based on pre-conceived notions about the superiority of one over the other. We also discuss methods whereby observational studies can become acceptable tools for causal inferences. Such approaches are especially important in a field like Nephrology where there are myriads of potential interventions based on complex pathophysiologic states, but where properly designed and conducted RCTs for all of these will probably never materialize.

Kovesdy, Csaba P; Kalantar-Zadeh, Kamyar

2011-01-01

350

Using Built Environmental Observation Tools: Comparing Two Methods of Creating a Measure of the Built Environment  

PubMed Central

Purpose Identify an efficient method of creating a comprehensive and concise measure of the built environment integrating data from geographic information systems (GIS) and the Senior Walking Environmental Assessment Tool (SWEAT). Design Cross-sectional study using a population sample. Setting Eight municipally defined neighborhoods in Portland, Oregon. Subjects Adult residents (N = 120) of audited segments (N = 363). Measures We described built environmental features using SWEAT audits and GIS data. We obtained information on walking behaviors and potential confounders through in-person interviews. Analysis We created two sets of environviental measures, one based on the conceptual framework used to develop SWEAT and another using principal component analysis (PCA). Each measure’s association with walking for transportation and exercise was then assessed and compared using logistic regression. Results A priori measures (destinations, safety, aesthetics, and functionality) and PCA measures (accessibility, comfort/safety, maintenance, and pleasantness) were analogous in conceptual meaning and had similar associations with walking. Walking for transportation was associated with destination accessibility and functional elements, whereas walking for exercise was associated with maintenance of the walking area and protection from traffic. However, only PCA measures consistently reached statistical significance. Conclusion The measures created with PCA were more parsimonious than those created a priori. Performing PCA is an efficient method of combining and scoring SWEAT and GIS data.

Keast, Erin M.; Carlson, Nichole E.; Chapman, Nancy J.; Michael, Yvonne L.

2011-01-01

351

Toward a general method to observe the phosphate groups of phosphoenzymes with infrared spectroscopy.  

PubMed

A general method to study the phosphate group of phosphoenzymes with infrared difference spectroscopy by helper enzyme-induced isotope exchange was developed. This allows the selective monitoring of the phosphate P-O vibrations in large proteins, which provides detailed information on several band parameters. Here, isotopic exchange was achieved at the oxygen atoms of the catalytically important phosphate group that transiently binds to the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA1a). [gamma-(18)O(3)]ATP phosphorylated the ATPase, which produced phosphoenzyme that was initially isotopically labeled. The helper enzyme adenylate kinase regenerated the substrate ATP from ADP (added or generated upon ATP hydrolysis) with different isotopic composition than used initially. With time this produced the unlabeled phosphoenzyme. The method was tested on the ADP-insensitive phosphoenzyme state of the Ca(2+)-ATPase for which the vibrational frequencies of the phosphate group are known, and it was established that the helper enzyme is effective in mediating the isotope exchange process. PMID:16798809

Karjalainen, Eeva-Liisa; Hardell, Amelie; Barth, Andreas

2006-06-23

352

Estimating antihypertensive effects of combination therapy in an observational study using marginal structural models.  

PubMed

The evaluation of the antihypertensive effect of multiple antihypertensive drugs using data from an observational study requires adjustment for time-dependent confounders. Marginal structural models (MSMs) have been proposed to address this type of confounding through inverse probability weighting. Generally, the probabilities are estimated using logistic regression models that assume linearity between the logistic link and the predictors, but the linearity might be inaccurate. In this article, we proposed MSMs to assess the blood pressure-lowering effects of combination therapy with olmesartan medoxomil (OLM) plus calcium channel blockers (CCB) (OLM+CCB) in an observational study of OLM, and extended estimation methods of the probabilities for the MSMs using generalized additive models (GAMs). The estimation using GAMs was suggested to improve the balance of the distributions of confounder values between the therapy groups in the pseudo-population. We obtained estimated changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) for OLM+CCB combination therapy after 12 wk compared with OLM monotherapy of -4.3 mmHg (95% confidence interval (CI): -7.7 and -0.9 mmHg) and -2.9 mmHg (95% CI: -5.1 and -0.7 mmHg), respectively. The estimated target BP (SBP<140 mmHg and DBP<90 mmHg) achievement rates for OLM+CCB combination therapy and OLM monotherapy were 62.0 and 46.7%, respectively. The results of the MSMs were closer to those in the randomized controlled trial, such as the combination of OLM and amlodipine besylate in controlling high blood pressure study, than those of conventional methods. The proposed MSMs provided useful information to evaluate the effects of combination therapy of antihypertensive drugs in the context of an observational study. PMID:19827055

Sugihara, Masahiro; Kushiro, Toshio; Saito, Ikuo; Matsushita, Yasuyuki; Hiramatsu, Katsutoshi

2009-10-01

353

Southampton mealtime assistance study: design and methods  

PubMed Central

Background Malnutrition is common in older people in hospital and is associated with adverse clinical outcomes including increased mortality, morbidity and length of stay. This has raised concerns about the nutrition and diet of hospital in-patients. A number of factors may contribute to low dietary intakes in hospital, including acute illness and cognitive impairment among in-patients. The extent to which other factors influence intake such as a lack of help at mealtimes, for patients who require assistance with eating, is uncertain. This study aims to evaluate the effectiveness of using trained volunteer mealtime assistants to help patients on an acute medical ward for older people at mealtimes. Methods/design The study design is quasi-experimental with a before (year one) and after (year two) comparison of patients on the intervention ward and parallel comparison with patients on a control ward in the same department. The intervention in the second year was the provision of trained volunteer mealtime assistance to patients in the intervention ward. There were three components of data collection that were repeated in both years on both wards. The first (primary) outcome was patients’ dietary intake, collected as individual patient records and as ward-level balance data over 24 hour periods. The second was clinical outcome data assessed on admission and discharge from both wards, and 6 and 12 months after discharge. Finally qualitative data on the views and experience of patients, carers, staff and volunteers was collected through interviews and focus groups in both years to allow a mixed-method evaluation of the intervention. Discussion The study will describe the effect of provision of trained volunteer mealtime assistants on the dietary intake of older medical in-patients. The association between dietary intake and clinical outcomes including malnutrition risk, body composition, grip strength, length of hospital stay and mortality will also be determined. An important component of the study is the use of qualitative approaches to determine the views of patients, relatives, staff and volunteers on nutrition in hospital and the impact of mealtime assistance. Trial registration Trial registered with ClinicalTrials.gov NCTO1647204

2013-01-01

354

A statistical analysis of the ``internal linear combination'' method in problems of signal separation as in cosmic microwave background observations  

NASA Astrophysics Data System (ADS)

Aims: The separation of foreground contamination from cosmic microwave background (CMB) observations is one of the most challenging and important problems of digital signal processing in Cosmology. In the literature, various techniques have been presented but no general consensus about their real performance and properties has been reached. This is due to the characteristics of these techniques that have been studied essentially through numerical simulations based on semi-empirical models of the CMB and the Galactic foreground. Such models often have different levels of sophistication and/or are based on different physical assumptions (e.g. the number of Galactic components and level of the noise). Hence, a reliable comparison is difficult. What is missing is a statistical analysis of the properties of the proposed methodologies. Here, we consider the Internal Linear Combination method (ILC) which, among the separation techniques, requires the smallest number of a priori assumptions. This feature is of particular interest in the context of CMB polarization measurements at small angular scales where the lack of knowledge of the polarized backgrounds represents a serious limit. Methods: The statistical characteristics of ILC are examined through an analytical approach and the basic conditions are fixed so as to work satisfactorily. Results: ILC provides satisfactory results only under rather restrictive conditions. This is a critical fact to take into consideration in planning future ground-based observations (e.g., with ALMA) where, contrary to satellite experiments, there is the possibility of having a certain control over the experimental conditions.

