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Correct Interpretation (correct + interpretation)

Distribution by Scientific Domains

Medical Sciences	35%
Life Sciences	21%
Chemistry	14%
Earth and Environmental Science	10%
5 Other Domains	20%

Selected Abstracts

CHARNIA AT 50: DEVELOPMENTAL MODELS FOR EDIACARAN FRONDS

PALAEONTOLOGY, Issue 1 2008
JONATHAN B. ANTCLIFFE
Abstract:, Correct interpretation of the Ediacara biota is critical to our understanding of the dramatic events at the base of the Cambrian. We review here the history of thought and examine new laser images of the holotype of Charnia masoniFord, 1958, of the Ediacara biota, in terms of growth and development. Growth and development are argued to provide critical tools for understanding this and other enigmatic fossil groups. We show that Charnia cannot be related to the modern cnidarian group, the sea pens, with which it has for so long been compared, because they have opposite growth polarities. This is shown by our work on material collected by HMS challenger. Recent evolutionary studies also show that sea pens are a highly derived group of actively burrowing cnidarians that are likely to have evolved later than the Palaeozoic. The traditional paradigm of translating Phanerozoic animal phyla back into the Ediacaran is therefore questioned. [source]

Guidelines for the descriptive presentation and statistical analysis of contact allergy data

CONTACT DERMATITIS, Issue 2 2004
Wolfgang Uter
The present guidelines aim to support clinical researchers in adequately presenting data on contact allergy, and to use statistical tests appropriate for their data. A description of the mode of selection of patients, and of their relevant demographic details, is an essential prerequisite for the correct interpretation of study results. Proportions and rates, if regarded as estimate of these parameters of a target populations, should normally be supplemented with confidence intervals to address precision. Concordance, i.e., agreement between two ratings in a dependent sample, must be quantified with a chance-corrected measure such as Cohen's kappa coefficient. If the diagnostic quality of an outcome is being assessed, standard measures like sensitivity and specificity, as well as the prevalence-dependent positive and negative predictive values should be calculated. Often, contact allergy to a certain substance depends on several factors. In this situation, depending on the research question, techniques like stratification, standardization or multifactorial analysis should be employed. With increasing complexity of statistical description and analysis, consulting with a biostatistician is often mandatory. [source]

Electrocardiogram Differentiation of Benign Early Repolarization Versus Acute Myocardial Infarction by Emergency Physicians and Cardiologists

ACADEMIC EMERGENCY MEDICINE, Issue 9 2006
Samuel D. Turnipseed MD
Abstract Objectives: ST-segment elevation (STE) related to benign early repolarization (BER), a common normal variant, can be difficult to distinguish from acute myocardial infarction (AMI). The authors compared the electrocardiogram (ECG) interpretations of these two entities by emergency physicians (EPs) and cardiologists. Methods: Twenty-five cases (13 BER, 12 AMI) of patients presenting to the emergency department with chest pain were identified. Criteria for BER required four of the following: 1) widespread STE (precordial greater than limb leads), 2) J-point elevation, 3) concavity of initial up-sloping portion of ST segment, 4) notching or irregular contour of J point, and 5) prominent, concordant T waves. Additional BER criteria were 1) stable ECG pattern, 2) negative cardiac injury markers, and 3) normal cardiac stress test or angiography. AMI criteria were 1) regional STE, 2) positive cardiac injury markers, and 3) identification of culprit coronary artery by angiography in less than eight hours of presentation. The 25 ECGs were distributed to 12 EPs and 12 cardiologists (four in academic medicine, four in community practice, and four in community academics [health maintenance organization] in each physician group). The physicians were informed of the patients' age, gender, and race, and they then interpreted the ECGs as BER or AMI. Undercalls (AMI misdiagnosed as BER) and overcalls (BER misdiagnosed as AMI) were calculated for each physician group. Results: Cardiologists correctly interpreted 90% of ECGs, and EPs correctly interpreted 81% of ECGs. The proportion of undercalls (missed AMI/total AMI) was 2.8% for cardiologists (95% confidence interval [CI] = 0.09% to 5.5%) compared with 9.7% for EPs (95% CI = 4.8% to 14.6%) (p = 0.02). The proportion of overcalls (missed BER/total BER) was 17.3% for cardiologists (95% CI = 11.4% to 23.3%) versus 27.6% for EPs (95% CI = 20.6% to 34.6%) (p = 0.03). The mean number of years in practice was 19.8 for cardiologists (95% CI = 19 to 20.5) and 11 years for EPs (95% CI = 10.5 to 12.0) (p < 0.001). Conclusions: Although correct interpretation was high in both groups, cardiologists, who had significantly more years of practice, had fewer misinterpretations than EPs in distinguishing BER from AMI electrocardiographically. [source]

Fine-needle aspiration of soft tissue leiomyosarcoma: An analysis of the most common cytologic findings and the value of ancillary techniques

