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PubMed1988

Validating the components of a taxonomic system for rapists: a path analytic approach.

This study was part of a series designed to validate a classification system for rapists developed at the Massachusetts Treatment Center. This system (MTC:R2) determines subtypes according to three major dimensions: the meaning of the aggression in the rapist's offenses (expressive versus instrumental), the meaning of the sexual behavior (compensatory, exploitative, displaced anger, or sadistic), and the degree of general lifestyle impulsivity (low or high). A total of 201 rapists were subtyped using this system. A path analytic approach was used to relate family, juvenile, and adult histories to the main decisions of subtype assignment. The classification of an offender on each of the three dimensions was informed by a developmental perspective. Results provided support for the use of the discriminators used and highlighted the deficiencies in our current knowledge regarding developmental precursors. These results were integrated with the findings from other studies using MTC:R2 and suggestions for revisions to the current classification system were discussed.

Aggression↗
PubMedDate not supplied

Administrative days in acute care facilities: a queueing-analytic approach.

After acute care services are no longer required, a patient in an acute care hospital often must remain there while he or she awaits the provision of extended care services by a nursing home, through social support services, or by a home health care service. This waiting period is often referred to as "administrative days" because the time is spent in the acute facility not for medical reasons, but rather for administrative reasons. In this paper we use a queueing-analytic approach to describe the process by which patients await placement. We model the situation using a state-dependent placement rate for patients backed up in the acute care facility. We compare our model results with data collected from a convenience sample of 7 hospitals in New York State. We conclude with a discussion of the policy implications of our models.

Appointments and Schedules↗
PubMed1996

The meta-analytic approach to research integration.

A quantitative research method for aggregating findings from empirical research, meta-analysis is useful for systematically integrating findings gleaned from individual studies. Meta-analysis goes beyond the mere summarization and critique of research findings, to conducting statistical analyses on the outcomes of similar studies. Overall, meta-analysis represents a vast improvement over traditional methods of research review, by providing a more thorough description of the current status of research in an area and a more precise estimate of the effects of treatments or interventions. This article describes the meta-analytic approach to research integration, discusses the advantages that it offers for integrating nursing research, and highlights some of the methodological issues surrounding this approach.

Data Interpretation, Statistical↗
PubMed2005

An analytical approach to the rise velocity of periodic bubble trains in non-Newtonian fluids.

The present study aims at providing insight into the acceleration mechanism of a bubble chain rising in shear-thinning viscoelastic fluids. The experimental investigation by the Particle Image Velocimetry (PIV), birefringence visualisation and rheological simulation shows that two aspects are central to bubble interactions in such media: the stress creation by the passage of bubbles, and their relaxation due to the fluid's memory forming an evanescent corridor of reduced viscosity. Interactions between bubbles were taken into account mainly through a linear superposition of the stress evolution behind each bubble. An analytical approach together with the rheological consideration was developed to compute the rise velocity of a bubble chain in function of the injection period and bubble volume. The model predictions compare satisfactorily with the experimental investigation.

Computer Simulation↗
PubMed2001

Estimation of growth hormone secretion rate: impact of kinetic assumptions intrinsic to the analytical approach.

We compared four common mathematical techniques to determine daily endogenous growth hormone (GH) secretion rates from diurnal plasma GH concentration profiles in 24 women (16 upper- or lower-body obese and 8 normal-weight individuals). Two forms of deconvolution analysis and two techniques based on a priori determined GH clearance estimates were employed. Deconvolution analyses revealed significant differences in the 24-h GH secretion rate between normal-weight and upper-body obese women, whereas the other two techniques did not. Moreover, deconvolution analyses predicted that the reduction in mean plasma GH concentrations in upper-body obese women was accounted for by impaired GH secretion, whereas the other methods suggested that obesity increases GH metabolic clearance. Thus we infer that disparate conclusions concerning GH secretion can be drawn from the same primary data set. The different inferences likely reflect dissimilar kinetic assumptions and the particular limitations intrinsic to each analytical approach. Accordingly, we urge caution in the facile comparison of calculated GH secretion data in humans, especially when kinetic and secretion measurements are performed under different conditions. The most appropriate way to determine the GH secretion rate in humans must be balanced by the exact intent of the experiment and the acceptability of different assumptions in that context.

Adult↗
PubMed1995

Working with anger in groups: a modern analytic approach.

