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PubMed2002

Synthesis of a robust broadband duct ANC system using convex programming approach.

A robust active controller using spatially feedforward structure is proposed for broadband attenuation of noise in ducts. To meet the requirements of performance and robust stability in the presence of plant uncertainties, an H2 cost function and an H(infinity) constrain are employed in the synthesis of the controller. The design is then converted into a convex programming problem using Q-parametrization and frequency discretization. An optimal controller that satisfies the quadratic cost functions and linear inequality constraints can be found by sequential quadratic programming. The optimal controller was implemented via a digital signal processor (DSP) and verified by experiments. Experiment results showed that the system attained 16.5 dB maximal attenuation and 5.9 dB total attenuation in the frequency band 200-600 Hz.

Journal Article↗
PubMed1996

[Evaluation of the effectiveness of arterial hypertension control in a primary health unit].

The present study is part of a performance evaluation of the Aging Health Care Program carried out at a Primary Health Care Clinic. Activities for Arterial Hypertension (AH), control oriented according to a risk assessment, in conformity with Ministry of Health norms, are included in the Program mentioned. The effectiveness of the reduction of blood pressure (BP) levels in hypertensive individuals subjected to programmatic activities for disease control, in an attempt to identify conditions association with that reduction, is evaluated. Of the 396 patients with AH registered under the Program between 01/01/92 and 06/30/93, 250 cases were included for this evaluation. These patients had, in addition to high blood pressure levels (BP > or = 160/95 mm Hg) on the first attendances at the health center (before registration in the programme), at least two medical consultations during program follow-up. The differences in blood pressure levels between measurements taken during consultations before the beginning of attendance at the program and those taken on the first attendances to the programme were analysed according to initial blood pressure level, age, sex, registering diagnosis and absences during the program follow-up. Reductions of > or = 5 mm Hg diastolic blood pressure (DBP) and/or > or = 10 mm Hg in systolic blood pressure (SBP) were obtained in 197 (78.8%) patients. The mean reduction was 8.8 mm Hg (sd = 11.4) for DBP and 17.7 mm Hg (sd = 18.6) for SBP. Results of several epidemiological studies allow the inference that a decrease in the mortality risk from Cardiovascular Disease can be achieved in a significant proportion of the individuals registered in the program. Blood pressure normalization according to program norms occurred in 111 (44.4%) individuals. Multiple linear regression analysis demonstrated that initial blood pressure and percentages of absenteeism during the follow-up were independently associated with the reductions in SBP and DBP. Age was independently associated only with the reductions in SBP. Participation of age and percentage of absenteeism during follow-up thus reveal that the final result of the programmed work is also a result of the different ways people take care of their own health.

Aged↗
PubMed2004

Accommodating ethnic diversity: a study of California hospice programs.

BACKGROUND: Studies have confirmed ethnic disparities in the use of hospice services and identified barriers that minorities face in accessing care. OBJECTIVES: We sought to determine whether hospices provide services that might affect minority participation. RESEARCH DESIGN: We surveyed California hospices to determine whether programs use diverse health care providers and volunteers, offer translation, diverse spiritual care, or outreach materials and whether they plan to expand such services. Linking the data to the California Office of Statewide Health Planning and Development annual home care and hospice survey and 2000 US Census, we used multivariate linear regression to evaluate the relationship of program characteristics (profit status, size, chain/freestanding status, urban/rural location, and proportion of nonwhite residents) to services that might affect minority participation. SUBJECTS: One hundred of 149 programs that we surveyed responded. RESULTS: Many programs offer translation (81%), diverse providers (63%) and volunteers (64%), and culturally diverse spiritual services (52%). Few (21%) were conducting outreach, but 23/25 programs expanding services reported plans to improve outreach. In multivariate models adjusted for program size, chain status, profit status, urban/rural location, proportion of nonwhite residents, we found that larger hospices and those in ethnically diverse zip codes were more likely to offer such services. Larger hospices are more likely to report expanding such services. CONCLUSIONS: Many hospices are making efforts to accommodate ethnically diverse patients, but a substantial number are not. Culturally appropriate care and outreach should be addressed in efforts to improve the acceptability and experience of hospice care among minorities.

California↗
PubMed1991

Application of non parametric methods to pharmacokinetic models of the Michaelis-Menten type.