Vio, R.; Andreani, P.

2008-08-01

355

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

356

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

357

Observation of Coulomb blockade in structures created by the method of SECO (step edge cut off)  

Microsoft Academic Search

For observation of the Coulomb blockade, SECO-structures with self-aligned gates with island size of 170×170×12 nm on Ti\\/Si3N4 were fabricated. On these structures, single-electron current oscillations from gate voltage were observed at a temperature of 4.2 K. The magnitude of the Coulomb gap was 6 mV

L. V. Litvin; V. A. Kolosanov; A. G. Cherkov; V. A. Tkachenko; D. G. Baksheyev; K. P. Mogilnicov; A. L. Aseev

1998-01-01

358

Optimization of an observation well network for monitoring groundwater level using statistical methods  

Microsoft Academic Search

The purpose of this paper is to optimize a network of observation wells in southeast of Austria, developed for monitoring groundwater level and groundwater resource in this area. As groundwater level data are collected over time, problems arise in defining an overall variogram valid for the whole period of observation, which is needed to estimate groundwater level properly. This paper

M. HUSSAIN; K. FUCHS; J. FANK

1995-01-01

359

Method for correction of errors in observation angles for limb thermal emission measurements  

Microsoft Academic Search

Thermal emission measurements of the earth's stratospheric limb from space platforms require an accurate knowledge of the observation angles for retrieval of temperature and constituent distributions. Without the use of expensive stabilizing systems, however, most observational instruments do not meet the required pointing accuracies, thus leading to large errors in the retrieval of atmospheric data. This paper describes a self-constituent

M. M. Abbas; G. L. Shapiro; B. J. Conrath; V. G. Kunde; W. C. Maguire

1984-01-01

360

TV Observations of Meteors in INASAN: Equipment, Methods and First Results  

Microsoft Academic Search

For the analysis the risk from particles of meteor streams, we must have proved information about masses and densities of meteors. The prime task is to select minor streams from sporadic meteors. Very few astronomers tried to do it, when others only mark observed meteor ``Sporadic'' without registering its track. So very few previous observations cannot be used for streams

Anna P. Kartashova; A. V. Bagrov; V. A. Leonov

2007-01-01

361

Feature selection methods in QSAR studies.  

PubMed

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

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

362

Statin Use and Risk of Prostate Cancer: A Meta-Analysis of Observational Studies  

PubMed Central

Background Emerging evidence suggests that statins may decrease the risk of cancers. However, available evidence on prostate cancer (PCa) is conflicting. We therefore examined the association between statin use and risk of PCa by conducting a detailed meta-analysis of all observational studies published regarding this subject. Methods Literature search in PubMed database was undertaken through February 2012 looking for observational studies evaluating the association between statin use and risk of PCa. Before meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using random-effects model (DerSimonian and Laird method). Subgroup analyses, sensitivity analysis and cumulative meta-analysis were also performed. Results A total of 27 (15 cohort and 12 case-control) studies contributed to the analysis. There was heterogeneity among the studies but no publication bias. Statin use significantly reduced the risk of both total PCa by 7% (RR 0.93, 95% CI 0.87–0.99, p?=?0.03) and clinically important advanced PCa by 20% (RR 0.80, 95% CI 0.70–0.90, p<0.001). Long-term statin use did not significantly affect the risk of total PCa (RR 0.94, 95% CI 0.84–1.05, p?=?0.31). Stratification by study design did not substantially influence the RR. Furthermore, sensitivity analysis confirmed the stability of results. Cumulative meta-analysis showed a change in trend of reporting risk from positive to negative in statin users between 1993 and 2011. Conclusions Our meta-analysis provides evidence supporting the hypothesis that statins reduce the risk of both total PCa and clinically important advanced PCa. Further research is needed to confirm these findings and to identify the underlying biological mechanisms.

Bansal, Dipika; Undela, Krishna; D'Cruz, Sanjay; Schifano, Fabrizio

2012-01-01

363

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

NASA Astrophysics Data System (ADS)

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

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

2004-02-01

364

Meso-moiré fringe observation of nano-particle structures by electron moiré method  

Microsoft Academic Search

A new method to measure the spacing and direction in the ordered assembled nanoparticles by using the electron Moiré new method to measure the spacing and direction in the ordered assembled nanoparticles by using the electron Moiré fringes has been developed. In this method an assembled nanoparticle array can be consider as a model grid. When the electron beam was

Satoshi Kishimoto; Yusuke Yamauchi

2009-01-01

365

Methods to Study Everyday Use of Products in Households: The Wageningen Mouthing Study as an Example  

Microsoft Academic Search

Several methods exist to study human behaviour in everyday life: e.g. an oral or written interview, measurement of physical variables and observation. All of them have their advantages and disadvantages, which are described in this paper. When a clear picture of actual human behaviour and information about an entire activity are required, for example to assess risks of exposure to

L. P. A. Steenbekkers

2001-01-01

366

Solar absorption at the surface and in the atmosphere as determined by different observational methods  

NASA Astrophysics Data System (ADS)

The concept of effective cloud cover, elaborated on the basis of an assumption that changes in the net radiation at the top of the atmosphere are mainly caused by changing cloudiness, has been used to deduce solar surface radiation from satellite data. It has been shown that the method permits a calculation of solar surface absorption distributions that agree well with the results obtained by other authors and that the existing disagreement can be to a great extent ascribed to the differences in the data sets and analysis periods. The method allows use of early satellite measurements to get longer time series of the surface radiation budget. In this study, it has been applied to the Nimbus-7 ERB WFOV data for 1979 1986. The net solar flux at the TOA (top of the atmosphere) can be partitioned into absorption at the surface and within the atmosphere. The geographical distributions of all the three quantities as well as the zonal averages of the surface absorption for January and July have been described. Special objectives of the present study are to estimate the interannual standard deviation for the 8-year period and to analyse the shortwave cloud-radiative forcing distributions at the surface and especially within the atmosphere. The standard deviation of the TOA and the surface solar absorption shows a temporal asymmetry, being much larger in January than in July. Noticeable is the disappearance of the wintertime strong variability over the central Pacific in July. As can be expected, the strong variability areas coincide with the strong variability areas of the cloud amount, showing the values up to 27 Wm-2 at the surface. According to our estimate, the shortwave cloud forcing at the surface is everywhere stronger than that at the TOA, so that the cloud forcing of the atmosphere is negative. This means that in the belt of 58.5° N 58.5° S a cloudy atmosphere absorbs more solar energy than a cloud-free atmosphere. Our mean annual value of the atmospheric cloud forcing for this belt is -11 Wm-2 which is somewhat stronger than that obtained by other investigators. It must be stressed that this value is within the uncertainty limits. Shortwave cloud forcing of the atmosphere is the strongest in the lower latitude areas of heavy cloudiness above the continents and negligible in the midlatitudes in winter. This gives evidence that the value of the shortwave cloud forcing of the atmosphere is modified by a combination of cloud absorption and cloud albedo.

