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PubMed1992

Changing trends in three decades of psychotherapy research: the flight from theory into pragmatics.

This article reviews 252 empirical studies of psychotherapy published in the Journal of Consulting and Clinical Psychology in the years 1967/1968, 1977/1978, and 1987/1988. Articles were rated on variables related to theoretical relevance, clinical validity and methodology. It is shown that the main trend over this period of time has been a decline in theory-guided and a rise in pragmatic, clinically oriented research. Related changes in specific norms and practices in this area are illustrated. The disadvantages of a purely empirical approach to psychotherapy research are discussed, and recommendations are made in light of the distinction between the different aims of pragmatic and theoretical research.

Cognitive Behavioral Therapy↗

PubMed1997

Why can't most people draw what they see?

The study presented a theoretical and empirical approach to the adult drawing process. Four possible sources of drawing inaccuracies were described: misperception of the object, inability to make good representational decisions, deficient motor skills, and misperception of the drawing. In four studies the degree to which the latter three sources contributed to drawing inaccuracies was assessed. The results suggest that (a) motor coordination is a very minimal source of drawing inaccuracies, (b) the artist's decision-making process is a relatively minor source of drawing inaccuracies, and (c) the artist's misperception of his or her work is not a source of drawing inaccuracies. These results suggest that the artist's misperception of the object is the major source of drawing errors.

Art↗

PubMed2005

Are current theories of panic falsifiable?

The authors examine 6 theories of panic attacks as to whether empirical approaches are capable of falsifying them and their heuristic value. The authors conclude that the catastrophic cognitions theory is least falsifiable because of the elusive nature of thoughts but that it has greatly stimulated research and therapy. The vicious circle theory is falsifiable only if the frightening internal sensations are specified. The 3-alarms theory postulates an indeterminate classification of attacks. Hyperventilation theory has been falsified. The suffocation false alarm theory lacks biological parameters that unambiguously index dyspnea or its distinction between anticipatory and panic anxiety. Some correspondences postulated between clinical phenomena and brain areas by the neuroanatomical hypothesis may be falsifiable if panic does not depend on specific thoughts. All these theories have heuristic value, and their unfalsifiable aspects are capable of modification.

Cognition↗

PubMed1994

Pharmacodynamic optimization of warfarin therapy.

Pharmacokinetic-pharmacodynamic information regarding warfarin is used to produce a predictive model based on the idea that pharmacodynamic variability is more important than pharmacokinetic variability in the overall dose-response variability to warfarin. A modification of the maximum effect model is tested on a group of patients initiating oral anticoagulation with warfarin. Results indicate that the model can account for at least half of the total variation in maintenance doses observed (sample coefficient of determination, 0.53) and offer the physician a framework for dose requirements at the onset of therapy. The basic prediction equation is as follows: Maintenance dose = (11/international normalized ratio)-1, with a coefficient of correlation of 0.73 (95% confidence limits, 0.46-0.88). Application of this model may improve on the traditional empiric approach to warfarin dose adjustment.

Dose-Response Relationship, Drug↗

PubMed2005

The global distribution of clinical episodes of Plasmodium falciparum malaria.

Interest in mapping the global distribution of malaria is motivated by a need to define populations at risk for appropriate resource allocation and to provide a robust framework for evaluating its global economic impact. Comparison of older and more recent malaria maps shows how the disease has been geographically restricted, but it remains entrenched in poor areas of the world with climates suitable for transmission. Here we provide an empirical approach to estimating the number of clinical events caused by Plasmodium falciparum worldwide, by using a combination of epidemiological, geographical and demographic data. We estimate that there were 515 (range 300-660) million episodes of clinical P. falciparum malaria in 2002. These global estimates are up to 50% higher than those reported by the World Health Organization (WHO) and 200% higher for areas outside Africa, reflecting the WHO's reliance upon passive national reporting for these countries. Without an informed understanding of the cartography of malaria risk, the global extent of clinical disease caused by P. falciparum will continue to be underestimated.

Africa↗

PubMed2004

The origin of highly efficient selective emission in rare-earth oxides for thermophotovoltaic applications.