DIAGNOSTIC CYTOPATHOLOGY, Issue 9 2006
Henryk A. Domanski M.D., Ph.D.
Abstract This study aims to determine the diagnostic accuracy of fine-needle aspiration cytology (FNAC) of primary leiomyosarcoma (LMS) of soft tissue and to review diagnostic criteria and adjunctive methods, which can contribute to a confident diagnosis. We evaluated the preoperative FNAC in 89 patients with primary LMS for the following: cytomorphology and correspondence of FNA to histological features of excised tumors and clinical data. In addition, the utility of adjunctive techniques was analyzed and other spindle-cell lesions in the differential diagnoses were discussed. An unequivocal, malignant diagnosis was rendered by FNAC in 78 cases; 74 tumors were diagnosed as sarcoma, of which 31 as LMS or suspicion of LMS. In addition, three smears were labeled as malignant tumor, one as carcinoma metastasis, and three as neurilemmoma. Seven aspirates were inconclusive and one insufficient. On reevaluation, the diagnostic smears in most cases contained tumor cell fascicles with an admixture of dispersed cells or stripped nuclei. The most common cells were spindle cells with elongated, blunt-ended, segmented or fusiform nuclei, and round/polygonal cells, often with rounded or indented nuclei. In addition, 51 cases showed pleomorphic, often multinucleated cells. Osteoclasts, intranuclear vacuoles, and mitoses occurred in 14, 47, and 27 cases, respectively. Thus, most high-grade LMSs have cytologic features that allow diagnosis of sarcoma. Ancillary studies can confirm the diagnosis of LMS and help in the correct interpretation of predominant spindle-cell or epitheloid-cell smears resembling neurilemoma or carcinoma, respectively. Diagn. Cytopathol. 2006;34:597,604. © 2006 Wiley,Liss, Inc. [source]

Normative data of bone mineral density in an unselected adult Austrian population

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 4 2003
S. Kudlacek
Abstract Background There is increasing evidence that correct interpretation of bone mineral density (BMD) measurements by dual energy X-ray absorptiometry (DEXA) requires a population-specific reference range. We therefore collected data on age-related BMD in a random sample of the normal adult Austrian population to establish an appropriate normative database. Methods We measured BMD by DEXA at five different skeletal sites in 1089 subjects, i.e. 654 females and 435 males, aged between 21,76 years, who had been recruited by 17 centres across Austria. Results Age-related bone loss was observed until age 65 years with significant changes at the lumbar spine (r = ,0·23), total hip (r = ,0·07), trochanter (r = ,0·10), femoral neck (r = ,0·30) and Ward's triangle (r = ,0·40) in the women but only at the femoral neck (r = ,0·23) and at Ward's triangle (r = ,0·40) in the men. When we calculated T scores from the BMD data of the young normal adult study population and used the T score set points according to the WHO classification of osteopenia and osteoporosis, we found that, depending on the skeletal site measured, 7·6,27·4% of the women and 16,41% of the men in our study group had low bone mass, whereas 0·6,2·7% of the female and 0·2,1·0% of the male study population were osteoporotic. However, osteoporosis was indicated in 4,9-fold more females and 5,15-fold more males when we based our estimates on the normative data provided by the manufacturers of the DEXA systems. Conclusion Our data underscore the importance of using a population-specific reference range for DEXA measurements to avoid overdiagnosis of osteoporosis. [source]

Electrocardiographic ST-segment Elevation: Correct Identification of Acute Myocardial Infarction (AMI) and Non-AMI Syndromes by Emergency Physicians

ACADEMIC EMERGENCY MEDICINE, Issue 4 2001
William J. Brady MD
Abstract. Objective: To determine the emergency physician's (EP's) ability to identify the cause of ST-segment elevation (STE) in a hypothetical chest pain patient. Methods: Eleven electrocardiograms (ECGs) with STE were given to EPs; the patient in each instance was a 45-year-old male with a medical history of hypertension and diabetes mellitus with the chief complaint of chest pain. The EP was asked to determine the cause of the STE and, if due to acute myocardial infarction (AMI), to decide whether thrombolytic therapy (TT) would be administered (the patient had no contraindication to such treatment). Rates of TT administration were determined; appropriate TT administration was defined as that occurring in an AMI patient, while inappropriate TT administration was defined as that in the non-AMI patient. Results: Four hundred fifty-eight EPs completed the questionnaire; levels of medical experience included the following: postgraduate year 2-3, 193 (42%); and attending, 265 (58%). The overall rate of correct interpretation of the study ECGs was 94.9% (4,782 correct interpretations out of 5,038 instances). Acute myocardial infarction with typical STE, ventricular paced rhythm, and right bundle branch block were never misinterpreted. The remaining conditions were misinterpreted with rates ranging between 9% (left bundle branch block, LBBB) and 72% (left ventricular aneurysm, LVA). The overall rate of appropriate thrombolytic agent administration was 83% (1,525 correct administrations out of 1,832 indicated administrations). The leading diagnosis for which thrombolytic agent was given inappropriately was LVA (28%), followed by benign early repolarization (23%), pericarditis (21%), and LBBB without electrocardiographic AMI (5%). Thrombolytic agent was appropriately given in all cases of AMI except when associated with atypical STE, where it was inappropriately withheld 67% of the time. Conclusions: In this survey, EPs were asked whether they would give TT based on limited information (ECG). Certain syndromes with STE were frequently misdiagnosed. Emergency physician electrocardiographic education must focus on the proper identification of these syndromes so that TT may be appropriately utilized. [source]