Keevallik, S.; Hindov, R.; Rannik, Ü.

1994-12-01

367

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

368

The effect of regular antenatal perineal massage on postnatal pain and anal sphincter injury: A prospective observational study  

Microsoft Academic Search

Objective. Antenatal perineal massage has been shown to reduce the incidence of perineal tears in primiparous women. The aim of this study was to determine whether perineal massage impacts on primary prevention of symptomatic disruption of the fecal continence mechanism. Methods. An observational study recruited two cohorts of women. The first, massage group (MG) chose to perform daily perineal massage

Maeve Eogan; Leslie Daly; Colm O'Herlihy

2006-01-01

369

International child care practices study: methods and study population.  

PubMed

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

Nelson, E A; Taylor, B J

1999-06-01

370

Clinical information transfer and data capture in the acute myocardial infarction pathway: an observational study.  

PubMed

Rationale, aims and objectives? Acute myocardial infarctions (MIs) or heart attacks are the result of a complete or an incomplete occlusion of the lumen of the coronary artery with a thrombus. Prompt diagnosis and early coronary intervention results in maximum myocardial salvage, hence time to treat is of the essence. Adequate, accurate and complete information is vital during the early stages of admission of an MI patient and can impact significantly on the quality and safety of patient care. This study aimed to record how clinical information between different clinical teams during the journey of a patient in the MI care pathway is captured and to review the flow of information within this care pathway. Method? A prospective, descriptive, structured observational study to assess (i) current clinical information systems (CIS) utilization and (ii) real-time information availability within an acute cardiac care setting was carried out. Completeness and availability of patient information capture across four key stages of the MI care pathway were assessed prospectively. Results? Thirteen separate information systems were utilized during the four phases of the MI pathway. Observations revealed fragmented CIS utilization, with users accessing an average of six systems to gain a complete set of patient information. Data capture was found to vary between each pathway stage and in both patient cohort risk groupings. The highest level of information completeness (100%) was observed only in the discharge stage of the MI care pathway. The lowest level of information completeness (58%) was observed in the admission stage. Conclusion? The study highlights fragmentation, CIS duplication, and discrepancies in the current clinical information capture and data transfer across the MI care pathway in an acute cardiac care setting. The development of an integrated and user-friendly electronic data capture and transfer system would reduce duplication and would facilitate efficient and complete information provision at the point of care. PMID:22587539

Kesavan, Sujatha; Kelay, Tanika; Collins, Ruth E; Cox, Benita; Bello, Fernando; Kneebone, Roger L; Sevdalis, Nick

2012-05-15

371

Central venous port-related infection in patients with malignant tumors: An observational study  

PubMed Central

Purpose We evaluated the characteristics of central venous port (CVP)-related infection with microbiological assessments in patients with malignant tumors. Materials and methods In a prospective setting, patients with CVP for the treatment of malignant tumors were enrolled in this study. The incidence of CVP-related infection during three months was determined. Microbiological surveillance from skin swab was performed before and after CVP placement. Results Fifty-nine patients were enrolled in this study, and 60 CVPs were implanted. Thirty-six (61%) patients had head and neck malignancies. Access route was subclavian vein in 43 (71.7%) CVPs and forearm vein in 17 (28.3%). CVP-related infection was observed in three (5.1%) patients: port-pocket infection in one and probable CVP-related infection in two patients, respectively. No definitive CVP-related bloodstream infection was observed. Before the placement of CVP, colonization at the insertion site was observed in ten subclavian CVP patients, while no colonization was observed in the forearm CVP patients. At 1 and 4 weeks, detection rates of colonization were also higher in subclavian CVP patients. No definitive relationship was demonstrated between skin colonization and clinical development of CVP-related infection. Conclusion The rate of CVP-related infection in this prospective evaluation in patients with malignant tumors was comparable to previous studies. Colonization of the skin was more prominent in the subclavian site than in the forearm site. Although skin colonization was not proven to be a risk factor of infection, these results may draw attention to the adequate maintenance of CVP. (Trial registration: UMIN000003664).

Sone, Miyuki; Ehara, Shigeru; Kato, Kenichi; Suzuki, Michiko; Tanaka, Ryoichi; Suwabe, Akira; Itabashi, Tetsuya; Masahiro, Kashiwaba

2012-01-01

372

Revisiting observables in generally covariant theories in the light of gauge fixing methods  

SciTech Connect

We derive for generally covariant theories the generic dependency of observables on the original fields, corresponding to coordinate-dependent gauge fixings. This gauge choice is equivalent to a choice of intrinsically defined coordinates accomplished with the aid of spacetime scalar fields. With our approach we make full contact with, and give a new perspective to, the 'evolving constants of motion' program. We are able to directly derive generic properties of observables, especially their dynamics and their Poisson algebra in terms of Dirac brackets, extending earlier results in the literature. We also give a new interpretation of the observables as limits of canonical maps.

Pons, J. M.; Salisbury, D. C.; Sundermeyer, K. A. [Departament d'Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Catalonia (Spain); Max-Planck-Institut fuer Wissenschaftsgeschichte, Boltzmannstrasse 22, 14195 Berlin, Germany and Department of Physics, Austin College, Sherman, Texas 75090-4440 (United States); Freie Universitaet Berlin, Fachbereich Physik, Institute for Theoretical Physics, Arnimallee 14, 14195 Berlin (Germany)

2009-10-15

373

[Oral care practice and procedures in intubated patients: an observational study].  