Non linear parametric regression methods for data fitting as applied to complex pharmacokinetic models give rise to convergence difficulties which have not been completely solved. The Cornich-Bowden non parametric method was applied by Shelver to the one compartment open model with first order absorption to simulated data with different error structures. The application of his procedure was extended to a pharmacokinetic model with Michaelis-Menten elimination. Simulated concentration/time data were generated by a microcomputer program which imposed the appropriate error structure:constant and proportional standard deviation with or without one outlier of different magnitude. Parameter optimization was performed using either a Newton-Raphson algorithm based on the integrated form of the Michaelis-Menten equation and a standard non linear regression program: NONLIN. In the case of the non parametric method, the median of the parameter values obtained for each combination of data points was used as best estimate of the parameters. One hundred data sets were used and performance of the two methods was assessed by comparing bias and standard deviation of the mean parameter value thus obtained, given the true values of the parameters used to generate the data. The non parametric performed well with homoscedastic data and was less sensitive to the presence of outliers than the non linear regression technique. In the case of heterosocedastic data both methods performed poorly but the non parametric method was more sensitive to the presence of outliers.

Algorithms↗
PubMed1997

Evaluation of two different protocols for peripheral blood stem cell collection with the Fresenius AS 104 blood cell separator.

OBJECTIVES: Reconstitution of hematopoiesis by means of peripheral blood stem cells is a valid alternative to autologous bone marrow transplantation. The aim of this investigation was to increase the efficiency of collection of circulating blood progenitor cells and to obtain a purer product for transplant. METHODS: We carried out leukapheresis procedures with the Fresenius AS 104 blood cell separator, using two different protocols, the previously used PBSC-LYM and a new mononuclear cell collection program. RESULTS: Both programs were highly effective in collecting mononuclear cells (MNC) and CD34+ cells. Some differences were found, especially regarding MNC yield and efficiencies. There are remarkable differences in the efficiency of collection of CD34+ cells (62.38% with the new program as opposed to 31.69% with the older one). Linear regression analysis showed a negative correlation between blood volume processed and MNC efficiency only for the PBSC-LYM program. Differences were also observed in the degree of inverse correlation existing in both programs between patients' white blood cell precount and MNC collection efficiency. The inverse correlation was stronger for the PBSC-LYM program. Seven patients with solid tumors and hematologic malignancies received high dose chemotherapy and were subsequently transplanted with peripheral blood stem cells collected using the new protocol. All patients obtained a complete and stable engraftment with the reinfusion product collected with one or two leukapheresis procedures. CONCLUSIONS: High efficiencies and yields were observed in the new protocol for MNC and CD34+ cells. These were able to effect rapid and complete bone marrow recovery after myeloablative chemotherapy.

Adolescent↗
PubMed1999

Comparison of soft tissue profile changes in serial extraction and late premolar extraction.

To assess soft tissue profile changes through time, a comparison was made of patients treated by serial extraction without subsequent orthodontic treatment (n=28), patients treated with serial extraction and orthodontic treatment (n=30), and patients treated orthodontically with late extraction (n=30). Cephalometric radiographs were traced and digitized; linear and angular measurements were made with a custom computer program that allowed digitization of specific soft tissue points. Maxillary, mandibular, and overall cephalometric superimpositions and linear measurements of change from the superimpositions were done by hand. Statistical analyses were made to determine if significant differences existed within each group at each time period and between groups at each time period, as well as between males and females at each time period. Data were also analyzed to determine if significant correlations existed between any hard tissue variable and any soft tissue variable, or between any soft tissue variable and any other soft tissue variable. It was found that in those patients treated with late premolar extraction, the most labial point of the mandibular incisor was more posterior from pretreatment to posttreatment than in the serial extraction group. While a great number of associations existed between variables, no significant differences were found between the soft tissue profiles of these three groups of patients. The gender differences that were found to exist were most likely due to normal maturational changes, not the treatment itself.

Adolescent↗
PubMed1988

FRAGMAP--a program for restriction site map comparison.

A program is described which aligns pairs of linear restriction site maps using an algorithm which maximizes the number of coincident sites through the addition of extra 'padding' fragments; and makes maps of the non-conserved sites between pairs and triplets of input maps. A range of display facilities, hardcopy functions and database management routines are also included. The program runs on a stand-alone microcomputer, and is stored along with a database of several hundred files on a single floppy disc.

Copying Processes↗
PubMed1989

Program in BASIC for Ferguson plot analysis, using a personal computer: application to gel electrophoresis in a continuous buffer.

A program in BASIC suitable for personal computers is described which is applicable to gel electrophoresis conducted in a single (continuous) buffer. The curve fitting is to a polynomial function, allowing for an objective selection of the most appropriate curve type and order--linear, convex or concave--in the particular application. Results do not differ significantly from previous programs for evaluation of linear Ferguson plots or of curve fitting to an exponential function for evaluating convex plots, executed on mainframe computers such as the DEC-10 (Digital) and IBM 370 computers. Thus, the program combines original versatility with, for the first time, the possibility for widespread application of Ferguson plot analysis on personal computers.