Viscoelastic displacement and gravity changes due to point magmatic intrusions in a gravitational layered solid earth

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2001
José Fernández
Summary We present a method for the computation of time-dependent geodetic and geophysical signatures (deformation, potential and gravity changes) due to magmatic intrusions in a layered viscoelastic,gravitational medium. This work is an extension of a deformation model previously developed to compute effects due to volcanic loading in an elastic gravitational layered media. The model assumes a planar earth geometry, useful for near field problems, and consists of welded elastic and viscoelastic layers overlying a viscoelastic half-space. Every layer can either be considered elastic or viscoelastic. The intrusion (treated as a point source) can be located at any depth, in any of the layers or in the half-space. Several examples of theoretical computations for different media are also presented. We have found that, in line with previous results obtained by other authors, introducing viscoelastic properties in all or part of the medium can extend the effects (displacements, gravity changes, etc.) considerably and therefore lower pressure increases are required to model given observed effects. The viscoelastic effects seem to depend mainly on the rheological properties of the layer (zone) where the intrusion is located, rather than on the rheology of the whole medium. We apply our model to the 1982,1984 uplift episode at Campi Flegrei, modelling simultaneously the observed vertical displacement and gravity changes. The results clearly show that for a correct interpretation of observed effects it is necessary to include the gravitational field in the anelastic theoretical models. This factor can change the value and pattern of time-dependent deformation as well as the gravity changes, explaining cases of displacement without noticeable gravity changes or vice versa, cases with uplift and incremental gravity values, and other cases. The combination of displacement and gravity changes is found to be especially effective in constraining the possible characteristics of the magmatic intrusion as well as the rheology of the medium surrounding it. [source]

Multichannel surface electromyography in ergonomics: Potentialities and limits

HUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 4 2010
Marco Gazzoni
Abstract The prevention of work-related musculoskeletal disorders is one of the main goals in ergonomics. Among others, surface electromyography (sEMG) is an important tool for the evaluation of risks related to work activity. Three main issues have been approached in ergonomics via sEMG: 1) the analysis of muscle activation, 2) the analysis of exerted forces and torques, and 3) the analysis of muscle fatigue. Many studies have been carried out in static conditions. In ergonomics, however, it is more relevant to study muscle activity and fatigue during real tasks that are, in general, dynamic. From isometric to dynamic contractions, the complexity of the interpretation of sEMG signals increases considerably. Changes in sEMG signals are related to the continuous modifications in force output, muscle fiber length, and relative position of surface electrodes and sources. To increase the reliability of the information extracted from sEMG, multichannel detection systems have been applied, showing the possibility of overcoming some limits of the standard technique. Some illustrative laboratory and field studies are reported in this work to illustrate the potentialities and the open problems in the use of multichannel sEMG in ergonomics. Case 1 is a laboratory study investigating the myoelectric manifestations of fatigue in the biceps brachii (BB) during dynamic elbow flexion/extension. Case 2 is a laboratory study investigating the myoelectric manifestations of fatigue during a repetitive lifting task. Case 3 is a field study, carried out in an automotive plant, investigating muscle activation during the welding of a car door. Many factors play a leading role in the correct interpretation of information provided by sEMG. Even though multichannel sEMG provides information able to improve the estimation of force and/or fatigue during working tasks, many problems related to the signal acquisition and interpretation are still open. Further improvements are necessary to develop multichannel sEMG into an effective tool supporting other methodologies for the evaluation of work-related risks. © 2010 Wiley Periodicals, Inc. [source]

Maternal sensitivity in interactions with three- and 12-month-old infants: Stability, structural composition, and developmental consequences

