Mathematical Index Research Articles

A computer model for the assessment of employee performance loss as a function of thermal discomfort or degree of heat stress

This article presents an overview of different research and researchers’ attempts to derive a mathematical relationship between the performance loss and the thermal (dis)comfort of working people, expressed in the mean temperature sensation. The goal of this article and research is to present a single computer model and manageable design tool for a variety of disciplines, that is, mechanical engineering, building services and facility management, disciplines that participate in the design of the indoor environment of new or existing buildings and the improvement of working conditions in the workplace. The single computer model proposed in this article is assembled using a validated mathematical human thermophysiological model and a validated mathematical Wet Bulb Globe Temperature Index model, in combination with various mathematical performance (loss) models, based on comfort indices and heat stress indices. Although not perfect, the model is especially useful in the situation of comparative studies. For instance, in the early stages of the design process, the computer model assists in making better/the right (design) decisions regarding the thermal aspects of the indoor environment, whether or not in combination with validated building simulation models. The use of a dynamic thermophysiological model, in combination with the aforementioned models, enables the evaluation of the thermal influence of every architectural and building service and related adjustments for people and organizations. The use of a combination of models, as shown above, makes it possible to negotiate solutions and better balance investments with regard for profits and workable hours.

M307 逆解析による細胞牽引力の推定 : 数理的アプローチによる最適条件の検討(GS2,3 材料力学(4),修士研究発表セッション)

M307 逆解析による細胞牽引力の推定 : 数理的アプローチによる最適条件の検討(GS2,3 材料力学(4),修士研究発表セッション)

Discriminant indices for distinguishing thalassemia and iron deficiency in patients with microcytic anemia: a meta-analysis.

More than 40 mathematical indices have been proposed in the hematological literature for discriminating between iron deficiency anemia and thalassemia trait in subjects with microcytic red blood cells (RBCs). None of these discriminant indices is 100% sensitive and specific and also the ranking of the discriminant indices is not consistent. Therefore, we decided to conduct the first meta-analysis of the most frequently used discriminant indices. An extensive literature search yielded 99 articles dealing with 12 indices that were investigated five or more times. For each discriminant index we calculated the diagnostic odds ratio (DOR) and summary ROC analysis was done for comparing the performance of the indices. The ratio of microcytic to hypochromic RBCs (M/H ratio) showed the best performance, DOR=100.8. This was significantly higher than that of all other indices investigated. The RBC index scored second (DOR=47.0), closely followed by the Sirdah index (DOR=46.7) and the Ehsani index (DOR=44.7). Subsequently, there was a group of four indices with intermediate and three with lower DOR. The lowest performance (DOR=6.8) was found for the RDW (Bessman index). Overall, the indices performed better for adults than for children. The M/H ratio outperformed all other discriminant indices for discriminating between iron deficiency anemia and thalassemia trait. Although its sensitivity and specificity are not high enough for making a definitive diagnosis, it is certainly of value for identifying those subjects with microcytic RBC in whom diagnostic tests for confirming thalassemia are indicated.

Foraminifera of the Toarcian-Aalenian boundary from the Lusitanian Basin (Portugal): a paleoecological analysis

The detailed study of 37 well preserved benthic foraminiferal assemblages sampled throughout the upper Toarcian-middle Aalenian in two well calibrated sections representing different facies within the Lusitanian Basin (Portugal) - the Maria Pares and the Zambujal de Alcaria sections - has been carried out, aiming at interpreting past environmental conditions. Several mathematical indexes related to diversity, which allows establishing the particular conditions to which the assemblages were submitted, were applied. All the studied assemblages are characteristic of the Jurassic carbonate platforms of the Boreal Realm, in which the Lenticulina genus usually dominates. The Lagenina Suborder is the most abundant, but taking the second more abundant suborder into account, the comparison between coeval sections in the Lusitanian Basin allows the recognition of a regional gradient ranging from the distal part of the platform (Murtinheira) towards the transitional and proximal parts of the shelf (Maria Pares and Zambujal de Alcaria sections respectively). The relative abundances values, as well as the obtained data from the diversity indexes indicate that the studied assemblages are relatively abundant and diverse, reflecting general appropriate paleoenvironmental conditions for their development. Detailed analysis of the data allows the identification in both sections of three different episodes, traducing particular environmental conditions: unstable (Mactra Subzone-lower part of the Opalinum Subzone), favorable and stable (lower part of the Opalinum Subzone-upper part of the Comptum Subzone), and unfavorable (upper part of the Comptum Subzone-lower Bradfordensis Subzone). These data are consistent with previous results obtained in the Murtinheira and São Gião sections, located in the Northern Lusitanian Basin and corresponding to the distal and transitional parts of the platform respectively, and they aimed at contributing to a better understanding of the paleoecological conditions prevailing within the Lusitanian Basin during the Early-Middle Jurassic times.