PubMed

Background: Effective oral care improves patient comfort and prevents oral infection. While common in general nursing practice, administering oral care to intubated patients is particularly challenging. Purpose: This study investigated practices and factors associated with oral care of intubated patients in intensive care units (ICUs). Methods: This study used a cross-sectional design and recruited nurses using purposive sampling. Data were collected with a structured observational checklist between January and April 2008 at a medical center in northern Taiwan. Observational data reflected oral care procedures performed by thirty-one ICU nurses on intubated patients in six ICUs. Results: Cotton and foam swabs were found to be the main oral care cleaning instruments used with intubated patients, with dilute mouthwash the primary cleaning solution. Nearly three-quarters (72.4%) of participants were found to employ proper oral care procedures. Participants selected different cleaning equipment, cleaning solutions, cleaning solution usage methods and oral endotracheal tube securement methods based on differing conditions. ICU nurse age was positively associated oral care completeness. The level of oral care completeness achieved by participants in medical ICUs was significantly higher those assigned to surgical ICUs. Conclusions/Implications for Practice: Study findings showed that ICU nurses did not follow procedures and steps recommended by current evidence-based practice (e.g., brushing the teeth and gums; positioning patients in a side or semi- / high-fowlers position when providing oral care to intubated patients). ICUs must establish policies and procedures for oral care of intubated patients that reflect patient characteristics. Furthermore, ICUs should provide oral care related on-the-job training and education in order to improve the quality of oral care administered to critical care patients. PMID:19953453

Lin, Ying-Siou; Chang, Jung-Chen Kristina; Chang, Tsyr-Huei; Lou, Meei-Fang

2009-12-01

374

Varenicline as a smoking cessation aid in a Greek population: a subanalysis of an observational study  

PubMed Central

Background Greece has the highest proportion of smokers in the European Union with 42% of Greeks admitting that they smoke, based on a 2009 survey. This post-hoc analysis of a prospective, observational study evaluated the effectiveness and safety profile of the smoking cessation aid varenicline, as well as potential predictors of quit success in a Greek population. Methods Participants were prescribed varenicline according to the recommendations of the European Summary of Product Characteristics (1 mg twice daily). The 7-day point prevalence of abstinence at Week 12 was determined based on verbal reporting using a nicotine use inventory. Abstinence was confirmed by carbon monoxide measurements of exhaled air at the last visit of the study. The safety profile of varenicline was also assessed. Results At baseline, the Greek subsample (n = 196) had a mean age of 42.6 years, with 54.6% of them being men. Participants had a smoking history of 23.5 years and a Fagerström Test for Nicotine Dependence total score of 6.6. After 12 weeks of varenicline therapy, 70.4% (95% CI, 64.0-76.7) of all participants had quit smoking. This increased to 86.2% among participants who had taken the study medication for 80% of the planned number of treatment days. Age was a significant predictor of quit success. The most frequently observed treatment-emergent adverse event was nausea, occurring in 13.3% of participants. Conclusions In this 'real-world' observational study, 70.4% of Greek smokers successfully quit smoking after 12 weeks of varenicline therapy, providing support that varenicline is an effective smoking cessation medication. Further studies with longer follow-up are warranted. Trial Registration ClinicalTrials.gov: NCT00669240

2012-01-01

375

Antithrombin III in patients admitted to intensive care units: a multicenter observational study  

PubMed Central

Introduction The administration of antithrombin III (ATIII) is useful in patients with congenital deficiency, but evidence for the other therapeutic indications of this drug is still uncertain. In Italy, the use of ATIII is very common in intensive care units (ICUs). For this reason we undertook an observational study to determine the pattern of use of ATIII in ICUs and to assess the outcome of patients given this treatment. Methods From 20 May to 20 July 2001 all consecutive patients admitted to ICUs in 20 Italian hospitals and treated with ATIII were enrolled. The following information was recorded from each patient: congenital deficiency, indication for use of ATIII, daily dose and duration of ATIII treatment, outcome of hospitalization (alive or dead). The outcome data of our observational study were compared with those reported in previously published randomized controlled trials (RCTs). Results Two hundred and sixteen patients were enrolled in the study. The clinical indications for using ATIII were sepsis (25.9%), disseminated intravascular coagulation (23.1%), and other clinical conditions (46.8%). At the end of the study, 65.3% of the patients were alive, 24.5% died and 10.2% were still in the hospital. Among the patients with sepsis (n = 56), 19 died during the observation period (33.9%; 95% confidence interval 22.1–47.5%). Discussion Our study described the pattern of use of ATIII in Italian hospitals and provided information on the outcome of the subgroup treated with sepsis. A meta-analysis of current data from RCTs, together with our findings, indicates that there is no sound basis for using this drug in ICU patients with sepsis.

Messori, Andrea; Vacca, Franca; Vaiani, Monica; Trippoli, Sabrina

2002-01-01

376

Cohort studies: history of the method. I. Prospective cohort studies.  

PubMed

The term "cohort study" was introduced by Frost in 1935 to describe a study that compared the disease experience of people born at different periods, in particular the sex and age specific incidence of tuberculosis and the method was extended to the study of non-communicable disease by Korteweg who used it 20 years later to analyse the epidemic of lung cancer in the Netherlands. Such studies are now best described as generation studies or generation cohort studies to distinguish them from the common type of study that is now carried out that consists in defining groups of individuals distinguished by some variable (such as place of residence, occupation, behaviour, or environmental exposure) and following them up to see if the incidence or mortality rates vary with the selected variable. This type of study is now one of the most important tools for epidemiological investigation. Initially called prospective studies, because the information characterising the individuals in the cohorts was recorded before the onset of disease, they are now preferably called cohort studies and distinguished as prospective cohort studies, If the information obtained relates to the subjects at the time the study is started and they are then followed, or retrospective cohort studies, if the information characterising the individuals was recorded sometime in the past (for example, the receipt of radiotherapy, or entry to a specific occupation). Studies of either type have the great advantage that they avoid all the most important sources of bias that may affect case-control-studies, but the disadvantage that because incidence rates and more specifically mortality rates are commonly low, large numbers of subjects have to be followed for several (if not many) years to obtain statistically significant results. Several early prospective studies are described: Namely, those of 34,000 male British doctors, 190,000 male and female American citizens with different smoking habits, some 5,000 middle aged residents of Framingham with different blood pressures, blood cholesterol levels, etc, and 13,000 children born in the UK in one week in 1946 with different family backgrounds. PMID:11446312

Doll, R

2001-01-01

377

Observations of Surface Wave Azimuthal Anisotropy in Southern California by Direct Application of the Beamforming Method  

NASA Astrophysics Data System (ADS)

We use the Southern California Seismic Network as an array and apply a beamforming method for 190 teleseismic events to determine their Rayleigh surface wave phase velocities and their arrival directions. Our results indicate that the array aperture has excellent resolution for periods 16-100 seconds but above 100 seconds phase velocities begin to show large error bars because of its spatial size. We recover the ubiquitous pattern of azimuthal phase velocity variation of Rayleigh waves for periods 16-50 seconds; the amplitude variations are about 1-1.5%, consistent with an assumption of a weakly anisotropic medium. Our results also confirm an assumption in most studies, of negligible dependence on the 4-theta component. Though these results apply only in Southern California, direct confirmation of small 4-theta variations seems to be rare. Our analysis shows that anisotropy is present in the period range 15-50 seconds which correspond approximately to 50-200 km wavelengths, and suggests anisotropy extends to the upper mantle with an prevalent anisotropic fast axis that is oriented along the direction SE-NW (110/290 degrees clockwise from North). This direction is interesting in that it is sub-parallel with the Mohave section of the San Andreas Fault. It is this section of the fault that is misaligned with the general direction of the North America-Pacific Plate boundary. Thus we speculate that the fast axis alignment may be associated with shear and compression of the Transverse Ranges.