INFANT AND CHILD DEVELOPMENT, Issue 3 2004
Arnold Lohaus
This study addresses three topics related to the structural components of maternal sensitivity: (a) The stability of sensitivity over a nine-month period, (b) the predictability of maternal sensitivity assessed at 12 months from early parameters of parenting and (c) the relation between maternal sensitivity and developmental outcomes assessed at 12 months. Maternal sensitivity and its components (signal perception, correct interpretation, prompt, and appropriate reaction) were evaluated for 60 mother,infant-dyads when their infants were aged three and 12 months. Additional parameters of early parenting were maternal emotional warmth and behavioural contingency. Developmental outcome measures were the amount of infant crying and the quality of attachment at twelve months. The results showed close correlations between the sensitivity components suggesting a unidimensional structure for maternal sensitivity. The sensitivity assessments were significantly related to measures of maternal warmth. Stability of maternal sensitivity over time was, however, quite low. There was no relation between the early sensitivity assessments and later developmental outcomes, whereas there was a significant relation between the sensitivity parameters assessed at twelve months and developmental outcomes. The results indicate changes in the meaning of maternal sensitivity during infants' development. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Limitations of previously published systematic reviews evaluating the outcome of endodontic treatment

INTERNATIONAL ENDODONTIC JOURNAL, Issue 8 2009
M-K. Wu
Abstract The aim of this work was to identify the limitations of previously published systematic reviews evaluating the outcome of root canal treatment. Traditionally, periapical radiography has been used to assess the outcome of root canal treatment with the absence of a periapical radiolucency being considered a confirmation of a healthy periapex. However, a high percentage of cases confirmed as healthy by radiographs revealed apical periodontitis on cone beam computed tomography (CBCT) and by histology. In teeth, where reduced size of the existing radiolucency was diagnosed by radiographs and considered to represent periapical healing, enlargement of the lesion was frequently confirmed by CBCT. In clinical studies, two additional factors may have further contributed to the overestimation of successful outcomes after root canal treatment: (i) extractions and re-treatments were rarely recorded as failures; and (ii) the recall rate was often lower than 50%. The periapical index (PAI), frequently used for determination of success, was based on radiographic and histological findings in the periapical region of maxillary incisors. The validity of using PAI for all tooth positions might be questionable, as the thickness of the cortical bone and the position of the root tip in relation with the cortex vary with tooth position. In conclusion, the serious limitations of longitudinal clinical studies restrict the correct interpretation of root canal treatment outcomes. Systematic reviews reporting the success rates of root canal treatment without referring to these limitations may mislead readers. The outcomes of root canal treatment should be re-evaluated in long-term longitudinal studies using CBCT and stricter evaluation criteria. [source]

The potential for non-invasive study of mummies: validation of the use of computerized tomography by post factum dissection and histological examination of a 17th century female Korean mummy

JOURNAL OF ANATOMY, Issue 4 2008
Do-Seon Lim
Abstract The socio-cultural antipathies of some descendants with regard to invasive examinations of age-old human remains make permission for dissection of Korean mummies of the Joseon Dynasty (1392,1910) difficult to obtain. Overcoming this obstacle necessitated the use of non-invasive techniques, such as multi-detector computerized tomography (MDCT) and endoscopic examination, enabling determination of the preservation status of internal organs of mummies without significantly damaging the mummies themselves. However, MDCT alone cannot clearly differentiate specific mummified organs. Therefore, in much the same way as diagnostic radiologists make their MDCT readings on living patients more reliable by means of comparison with accumulated post-factum data from autopsies or histological studies, examinations of mummies by invasive techniques should not be decried as mere destruction of age-old human remains. Rather, providing that due permission from descendants and/or other relevant authorities can be obtained, dissection and histological examination should be performed whenever opportunities arise. Therefore, in this study, we compared the radiological data acquired from a 17th century mummy with our dissection results for the same subject. As accumulation of this kind of data could be very crucial for correct interpretation of MDCT findings on Korean mummies, we will perform similar trials on other Korean mummies found in forthcoming days if conditions permit. [source]

X-ray extinction changes due to dislocations

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2007
M. Masimov
A correct interpretation of the diffraction phenomenon in crystals with low dislocation content, for which the kinematical scattering theory does not yield any reasonable results, was carried out by X-ray extinction treatments. Different approaches to investigating the dislocation-induced X-ray extinction changes are reviewed and the applicability of the statistical dynamical theory to analysis of the substructure characteristics of crystals is discussed. A relationship between the scattering amplitudes and the dislocation density in crystals is established by using pair correlation functions. A procedure for determination of the substructure characteristics by means of measurements of the integrated intensities is proposed. The tests illustrate satisfactory agreement of the investigated approaches with experimental data. [source]

Asymmetrical flow field-flow fractionation coupled to multiangle laser light scattering detector: Optimization of crossflow rate, carrier characteristics, and injected mass in alginate separation

