Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MATHEMATICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed2005

Sex- and age-related differences in mathematics.

This study examined sex differences and age-related changes in mathematics based on Eccles's 1985 expectancy-value model of "achievement-related choices" and Dweck's 1986 motivation-process model. We have assessed motivational variables and performance in mathematics for youth in Grades 5, 7, and 9 in a German comprehensive secondary school. Significant sex differences in Grades 7 and 9 were observed even when school marks were controlled for. Furthermore, the results indicated differences between Grade 7 and Grade 9 on most of the motivational variables. Older students show a less favorable motivational pattern. Our results give evidence of the importance of motivational encouragement in mathematics classes, especially for girls and low achieving learners.

Adolescent↗
PubMed1998

Mathematical modeling of immunological reactions.

The immune system is a highly regulated, complex and integrated system which has evolved to provide the organism with substantial defenses against pathogenic organisms. Over the last several decades there has been an explosion of experimental data in this area, and new techniques in molecular and cellular biology have been crucial in deepening our understanding of immune processes. Most of these new techniques have allowed the isolation of the process or cell under study so that the results can be readily interpretable. At the present time, however, there is an emerging need to understand the system as it functions as a whole and the language of mathematics is the one best suited for this purpose. This review, written from the perspective of an experimental immunologist, describes some of the recent advances in the development of mathematical models of the immune system. Particular emphasis is placed on the rapidly growing field of modeling in HIV infection and T cell activation. Immunology as a whole will benefit from the introduction of the language of mathematics in much the same way as neuroscience has done in the last decade.

Animals↗
PubMed1998

Different mathematical approaches to estimating microbial protein supply in ruminants.

Many of the amino acids that are available for absorption in ruminants are derived from microbial protein that has been synthesized in the reticulorumen. This paper focuses on the prediction of the microbial protein supply and evaluates different approaches to represent mathematically the process of microbial protein synthesis. In current protein evaluation systems for ruminants, the microbial protein supply is predicted using empirical equations that relate microbial protein production to the amounts of ruminally available energy and nitrogen. In contrast, mechanistic models of rumen function endeavor to describe quantitatively the microbial protein production that is based on underlying identifiable processes. A brief description is presented of two culture techniques used to examine microbial ecosystems, namely, batch culture and chemostat culture. The mathematical equations describing these cultures are helpful in understanding key parameters of microbial production for inclusion in models, including specific growth rate, growth yield, and substrate affinity. The availability of carbohydrates is a primary determinant of microbial protein production in the rumen, and the adequacy of mathematical representations of this relationship in empirical and mechanistic models is assessed. The representation of substrate utilization for nongrowth processes and the relationship between microbial protein production and the availability of various nitrogen sources are discussed. A variable part of the synthesized microbial protein does not reach the duodenum but is degraded in the rumen, and its representation is examined. The prediction of microbial protein supply should be based on a sound representation of the underlying mechanisms, including the interactions among microbes and between microbial activity and substrate degradation.

Animals↗
PubMedDate not supplied

Nursing mathematics: the importance of application.

This study explores the effectiveness of a revision programme in nursing mathematics for student nurses. Students who took the revision programme achieved a marked improvement in test results, although some still scored low in written tests. When interviewed, the students reported that they had difficulty applying written work in the classroom to actual calculations in the workplace. They found that only by 'doing' mathematics did the theory make sense. The author recommends that students should be encouraged to maximise the opportunities to practise mathematics in the clinical setting.

Attitude of Health Personnel↗
PubMedDate not supplied

[Is the correlation between adequate dialysis in peritoneal dialysis and nutritional parameters mathematical or biological? Influence of residual renal function and comorbidity].