Blood Protein Electrophoresis↗
PubMed1986

Solving algebraic equations on a microcomputer.

Equation-solving programs for microcomputers make the numerical solution of algebraic equations an easy task. It is no longer necessary to learn or to program algorithms for the solution of many different types of equations. A single equation or a set of simultaneous equations may simply be entered into the computer and numerically solved for unknowns without concern as to whether the equations are linear or non-linear. Several examples of possible applications of equation-solving programs are discussed. Solution times for these examples are given for SEQS on the Apple II and Macintosh computers. The example sets of equations, which include chemical equilibrium and enzyme kinetics problems, have been chosen to demonstrate important aspects of the uses and limitations of equation solving. The four examples discussed are: a two-compartment pharmacokinetic model, citric acid ionization in aqueous solution, an enzyme inhibition model, and an example of the application of an equation-solving program in doing a simple non-linear regression problem.

Mathematical Computing↗
PubMed1990

[Evaluation of FCR (Fuji Computed Radiography) images applied to standard radiography for the diagnosis of chest diseases].

FCR (Fuji Computed Radiography) was added to plain chest radiography in order to evaluate its image characteristics and to determine the best image characteristics and to determine the best image processing program by comparing the visibility of shadows on conventional X-rays and on six FCR hard copy images processed by six mutually different image processing program. FCR showed excellent ability to visualize abnormal lung shadows as well as normal chest structures when processed by a moderate spatial frequency enhancement (spatial frequency 0.11 cycle/mm, level of enhancement). FCR also proved superior to the conventional film-screen system in the visualization of hilar and mediastinal structure as well as lung shadows. The effects of the image processing program on the visibility of shadow, granular and linear shadows were clearly demonstrated when a more intense spatial frequency enhancement (spatial frequency 0.18 cycle/mm, level of enhancement) was performed. The same results were obtained in terms of reticular and linear shadows and calcified lesions. On the contrary, low density shadows with poorly defined margins the lung field and infiltrates from mycoplasma pneumonia were well depicted by a program with a slightly steeper gradation (gamma; 1.0) and minimal frequency enhancement. Accordingly, FCR was found to be useful for the screening of abnormal chest X-ray shadows whereas it was also likely to demonstrate the best image when processed by the most appropriate image processing programs, depending on the characteristics of the shadows.

Adult↗
PubMed1995

Comparative study of three automatic programs of left ventricular ejection fraction evaluation.

The aim of this study was to compare three automatic programs (P1, P2, P3) for evaluating radionuclide left ventricular ejection fraction (LVEF) and to emphasize the clinical consequences. Gated radionuclide ventriculography was performed in 73 subjects, 15 of whom were healthy and 58 of whom had experienced heart failure. All scintigraphic data were processed with the three programs. Good inter-observer, intra-observer and automatic-manual reproducibility were observed using each of the three programs. On the other hand, in the normal subjects, the three mean normal LVEF values were significantly different from each other (P1 = 77 +/- 5%, P2 = 63 +/- 7%, P3 = 68 +/- 8%; P < 0.0001) In the pathological patients, the values obtained with P2 were significantly different from those obtained using P1 and P3 (P1= 32 +/- 15%, P2 = 26 +/- 13%; P < 0.0001), Moreover, the linear regression studies between the three automatic programs were always significantly different from the identity line equation (y = x). This study shows that LVEF criteria for normality depend on the program used, and inter-program measurement of LVEF is poorly reproducible. Caution is recommended when comparing data obtained from different centres (or different computers), either in the follow-up of a given patient or in gathering results from patient groups.

Adult↗
PubMed2000

How to program rate responsive pacemakers.