Detection of Failures Within Transformers by FRA Using Multiresolution Decomposition

The detection of failures within power transformers is considered an important issue since these components are of critical importance for power system reliability; moreover, their replacement cost is extremely high. In monitoring the transformer condition along its useful life, frequency-response analysis (FRA) has gained great interest due to its sensitivity to failures in the windings and the iron core. These failures can be detected by evaluating transfer function changes by means of statistical and mathematical indices and classified according the frequency band in which these changes take place. However, this procedure involves evaluation inaccuracies due to disturbances or minor changes during FRA measurements. The new methodology is based on the decomposition of the original responses in several levels of decomposition (filtering) using the discrete wavelet transform, and the subsequent comparison using smooth versions of the responses. Fault detection is further supported with statistical indices calculated using the frequency band where abnormal differences appear. This procedure gives more robustness to the method and reduces the possible influence of disturbances during measurement in the diagnosis result. The methodology has been tested using different failure cases and two of them are used for validation purposes in this paper.

Screening Obese Children and Adolescents for Prediabetes and/or Type 2 Diabetes in Pediatric Practices

Increased prevalence of type 2 diabetes mellitus (T2DM) makes it important for pediatricians to use effective screening tools for risk assessment of prediabetes/T2DM in children. Children (n = 149) who had an oral glucose tolerance test (OGTT) and glycated hemoglobin (HbA1c) were studied. American Diabetes Association recommended screening criteria-HbA1c ≥5.7% and fasting plasma glucose (FPG) ≥100 mg/dL-were compared against OGTT. The homeostatic model assessment of insulin resistance (HOMA-IR), a mathematical index derived from fasting insulin and glucose, was compared with OGTT. We studied whether combining screening tests (HbA1c and fasting glucose or HbA1c and HOMA-IR) improved accuracy of prediction of the OGTT. HbA1c of ≥5.7% had a sensitivity of 75% and specificity of 57% when compared with the OGTT. Combining screening tests (HbA1c ≥5.7% and FPG ≥100 mg/dL; HbA1c ≥5.7% and HOMA-IR ≥3.4) resulted in improved sensitivity (95.5% for each), with the HbA1c-FPG doing better than the HbA1c-HOMA-IR combination in terms of ability to rule out prediabetes (likelihood ratio [LR]) negative. 0.07 vs 0.14). HbA1c of ≥5.7% provided fair discrimination of glucose tolerance compared with the OGTT. The combination of HbA1c and FPG is a useful method for identifying children who require an OGTT.

Assessing the dynamics of El-Rayan lakes, Egypt, using remote sensing techniques

The present study provided an integrated scheme of utilizing digital elevation models (DEMs) along with five Landsat satellite images between 1973 and 2013 in order to delineate the extent and capacity of El-Rayan depression, Egypt, and to highlight temporal changes which occurred upon the two anthropogenic lakes formed from the discharge of agricultural drainage wastewater within the depression. The capacity of the valley as well as water volume was estimated from DEM data, and water surface area was estimated by applying mathematical indices compiled from spectral bands in satellite data. The modified normalized difference water index (MNDWI) was the algorithm operated in this study. Results showed that the area of the depression at the sea level approaches about 352 km2, and the depression can store as much water as 6.45 billion m3. Water body of the two lakes has experienced reduction by seepage, evaporation, and shrinking to about 86 km2 in July 2013. Most shrinking was encountered at the lower lake due to drifting sand and local cultivation.

Functionality indexes assessed through a simple model of muscle activation, fatigue and recovery

A nonlinear dynamical system is proposed as a qualitative mathematical model with the twofold aim to reasonably describe the force behavior in a fatiguing sub-maximal contraction and to be possibly employed in assessing muscular activation indexes. The model's properties are studied in terms of its equilibria and their stability properties and the existence of the fatigue equilibrium is ensured as the only system's attractor in the feasibility range of the parameters. Suitable mathematical indicators — related to the dynamical properties of resilience and reactivity — are introduced to characterize the asymptotic and the transient system's behavior. The practical impact of the analytical results is elucidated and a connection is established between the introduced mathematical indicators and muscle functionality indexes as rate of force development, task failure time and complete restore time. Experimental validation with handgrip force signal at high load and possible practical applications are also presented.