Rare-earth oxide materials emit thermal radiation in a narrow spectral region, and can be used for a variety of different high-temperature applications, such as the generation of electricity by thermophotovoltaic conversion of thermal radiation. However, because a detailed understanding of the mechanism of selective emission from rare-earth atoms has so far been missing, attempts to engineer selective emitters have relied mainly on empirical approaches. In this work, we present a new quantum thermodynamic model to describe the mechanisms of thermal pumping and radiative de-excitation in rare-earth oxide materials. By evaluating the effects of the local crystal-field symmetry around a rare-earth ion, this model clearly explains how and why only some of the room-temperature absorption peaks give rise to highly efficient emission bands at high temperature (1,000-1,500 degrees C). High-temperature emissivity measurements along with photoluminescence and cathodoluminescence results confirm the predictions of the theory.

Computer Simulation↗

PubMed2006

Moving forward in reverse: genetic technologies to enable genome-wide phenomic screens in Arabidopsis.

Genome sequencing, in combination with various computational and empirical approaches to sequence annotation, has made possible the identification of more than 30,000 genes in Arabidopsis thaliana. Increasingly sophisticated genetic tools are being developed with the long-term goal of understanding how the coordinated activity of these genes gives rise to a complex organism. The combination of classical forward genetics with recently developed genome-wide, gene-indexed mutant collections is beginning to revolutionize the way in which gene functions are studied in plants. High-throughput screens using these mutant populations should provide a means to analyse plant gene functions--the phenome--on a genomic scale.

Arabidopsis↗

PubMed1975

Quantitative interpretation of concentration-dependent migration in gel chromatography of reversibly polymerizing solutes.

A theoretical expression is derived for concentration dependence of elution volume in the gel chromatography of a non-interacting solute. Experimental results for bovine serum albumin on Sephadex G-100 are shown to be in good agreement with the predicted gel-chromatographic behaviour. The theoretical treatment of concentration dependence is extended to include a solute undergoing rapid reversible polymerization (nA in equilibrium C). Computer simulation of gel-chromatographic data for monomer-dimer systems on Sephadex G-100 is used to illustrate the deficiencies of earlier empirical approaches, and also the potential of the present treatment, of allowing for non-chemical concentration dependence in gel chromatography of polymerizing solutes.

Chemical Phenomena↗

PubMed1999

Close encounters: the use of critical reflective analysis as an evaluation tool in teaching and learning.

Teaching and learning are complex activities which, when combined with professional practice-based activity, take on additional dimension and depth. This makes the use of traditional, product-based evaluation problematic in that a purely empirical approach does not facilitate thorough evaluation of every facet of such an encounter. This paper describes the use of critical reflective analysis as an alternative method of evaluation. The reflective framework facilitating this process has been adapted from three key sources: patterns of nursing knowledge; evaluative paradigms based upon knowledge - constitutive interests; descriptors for a reflective practicum. The reflective activity is structured around a teaching and learning encounter in a care-based setting and focuses on 'doing the drug round'. Descriptive vignettes are used to facilitate reflection-on-action and, through critical reflective analysis, the author identifies the essential value (e-value-ation) of the encounter in terms of credibility, utility and worth.

Education, Nursing, Graduate↗

PubMed1996

Centred contact density functions for the statistical analysis of random sets. A stereological study on benign and malignant glandular tissue using image analysis.

Real structures investigated in the material and biological sciences, such as minerals or tissues, can often be reduced to two phases. In a stochastic approach, the components of such binary structures may be considered as the union of grains--random sets implanted with their centres at random points--and their complementary space, which is called the pore space. The simplest stochastic germ-grain model is the Boolean model of random sets, which we use here instrumentally as a null model (reference model) for comparison with our biological material. After a brief review of basic properties of the Boolean model and related statistical methods, we introduce centred contact density functions as a new approach. Empirical contact density functions are estimated from the empirical contact distribution functions with an image analyser by dilation of the grain phase. Theoretical contact density functions are then predicted from a set of image parameters, under the assumption that the Boolean model holds. A centred contact density function is the difference between the estimated and the predicted contact density function. Apart from a random error term, centred contact density functions amount to zero irrespective of the area fraction of the grain phase, when the germ-grain model is Boolean. As a section of a spatial Boolean model is a planar Boolean model, the method is also applicable in stereological studies where digitized images are obtained from sections of a three-dimensional structure. Centred contact density functions were determined for mastopathic tissue as compared to mammary cancer, and for tumour-free prostatic tissue as compared to prostatic cancer. For each category of specimens, twenty cases with 10 images each were analysed. Benign and malignant glandular tissue of the aforementioned types deviates significantly from the Boolean model. Centred contact density functions show that malignant transformation is connected with profound geometric remodelling of the pore space.