Because oxygen uptake (VO2) increases linearly with heart rate during exercise, the oxygen pulse reserve (OPR) method (VO2 reserve divided by heart rate reserve) may provide a valid guide for rate responsive parameter tailoring. Using custom-made software (Pacing Rate Profile Software [PRPS]) it is possible to predict the exercise pacing rate profile with significant accuracy, according to the patient's functional class when ergospirometry apparatus is not available for a cardiopulmonary stress test (CPX). PRPS for Windows is based on the OPR method and some known workload/metabolic cost of exercise relationships during effort. The present study had two aims; first, to evaluate the reliability of PRPS in accurately predicting pacing rate profiles; and second, the suitability of activity and metabolic rate responsive sensors in supplying pacing rates sufficiently near to those predicted using CPX or PRPS. To test the reliability of PRPS we studied 244 patients, NYHA Class I-II, under two different stress test protocols. In one, the bicycle protocol (25 W, 2-minute steps), we tested 137 normal patients (94 men and 43 women, mean age 67 +/- 15 years). Sixty-eight of these were simultaneously CPX tested. PRPS predicted pacing rates were matched against the patients' sinus rhythms or their theoretical CPX measured VO2 heart rates (OPR method). Linear regression analysis was highly significant (r = 0.93 and r = 0.97, respectively). The other, the treadmill protocol, consisted of three different protocols. (1) Speed Incremental Treadmill Stress Test (SITST): 57 patients underwent CPX (33 men and 24 women, mean age 67 +/- 15 years, NYHA Class I-II). All had been pacemaker implanted for SSS and/or advanced atrioventricular block (AVB). PRPS pacing rates were matched against CPX VO2 OPR calculated heart rates (r = 0.93), (linear regression analysis). (2) CAEP: 30 patients underwent CPX (26 men and 4 women, mean age 61 +/- 11 years, NYHA Class I-II). Thirteen of them had been pacemaker implanted for SSS and/or advanced AVB. In all 30 patients the PRPS rates were matched against CPX VO2 calculated rates (r = 0.90). In the 17 normal nonimplanted patients, the PRPS rates were also matched against sinus rhythms, (r = 0.80). (3) Weber: 20 patients underwent CPX (16 men and 4 women, mean age 68 +/- 8 years, NYHA Class I-II). As above, in six normal nonimplanted patients, statistical analysis between PRPS rates and sinus rhythms was performed (r = 0.89). The comparison between PRPS theoretical pacing rates and VO2 predicted rates in all 20 patients was also statistically significant (r = 0.93). Finally, to test the reliability of PRPS also in NYHA Class III-IV patients, we tested 22 implanted patients (15 men and 7 women, mean age 70 +/- 9 years) and compared PRPS predicted rates against VO2 CPX measured rates (r = 0.92). To determine if the wide variety of RR pacers were able to supply pacing rates near to those predicted, whether by means of CPX or PRPS, we studied a total of 89 patients: 49 of these (26 men and 23 women, mean age 66 +/- 12 years) had been implanted with activity sensors; 12 patients (11 men and one woman, mean age 70 +/- 7 years) had been implanted with metabolic sensors, and finally 28 patients (19 men and 9 women, mean age 70 +/- 12 years) had been implanted with dual sensors (activity + QT or minute ventilation). Linear regression analysis showed r = 0.93 for activity sensors, r = 0.94 for metabolic sensors, and r = 0.92 for dual sensor. In conclusion, when rate responsive pacing causes symptoms or functional impairment, physicians must provide a personalized rate response tailoring derived from precise, simple physiological testing. OPR is an easy physiological method for tailoring rate response settings, suitable for activity and metabolic sensors. When ergospirometry apparatus is not available, PRPS can successfully replace CPX testing for tailoring.

Aged↗
PubMed1992

A computer program (DCN) for numerical convolution and deconvolution of pharmacokinetic functions.

A program adapted for use on microcomputers (DCN) has been developed which permits one to perform operations of numerical convolution and deconvolution using polyexponential functions, that are often implemented in pharmacokinetic analysis. The program is written in Microsoft GWBASIC and can be used in personal computers with no modification. The user supplies information relating to the coefficients and exponentials defining the polyexponential equation of the response and weighting functions and the program performs the deconvolution operation by numerical integration using trapezoidal rule and provides numerical and graphic information concerning the input function. The program can be applied to the deconvolution of many linear pharmacokinetic systems and allows one to solve problems related to drug release, absorption, distribution, as well as others. Additionally, the program is able to perform the convolution operation if information about the input and weighting functions and is also able to simulate pharmacokinetic processes. The efficacy of the program was evaluated by comparison with several deconvolution algorithms, in particular that proposed by Veng-Pedersen and Iga.

Algorithms↗
PubMed2006

Estimation of non-linear growth models by linearization: a simulation study using a Gompertz function.

A method based on Taylor series expansion for estimation of location parameters and variance components of non-linear mixed effects models was considered. An attractive property of the method is the opportunity for an easily implemented algorithm. Estimation of non-linear mixed effects models can be done by common methods for linear mixed effects models, and thus existing programs can be used after small modifications. The applicability of this algorithm in animal breeding was studied with simulation using a Gompertz function growth model in pigs. Two growth data sets were analyzed: a full set containing observations from the entire growing period, and a truncated time trajectory set containing animals slaughtered prematurely, which is common in pig breeding. The results from the 50 simulation replicates with full data set indicate that the linearization approach was capable of estimating the original parameters satisfactorily. However, estimation of the parameters related to adult weight becomes unstable in the case of a truncated data set.