Quantifying the role of personal management style in the success of investment portfolios

It is extremely difficult to quantify the effect of different management styles of portfolio managers upon the success of their portfolios. Various mathematical models in the literature attempt to predict the risk and returns of portfolios according to changes in the economic arena, but these models usually do not take into account the personal styles of portfolio managers. The aim of this paper is a modest attempt at quantifying the effect of different managerial styles upon decisions regarding portfolios. This is accomplished by the formulation of a mathematical performance index that portrays the influence of a portfolio manager's personal and managerial characteristics on the success of his portfolio.

Bibliometric indicators for evaluating the quality of scientifc publications.

Evaluation of quality and quantity of publications can be done using a set of statistical and mathematical indices called bibliometric indicators. Two major categories of indicators are (1) quantitative indicators that measure the research productivity of a researcher and (2) performance indicators that evaluate the quality of publications. Bibliometric indicators are important for both the individual researcher and organizations. They are widely used to compare the performance of the individual researchers, journals and universities. Many of the appointments, promotions and allocation of research funds are based on these indicators. This review article describes some of the currently used bibliometric indicators such as journal impact factor, crown indicator, h-index and it's variants. It is suggested that for comparison of scientific impact and scientific output of researchers due consideration should be given to various factors affecting theses indicators.

Assessment of Seed Viability and Vigour in Neem (Azadirachta indica A. Juss.)

Rapid loss in viability of neem (Azadirachta indica A. Juss.) seed is a major problem. Present effort was undertaken for developing a set pattern for assessing of viability and vigour in seed of various mother tree age of neem (Age I-06 years, Age II-15 years, Age III-25 years and Age IV->30 years old). Various viability test viz. triphenyle tetrazolium chloride test, electrical conductivity, excised embryo test, and germination test have been performed on seeds obtained from mother tree age classes. Inconsistency was observed with the TTC and EC test in germination of seed in laboratory as well as nursery. While various vigour tests viz. cold test, chemical stress test (methanol stress test), and accelerated ageing test alongwith ageing index, germination test (G%, MGT and GV) and various seedling growth parameters like seedling length (cm), number of leaves, collar diameter (cm), total biomass (g) alongwith mathematical indices i.e. vigour index, sturdiness quotient, volume index, quality index, root shoot ratio in nursery as well have been taken for study and showed better consistency. On the basis present study results of various viability and vigour test indicated that mother tree age class II performed better in comparison to others and it can be recommended for seed collection. Further it is also recommended that viability of neem seed may be assessed using various laboratory tests like excise embryo test and germination test (G%, MGT and GV) and vigour test may be taken preferably by cold germination test, chemical (methanol) stress test, accelerated ageing test in laboratory and germination alongwith various seedling growth parameters seedling length (cm), number of leaves, collar diameter (cm), total biomass (g) alongwith mathematical indices like Vigour Index, Sturdiness quotient, Volume Index, Quality index, root shoot ratio in nursery as discussed in this study.

Analysis of temperature time-series: Embedding dynamics into the MDS method

Global warming and the associated climate changes are being the subject of intensive research due to their major impact on social, economic and health aspects of the human life. Surface temperature time-series characterise Earth as a slow dynamics spatiotemporal system, evidencing long memory behaviour, typical of fractional order systems. Such phenomena are difficult to model and analyse, demanding for alternative approaches. This paper studies the complex correlations between global temperature time-series using the Multidimensional scaling (MDS) approach. MDS provides a graphical representation of the pattern of climatic similarities between regions around the globe. The similarities are quantified through two mathematical indices that correlate the monthly average temperatures observed in meteorological stations, over a given period of time. Furthermore, time dynamics is analysed by performing the MDS analysis over slices sampling the time series. MDS generates maps describing the stations’ locus in the perspective that, if they are perceived to be similar to each other, then they are placed on the map forming clusters. We show that MDS provides an intuitive and useful visual representation of the complex relationships that are present among temperature time-series, which are not perceived on traditional geographic maps. Moreover, MDS avoids sensitivity to the irregular distribution density of the meteorological stations.

HEART RATE VARIABILITY STRUCTURE FEATURES IN PERSONS BORN IN MAGADAN REGION DEPENDING ON VEGETATIVE REGULATION TYPE

390 senior schoolboys born in the Magadan region in the 1st-3rd generation aged 15-16 y. o. have been examined at rest to study 16 parameters of their heart rate variability. Based on the values of the index of tension (the stress index SI), the variation swing (MxDMn) and the spectrum total power (TP), the examined subjects were divided into three groups with prevalence of vagal, sympathetic or normotonic reactions of their vegetative nervous system. It has been found that the ranges of variability of the heart rate mathematical indices differed significantly depending on activity of the sympathetic or parasympathetic components of the nervous system, what conditioned methodically compulsory differentiation of the examinees according to the types of their vegetative regulation.