Breast Neoplasms↗

PubMed1996

Comparison of real-time ultrasonography and magnetic resonance imaging in the assessment of urinary bladder volume.

OBJECTIVE: To compare estimates of bladder volume obtained by conventional real-time ultrasonography with those obtained from magnetic resonance imaging (MRI) by the Cavalieri method of unbiased stereology. SUBJECTS AND METHODS: The study comprised nine subjects (four men and five women, mean age 23 years, range 18-34) with no history of bladder disease. Before micturition, each volunteer underwent ultrasonography, immediately followed by MRI. The volunteers then voided the true voided volume of urine was measured and the imaging protocols were repeated in the same order after micturition. The bladder volume was estimated from ultrasonography using the formula: volume = 0.7 (L x TS x AP), (where L is the maximum supero-inferior diameter. AP the maximum anteroposterior diameter and TS the maximum transverse diameter) and from MRI using the Cavalieri method. For each imaging modality, the volume of urine voided was estimated as the difference in the volume estimate before and after micturition. RESULTS: The mean percentage coefficient of variation for the estimates of bladder volume by ultrasonography was 2.17 before and 4.43 after micturition. There was no significant difference in the replicate estimates of each bladder diameter by ultrasonography before and after micturition (P = 0.98). The MRI method consistently underestimated the voided volume: the mean discrepancy between the estimated voided volume and the true voided volume was 7.7 ml, and -67.7 ml for the ultrasonographic and MRI estimates, respectively, which are significantly different (P = 0.02) when assessed using a multifactor ANOVA. Further analysis using multiple-range tests showed a significant difference between the voided volume estimated by MRI and the corresponding true voided volume. There was no difference between the voided volume estimated by ultrasonography and the corresponding true volume. CONCLUSION: Ultrasonographic estimates of voided volume were more reliable than the those obtained using the MRI method. This is possibly due to a delay between micturition and the acquisition of MR images after micturition, which allowed the bladder to partly refill with urine. The empirical approach using measurements from ultrasonograms provides a fast and reliable technique: ultrasonography remains the recommended imaging modality for estimating bladder volume.

Adolescent↗

PubMed1997

Optimization of RAPD for fingerprinting Salmonella.

Random amplification of polymorphic DNA (RAPD) is proving to be a useful technique in studying the epidemiology of micro-organisms. The technique can be troublesome and time consuming to establish due to the essentially empirical approach to optimization. By standardization of certain parameters and use of a commercially available PCR buffer optimization kit, a particularly promising primer was identified and RAPD conditions for a highly discriminatory and reproducible characterization of Salmonella isolates was achieved. In addition, a technique to obtain reproducible RAPD fingerprints of Salmonella isolates without the need to purify genomic DNA is described.

Animals↗

PubMed1995

Development of a mechanistic model for rumen digestion validated using the duodenal flux of amino acids.

A mechanistic model describing rumen digestion is presented. The model consists of 22 compartments for classical nutrients, microbes associated with either solids or fluid, and 8 amino-acid compartments. An empirical approach for volatile fatty acids production is used. Sensitivity and behavioural analysis on several parameters demonstrated the need to improve knowledge concerning certain factors. Model results on general criteria are in good agreement with observed data. Validation on 49 experimental lysine and methionine duodenal fluxes were satisfactory. A comparison between observed and predicted values of LysDi and Metdi on several feedstuffs showed good results. This model is a first step in the building of a rumen model suitable for research and application.

Adenosine Triphosphate↗

PubMed2004

[The development of a toxic megacolon due to Amanita phalloides poisoning. A rare complication].

