Implicit Indicators Research Articles

A Posteriori error estimates for a discontinuous galerkin method applied to elliptic problems. Log number: R74

A posteriori error estimates for locally mass conservative methods for subsurface flow are presented. These methods are based on discontinuous approximation spaces and referred to as discontinuous Galerkin methods. In the case where penalty terms are added to the bilinear form, one obtains the nonsymmetric interior penalty Galerkin methods. In a previous work, we proved optimal rates of convergence of the methods applied to elliptic problems. Here, h adaptivity is investigated for flow problems in 2D. We derive global explicit estimators of the error in the L 2 norm and we numerically investigate an implicit indicator of the error in the energy norm. Model problems with discontinuous coefficients are considered.

Inferring user interest

As the World Wide Web continues to grow, people find it impossible to access even a small portion of the information generated in a day from Usenet news, e-mail, and Web postings. Automated filters help us to prioritize and access only the information in which we're interested. Because opinions differ about the importance or relevance of information, people need personalized filters. Implicit indicators captured while users browse the Web can be as predictive of interest levels as explicit ratings.

Implicit Indicators of Women's Persistence in Math, Science, and Engineering

Implicit Indicators of Women's Persistence in Math, Science, and Engineering

Implicit cognition and HIV risk behavior.

Implicit cognition theory differs from most other approaches to health behavior in that it emphasizes neurobiologically plausible and experimentally documented memory association processes rather than rational decisions, considerations of pros and cons, or beliefs. The present study of adults from a community population investigated the predictive effects of implicit cognition, as well as behavioral and personality variables (sensation seeking, hostility, conscientiousness, and polydrug use), on risky sexual behaviors (lack of condom use, sex after drug use, and multiple sexual partners). In addition, this study simultaneously investigated the predictors in both a high-risk and a low-risk sample. Results showed that the implicit cognition indicator was a significant, independent predictor of lack of condom use in the high-risk sample. Polydrug use and sensation seeking also had important predictive effects. The results encourage more research on implicit cognition in health behavior and further document links among drug use, personality, and HIV risk behavior.

Consistency, inter-rater reliability, and validity of 441 consecutive mock oral examinations in anesthesiology: implications for use as a tool for assessment of residents.

Oral practice examinations (OPEs) are used extensively in many anesthesiology programs for various reasons, including assessment of clinical judgment. Yet oral examinations have been criticized for their subjectivity. The authors studied the reliability, consistency, and validity of their OPE program to determine if it was a useful assessment tool. From 1989 through 1993, we prospectively studied 441 OPEs given to 190 residents. The examination format closely approximated that used by the American Board of Anesthesiology. Pass-fail grade and an overall numerical score were the OPE results of interest. Internal consistency and inter-rater reliability were determined using agreement measures. To assess their validity in describing competence, OPE results were correlated with in-training examination results and faculty evaluations. Furthermore, we analyzed the relationship of OPE with implicit indicators of resident preparation such as length of training. The internal consistency coefficient for the overall numerical score was 0.82, indicating good correlation among component scores. The interexaminer agreement was 0.68, indicating moderate or good agreement beyond that expected by chance. The actual agreement among examiners on pass-fail was 84%. Correlation of overall numerical score with in-training examination scores and faculty evaluations was moderate (r = 0.47 and 0.41, respectively; P < 0.01). OPE results were significantly (P < 0.01) associated with training duration, previous OPE experience, trainee preparedness, and trainee anxiety. Our results show the substantial internal consistency and reliability of OPE results at a single institution. The positive correlation of OPE scores with in-training examination scores, faculty evaluations, and other indicators of preparation suggest that OPEs are a reasonably valid tool for assessment of resident performance.

Systematic weighting and ranking: Cutting the Gordian knot

A powers-of-two algorithm is described that automatically creates discrete, well-defined, and unique result sets, displaying them in decreasing order of likely relevance. All computations are transparent, and a simple query form allows the searcher to focus on the choice of terms and their sequence-an implicit indicator of their relative importance. The program can be used with traditional databases or with search engines designed for the Word Wide Web. It also can be used with an intelligent agent to search the Web with a pushdown store, returning only those items that best reflect the searcher's stated interests.