Are delusional contents replayed during dreams?

The relationship between dream content and waking life experiences remains difficult to decipher. However, some neurobiological findings suggest that dreaming can, at least in part, be considered epiphenomenal to ongoing memory consolidation processes in sleep. Both abnormalities in sleep architecture and impairment in memory consolidation mechanisms are thought to be involved in the development of psychosis. The objective of this study was to assess the continuity between delusional contents and dreams in acutely psychotic patients. Ten patients with a single fixed and recurring delusional content were asked to report their dreams during an acute psychotic break. Sixteen judges with four different levels of acquaintance to the specific content of the patients' delusions were asked to group the dreams, expecting that fragments of the delusional thought would guide the task. A mathematical index (f,t) was developed in order to compare correct groupings between the four groups of judges. Most judges grouped the dreams slightly above chance level and no relevant differences could be found between the four groups [F(3,12)=1.297; p=n.s.]. Scoring of dreams for specific delusional themes suggested a continuity in terms of dream and waking mentation for two contents (Grandiosity and Religion). These findings seem to suggest that at least some delusional contents recur within patients' dreams. Future studies will need to determine whether such continuity reflects ongoing consolidation processes that are relevant to current theories of delusion formation and stabilization.

Development of multi-parametric functional index model for evaluating the indoor comfort in built environment

Due to rapid urbanization of developing cities, the planners have a major challenge in designing climate responsive built environment for modern urban dwellers. In order to maintain a good built environmental quality, the various key design parameters of existing built form would need to be reviewed and analyzed to seek appropriate improvement. The present paper highlights the case study of a test room model in an educational campus. The experimentation was carried out in composite climatic zone of Nagpur in India. The desired built environment parameters viz., indoor light intensity, temperature and humidity was recorded and analyzed during experiments under controlled conditions of room openings. A functional index model was developed by this study using the multi-parametric regression analysis of the results. The qualitative assessment of the aforesaid parameters in terms of indoor comfort in the built environment was carried out. The developed mathematical index model for various functional parameters over the given geographic location can suitably be used by the designers for evaluating and enhancing the indoor comfort of a built environment suitable for the climate of Nagpur, India.

Geometric calibration of a terrestrial laser scanner with local additional parameters: An automatic strategy

Terrestrial laser scanning systems are steadily increasing in many fields of engineering, geoscience and architecture namely for fast data acquisition, 3-D modeling and mapping. Similarly to other precision instruments, these systems provide measurements with implicit systematic errors. Systematic errors are physically corrected by manufacturers before delivery and sporadically afterwards. The approach presented herein tackles the raw observables acquired by a laser scanner with additional parameters, a set of geometric calibration parameters that model the systematic error of the instrument to achieve the most accurate point cloud outputs, improving eventual workflow owing to less filtering, better registration and best 3D modeling. This paper presents a fully automatic strategy to calibrate geometrically terrestrial laser scanning datasets. The strategy is tested with multiple scans taken by a FARO FOCUS 3D, a phase-based terrestrial laser scanner. A calibration with local parameters for datasets is undertaken to improve the raw observables and a weighted mathematical index is proposed to select the most significant set of additional parameters. The improvements achieved are exposed, highlighting the necessity of correcting the terrestrial laser scanner before handling multiple data sets.

A Note on the Distribution of Some Sponges and Corals in a Seagrass Bed, Long Key, Florida

The ecology of sponges and corals in Florida reefs and on other hard bottoms has received attention in the literature, but in some tropical environments, such as seagrass beds, these organisms are less well known. Surveys reported here provide quantitative baseline estimates of the densities and distributions of some of the common sponges (Tedania ignis, Chondrilla sp., Chalinula sp.) and corals (Manicina areolata, Porites sp., Cladocora arbuscula). A seagrass bed dominated by turtle grass, Thalassia testudinum, directly off the eastern coast of Long Key State Park in the Florida Keys was monitored. The numbers of corals and sponges were recorded by snorkelers using 3X3 m random individual quadrats or quadrats in a continuous tract. Seagrass density was recorded on an ordinal scale. Of the organisms examined, only Manicina sp. numbers showed a significant, although negative, correlation with seagrass; weak positive relationships between the numbers of Chondrilla sp. and Chalinula sp. sponges and between the C. arbuscula and Porites sp. corals were observed. Based on a comparison of the observed numbers with those in Poisson and negative binomial distribution models, all six species that appear have aggregated distributions. The degree of clumping was also quantified using several mathematical indices and was in general agreement with the Poisson probabilities, although when Morista’s index is calculated, M. areolata clumping resulted in what is probably a high estimate. The data from the continuous grids were used to estimate the size and discreteness of the clumps; the species that had shown positive correlations had radii that were very similar.