The development of Modern Psychoanalytic psychotherapy with schizophrenic and borderline patients is briefly traced, and the major themes of the treatment approach that derived from that early work are discussed with attention to their application in group therapy. These themes include the concepts of the narcissistic defense, narcissistic transference, joining or reinforcing defenses, emotional communication, and a shift away from the classical psychoanalytic emphasis on interpretation and insight to a strategy of helping the patient put all his or her thoughts and feelings into language in a constructive manner. These principles are discussed in connection with three kinds of problems involving anger in therapy groups: members' anger destructively turned against their own egos, anger expressed toward the leader within a negative transference, and anger destructively expressed toward others in the group. Lastly, consideration is given to the group leader's anger and its expression within the group. Some contrasts are made between the Modern Analytic approach and the classical Freudian position as well as Kohut's self psychology.

Anger↗
PubMed1986

31P NMR studies of the intact perfused rat heart: a novel analytical approach for determining functional-metabolic correlates, temporal relationships, and intracellular actions of cardiotoxic chemicals nondestructively in an intact organ model.

Intact hearts isolated from adult male, Sprague-Dawley rats were perfused under standardized conditions in an apparatus designed for use in a high-resolution nuclear magnetic resonance (NMR) spectrometer system. Myocardial phosphate metabolite concentrations (ATP, PCr, Pi, and phosphomonoesters) and intracellular pH were determined sequentially at timed intervals coincident with the functional assessments of the intact heart by phosphorus-31 (31P) NMR spectroscopic methods. Myocardial functional and metabolic parameters were unaffected by sustained control perfusion (2 hr). The negative inotropic actions of cadmium were associated with significant changes in the chemical environment of inorganic phosphate (Pi) within the cells. This initial cellular response to cadmium, which correlated with the onset and magnitude of the contractile disturbances, appeared to represent the formation of an acidic, intracellular Pi pool (pH, 6.0). This pH compartment reached a steady state during the period in which maximal changes in contractile function were manifested, and before cellular ATP and PCr concentrations were altered. These findings are consistent with the interpretation that the functional deficits caused by cadmium originated primarily from changes in the chemical environment experienced by intracellular metabolites, rather than changes in the amounts of cellular high energy substrates. In contrast, the time-dependent negative inotropic effects of arsenate were proportional to the loss of cellular ATP stores. Intracellular pH was not affected in these hearts. A distinctive metabolic finding associated with the cardiotoxicity of arsenate was the time-dependent accumulation of previously undetected phosphate metabolites in the arsenate-treated hearts. Efforts to chemically identify these metabolites proved inconclusive; however, existing evidence suggests the possibility that these phosphorus-containing compounds may be arsenophosphate derivatives of naturally occurring cellular metabolites. The present findings provide experimental evidence demonstrating that toxicologic assessments in an intact organ model are feasible using whole organ 31P NMR spectroscopic methods and that meaningful, new insights regarding the biochemical mechanisms responsible for the cardiotoxic actions of xenobiotic agents can be obtained by this analytical approach.

Animals↗
PubMed2003

Salivary metal levels of orthodontic patients: a novel methodological and analytical approach.

The purpose of this study was to qualitatively and quantitatively assess the nickel, chromium, and ferrous levels in a population of 17 orthodontic patients undergoing treatment, compared with seven untreated individuals, employing a novel methodological approach and a new analytical technique. Salivary samples obtained from patients before and after rinsing with double distilled water were processed for Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) for simultaneous estimation of the concentration of the metallic elements. No statistically significant difference was detected between control and patient groups with respect to salivary metal content, regardless of element. The range of salivary metal levels found did not exceed those of daily intake through food and air. The lack of a continuous monitoring scheme for salivary metal concentrations in real time may impose substantial obstacles to defining the release rate of metals in vivo. The results of this study emphasize the necessity of incorporating the dimension of time in assessing the release potential of orthodontic alloys.

Adolescent↗
PubMed1998

Validation of home blood glucose meters with respect to clinical and analytical approaches.

