Assessment of the Transport Properties and Strength of Concretes Having Different Mix Proportions, Silica Fume and Fly Ash Additions

Measurement of concrete permeability is increasingly being used as an index for quality control in addition to concrete compressive strength. In the present work, the behavior of three different types of concrete was investigated to determine the transport properties and concrete compressive strength up to one year. The mix variables investigated include: cement content (300, 350, 400 and 450 kg/m3), water/cement ratio (0.35, 0.40, 0.45 and 0.50) and mineral pozzolanic materials (10% silica fume and 20% fly ash as a partial replacement of cement content). The experimental results were statistically analyzed to develop correlations between the concrete constituents and the selected durability indices of concrete. The test results showed an improvement in transport properties at higher levels of cement content and lower water/cement ratios. The permeability was significantly influenced by the inclusion of silica fume and fly ash in concrete. Test results showed that silica fume concrete (SFC) gives better performance when compared with normal and fly ash concrete (FAC) in terms of concrete compressive strength, chloride ion permeability and water penetration depth

Subspace Identification of a Glucose-Insulin model Using Meal Tracer Protocol Measurements

In this study, the problem of identifying a low complexity state space model describing glucose and insulin dynamics from low sample meal tracer experiments is investigated. Triple tracer meal protocol measurements (sampled as low as 15 samples per meal) together with continuous glucose monitoring measurements, measured concurrently at a rate of 5 minutes per sample, are used. A new formulation to estimate the missing input and output measurements at such low sample rates is developed. Nuclear norm minimization is used to exploit low rankness of the stacked input and output matrix, while the {ell1} norm is used to exploit an available sparse basis for the glucose flux profiles. Simulation results, using the UVa Padova simulator, show that the technique outperforms previous methods and also demonstrate the possibility of identifying state space models from triple tracer measurements with good prediction performance under non-ideal conditions

How Noisy Adaptation of Neurons Shapes Interspike Interval Histograms and Correlations

Channel noise is the dominant intrinsic noise source of neurons causing variability in the timing of action potentials and interspike intervals (ISI). Slow adaptation currents are observed in many cells and strongly shape response properties of neurons. These currents are mediated by finite populations of ionic channels and may thus carry a substantial noise component. Here we study the effect of such adaptation noise on the ISI statistics of an integrate-and-fire model neuron by means of analytical techniques and extensive numerical simulations. We contrast this stochastic adaptation with the commonly studied case of a fast fluctuating current noise and a deterministic adaptation current (corresponding to an infinite population of adaptation channels). We derive analytical approximations for the ISI density and ISI serial correlation coefficient for both cases. For fast fluctuations and deterministic adaptation, the ISI density is well approximated by an inverse Gaussian (IG) and the ISI correlations are negative. In marked contrast, for stochastic adaptation, the density is more peaked and has a heavier tail than an IG density and the serial correlations are positive. A numerical study of the mixed case where both fast fluctuations and adaptation channel noise are present reveals a smooth transition between the analytically tractable limiting cases. Our conclusions are furthermore supported by numerical simulations of a biophysically more realistic Hodgkin-Huxley type model. Our results could be used to infer the dominant source of noise in neurons from their ISI statistics

Sparse Reconstruction of Glucose Fluxes Using Continuous Glucose Monitors

A new technique for estimating postprandial glucose flux profiles without the use of glucose tracers is proposed. A sparse vector space representation is first found for the space of plausible glucose flux profiles using sparse encoding. A Lasso formulation is then used to estimate the glucose fluxes that combines (1) known patient model parameters; (2) the vector space of plausible glucose flux profiles; (3) continuous glucose monitor measurements taken during the meal; (4) amount of insulin injected; (5) amount of meal carbohydrates; and (6) an estimate of the initial conditions. Three glucose fluxes are then estimated, namely; glucose rate of appearance from the intestine; endogenous glucose production from the liver; insulin dependent glucose utilization; and other important state variables. The simulation results show that the technique is capable of estimating the glucose fluxes with high accuracy, even for complex meal scenarios. The experimental results indicate that the technique is capable of reproducing the triple tracer measurements for three T1DM undergoing the triple tracer protocol while estimating the missing measurements for a certain model parameter selection

Spontaneous Chylothorax Secondary to Kyphoscoliosis: A Case Report

chylothorax refers to the accumulation of fluid in the pleural cavity containing chylomicrons due to disruption of the thoracic duct. Currently, the most common causes of chylothorax are surgery and tumors; however, spontaneous chylothorax is still rare. Here we report an unusual presentation of spontaneous chylothorax secondary to severe kyphoscoliosis in a 9-year-old girl who presented with a symptomatic left chylothorax

Dysmenorrhea Among High-School Students and It\u27s Associated Factors in Kuwait

Background Although dysmenorrhea is not a life-threatening condition, it can cause a substantial burden on individuals and communities. There is no data on the prevalence of dysmenorrhea in Kuwait. This study aimed to estimate the prevalence of dysmenorrhea among female public high-school students in Kuwait and investigate factors associated with dysmenorrhea. Methods A cross-sectional study using multistage cluster sampling with probability proportional to size method was conducted on 763 twelfth grade female public high-school students (aged 16–21 years). We used face-to-face interview with a structured questionnaire to collect data on dysmenorrhea and presumed risk factors. Weight and height of the students were measured using appropriate weight and height scales in a standardized manner. The association between dysmenorrhea and potential risk factors was assessed using multiple logistic regression. Results The one-year prevalence of dysmenorrhea was found to be 85.6% (95%CI: 83.1–88.1%). Of the participants with dysmenorrhea, 26% visited a public or a private clinic for their pain and 4.1% were hospitalized for their menstrual pain. Furthermore, 58.2% of students with dysmenorrhea missed at least one school day and 13.9% missed at least one exam. Age of menarche (p-value = 0.005), regularity and flow of the menstrual period (p-value = 0.025, p-value = 0.009; respectively), and drinking coffee (p-value = 0.004) were significantly associated with dysmenorrhea in multivariable analysis. Conclusion Dysmenorrhea seems to be highly prevalent among female high-school students in Kuwait, resembling that of high-income countries. Because of the scale of the problem, utilizing school nurses to reassure and manage students with primary dysmenorrhea and referring suspected cases of secondary dysmenorrhea is recommended

Pharmaceutical versus mechanical induction of labor

Labor induction is one of the most common obstetric interventions carried out in obstetric institutions. More than one fifth of labors needs induction. To date, many methods are available for labor induction with the pharmaceutical and mechanical methods being the commonest. The most common pharmaceutical agents used are prostaglandins, oxytocin, synthetic progesterone antagonists, and nitric oxide. Mechanical induction is carried out through using balloon catheters, hygroscopic dilators, artificial membrane rupture, or membrane stripping. Though pharmaceutical methods had largely replaced mechanical induction of labor, no consensus guidelines recommend their use. Studies from literature are still conflicting. However, it is generally agreed that the use of a combined approach with both pharmaceutical and mechanical methods of induction yields the best outcome. This article will review the different methods for labor induction, their effectiveness, and adverse events