The relationship between urea Kt/V and nPCR (nPNA) is partly due to a mathematical coupling and greatly depends on the residual renal function (RRF). On the other hand, albumin could be just a comorbidity marker. Our objective in this study was to verify whether dialysis dose in peritoneal dialysis (PD) is biologically related to the nutritional state measured by the mean values of several parameters not mathematically related while analyzing the influence of RRF and comorbidity (C). 101 stable PD patients, 60M and 41F with a mean age of 59.3 +/- 14.3 years, were studied and followed up every six months for a mean time of 35.8 +/- 22.3 months (8-112). The variables studied were initial comorbidity, plasma albumin, normalized protein nitrogen appearance (nPNA), lean body weight % (LBW%) and fat-free mass index (FFMI) derived from creatinine, and RRF. In every study (n = 471) the 24 hours dialysate and urine volumes were collected and the total (T), dialytic (P) and renal (R) urea KT/V and normalized creatinine clearance (CCR) were determined and compared with the nutritional parameters. When starting PD 48 patients (47.5%) had some C and 34 (33.7%) were already anuric. The correlations of nPNA with T-KT/V and T-CCR (n = 101) were r = 0.67 and 0.50 (p < 0.0005) while the correlations of LBW% with T-KT/V and T-CCR were r = 0.36 and 0.40 (p < 0.0005) respectively. The correlations of albumin with T, P and R KT/V and CCR did not reach significance. The nutritional state was better in patients with a higher RRF and albumin showed significant differences when related to morbidity. KT/V and CCR correlations with nutritional variables not mathematically related verify the hypothesis that dialysis dose is biologically associated with the nutritional state.

Adult↗
PubMed2004

Comparisons of mathematics achievement of grade 8 students in the United States and the Russian Federation.

Using the Mantel-Haenszel (MH) Procedure, we analyzed data for 7,087 American and 4,022 Russian Grade 8 students from the Third International Mathematics and Science Study (TIMSS) to compare mathematics achievement in the two countries on each of the 124 multiple-choice items. The results of the analyses indicate that the performance of the students on individual multiple-choice mathematics items vary by country. The results also suggest that the relationship between country and item performance differ as a function of content area. A total score of a country's achievement does not provide the whole picture of achievement dynamics; it averages out potentially important information on student achievement and the causes of their performance relative to other countries. The dynamics of achievement across countries will not be revealed unless the analyses are done at the item level.

Adolescent↗
PubMedDate not supplied

[Mathematical analyses in the study of electroencephalographic signals].

AIM: The principal mathematical techniques applied to the EEG are reviewed. DEVELOPMENT: After the introduction of digital EEG, new mathematical tools have been developed for the EEG analysis. Nowadays there are several techniques that analyse the EEG signal in different ways, getting a better understanding of the EEG: development of new montages; artifact removal; analysis in time domain, phase coherence and synchrony; source analysis; epileptic seizures detection and prediction; superposition of electrical activity and other neuroimaging techniques. Although they have demonstrated their efficacy, the comparison between them is not always easy. CONCLUSIONS: The development of mathematical tools for EEG analysis has improved the knowledge of the electric cerebral activity in normal and pathological conditions. They study many different aspects of the EEG signal. Their continuous development will produce an increase the knowledge of the normal and pathological cerebral functions.

Diagnosis, Computer-Assisted↗
PubMed2006

[Learning difficulties in mathematics in children with attention deficit hyperactivity disorder].

INTRODUCTION: Attention deficit hyperactivity disorder (ADHD) and learning difficulties are two diagnostic categories of great social importance and impact, and which are associated in around 25-35% of cases. One explanation offered by researchers to account for this overlap is a deficit in executive functioning (EF). AIMS: 1) To compare EF and applied mathematical knowledge in children with ADHD, difficulties in learning mathematics (DLM) or ADHD + DLM, and to identify the deficiencies they experience. 2) To verify whether the phenotype hypothesis is fulfilled in the case of the ADHD + DLM condition. SUBJECTS AND METHODS: The study involved a quasi-experimental 2 x 2 design, with a sample made up of 78 participants (6-13 years old) who were divided into four groups: ADHD (n = 33), DLM (n = 15), ADHD + DLM (n = 15) and a control group (n = 15). Tests aimed at evaluating different cognitive processes as well as applied mathematical knowledge were administered: inhibitory control (go/no go); verbal working (backward digit-recall and counting memory task) and temporal-visual-spatial memory; short-term memory (direct digit-recall); attention (CPT); calculation speed (Canals) and real-life problems. RESULTS AND CONCLUSIONS: Taking the variables age, gender and intelligence quotient as covariables, results showed that the three groups with problems displayed a deficit of attention and in working memory; the DLM group stood out from the other owing to the presence of a specific deficiency affecting the ability to recall temporal-visual-spatial information. In contrast, deficits in inhibitory control were seen to be specific to ADHD. Finally, findings did not support the phenotype hypothesis, and it was therefore an accumulative profile.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

Mathematical disabilities in young primary school children with velo-cardio-facial syndrome.