HISTORY: A 71-year-old previously healthy man consumed a mushroom meal containing Amanita phalloides, which he had confused with Agaricus campestris. Approximately 8 hours later, typical gastrointestinal symptoms began with copious loss of fluids. Treatment with penicillin G was initiated followed by a continuous silibinin infusion before the patient was transferred to our toxicological department. Other than a transient tachycardia and diffuse pain on abdominal palpation clinical examination was without abnormal findings. INVESTIGATIONS: Laboratory findings showed severe hepatic damage with 100-fold increased transaminases, elevation of serum creatinine, hyperbilirubinemia and a serious disturbance of coagulation. Infection with HIV, hepatitis- and CMV as well as pathogenic enteric bacteria and antibiotic-associated pseudo-membranous colitis were excluded. 11 days after the mushroom meal x-ray of abdomen showed a 6 cm dilatation of the small intestine and an 8 cm dilatation of the colon. DIAGNOSIS AND TREATMENT: Although clinical condition and laboratory findings nearly fulfilled transplantation criteria, hepatic injury resolved during intensive care therapy. Intractable diarrhea, dilatation of the intestine on x-ray as well as other findings met criteria of toxic megacolon. Therapy with antibiotics and systemic steroids was ineffective, so the patient needed decompression by a catheter, which was placed by colonoscopy. 30 days after the serious amanita poisoning complicated by development of toxic megacolon, the patient's condition resolved without sequelae and he was discharged. CONCLUSIONS: In addition the well known complications of amanita-poisoning, such as hepatic failure, encephalopathy and multi-organ failure, involvement of other organs like bone marrow, pancreas, kidney and gastrointestinal tract (except for the initial cholera-like gastroenteritis) are not well documented in the literature. Uncommon complications like toxic megacolon require an empirical approach.

Aged↗

PubMed1988

[The problem of need for psychiatric facilities: problem presentations and models].

The article provides a viewpoint on the range of problems which must be met when planning institutions of psychosocial care. Definitions of needs for treatment (supplied by professionals, patients and their social environment) and characteristics of target groups (in terms of diagnosis, degree of impairment, symptoms, demographic variables, aptitude etc.) are presented. The applicability and usefulness of different epidemiological parameters and empirical approaches to estimate care requirements which have still not been fulfilled are discussed; influences on the dynamics of supply and demand are described. Planning is demonstrated as a feedback process in which the definition of participants, clarification of roles, demands and basic standards, agreement on procedures as well as implementation and evaluation are consecutive steps.

Community Mental Health Centers↗

PubMed2005

Optimal allocation of replicas in parallel tempering simulations.

We have studied the efficiency of parallel tempering simulations for a variety of systems including a coarse-grained protein, an atomistic model polypeptide, and the Lennard-Jones fluid. A scheme is proposed for the optimal allocation of temperatures in these simulations. The method is compared to the existing empirical approaches used for this purpose. Accuracy associated with the computed thermodynamic quantities such as specific heat is also computed and their dependence on the trial-exchange acceptance rate is reported.

Bacterial Proteins↗

PubMed2006

Universal scaling features of spectroscopic constants for diatomic systems.

Based on a new criterion that was proposed to search for the universality of spectroscopic constants for bound ground-state diatomics [R. H. Xie and P. S. Hsu, Phys. Rev. Lett. 96, 243201 (2006)], we have found universal scaling relations between spectroscopic constants of diatomic systems with s-, p-, and d-type valence-shell constituents. Our study suggests a useful empirical approach for the prediction of molecular spectroscopic constants.

Journal Article↗

PubMedDate not supplied

There is no gap 'per se' between theory and practice: Research knowledge and clinical knowledge are developed in different contexts and follow their own logic.

The aim of this article is to highlight relations between theory and practice and the genesis of professional action in clinical nursing and among researchers. With use of a sociologically based empirical approach, focus is placed on the knowledge involved in the work of researchers and practitioners in terms of the source of their knowledge. Unlike a dominant barrier paradigm, theory and practice have different logics; they are not on a continuum nor are they hierarchically ordered. They exist in their own right as theoretical knowledge and practical knowledge. In daily practice, clinical nurses are inspired and learn from the context, including each other, and they are active producers of knowledge, not simply recipients of knowledge. This study, therefore, claims that there is no research-practice gap "in itself" (per se) as argued in the "barriers paradigm."

Ethics, Clinical↗