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2007
Enrica Alasonati
Abstract The coupling of the flow field-flow fractionation (FlFFF) to differential refractive index (DRI) and multiangle laser light scattering (LS) detectors is a powerful tool for characterizing charged polysaccharides such as alginate. However, the correct interpretation of the experimental results and extrapolation of meaningful molecular parameters by using an analytical tool with such a level of complexity requires improvement of the knowledge of the alginate behavior in the channel and careful optimization of the operating conditions. Therefore, the influence of the critical operating parameters, such as crossflow rate, carrier composition and concentration, and sample load, on the alginate retention was carefully evaluated. Combined information obtained simultaneously by DRI and LS detectors over the wide range of the crossflow rate, carrier liquid concentration, and injected amount, allowed to set the appropriate combination of optimal parameters. It was found that the crossflow rate of 0.25 mL/min, carrier solution containing 5×10,2 mol/L ammonium or sodium chloride, and 50,100 ,g of injected sample mass were necessary to achieve complete separation and determination of the meaningful molecular characteristics. The values of the weight-average hydrodynamic radius (RHw), radius of gyration (RG), and molar mass (M), obtained under the optimal conditions were in good agreement to those found for alginates in the literature. [source]

A query language for discovering semantic associations, Part II: sample queries and query evaluation

JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 11 2007
Timo Niemi
In our query language introduced in Part I (Niemi & Jämsen, in press) the user can formulate queries to find out (possibly complex) semantic relationships among entities. In this article we demonstrate the usage of our query language and discuss the new applications that it supports. We categorize several query types and give sample queries. The query types are categorized based on whether the entities specified in a query are known or unknown to the user in advance, and whether text information in documents is utilized. Natural language is used to represent the results of queries in order to facilitate correct interpretation by the user. We discuss briefly the issues related to the prototype implementation of the query language and show that an independent operation like Rho (Sheth et al., 2005; Anyanwu & Sheth, 2002, 2003), which presupposes entities of interest to be known in advance, is exceedingly inefficient in emulating the behavior of our query language. The discussion also covers potential problems, and challenges for future work. [source]

Insulin resistance is a major determinant of liver stiffness in nondiabetic patients with HCV genotype 1 chronic hepatitis

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2009
S. PETTA
Summary Background, In patients with chronic hepatitis C (CHC), liver stiffness measurement (LSM) by transient elastography (TE), is closely related to the stage of fibrosis, but may be affected by necroinflammation. Other factors, such as insulin resistance (IR), might influence the performance of LSM. Aims, To evaluate in a cohort of nondiabetic patients with genotype 1 CHC, whether IR and other anthropometric, biochemical, metabolic and histological factors contribute to LSM and to identify the best cut-off values of LSM for predicting different stages of fibrosis. Methods, Nondiabetic patients with genotype 1 CHC (n = 156) were evaluated by liver biopsy (Metavir score), anthropometric, biochemical and metabolic features including IR. Furthermore, all subjects underwent LSM by TE. Results, Severe fibrosis (F3,F4) was associated with LSM (OR 1.291; 95%CI 1.106,1.508). LSM was also independently correlated with low platelets (P = 0.03), high ,GT (P < 0.001) and high HOMA (P = 0.004) levels. A stiffness value ,8 KPa was identified as the best cut-off for predicting severe fibrosis (AUC 0.870); yet this cut-off still failed to rule out F3,F4 fibrosis in 22.7% of patients (false-negative rate) or rule in F3,F4 in 19.6% (false-positive rate). Platelets <200 × 103/mmc and a HOMA of >2.7 were the major determinants of these diagnostic errors in predicting severe fibrosis. Conclusions, In nondiabetic patients with genotype 1 CHC, insulin resistance, ,GT and platelet levels contribute to LSM independently of liver fibrosis. The identification of these three factors contributes to a more correct interpretation of LSM. [source]

Forecast verification: current status and future directions

METEOROLOGICAL APPLICATIONS, Issue 1 2008
Dr B. Casati
Abstract Research and development of new verification strategies and reassessment of traditional forecast verification methods has received a great deal of attention from the scientific community in the last decade. This scientific effort has arisen from the need to respond to changes encompassing several aspects of the verification process, such as the evolution of forecasting systems, or the desire for more meaningful verification approaches that address specific forecast user requirements. Verification techniques that account for the spatial structure and the presence of features in forecast fields, and which are designed specifically for high-resolution forecasts have been developed. The advent of ensemble forecasts has motivated the re-evaluation of some of the traditional scores and the development of new verification methods for probability forecasts. The expected climatological increase of extreme events and their potential socio-economical impacts have revitalized research studies addressing the challenges concerning extreme event verification. Verification issues encountered in the operational forecasting environment have been widely discussed, verification needs for different user communities have been identified, and models to assess the forecast value for specific users have been proposed. Proper verification practice and correct interpretation of verification statistics has been extensively promoted with recent publications and books, tutorials and workshops, and the development of open-source software and verification tools. This paper addresses some of the current issues in forecast verification, reviews some of the most recently developed verification techniques, and provides recommendations for future research. Copyright © 2008 Royal Meteorological Society and Crown in the right of Canada. [source]

Movement patterns and study area boundaries: influences on survival estimation in capture,mark,recapture studies