The aim of the present study was to examine the previously reported mathematical disabilities (MD) of children with Velo-Cardio-Facial Syndrome (VCFS) in children of a younger age range. Fourteen children with VCFS (aged 6-10 years) participated in this study. These children were individually matched on sex, IQ, age and parental educational level to a control group of peers, selected from the same classes. A broad range of mathematical abilities were assessed, comprising number reading and writing, number comparison, counting, single-digit arithmetic, multidigit arithmetic and word problem solving. Consistent with previous reports, children with VCFS were significantly slower in counting numerosities and they tended to perform more poorly on number comparison. These results indicate that difficulties in low-level number processing in children with VCFS occur already at a very young age. Furthermore, children with VCFS demonstrated preserved retrieval of arithmetic facts, but, in contrast to older children with VCFS, no procedural difficulties in mathematics were observed. Finally, word problem solving appeared to be an important area of weakness, starting already at this young age.

Achievement↗
PubMedDate not supplied

[The mathematical modelling of the processes in the natural multiplication of human lice (exemplified by the head louse population].

Methods of mathematical modelling and prediction of louse propagation processes in the natural habitation medium are presented. Theoretical and experimental data on head louse ecology served the basis for the elaboration of a mathematical model predicting the population dynamics. The model structure corresponds to 3 stages of louse development cycle (eggs, larva, lice) and parameters corresponding to natural characteristics of louse propagation process: mean lifespan of each individual during each phase of the cycle, age, fertility and so forth. The model helped to study some properties of the population, assess maximum rate of head louse population growth, detect threshold effects, establish the effects of coefficients, limiting the number of louse per unit of the body surface. The model made it possible to formulate necessary data (distribution functions) for the creation of the mathematical model of Pediculosis.

Animals↗
PubMed1991

Comparison of mathematical indices of fetal heart rate variability with visual assessment in the human and sheep.

Mathematical indices for quantitation of fetal heart rate variability have been proposed by numerous authors, but there have only been infrequent attempts to determine which such indices correspond to the semi-subjective evaluation of variability observed by clinicians. We have previously examined most of the published indices by using them for calculation of the variability of sets of computer-generated numbers, and seeing if they fulfill certain criteria of validity. Two sets of indices (each measuring short-term and long-term variability) were selected as acceptable. Segments of fetal heart rate records from both humans and sheep, with a wide range of subjective variability, were used to compare the mathematically derived indices with the semi-subjective evaluation of three observers. The results show that the mathematical indices of short-term variability compare closely to its subjective evaluation of being present or absent. The long-term variability of indices also increase progressively with the observers' evaluations of increasing variability. The agreement among observers, measured by Cohen's kappa test, is generally "substantial", although for some indices the agreement was "moderate" to "almost perfect". We conclude that the two sets of indices examined do quantitate what is clinically regarded as fetal heart rate variability.

Animals↗
PubMed1989

[Medicine and symmetry. On the use of a mathematical concept in the early writings of the Corpus Hippocraticum].

The conception of symmetry in medical texts of the 5th century has never been connected with the development of the mathematical theory of proportions. However, we can find in Alcmaion and the hippocratic writings de vetere medicina, de natura hominis and de victu the differentiation between an arithmetical determinable measure and a qualitative determinable measure which is defined by a common lógos for incommensurable sizes. In de vetere medicina and de victu we see a conception of proportion and symmetry/commensurability, which requires the discovery of incommensurability. This discovery can be connected with the greek mathematician Hippocrates of Chios and his theorems of doubling the cube. We can detect an answer to this revolutionary development in mathematics in the methodological ideas of medical writers, who wanted to turn away medicine from the anti-descriptive and anti-empirical attitude in mathematics and philosophy.

Greece, Ancient↗
PubMed1989

[A statement on the mathematical tasks of optimization in dermatology].

The authors set forth the theoretical basis for the introduction of optimal management mathematical methods into clinical practice. Purely medical problems and those borderline with applied mathematics have been investigated. Recommendations on the choice of a purposeful functional system of differential equations describing physiological processes over the disease course, initial conditions, and restriction system are given. This helps plan the methods for and course of the clinical examinations and come closer to the creation of mathematical and program background for the problem of optimal management of dermatologic diseases treatment.

Arthritis, Psoriatic↗
PubMed1989

[Mathematical analysis of equilibrium on 2-site immunoradiometric assay using anti-human TSH monoclonal antibody].