Alvizuri, C. R.; Tanimoto, T.

2010-12-01

378

CMB observations from the CBI and VSA: A comparison of coincident maps and parameter estimation methods  

Microsoft Academic Search

We present coincident observations of the Cosmic Microwave Background (CMB)\\u000afrom the Very Small Array (VSA) and Cosmic Background Imager (CBI) telescopes.\\u000aThe consistency of the full datasets is tested in the map plane and the Fourier\\u000aplane, prior to the usual compression of CMB data into flat bandpowers. Of the\\u000athree mosaics observed by each group, two are found

Nutan Rajguru; Steven T. Myers; Richard A. Battye; J. Richard Bond; Kieran Cleary; Carlo R. Contaldi; Rod D. Davies; Richard J. Davis; Clive Dickinson; Ricardo Genova-Santos; Keith Grainge; Yaser A. Hafez; Michael P. Hobson; Michael E. Jones; Rudiger Kneissl; Katy Lancaster; Anthony Lasenby; Brian S. Mason; Timothy J. Pearson; Guy G. Pooley; Anthony C. S. Readhead; Rafael Rebolo; Graca Rocha; Jose Alberto Rubino-Martin; Richard D. E. Saunders; Richard S. Savage; Anna Scaife; Paul F. Scott; L. Sievers; Anÿze Slosar; Angela C. Taylor; David Titterington; Elizabeth Waldram; Robert A. Watson; Althea Wilkinson

2005-01-01

379

Interobserver repeatability and validity of an observation method to assess physical loads imposed on the upper extremities  

Microsoft Academic Search

Interobserver repeatability and validity were assessed for a new semiquantitative, time-based observation method for the estimation of physical loads imposed on the upper extremities. Six risk factors of upper extremity disorders were included in the method: repetitive use of hand, use of hand force, pinch grip, non-neutral wrist posture, elevation of upper arm, local mechanical pressure. Two occupational health nurses

Ritva Ketola; Risto Toivonen IV; Eira Viikari-Juntura II

2001-01-01

380

An intravital microscopy method permitting continuous long-term observations of ovulation in vivo in the rabbit  

Microsoft Academic Search

BACKGROUND: A method for intravital microscopy of the rabbit ovary was developed to enable observations of real-time changes during ovulation in vivo. The aim was to correlate these events to biochemical events at specific stages of ovulation. METHODS: Virgin, female rabbits were primed with equine chorionic gonadotrophin (CG) (30- 100 IU) then HCG (100 IU) 2 days later to induce

Pernilla Dahm-Kähler; Carl Löfman; Ryota Fujii; Michael Axelsson; Per Olof Janson; Mats Brännström

2006-01-01

381

A second life for old data: global patterns in pollution ecology revealed from published observational studies.  

PubMed

A synthesis of research on the responses of terrestrial biota (1095 effect sizes) to industrial pollution (206 point emission sources) was conducted to reveal regional and global patterns from small-scale observational studies. A meta-analysis, in combination with other statistical methods, showed that the effects of pollution depend on characteristics of the specific polluter (type, amount of emission, duration of impact on biota), the affected organism (trophic group, life history), the level at which the response was measured (organism, population, community), and the environment (biome, climate). In spite of high heterogeneity in responses, we have detected several general patterns. We suggest that the development of evolutionary adaptations to pollution is a common phenomenon and that the harmful effects of pollution on terrestrial ecosystems are likely to increase as the climate warms. We argue that community- and ecosystem-level responses to pollution should be explored directly, rather than deduced from organism-level studies. PMID:21071124

Kozlov, Mikhail V; Zvereva, Elena L

2010-11-11

382

Sydney epilepsy incidence study to measure illness consequences: the SESIMIC observational epilepsy study protocol  

PubMed Central

Background Epilepsy affects an estimated 50 million people and accounts for approximately 1% of days lost to ill health globally, making it one of the most common, serious neurological disorders. While there are abundant global data on epilepsy incidence, prevalence and treatment, there is a paucity of Australian incidence data. There is also a general lack of information on the psychosocial impact and socioeconomic consequences of a new diagnosis of epilepsy on an individual, their family, household, and community which are often specific to the health and social system of each country. Methods/Design The Sydney Epilepsy Incidence Study to Measure Illness Consequences (SEISMIC) is an Australian population-based epilepsy incidence and outcome study that will recruit every newly diagnosed case of epilepsy in the Sydney South West Area Health Service to an epilepsy register. Multiple and overlapping sources of notification will be used to identify all new cases of epilepsy over a 24 month period in the Eastern Zone of the Sydney South West Area Health Service (SSWAHS) and follow up will occur over 12 months. SEISMIC will use the International League Against Epilepsy (ILAE) definitions and classifications for epidemiologic studies of epilepsy. The study will examine outcomes including mood, quality of life, employment, education performance, driving status, marital and social problems, medication use, health care usage, costs and stigma. Discussion This study is designed to examine how clinical, psychological factors, socioeconomic circumstances, and healthcare delivery influence the experience of epilepsy for individuals and families allowing better targeting of specific services and informing policy makers and practitioners. In addition, the study will provide the basis for a longitudinal population-based cohort study and potentially inform qualitative sub-studies and randomised controlled trials of intervention strategies. The study has been registered on the Australia New Zealand Clinical Trial Registration database with ANZCTRN12609000059268.

2011-01-01

383

Taguchi Methods in Electronics: A Case Study.  

National Technical Information Service (NTIS)

Total Quality Management (TQM) is becoming more important as a way to improve productivity. One of the technical aspects of TQM is a system called the Taguchi method. This is an optimization method that, with a few precautions, can reduce test effort by a...

R. Kissel

1992-01-01

384

Some Observations on the Houbolt-Rainey and Peak-Hold Methods of Flutter Onset Prediction.  

National Technical Information Service (NTIS)

A subcritical response method for flutter onset prediction developed by Houbolt and Rainey in 1958 is compared with the Peak-Hold Method which was apparently first applied to flutter onset prediction by Sandford, Abel, and Gray in the early 1970's. The ra...

R. V. Doggett

1990-01-01

385

Cardiac Abnormalities in HIV-Positive Patients: Results from an Observational Study in India.  