Influence of lean and fat mass on bone mineral density and on urinary stone risk factors in healthy women

BackgroundThe role of body composition (lean mass and fat mass) on urine chemistries and bone quality is still debated. Our aim was therefore to determine the effect of lean mass and fat mass on urine composition and bone mineral density (BMD) in a cohort of healthy females.Materials and methods78 female volunteers (mean age 46 ± 6 years) were enrolled at the Stone Clinic of Parma University Hospital and subdued to 24-hour urine collection for lithogenic risk profile, DEXA, and 3-day dietary diary. We defined two mathematical indexes derived from body composition measurement (index of lean mass-ILM, and index of fat mass-IFM) and the cohort was split using the median value of each index, obtaining groups differing only for lean or fat mass. We then analyzed differences in urine composition, dietary intakes and BMD.ResultsThe women with high values of ILM had significantly higher excretion of creatinine (991 ± 194 vs 1138 ± 191 mg/day, p = 0.001), potassium (47 ± 13 vs 60 ± 18 mEq/day, p < 0.001), phosphorus (520 ± 174 vs 665 ± 186 mg/day, p < 0.001), magnesium (66 ± 20 vs 85 ± 26 mg/day, p < 0.001), citrate (620 ± 178 vs 807 ± 323 mg/day, p = 0.002) and oxalate (21 ± 7 vs 27 ± 11 mg/day, p = 0.015) and a significantly better BMD values in limbs than other women with low values of ILM. The women with high values of IFM had similar urine composition to other women with low values of IFM, but significantly better BMD in axial sites. No differences in dietary habits were found in both analyses.ConclusionsLean mass seems to significantly influence urine composition both in terms of lithogenesis promoters and inhibitors, while fat mass does not. Lean mass influences bone quality only in limb skeleton, while fat mass influences bone quality only in axial sites.

Visceral adiposity index is highly associated with adiponectin values and glycaemic disturbances

Visceral Adiposity Index (VAI) is a gender-specific mathematical index estimated with the use of simple anthropometric (body mass index and waist circumference) and biochemical (triglycerides and high density lipoprotein cholesterol) parameters. Recent studies have shown that VAI reflects accurately the degree of visceral adiposity and insulin resistance. However, up to now, VAI has not been evaluated if it correlates with carbohydrate metabolism disorders, as well as with adipokine secretion from the fat mass. In a cohort of 308 out of 414 adult Saudi subjects screened for the study, detailed personal medical history, anthropometrics and metabolic/hormonal profiles were obtained. Additionally, the circulating concentrations of several circulating adipokines, namely adiponectin, leptin, tumour necrosis factor-α (TNF-α) and resistin, were measured. Stepwise multivariate analysis showed that VAI was the sole determinant of adiponectin levels (R(2) =0·07, beta±SE: -0·25±0·05), while BMI and female gender predicted leptin levels (R(2) =0·26, 0·10±0·01 and 0·61±0·15, respectively). Furthermore, the presence of impaired fasting glucose (IFG)/diabetes was predicted only by age and VAI. We report for the first time the direct relations of VAI with adipose tissue secretion, as well as with functional glycaemic disorders. Because VAI is estimated easily with data obtained in everyday practice, it could be used as an indirect index of adiponectin levels and the risk of impaired glucose metabolism.

Maternal heart rate analysis during labor. Has the time come for computerized analysis?

Sir, We welcome the article on maternal heart rate (MHR) analysis during labor by van Veen et al. (1). Hopefully, this will bring more visibility to the important issue of misidentification of MHR during fetal heart rate (FHR) recording in labor and to new developments in computerized analysis that are underway (2, 3). Visual analysis of FHR tracings has been shown to be poorly reproducible (4) and it is possible that the same occurs with MHR tracings. Could this be an explanation for the finding reported by van Veen et al. of the occurrence of MHR decelerations during the first stage of labor, in contrast to the more well-known MHR accelerations during contractions and pushing, that we have consistently found with a system for computer analysis of MHR tracings, under development and validation by our group? In addition, computer analysis may provide a deeper understanding of the physiological basis of some MHR features during labour, by evaluating complex mathematical indices that have been shown to be associated with different maternal-fetal physiopathological conditions (2, 3).