OIKOS, Issue 8 2008
Gregg E. Horton
The inability to account for the availability of individuals in the study area during capture,mark,recapture (CMR) studies and the resultant confounding of parameter estimates can make correct interpretation of CMR model parameter estimates difficult. Although important advances based on the Cormack,Jolly,Seber (CJS) model have resulted in estimators of true survival that work by unconfounding either death or recapture probability from availability for capture in the study area, these methods rely on the researcher's ability to select a method that is correctly matched to emigration patterns in the population. If incorrect assumptions regarding site fidelity (non-movement) are made, it may be difficult or impossible as well as costly to change the study design once the incorrect assumption is discovered. Subtleties in characteristics of movement (e.g. life history-dependent emigration, nomads vs territory holders) can lead to mixtures in the probability of being available for capture among members of the same population. The result of these mixtures may be only a partial unconfounding of emigration from other CMR model parameters. Biologically-based differences in individual movement can combine with constraints on study design to further complicate the problem. Because of the intricacies of movement and its interaction with other parameters in CMR models, quantification of and solutions to these problems are needed. Based on our work with stream-dwelling populations of Atlantic salmon Salmo salar, we used a simulation approach to evaluate existing CMR models under various mixtures of movement probabilities. The Barker joint data model provided unbiased estimates of true survival under all conditions tested. The CJS and robust design models provided similarly unbiased estimates of true survival but only when emigration information could be incorporated directly into individual encounter histories. For the robust design model, Markovian emigration (future availability for capture depends on an individual's current location) was a difficult emigration pattern to detect unless survival and especially recapture probability were high. Additionally, when local movement was high relative to study area boundaries and movement became more diffuse (e.g. a random walk), local movement and permanent emigration were difficult to distinguish and had consequences for correctly interpreting the survival parameter being estimated (apparent survival vs true survival). [source]

Mechano-Chemical Changes of Nano Sized ,-Al2O3 During Wet Dispersion in Stirred Ball Mills

PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 1 2004
Frank Stenger
Abstract The mechano-chemical changes in synthetic ,-Al2O3 during wet dispersion in a stirred ball mill, are studied. It is shown that a second phase is generated which can be identified as an aluminum hydroxide (Bayerite) by use of dynamic scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetry (TG), Fourier transformed infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). The amount of the Bayerite phase produced increases with milling time. A comparison of the evaluated amounts from TG- and DSC-measurements are in reasonable agreement. Furthermore, the measured BET surface area shows a strong dependence on the temperature of sample preparation. Depending on the temperature, the bayerite phase is seen to convert to the ,-phase again and also forms meso- and possibly micro-pores, leading to a high BET surface area. In this paper, we highlight the necessity for using different methods to characterize the dispersion process, and for a correct interpretation of the measurement results. [source]

Experimentally generated footprints in sand: Analysis and consequences for the interpretation of fossil and forensic footprints

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010
K. D'Août
Abstract Fossilized footprints contain information about the dynamics of gait, but their interpretation is difficult, as they are the combined result of foot anatomy, gait dynamics, and substrate properties. We explore how footprints are generated in modern humans. Sixteen healthy subjects walked on a solid surface and in a layer of fine-grained sand. In each condition, 3D kinematics of the leg and foot were analyzed for three trials at preferred speed, using an infrared camera system. Additionally, calibrated plantar pressures were recorded. After each trial in sand, the depth of the imprint was measured under specific sites. When walking in sand, subjects showed greater toe clearance during swing and a 7° higher knee yield during stance. Maximal pressure was the most influential factor for footprint depth under the heel. For other foot zones, a combination of factors correlates with imprint depth, with pressure impulse (the pressure-time integral) gaining importance distally, at the metatarsal heads and the hallux. We conclude that footprint topology cannot be related to a single variable, but that different zones of the footprint reflect different aspects of the kinesiology of walking. Therefore, an integrated approach, combining anatomical, kinesiological, and substrate-mechanical insights, is necessary for a correct interpretation. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source]