Clinical neuromythology XV. Feinting science

Reply from the Authors: We are gratified by Dr. Benditt's interested astonishment and by his ill-tempered concern with diagnostic validity and reliability. We pointed out that the only diagnostic gold standard (his is right) is rarely achieved: direct observation of the spontaneous syncopal event. In the real clinical world, the challenge is to attain a silver standard, a reasonably probable working diagnosis based on detailed history of symptoms including witness reports, risk factors of past history, and current interval examination. For example, no extensive study is needed for the report of a single syncopal episode when a woman's hand is smashed by a car door or when she is roused from bed to be informed that her child was killed. Specific suspicion is warranted by history of provocative medication, current examination evidence of postural hypotension, or by symptoms similar to those of the fainting complaint elicited by voluntary hyperventilation. On the other hand, fainting when not standing suggests something other than vasovagal syncope. Our emphasis on the working diagnosis is the implicit indication for close follow-up management and diagnostic challenge by a well-informed and responsible physician. Although Benditt claims absolute security in his own right diagnosis, Kapoor,2 the authority whom he cites, has a more realistic and diffident diagnostic style [italics ours]: In those patients in whom a diagnosis can be assigned , the history and physical examination identify a potential cause in 49% to 85%. Furthermore in 8% of additional patients, history and physical examination are suggestive of causes that need confirmation by specific tests.... Diagnosis of arrhythmias as a cause of syncope is problematic because symptomatic correlation during electrocardiographic monitoring is rarely found (approximately 4%), and as a result, there is no uniform agreement on diagnostic criteria for abnormalities. Similar problems exist in the use of …

The Linguistic Intergroup Bias As an Implicit Indicator of Prejudice

The Linguistic Intergroup Bias (LIB) is the tendency to describe stereotypic events in more abstract terms than counterstereotypic events. We examined whether a paper-and-pencil measure based on the LIB could be used as an implicit indicator of prejudice. Experiment 1 demonstrated that a measure of implicit racial prejudice based on the LIB predicted whether subjects evaluated an African-American or a Caucasian as threatening. Experiment 2 extended this finding with indirect measures of threat. In both of these experiments, an explicit measure of prejudice failed to predict subjects' evaluations. Experiment 3 demonstrated that a measure of implicit gender prejudice based on the LIB was correlated with an implicit prejudice measure based on biased attributional processing. Across these three experiments, implicit and explicit measures of prejudice were largely uncorrelated.

Phase synchronization of chaotic oscillators by external driving

We extend the notion of phase locking to the case of chaotic oscillators. Different definitions of the phase are discussed. and the phase dynamics of a single self-sustanined chaotic oscillator subjected to external force is investigated. We describe regimes where the amplitude of the oscillator remains chaotic and the phase is synchronized by the external force. This effect is demonstrated for periodic and noisy driving. This phase synchronization is characterized via direct calculation of the phase, as well as by implicit indications, such as the resonant growth of the discrete component in the power spectrum and the appearance of a macroscopic average field in an ensemble of driven oscillators. The Rössler and the Lorenz systems are shown to provide examples of different phase coherence properties, with different response to the external force. A relation between the phase synchronization and the properties of the Lyapunov spectrum is discussed.

A Proposed Revision of the Hubble Sequence for Elliptical Galaxies

The Hubble classification scheme has a well-known drawback for elliptical galaxies: the sequence E0-E6 correlates primarily with inclination and not with fundamental properties. In contrast, later-type galaxies are ordered by fundamental physical parameters. We propose to revise the Hubble sequence so that it orders ellipticals by isophote shape. Specifically, we suggest that the Im-spiral-S0 sequence be connected to disky ellipticals and thence to boxy ellipticals. The sequence is continuous from S0's to disky E's. However, boxy E's may be unrelated to other ellipticals: global and core properties both show signs of a dichotomy between (1) normal- and low-luminosity ellipticals that rotate rapidly, that are nearly isotropic and oblate-spheroidal, that are coreless, and that have disky-distorted isophotes, and (2) giant ellipticals that are essentially nonrotating, that are anisotropic and moderately triaxial, that have cuspy cores, and that are boxy-distorted. In the classification, we use isophote shape as an implicit indicator of velocity anisotropy. Two observations support this interpretation: (1) ellipticals with disky isophote distortions rotate rapidly while boxy ellipticals tend to rotate slowly; (2) disky ellipticals show little minor-axis rotation while boxy ellipticals often have large amounts of minor-axis rotation. An approximate classification by velocity anisotropy extends the Im-spiral-S0 sequence through the ellipticals in a physically reasonable way, and it is diagnostic of formation mechanisms. Care is required to recognize unfundamental complications, such as the building by accretion of disky substructure inside a boxy elliptical. However, we believe that the proposed scheme distills the essential physics that should be embodied in a relevant morphological classification.