OBJECTIVE: To evaluate the clinical and analytical accuracy of home blood glucose meters. RESEARCH DESIGN AND METHODS: Six blood glucose meters--Reflolux S (Boehringer Mannheim, Mannheim, Germany), One Touch II (LifeScan, Milpitas, CA), Glucocard Memory (Menarini, Florence, Italy), Precision QID (Medisense, Cambridge, U.K.), HaemoCue (HaemoCue, Angelholm, Sweden), and Accutrend alpha (Boehringer Mannheim, Mannheim, Germany)--were compared with a reference method (Beckman Glucose Analyzer II) under controlled conditions (glucose clamp technique). Validation of the blood glucose meters was accomplished by clinically oriented approaches (error grid analysis), statistical approaches (variance components analysis), and by the criteria of the American Diabetes Association (ADA), which recommend a target variability of < 5%. RESULTS: A total of 1,794 blood glucose monitor readings and 299 reference values ranging from 2.2 to 18.2 mmol/l were analyzed (705 readings < 3.89 mmol/l, 839 readings between 3.89 and 9.99 mmol/l, and 250 readings > 9.99 mmol/l). According to error grid analysis, only Reflolux S and Glucocard M had 100% of estimations within the clinically acceptable zones A and B. Assessment of analytical accuracy revealed substantial differences between the glucose meters after separation of the data into defined glycemic ranges. None of the devices met the ADA criteria. CONCLUSIONS: To evaluate accuracy of blood glucose meters, error grid analysis, as well as statistical models, are helpful means and should be performed together. Analytical performance of currently available home blood glucose meters differs substantially within defined glycemic ranges.

Blood Glucose Self-Monitoring↗
PubMed1985

Analytical approaches for biomedical elemental analysis.

Several different analytical systems are available for biomedical elemental analysis related to human nutrition. The principle, detection limits, analytical artifacts, and applications are presented for the following analytical systems for elemental analysis classified by sample volume: macro volume systems--flame atomic absorption spectroscopy (FAAS) and inductively coupled plasma (ICP); micro volume systems--electrothermal atomization (graphite furnace) atomic absorption spectroscopy (ETA-AAS) and x-ray fluorescence (XRF); and ultramicro volume systems--electron probe x-ray microanalysis (EPX) and laser microprobe mass analysis (LAMMA).

Electron Probe Microanalysis↗
PubMed1998

Optimal design of planar-concave collimators for SPECT--an analytical approach.

In this paper we present an analytical tool for the design and optimization of planar-concave collimators for SPECT. We conclude that a single general planar-concave collimator that eliminates the non-isotropic blurring for all SPECT applications does not exist. On the other hand, it is possible to achieve pseudo-optimal collimators for different clinical applications by a careful choice of the design parameters. By classifying the clinical applications into two groups, for instance body and brain studies, the non-isotropic blurring for most SPECT situations may be dramatically reduced by means of planar-concave collimators. The results based on Monte Carlo simulations show that the shape of the point source response function of the reconstructed image obtained from the planar-concave collimator is more isotropic than that obtained from a conventional parallel-hole collimator. Specifically, the ratio of the FWHM of the reconstructed point response function in the radial and tangential direction is increased from 0.5 for the parallel-hole to 0.85 for the planar-concave collimator for sources 200 mm away from the centre of rotation.

Algorithms↗
PubMed1980

A decision analytic approach to cleft palate treatment evaluation.

An analytic methodology, developed from the field of decision analysis, is presented for the evaluation of treatment alternatives. The management of velopharyngeal incompetence illustrates the method. Nasal quality is utilized as a primary means of measuring outcome. Results indicate that treatment alternatives can be preferentially ordered using analytic methods which incorporate costs, benefits, and probabilities of successful and unsuccessful outcomes. Extensions of the mathematical formulations are discussed in relationship to treatment outcomes.

Cleft Palate↗
PubMedDate not supplied

The analytical approach to the nature of lipofuscin (age pigment).

Analytical studies of three lipopigments show that much can be achieved. Lipopigment from ovine ceroid-lipofuscinosis is composed of discrete protein and lipid molecules in orderly arrays and lipid peroxidation is not involved in its formation. Subunit c of mitochondrial ATP synthase accounts for approximately 50% of accumulated material and is specific to the disease process in this and other forms of the disease. Lipofuscin from bovine heart was mostly soluble and also contained discrete proteins, lipids and metals. Equine thyroid lipofuscin was less soluble but also had a relatively high protein content, probably derived from thyroglobulin. Although sugar could not be measured quantitatively, staining reactions and elemental analyses suggested it could also be a significant component. Some may be present as derivatives in the form of advanced glycation products. It is proposed that protein, the dominant molecular species present, is the important constituent in lipofuscinogenesis rather than lipid peroxidation. Whereas this latter may play some part in the maturation of lipofuscin, this has not been shown experimentally and is not likely to be the initiating mechanism.