PubMed

Background: The clinical presentation of cardiac abnormalities in HIV-infected patients may be atypical or masked by concurrent illnesses that lead to misdiagnosis or they remain undiagnosed; therefore, this study was aimed to determine the frequency of cardiac abnormalities in HIV-infected patients. Material and METHODS: Consecutive HIV-infected patients of age >13 years were studied for 3 months, after obtaining their consent. After clinical assessment, chest x-ray, electrocardiogram, 2-dimensional echocardiography and serum Troponin T levels were done. RESULTS: A total of 100 patients were studied, cardiomegaly was observed in the x-ray of 15% of them, abnormal electrocardiogram was seen in 18%, 2-dimensional echocardiography was abnormal in 67%; and diastolic dysfunction (42.8%) was the commonest abnormality followed by dilated cardiomyopathy (17.6%). Serum troponin T was elevated in 8%. The variables, opportunistic infections (OIs), antiretroviral therapy (ART), stage of HIV disease, and CD4 counts, did not affect the frequency of diastolic dysfunction. CONCLUSION: The diastolic dysfunction is the most common cardiac abnormality observed in HIV-infected patients. PMID:22968352

Jain, Nirdesh; Reddy, Dandu H; Verma, Shailendra Prasad; Khanna, Roopali; Vaish, Arvind Kumar; Usman, Kauser; Tripathi, Anil Kumar; Singh, Abhishek; Mehrotra, Sanjay; Gupta, Alok

2012-09-11

386

Antiepileptic Drugs for Bipolar Disorder and the Risk of Suicidal Behavior: A 30 -Year Observational Study  

PubMed Central

Objective In 2009 the U.S. Food and Drug Administration issued a warning regarding suicidality and antiepileptic drugs based on meta-analyses of 199 randomized trials (over 43,000 subjects with different illnesses) of 11 antiepileptics. The present study examines the hypothesis that the three antiepileptics approved for bipolar disorder (carbamazepine, lamotrigine, and valproate) are associated with an elevated risk of suicide attempts and suicides. Method A prospective observational study was conducted at five U.S. academic medical centers from 1978 to 2009. Analyses included 199 participants with bipolar disorder for whom 1,077 time intervals were classified as either exposed to an antiepileptic (carbamazepine, lamotrigine, or valproate) or not exposed to an antiepileptic, an antidepressant, or lithium during 30 years of follow-up. Results Participants who had more severe manic symptoms were more likely to receive antiepileptic drugs. Mixed-effects grouped-time survival models revealed no elevation in risk of suicide attempt or suicide during periods when participants were receiving antiepileptics relative to periods when they were not (hazard ratio= 0.93, 95% CI=0.45–1.92), controlling for demographic and clinical variables through propensity score matching. Conclusions In this longitudinal observational study, the risk of suicide attempts or suicides was not associated with the antiepileptics approved for bipolar disorder.

Leon, Andrew C.; Solomon, David A.; Li, Chunshan; Fiedorowicz, Jess G.; Coryell, William H.; Endicott, Jean; Keller, Martin B.

2013-01-01

387

Statin use and risk of breast cancer: a meta-analysis of observational studies.  

PubMed

Emerging evidence suggests that statins' may decrease the risk of cancers. However, available evidence on breast cancer is conflicting. We, therefore, examined the association between statin use and risk of breast cancer by conducting a detailed meta-analysis of all observational studies published regarding this subject. PubMed database and bibliographies of retrieved articles were searched for epidemiological studies published up to January 2012, investigating the relationship between statin use and breast cancer. Before meta-analysis, the studies were evaluated for publication bias and heterogeneity. Combined relative risk (RR) and 95 % confidence interval (CI) were calculated using a random-effects model (DerSimonian and Laird method). Subgroup analyses, sensitivity analysis, and cumulative meta-analysis were also performed. A total of 24 (13 cohort and 11 case-control) studies involving more than 2.4 million participants, including 76,759 breast cancer cases contributed to this analysis. We found no evidence of publication bias and evidence of heterogeneity among the studies. Statin use and long-term statin use did not significantly affect breast cancer risk (RR = 0.99, 95 % CI = 0.94, 1.04 and RR = 1.03, 95 % CI = 0.96, 1.11, respectively). When the analysis was stratified into subgroups, there was no evidence that study design substantially influenced the effect estimate. Sensitivity analysis confirmed the stability of our results. Cumulative meta-analysis showed a change in trend of reporting risk of breast cancer from positive to negative in statin users between 1993 and 2011. Our meta-analysis findings do not support the hypothesis that statins' have a protective effect against breast cancer. More randomized clinical trials and observational studies are needed to confirm this association with underlying biological mechanisms in the future. PMID:22806241

Undela, Krishna; Srikanth, Vallakatla; Bansal, Dipika

2012-07-18

388

A sparse representation-based deployment method for optimizing the observation quality of camera networks.  

PubMed

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

2013-08-28

389

A Method for Studying Imagery in Animals  

Microsoft Academic Search

A short-term memory task was developed to determine whether the representation controlling the choice behavior of pigeons is an image. The task involved observation of a clock hand stimulus that rotated from an initial location of 0° (12:00 position). On perceptual trials, the clock hand moved at constant speed and was always visible to the subject. Imagery trials were identical

Julie J. Neiworth; Mark E. Rilling

1987-01-01

390

Hybrid terminal sliding mode observer design method for permanent magnet synchronous motor control system  

Microsoft Academic Search

This paper proposes a hybrid terminal sliding mode observer based on the nonsingular terminal sliding mode and the high-order sliding mode for the rotor position and speed estimation in the permanent magnet synchronous motor control system. A nonsingular terminal sliding mode manifold is utilized to realize both fast convergence and better tracking precision. Meanwhile, a high-order sliding mode control law

Jianfei Zheng; Yong Feng; Xinghuo Yu

2008-01-01

391

Observation of charge accumulation process in electron beam irradiated polymers using pressure wave propagation method  

Microsoft Academic Search

Bulk charge accumulation in insulating materials under electron beam irradiation in vacuum environment was observed using newly developed measurement system. Recently, some accidents in spacecraft due to the charging up of the electric potential have been reported. Some of them seem to be caused by discharge due to the charge accumulation in bulk of insulating materials at relatively higher altitude

F. Fukuyoshi I; D. Gotoh; Y. Tanaka; T. Takada; R. Watanabe; N. Tomita; R. Liu

2005-01-01

392

Longitudinal Study of Observed and Perceived Family Influences on Problem-Focused Coping Behaviors of Preadolescents With Spina Bifida  

Microsoft Academic Search

Objective: To study coping socialization longitudinally by examining reported and observed family environ- ment and parenting variables in relation to children's problem-focused coping in a sample of 68 families of preadolescents with spina bifida and 68 matched able-bodied comparison families. Methods: Family environment and parenting variables were assessed with mother and father reports and observational measures. Children's problem-focused coping was

Wendy L. McKernon; Grayson N. Holmbeck; Craig R. Colder; Jennifer S. Hommeyer; Wendy Shapera; Venette Westhoven

2001-01-01

393

Mathematical methods to study the polling systems  

Microsoft Academic Search

Reviewed were the mathematical methods that are used to investigate the polling systems which found wide application in modeling\\u000a and design of various transport and industrial processes. Emphasis was made on the models of polling systems used to investigate\\u000a the wireless broadband networks. The polling systems were classified; presented were stochastic models and methods of investigating\\u000a discrete-time and continuous-time systems,

V. M. Vishnevskii; O. V. Semenova

2006-01-01

394

Elicitation of Slips of the Tongue from Young Children: A New Method and Preliminary Observations.  