Determination of urinary S -phenylmercapturic acid, a specific metabolite of benzene, by liquid chromatography/single quadrupole mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2005
Luciano Maestri
A high-performance liquid chromatography/single quadrupole mass spectrometry (LC/MS) method is described for the determination of urinary S -phenylmercapturic acid (S-PMA), a specific metabolite of benzene. Urine samples were spiked with [13C6]S-PMA (used as the internal standard) and acidified; then they were purified by solid-phase extraction (SPE) on C18 cartridges. Analyses were conducted on a reversed-phase column by gradient runs with 1% aqueous acetic acid/methanol mixtures at different proportions as the mobile phase. The detector was used in electrospray negative ion mode (ESI,), the ions m/z 238 for S-PMA and 244 for [13C6]S-PMA being recorded simultaneously. The detection limit (for a signal-to-noise ratio,=,3) was 0.2,,g/L, thus allowing for the measurement of background excretion of S-PMA in the general population. The use of the internal standard allowed us to obtain good precision (CV% values <3%) and a linear calibration curve within the range of interest for monitoring occupational exposure to benzene (up to 500,,g/L). The method was applied to assay the metabolite concentration in a group of 299 workers (68 smokers and 231 non-smokers) occupationally exposed to relatively low levels of benzene (environmental concentration,=,0.4,220,,g/m3, mean 11.4,,g/m3) and 236 non-exposed subjects (134 smokers and 102 non-smokers). The results clearly showed that smoking must be taken into account for the correct interpretation of the results of S-PMA measurements for the assessment of work-related benzene exposure. When only non-smokers were selected, the mean excretion of S-PMA was significantly higher in workers exposed to benzene (1.2,±,0.9,,g/g creatinine) than in the control group (0.7,±,0.6,,g/g creatinine) (p,<,0.001), thus confirming the role of S-PMA as a biomarker of benzene on a group basis, even for relatively low exposure degrees. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Intra- and Interannual Vegetation Change: Implications for Long-Term Research

RESTORATION ECOLOGY, Issue 1 2008
Julie E. Korb
Abstract To draw reliable conclusions from forest restoration experiments, it is important that long-term measurements be repeatable or year-to-year variability may interfere with the correct interpretation of treatment effects. We used permanent plots in a long-term restoration study in southwestern Colorado to measure herbaceous and shrub vegetation at three dates within a single year (June, July, and August), and between years (2003 and 2005), on untreated control plots in a warm, dry mixed conifer forest. Growing season precipitation patterns were similar between 2003 and 2005, so differences in vegetation should be related primarily to differences in the sampling month. Significant indicator species for each sampling month were present within a single year (2005), primarily reflecting early-season annuals. We found no significant differences for total species abundance (2005). Species richness, abundance, and indicator species were significantly different between years for different sampling months indicating that sampling should be conducted within a similar time frame to avoid detecting differences that are not due to treatment effects or variations in year-to-year climate. These findings have implications for long-term research studies where the objectives are to detect changes over time in response to treatments, climate variation, and natural processes. Long-term sampling should occur within a similar phenological time frame each year over a short amount of time and should be based on the following criteria: (1) the sampling period is congruent with research objectives such as detecting rare species or peak understory abundance and (2) the sampling period is feasible in regard to personnel and financial constraints. [source]

The use of Artificial Neural Networks to classify primate vocalizations: a pilot study on black lemurs

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2010
Luca Pozzi
Abstract The identification of the vocal repertoire of a species represents a crucial prerequisite for a correct interpretation of animal behavior. Artificial Neural Networks (ANNs) have been widely used in behavioral sciences, and today are considered a valuable classification tool for reducing the level of subjectivity and allowing replicable results across different studies. However, to date, no studies have applied this tool to nonhuman primate vocalizations. Here, we apply for the first time ANNs, to discriminate the vocal repertoire in a primate species, Eulemur macaco macaco. We designed an automatic procedure to extract both spectral and temporal features from signals, and performed a comparative analysis between a supervised Multilayer Perceptron and two statistical approaches commonly used in primatology (Discriminant Function Analysis and Cluster Analysis), in order to explore pros and cons of these methods in bioacoustic classification. Our results show that ANNs were able to recognize all seven vocal categories previously described (92.5,95.6%) and perform better than either statistical analysis (76.1,88.4%). The results show that ANNs can provide an effective and robust method for automatic classification also in primates, suggesting that neural models can represent a valuable tool to contribute to a better understanding of primate vocal communication. The use of neural networks to identify primate vocalizations and the further development of this approach in studying primate communication are discussed. Am. J. Primatol. 72:337,348, 2010. © 2009 Wiley-Liss, Inc. [source]

Technical Mistakes during the Acquisition of the Electrocardiogram

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2009
Javier García-Niebla R.N.
In addition to knowledge of normal and pathological patterns, the correct interpretation of electrocardiographic (ECG) recordings requires the use of acquisition procedures according to approved standards. Most manuals on standard electrocardiography devote little attention to inadequate ECG recordings. In this article, we present the most frequent ECG patterns resulting from errors in limb and precordial lead placement, artifacts in 12-lead ECG as well as inadequate filter application; we also review alternative systems to the standard ECG, which may help minimize errors. [source]

Maximized PUFA measurements improve insight in changes in fatty acid composition in response to temperature