A priori actor negligence mediates a posteriori outcome effects on moral judgment

Alicke and Davis (1989) reported that subjects blamed a hypothetical homeowner more when an apparent intruder he shot and killed turned out to be an innocent person than a dangerous criminal, even though the identity of the victim was not known at the time of the killing. We proposed that this a posteriori outcome effect was mediated by implicit indications that the actor had behaved negligently at the beginning of the event sequence. We conducted three studies with young adult subjects to test this hypothesis. In Study 1, a three treatment one-way design, we established that home defense weapons differ in perceived a priori owner negligence and recklessness, and that the weapon used by the homeowner in the study by Alicke and Davis established a relatively high degree of perceived a priori negligence. Study 2 was a 2 × 2 design in which we compared judgments of blame for the death of an innocent or criminal victim that came about as a result of actor decisions about weapons that were relatively high or low in implicit a priori negligence. The predicted significant interaction effect showed an attenuation of the a posteriori victim information effect when a priori negligence was relatively low. Study 3 was a 2 × 3 design in which we varied explicit information about a priori actor negligence (low vs moderate vs high) in making a mundane decision and a posteriori information about outcomes (positive vs negative). A significant interaction effect on moral judgment again supported our hypothesis. Moral judgment was affected by a posteriori outcome information only when there was substantive evidence of a priori actor negligence.

The properties of dense molecular cloud cores

Abstract Results of recent studies of dense interstellar molecular clouds are discussed. Observations in molecular lines excited at high densities revealed dense cores in many clouds with gas densities n ∼ (0.3 ÷ 3) × 105 cm−9, kinetic temperatures Tk ∼ 10 ÷ 100 K, masses (0.3 ÷ 104) M⊙. The cores are close to the virial equilibrium. There are correlations between velocity dispersion and size, between mass and size and some others similar to those found for less dense clouds but with different coefficients. Implicit indications of fragmentary structure on 40’ scales are obtained.

Adenocarcinoma of the uterine cervix. Prognostic significance of pretreatment serum ca 125, squamous cell carcinoma antigen, and carcinoembryonic antigen levels in relation to clinical and histopathologic tumor characteristics

The prognostic value of the pretreatment serum CA 125, squamous cell carcinoma antigen (SCC), and carcinoembryonic antigen (CEA) levels in relation to tumor type, vascular invasion by tumor cells, and lymph node metastases was investigated in 77 patients with cervical adenocarcinoma. In Stage IB (International Federation of Gynecology and Obstetrics [FIGO]), the five-year actuarial survival of patients with pretreatment serum CA 125 levels greater than 16 U/ml was 52.4% versus 95.6% when normal serum CA 125 levels were determined (P less than 0.01). Pretreatment serum SCC or CEA levels had no substantial prognostic value. In Stage IB (FIGO), 42% of the patients with elevated serum CA 125 levels had lymph node metastases versus 4% when normal levels were found (P = 0.012). The presence of vascular invasion (P = 0.01) or lymph node metastases (P = 0.001) was associated with an increased risk for recurrent disease. Adenosquamous tumors showed a higher incidence of vascular invasion (P = 0.05) and a higher incidence of elevated serum CA 125 levels (P = 0.03). Particularly in Stage II, adenosquamous tumors were found to have a poorer prognosis than adenocarcinomas (P = 0.0566). We conclude that in cervical adenocarcinoma serum CA 125 is an important prognostic factor and an implicit indicator of tumor virulence.

Becoming a Journeyman Electrician

Tools, costume, and jargon are used as implicit indicators of the occupational socialization process for a sample of apprentice construction electricians (195). The data support the notion that occupational identification increases in a linear fashion as the apprentice moves through a five-year program toward journeyman status.