ERIC Educational Resources Information Center

Examination of the use of short "tongue-twister" phrases in eliciting spontaneous slips of the tongue in five year olds indicated that the technique was a feasible and beneficial method for collecting spoonerism data from children. (24 references) (CB)

Smith, Bruce L.

1990-01-01

395

Compliance with Seat Belt Use in Makurdi, Nigeria: An Observational Study  

PubMed Central

Background: Seat belts are designed to reduce injuries due to road crash among vehicle occupants. Aims: This study aims to determine the availability of seat belt in vehicles and compliance with seat belt use among vehicle occupants. Materials and methods: This was a 24-h direct observational study of seat belt usage among vehicle occupants in Makurdi, Benue State, Nigeria. By direct surveillance and using a datasheet, we observed 500 vehicles and their occupants for seat belt availability and compliance with its use. Chi-square test was used for test of significance between variables. Results: Twenty-five (5.0%) of the observed 500 vehicles had no seat belt at all. Overall, compliance was 277/486 (57.0%). Use of seat belt was highest in the afternoon with 124/194 (64.4%), followed by 111/188 (59.0%) in the morning and 42/95 (44.2%) at night. Compliance was highest among car occupants [209/308 (67.9%)] and private vehicles, and lowest among commercial vehicle occupants. Compliance among female drivers was 77.1% compared with 51.4% among male drivers. Among drivers, the mean age of seat belt users was 38.4 (7.7) years, which was significantly younger than the 41.3 (8.7) years mean age of non-users. Similar figures were obtained among other vehicle occupants. Conclusions: Compared with previous studies, seat belt usage has improved among Nigerian road users, but there is still room for improvement, especially early in the mornings and at nights. Since these were times when law enforcement agencies were not likely to be on the roads, we advocate for improved coverage by enforcement agents to enforce better compliance.

Popoola, SO; Oluwadiya, KS; Kortor, JN; Denen-Akaa, P; Onyemaechi, NOC

2013-01-01

396

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.

2012-01-01

397

Taguchi methods in electronics: A case study  

NASA Astrophysics Data System (ADS)

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

Kissel, R.

1992-05-01

398

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

399

The assessment of maladaptive parent-child interaction by direct observation: An analysis of methods  

Microsoft Academic Search

Six direct observation technologies for assessing parent-child interactions are examined: Descriptive-narrative, event recording, three types of interval sampling, and sequential event recording. Selected articles in the clinical literature are reviewed to illustrate use of each technology. Furthermore, the yield of each procedure in terms of four assessment criteria was evaluated: precise description of the parent-child interaction, target selection, identification of

Mark W. Roberts; Rex Forehand

1978-01-01

400

Resistance profiles of urinary tract infections in general practice - an observational study  

PubMed Central

Background Guideline recommendations on therapy in urinary tract infections are based on antibiotic resistance rates. Due to a lack of surveillance data, little is known about resistance rates in uncomplicated urinary tract infection (UTI) in general practice in Germany. In a prospective observational study, urine cultures of all women presenting with urinary tract infections in general practice were analysed. Resistance rates against antibiotics recommended in German guidelines on UTI are presented. Methods In a prospective, multi-center observational study general practitioner included all female patients???18 years with clinically suspected urinary tract infection. Only patients receiving an antibiotic therapy within the last two weeks were excluded. Results 40 practices recruited 191 female patients (mean age 52 years; range 18–96) with urinary tract infections. Main causative agent was Escherichia coli (79%) followed by Enterococcus faecalis (14%) and Klebsiella pneumoniae (7.3%). Susceptibiliy of E.coli as the main causative agent was highest against fosfomycin and nitrofurantoin, with low resistance rates of 4,5%; 2,2%. In 17,5%, E.coli was resistant to trimethoprim and in 8,5% to ciprofloxacin. Conclusions Resistance rates of uropathogens from unselected patients in general practice differ from routinely collected laboratory data. These results can have an impact on antibiotic prescribing and treatment recommendations.

2012-01-01

401

Recurring mass movements on the Danube's bank at Dunaszekcs? (Hungary) observed by geodetic methods  

NASA Astrophysics Data System (ADS)

In September 2007 a geodetic network based on GPS measurements, precise levelling and continuous borehole tilt measurements was established for surface displacement monitoring on the high bank of the River Danube at Dunaszekcs? where a serious landslide began to develop at that time. The landslide took place on February 12, 2008. After rapid, enormous movements, which resulted in significant subsidence (8-10 m) and lateral displacements (4-5 m) on the high bank at Dunaszekcs? and the emergence of a peninsula consisting of clastic material in the Danube's bed, the deformation rates significantly dropped. This observation was explained by the secondary metastable equilibrium of the moving blocks at that time. However, our subsequent geodetic data clearly showed that slow post-event movements (mainly subsidence, 0.5-1.0 cm/month) on both the northern and southern sliding blocks have been occurring for the last two years, which means that the sliding blocks did not reach an equilibrium in the mentioned period. At the same time, measurements on our extended geodetic network in the second half of 2010 referred to a possible southward spread of sliding (southern part of the Vár Hill) in the near future. Later on (spring 2011), field observations were also indicative of the initiation of movements on the southern part of the Vár Hill as predicted by the geodetic measurements. The areal extent of the block becoming unstable closely corresponds with the danger zone assigned by GPS observations.

Mentes, Gyula; Bányai, László; Újvári, Gábor; Papp, Gábor; Gribovszki, Katalin; Bódis, Virág Bereniké

2012-11-01

402

Homeopathic treatment of patients with dysmenorrhea: a prospective observational study with 2 years follow-up  

Microsoft Academic Search

Purpose  Evaluating homeopathic treatment for dysmenorrhea.\\u000a \\u000a \\u000a \\u000a Methods  Prospective multicenter observational study in primary care, using standardized questionnaires to record for 2 years diseases,\\u000a quality of life, medical history, consultations, all treatments, other health services use.\\u000a \\u000a \\u000a \\u000a Results  Fifty-seven physicians treated 128 women (age 32.4 ± 7.5 years, mean ± SD) and 11 girls (13.7 ± 4.0). Women had dysmenorrhea\\u000a for 11.6 ± 9.0 (girls 3.1 ± 1.5) years. Patients received 7.5 ± 6.5 (5.9 ± 3.7) homeopathic prescriptions. Diagnoses and

Claudia M. Witt; Rainer Lüdtke; Stefan N. Willich

2009-01-01

403

Study on the methods of financial supervision  

Microsoft Academic Search

In this paper, I am delighted to address the topic of methods to regulating financial institutions. Given the current level of global financial upset, which can be traced in part to poor banking regulation in many countries, I think that no subject is more timely. In this paper, I focus on two topics: First, what are the respective roles of

Xiaoyu Zhang

2009-01-01

404

Healthy User and Related Biases in Observational Studies of Preventive Interventions: A Primer for Physicians  