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2009
Coby van Dooremalen
Abstract A general mechanism underlying the response of ectotherms to environmental changes often involves changes in fatty acid composition. Theory predicts that a decrease in temperature causes an increase in unsaturation of fatty acids, with an important role for long-chain poly-unsaturated fatty acids (PUFAs). However, PUFAs are particularly unstable and susceptible to peroxidation, hence subtle differences in fatty acid composition can be challenging to detect. We determined the fatty acid composition in springtail (Collembola) in response to two temperatures (5°C and 25°C). First, we tested different sample preparation methods to maximize PUFAs. Treatments consisted of different solvents for primary lipid extraction, mixing with antioxidant, flushing with inert gas, and using different temperature exposures during saponification. Especially slow saponification at low temperature (90,min at 70°C) in combination with replacement of headspace air with nitrogen during saponification and methylation maximized PUFAs for GC analysis. Applying these methods to measure thermal responses in fatty acid composition, the data showed that the (maximized) proportion of C20 PUFAs increased at low acclimation temperature. However, C18 PUFAs increased at high acclimation temperature, which is contrary to expectations. Our study illustrates that PUFA levels in lipids may often be underestimated and this may hamper a correct interpretation of differential responses of fatty acid composition. © 2009 Wiley Periodicals, Inc. [source]

Tutorial: Using Confidence Curves in Medical Research

BIOMETRICAL JOURNAL, Issue 2 2005
Ralf Bender
Abstract Confidence intervals represent a routinely used standard method to document the uncertainty of estimated effects. In most cases, for the calculation of confidence intervals the conventional fixed 95% confidence level is used. Confidence curves represent a graphical illustration of confidence intervals for confidence levels varying between 0 and 100%. Although such graphs have been repeatedly proposed under different names during the last 40 years, confidence curves are rarely used in medical research. In this paper, we introduce confidence curves and present a short historical review. We draw attention to the different interpretation of one- and two-sided statistical inference. It is shown that these two options also have influence on the plotting of appropriate confidence curves. We illustrate the use of one- and two-sided confidence curves and explain their correct interpretation. In medical research more emphasis on the choice between the one- and two-sided approaches should be given. One- and two-sided confidence curves are useful complements to the conventional methods of presenting study results. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Genetic skeletal disorders of the fetus and infant: Pathologic and molecular findings in a series of 41 cases,

BIRTH DEFECTS RESEARCH, Issue 10 2009
Anastasia E. Konstantinidou
Abstract BACKGROUND: Genetic skeletal disorders of the fetus and infant are a large group of genetic disorders, comprising the groups formerly assigned as skeletal dysplasias (osteochondrodysplasias), dysostoses, and malformation syndromes with a skeletal component. Genetic skeletal disorders may be prenatally detected by ultrasonography or result in intrauterine or early postnatal death, constituting one difficult diagnostic field met by the pathologist who performs the perinatal autopsy. METHODS: In this retrospective study, we have gathered radiologic, physical, histopathologic, and molecular data regarding 41 cases of genetic skeletal disorders diagnosed among 1980 fetal and perinatal autopsies over a 10-year period. RESULTS: Our series of cases were classified according to the 2006 Nosology and Classification of Genetic Skeletal Disorders. The overall frequency of genetic skeletal disorders was 1:48 autopsies. The FGFR3 group and osteogenesis imperfecta type 2 were the more frequently encountered disorders. The mean gestational age at autopsy was 21.9 weeks (range, 12,37 weeks). A final diagnosis was obtained in 95% of cases. Genetic skeletal disorders were detected by prenatal ultrasound in 90% of cases, with a correct typing of the disorder achieved in only 34%. Molecular analysis was confirmative in 5 cases. CONCLUSIONS: The central role of the perinatal pathologist in collaboration with specialized services is essential for the correct interpretation of the radiologic, physical, and histopathologic findings, to accurately classify specific types of genetic skeletal disorders and enable genetic counseling. Birth Defects Research (Part A), 2009. © 2009 Wiley-Liss, Inc. [source]

Antiepileptic monotherapy significantly impairs normative scores on common tests of executive functions

ACTA NEUROLOGICA SCANDINAVICA, Issue 3 2009
E. Hessen
Background,,, Understanding how antiepileptic (AED) monotherapy influences normative test scores is of importance in the clinic for correct interpretation of neuropsychological profiles. Previous studies have primarily reported minor influence on neuropsychological raw scores, and the clinical relevance of these findings is unclear. Aim of the study ,To obtain a clinical valid answer to this question, we analysed changes in T-scores after AED withdrawal in a large group of well-controlled epilepsy patients, for tests previously shown to be sensitive to AED withdrawal. Methods ,We report outcomes on measures of choice reaction time from the California Computerized Assessment Package, on the Controlled Oral Word Association Test and on the Stroop Color-Word Interference Test. Results ,Significantly improved T-scores were revealed after AED withdrawal on five of the six tests of executive functions with mean improvement of 5 T-scores. Comparable results were achieved in the subgroup taking carbamazepine, with a mean improvement of 6.2 T-scores. Conclusion ,The present results suggest that T-scores for computerized tests of choice reaction time and tests of verbal fluency and response inhibition may be significantly impaired as a consequence of AED monotherapy, and that careful interpretation of these scores is required in diagnostic assessment of patients receiving AED monotherapy. [source]