Algorithms↗
PubMed1981

Microcomputers in enzymology. A versatile BASIC computer program for analyzing kinetic data.

Direct curve-fitting is uncontested as the method of choice for evaluating kinetic experiments. If carried out by computer, the numerical solution of such problems is superior to customary graphical procedures in any respect. However, most programs available to date, cannot be executed by small systems. We now describe a BASIC program for desk-top microcomputers that performs linear and non-linear regression analysis of kinetic data. It may be directly applied to a number of problems common in enzyme kinetics, and is easily modified to handle further ones. The performance of the program is illustrated by some typical applications; in addition, fundamental statistical methods are discussed that allow a critical examination of the results obtained.

Aminopeptidases↗
PubMed1997

Relationships of growth hormone gene and milk protein polymorphisms to milk production traits in Simmental cattle.

The importance of milk proteins and the positive effect of administration of growth hormone (GH) on milk production, and the presence in some dairy cattle lines of greater GH concentrations prompted us to examine the presence of restriction fragment length polymorphism at the GH gene using the restriction enzyme TaqI and to investigate associations between this polymorphism in Simmental cows and bulls, as well as milk protein variants in Simmental cows, and milk production traits. Blood and milk were sampled from 279 Italian Simmental cows and semen was collected from 148 bulls of the same breed. Two fragment bands, denoted A and B, of 6200 and 5200 bp respectively, were examined and three patterns, AA, AB and BB, were found in both animal samples. All variants previously reported in other studies, for kappa, beta, and alpha s1-caseins, and beta-lactoglobulin, were found in the cows' samples. For the cows' samples, a BLUP (Best Linear Unbiased Predictor) analysis of results was performed using a REML (Restricted Maximum Likelihood) program and known heritabilities, whereas for bulls we have performed a General Linear Model analysis. The effect of GH gene polymorphism, using TaqI restriction enzyme, on milk production traits was not significant, but bulls of BB pattern had a higher breeding value for milk yield than AA bulls (P < 0.05). For the kappa-casein genotypic effects, cows of AB genotype gave milk with 1.53 +/- 0.70 g/kg less fat than cows of AA genotype. In addition, breeding values for milk protein content were significantly higher in BB bulls, with 0.87 +/- 0.32 and 0.71 +/- 0.34 g/kg more milk protein than AA and AB bulls respectively. Thus, our results revealed a GH gene polymorphism and indicated significant effects of milk protein polymorphisms on milk production traits in the Italian Simmental breed.

Animals↗
PubMed2006

Serum calcium is an independent predictor of quality of life in multiple myeloma.

Bone disease is an important feature of multiple myeloma, and hypercalcaemia is a frequent complication of this disease. We examined the association between serum calcium and quality of life (QOL) scores of 686 multiple myeloma patients at the time of diagnosis. Data from two Nordic studies using the EORTC QLQ-C30 questionnaire were analysed by means of linear regression analysis and a curve fitting program. Serum calcium was independently related to appetite loss, nausea/vomiting and physical functioning (P < 0.001) and to cognitive functioning (P = 0.001), i.e. scores reflecting symptoms that are well known in non-malignant hypercalcaemia. In addition, we found a highly significant independent relationship between serum calcium and the scores for fatigue and pain (P < 0.001). Serum calcium appeared to be as strong a predictor for fatigue as the concentration of haemoglobin. A cubic model (y = a + bx3) fitted the data slightly better than the simple linear model (y = a + bx) and suggested worsening QOL scores at levels of serum calcium above 2.5-3.0 mmol/L. Hypercalcaemia in patients with multiple myeloma seems to be associated with the same symptoms as in non-malignant hypercalcaemia. In addition, an increased level of serum calcium may aggravate the pain and fatigue caused by the skeletal disease itself.

Adult↗
PubMed1997

ReAligner: a program for refining DNA sequence multi-alignments.

We present a round-robin realignment algorithm that improves a potentially crude initial alignment of an assembled collection of DNA sequence fragments, as might, for example, be output by a typical fragment assembly program. The algorithm uses a weighted combination of two scoring schemes to achieve superior multi-alignments, and employs a banded dynamic programming variation to achieve a running time that is linear in the amount of sequence in the data set. We demonstrate that the algorithm improves upon the alignments produced by other assembly programs in a series of empirical experiments on simulated data. Finally, we present a pair of programs embodying the algorithms that are available from the Web site ftp://ftp.cs.arizona.edu/realigner.

Algorithms↗