Journal Article↗
PubMed2001

An accurate analytical approach to electron crystallography.

A much more accurate analytical expression of dynamical electron diffraction than the phase object approximation (POA) formula has been derived in this paper which decreases the restriction of sample thickness up to almost one order of magnitude compared to POA theory. The importance of the new expression is twofold. First, a sample with such a thickness that new expression remains valid can be prepared experimentally. Second, the new expression reveals a clear and straightforward relationship between the wave function and crystal potential. In the expression, the effect of dynamical diffraction on wave function can be simply attributed to two factors TP(D) = (sin(lambda pi zg2))/(4pi2g2) and TA(D) = [1 - cos(lambda pi zg2)]/4pi2g2. Compared to the effect of transfer functions of an electron microscope on wave function, we found that TP(d) and TA(d) play the same role as transfer function but are independent of the instrument. For this reason, we here call the former as "extrinsic transfer functions" and the latter as "intrinsic" ones. In principle, one should correct not only extrinsic transfer functions but also intrinsic ones if one desires to achieve higher resolution.

Journal Article↗
PubMed1998

Force regulation is deficient in patients with parietal lesions: a system-analytic approach.

By means of a quantitative system-analytic investigation strategy, the postural motor control of the fingers was evaluated, to characterise the possible deficit of force regulation in patients with parietal lesions. In spite of a normal response to short torque pulses, the parietal-lesion patients had difficulties in returning to the preload level after the application of an additional step torque load to fingers II-IV of their left or right hands. The control offset (measured 500 ms after step torque application) was significantly larger in the patient group. This deficit in the investigated patients with parietal lesions to compensate for step torque loads was not due to a paresis, but rather resulted from a disturbance in the generation of a sufficient counterforce against the applied step torque within an adequate time window and motor pattern. This distinct force-regulation deficit was found in patients with left- and right-sided parietal lesions.

Adult↗
PubMed2006

Multivesicular release at developing Schaffer collateral-CA1 synapses: an analytic approach to describe experimental data.

We developed and analytically solved a simple and general stochastic model to distinguish the univesicular from the multivesicular mode of glutamate release. The model solution gives analytical mathematical expressions for average values of quantities that can be measured experimentally. Comparison of these quantities with the experimental measures allows one to discriminate the release mode and to determine the most probable values of model parameters. The model has been validated at glutamatergic CA3-CA1 synapses in the hippocampus from newborn (P1-P5 old) rats. Our results strongly support a multivesicular type of release process requiring a variable pool of immediately releasable vesicles. Moreover, computing quantities that are functions of the model parameters, the mean amplitude of the synaptic response to the release of a single vesicle (q) was estimated to be 5-10 pA, in very good agreement with experimental findings. In addition a multivesicular type of release was supported by the following experimental evidences: 1) a high variability of the amplitude of successes, with a coefficient of variation ranging from 0.12 to 0.73; 2) an average potency ratio a2/a1 between the second and first response to a pair of stimuli >1; and 3) changes in the potency of the synaptic response to the first stimulus when the release probability was modified by increasing or decreasing the extracellular calcium concentration. Our results indicate that at Schaffer collateral-CA1 synapses of the neonatal rat hippocampus a single action potential may induce the release of more than one vesicle from the same release site.

Action Potentials↗
PubMed2006

High-gain Brillouin amplification: an analytical approach.

We derive a closed-form approximate analytical formula for the gain of a Brillouin fiber amplifier operating in the depleted pump regime. We take into account the material loss of the medium, which is a strong effect in optical fibers. We validate obtained results numerically and experimentally. The presented analysis can be used to accurately predict the performance of high-gain Brillouin fiber amplifiers.

Journal Article↗
PubMed2003

Analytical approach for description of ion motion in quadrupole mass spectrometer.

Implementation of the analytical method of the solution of the Mathieu equation in conjunction with the algebraic presentation of Mathieu functions is discussed in this work. This approach is used for the analytical expression of fundamental properties of the quadrupole field such as ion trajectory stability and transmission. Extensive comparison with the matrix method is presented with demonstration of the fundamental advantages of the analytical method. However, contrary to the matrix method, the analytical method is limited to the cos trapping waveforms.

Energy Transfer↗