Microsoft Academic Search

The current emphasis on comparative effectiveness research will provide practicing physicians with increasing volumes of observational\\u000a evidence about preventive care. However, numerous highly publicized observational studies of the effect of prevention on health\\u000a outcomes have reported exaggerated relationships that were later contradicted by randomized controlled trials. A growing body\\u000a of research has identified sources of bias in observational studies that

William H. Shrank; Amanda R. Patrick; M. Alan Brookhart

2011-01-01

405

Improvement of staining method for observation of mitotic chromosomes in octoploid strawberry plants  

Microsoft Academic Search

An important strategy to conduct intentional breeding of octoploid strawberry plants is to recognize the functions of every chromosome. To do so, a methodology must be developed to distinguish chromosomes one by one. We reported the possibility of distinguishing chromosomes using light microscopy when somatic cells of octoploid strawberry plants were stained using ordinary methods with lacto-propionic orcein (LPO). However,

Preeda Nathewet; Tomohiro Yanagi; Yoshikane Iwastubo; Kazuyoshi Sone; Takejiro Takamura; Nobuyuki Okuda

2009-01-01

406

An Optically Efficient Method for observing Single Plant Cells from Shake Cultures during Growth and Division  

Microsoft Academic Search

THE ease with which the individual cells of callus cultures of tissues of higher plants separate from each other has led to several successful methods of growing them singly. Muir, Hildebrandt and Riker1 grew a single crown-gall callus cell on a piece of filter paper over a large callus of the same strain. Torrey2 placed many separate cells around a

Ernest Ball

1963-01-01

407

Contingency Space Analysis: An Alternative Method for Identifying Contingent Relations from Observational Data  

ERIC Educational Resources Information Center

Descriptive assessment methods have been used in applied settings to identify consequences for problem behavior, thereby aiding in the design of effective treatment programs. Consensus has not been reached, however, regarding the types of data or analytic strategies that are most useful for describing behavior-consequence relations. One promising…

Martens, Brian K.; DiGennaro, Florence D.; Reed, Derek D.; Szczech, Frances M.; Rosenthal, Blair D.

2008-01-01

408

Methods for attitude guidance and precise robust gyromoment control of large-scale agile observation spacecraft  

NASA Astrophysics Data System (ADS)

Problems on guidance and robust gyromoment attitude control of agile information satellite for remote sensing the Earth surface are considered. Elaborated methods for dynamic research of the spacecraft programmed angular motion at principle modes under external and parametric disturbances, partial discrete measurement of the state and digital control of the gyro moment cluster by the excessive gyrodine schemes, are presented.

Somov, Sergey; Butyrin, Sergey; Somov, Yevgeny

2012-11-01

409

Contingency Space Analysis: An Alternative Method for Identifying Contingent Relations from Observational Data  

ERIC Educational Resources Information Center

|Descriptive assessment methods have been used in applied settings to identify consequences for problem behavior, thereby aiding in the design of effective treatment programs. Consensus has not been reached, however, regarding the types of data or analytic strategies that are most useful for describing behavior-consequence relations. One promising…

Martens, Brian K.; DiGennaro, Florence D.; Reed, Derek D.; Szczech, Frances M.; Rosenthal, Blair D.

2008-01-01

410

Separating root and soil microbial contributions to soil respiration: A review of methods and observations  

Microsoft Academic Search

Forest soil respiration is the sum of heterotrophic (microbes, soil fauna) and autotrophic (root) respiration. The contribution of each group needs to be understood to evaluate implications of environmental change on soil carbon cycling and sequestration. Three primary methods have been used to distinguish hetero- versus autotrophic soil respiration including: integration of components contributing to in situ forest soil CO2

P. J. Hanson; N. T. Edwards; C. T. Garten; J. A. Andrews

2000-01-01

411

Academic success or failure in nursing students: Results of a retrospective observational study.  

PubMed

BACKGROUND: Nursing student academic failure is a phenomenon of growing international interest, not only because of its economic impact but also because it negatively affects the availability of future nurses in different healthcare systems. To recruit the students with the highest probability of academic success, an open challenge for universities is to recruit students who have previously demonstrated superior scholastic aptitudes that appear to be associated with a greater likelihood of academic success. Documenting the relationship between the selection methods used when selecting nursing students and academic failure will contribute to the international debate concerning the optimisation of the selection strategies. OBJECTIVES: The principal aim of this study was to investigate the role in predicting nursing student academic success of (1) the upper-secondary diploma grades and (2) the score obtained by students in the nursing degree program admission test. DESIGN: A retrospective observational study was conducted. PARTICIPANTS AND METHODS: Five cohorts of nursing students, matriculated in consecutive academic years from 2004 to 2008, in an Italian bachelor's degree program were observed retrospectively. RESULTS: Overall, 61.2% of the 1006 considered students concluded their degree within the legal duration allowed for the nursing degree. Students who failed were those who had lowest grades associated with their upper-secondary diploma coursework (p=0.000) and were male (p=0.000). The grades associated with the upper-secondary diploma coursework, unlike the admission test score, correlates positively with the final degree grade and the average value of degree program examination scores. No correlation was found between the upper-secondary diploma coursework grades and the scores obtained in the test for the nursing degree program admission test (r=-0.037). CONCLUSIONS: These results suggest that upper-secondary diploma coursework grades are a parameter that should receive great consideration, especially in cases where there are planned numbers of incoming nursing degree students. PMID:23706940

Lancia, Loreto; Petrucci, Cristina; Giorgi, Fabio; Dante, Angelo; Cifone, Maria Grazia

2013-05-22

412

New method for deriving total ozone from Brewer zenith sky observations  

NASA Astrophysics Data System (ADS)

The Brewer spectrophotometer derives total column ozone from UV measurements using two operational modes: observing either direct sunlight (DS) or zenith sky (ZS) scattered sunlight. While DS measurements are more accurate, ZS measurements are necessary for generating long-term ozone time series unbiased by meteorological conditions and for the validation of satellite algorithms for cloudy scenes. In the ZS mode, column ozone (X) is obtained using the slant path (?) and a weighted sum of the logarithms of the ZS intensities (F). Prior to this, however, a set of nine empirical coefficients, specific to each instrument, must be derived that relate ? and X to F. This requires a large set of near-simultaneous ZS and DS measurements that span the operational range of X and ?, which is difficult to obtain. In this work, a modified algorithm is presented in which radiative transfer model simulations of ZS observations are used to derive generic coefficients that describe the sky response to different observing conditions. Instrument-specific coefficients are obtained through a simple scaling and offset of these generic values, derived through ZS-DS comparisons. These two parameters may be accurately determined in a relatively short period of time and using a much more limited data set, such as during regular instrument calibrations. Since the new algorithm provides nine coefficients, no changes to the existing Brewer software are required. It is demonstrated that the new algorithm is as useful as the standard Brewer ZS algorithm with nine empirically estimated parameters derived using a vastly more extensive data set.

Fioletov, V. E.; McLinden, C. A.; McElroy, C. T.; Savastiouk, V.

2011-04-01