A mathematical analysis of equilibrium was adapted on a practical 2-site immunoradiometric assay (IRMA) using 10 murine monoclonal antibodies (Mabs) to human TSH. The affinity constant of 10 Mabs was from 2.5 x 10(8) to 3.3 x 10(10) M-1. The dose-response curves using appropriate combinations of Mab-coated bead and 125I-labeled Mab were compared with the theoretical curves calculated from mathematical analysis of equilibrium. Theoretical curves were directly affected by the affinity constants in which antibodies with higher affinity constants showed higher binding activity of tracer. However, the curves which antibodies have more than 1 x 10(9) M-1 and 1 x 10(10) M-1 for capture antibody and tracer antibody did not show remarkable change, but were similar with the curve obtained from unlimited affinity constant. From these curve, the maximum and minimum detectable dose were approx. 2 x 10(-10) M and 4 x 10(-14) M, respectively. Seven out of 10 experimental curves for TSH showed good consistency with the corresponding theoretical curves which indicated that a mathematical analysis of equilibrium was useful to presume experimental results using monoclonal antibody.

Antibodies, Monoclonal↗
PubMed1989

[Mathematical approach to modeling of the treatment of suppurative processes].

Consideration of an inflammation focus as an "open system" provided analogy between microbiological processes in inflamed wounds and in systems of continuous cultivation of microorganisms. Mathematical modeling of such systems is widely used. Some of the methods for the mathematical modeling were applied to chemoprophylaxis and chemotherapy of postoperative wounds. In modeling continuous cultivation of microorganisms it is usually necessary to determine optimal conditions for the maximum yield of their biomass. In modeling of wound treatment the aim was to determine the process parameters providing the minimum biomass. The described simple models showed that there could be certain optimal flow rate of the washing fluid in the aspiration-washing procedure for wound treatment at which the drug was not completely washed out while the growth rate of the microbial population was minimal. Such mathematical models were shown valuable in optimizing the use of bactericidal and bacteriostatic antibiotics.

Anti-Infective Agents, Local↗
PubMed1988

[Methodologic bases for the mathematical planning of experiments in sanitary chemical research on polymeric building materials].

The most simple approaches and principles of orthogonal mathematic planning of one-, two- and three-factor experiments are discussed. The matrices of planning and the way of calculating the coefficients of regression of linear and quadratic models are given, as well as the way of control the rate of compliance of the established mathematical model with the experimental data by its average quadratic deviation, which should not surpass the error of the experiment. In spite developed in connection with the sanitary-chemical studies of the polymer building materials, the mathematical planning of the experiment can be applied also in other fields of hygiene, medicine etc. if the respective conditions are present.

Animals↗
PubMed1988

[Study of the combined action of an antibiotic and an immunostimulator using mathematical modeling].

A mathematical model of antibiotic and immunostimulator (IMS) combined effect on various elements of the immune system and general state of patients with infectious diseases is described. The model was constructed as a system including 6 usual differential equations of the 1st order. With the use of this model and a computer many diverse variants of infection development under conditions of treatment with IMS at the background of antibiotic therapy were modeled. Ii was shown that IMS-antibiotic complexes markedly improved the indices of antibiotic therapy as compared to the use of the antibiotics alone. In combined use of IMS and antibiotics it was possible to lower the antibiotic doses without lowering the antimicrobial effect. The use of IMS at the optimal period led to balanced activation of the host specific and nonspecific resistance factors at the background of antibacterial therapy. The results of the mathematical modeling corresponded to the data on protective effect of salmozan (IMS) and doxycycline (antibiotic) combination in animals (albino mice). It was concluded that the described mathematical model was adequate for validation and optimization of schemes for combined use of IMS and antibacterial agents.

Adjuvants, Immunologic↗
PubMed1978

[Role of computer technology and mathematical modelling in the treatment of patients after operations on the heart].

On the basis of ten-year experience in theoretical studies and experimental tests mathematical models of hemodynamics were built for the follow-up of parameters of the cardiovascular system which cannot be determined by means of any other modern methods. Three years of clinical studies of the Hewlett-Pachard monitoring computer system and its modification helped to elaborate the mathematical backing, a bank of mathematical models, original automatic programs for measuring the cardiac index, the index of myocardial viability, etc. The automatic system provides for an individual approach in assessing the patient's condition in actual time and for control of the treatment.

Cardiac Surgical Procedures↗