Effect of vitamin A deficiency on respiratory infection: Causal inference for a discretely observed continuous time non-stationary Markov process

2012 ◽  
Vol 40 (4) ◽  
pp. 646-662 ◽  
Author(s):  
Mingyuan Zhang ◽  
Dylan S. Small
Keyword(s):  
Markov Process ◽  
Vitamin A ◽  
Causal Inference ◽  
Respiratory Infection ◽  
Continuous Time ◽  
Vitamin A Deficiency ◽  
Stationary Markov Process

scholarly journals Vitamin A deficiency alters airway resistance in children with acute upper respiratory infection

2012 ◽  
Vol 48 (5) ◽  
pp. 481-489 ◽  
Author(s):  
Cleia T. Amaral ◽  
Núbia N. Pontes ◽  
Bruna L.L. Maciel ◽  
Hugo S.M. Bezerra ◽  
Ana Nataly A.B. Triesta ◽  
...  
Keyword(s):  
Vitamin A ◽  
Respiratory Infection ◽  
Airway Resistance ◽  
Vitamin A Deficiency ◽  
Upper Respiratory Infection ◽  
Upper Respiratory

scholarly journals Absorption of labelled vitamin A in children during infection

1972 ◽  
Vol 27 (2) ◽  
pp. 299-304 ◽  
Author(s):  
B. Sivakumar ◽  
Vinodini Reddy
Keyword(s):  
Vitamin A ◽  
Intestinal Absorption ◽  
Respiratory Infection ◽  
Vitamin A Deficiency ◽  
Retinyl Acetate ◽  
Normal Children ◽  
Poor Communities

1. The intestinal absorption of [11,12 3H2] retinyl acetate was studied in five apparently normal children, eight children with respiratory infection and three with gastroenteritis.2. The absorption of vitamin A was significantly lower in children with respiratory infection or gastroenteritis than in normal children.3. In the light of these observations, it is suggested that repeated attacks of infections may significantly contribute to the prevalence of vitamin A deficiency in children of poor communities.

COMPARISONS OF DEPENDENCE FOR STATIONARY MARKOV PROCESSES

2000 ◽  
Vol 14 (3) ◽  
pp. 299-315 ◽  
Author(s):  
Taizhong Hu ◽  
Xiaoming Pan
Keyword(s):  
Markov Process ◽  
Markov Processes ◽  
Waiting Time ◽  
Continuous Time ◽  
Queueing Theory ◽  
Stationary Markov Process ◽  
Stationary Waiting Time ◽  
Markov Modulated ◽  
Stationary Workload ◽  
Monotonicity Results

Results and conditions which quantify the decrease in dependence with lag for a stationary Markov process and enable one to compare the dependence for two stationary Markov processes are obtained. The notions of dependence used in this article are the supermodular ordering and the concordance ordering. Both discrete-time and continuous-time Markov processes are considered. Some applications of the main results are given. In queueing theory, the monotonicity results of the waiting time of the nth customer as well as the stationary waiting time in an MR/GI/1 queue and the stationary workload in a Markov-modulated queue are established, thus strengthening previous results while simplifying their derivation. This article is a continuation of those by Fang et al. [7] and Hu and Joe [10].

Quantification of Vitamin A in Fortified Rapeseed, Groundnut and Soya Oils Using a Simple Portable Device: Comparison to High Performance Liquid Chromatography

2013 ◽  
Vol 83 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Cécile Renaud ◽  
Jacques Berger ◽  
Arnaud Laillou ◽  
Sylvie Avallone
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Vitamin A ◽  
High Performance ◽  
Vitamin A Deficiency ◽  
Developed Countries ◽  
Portable Device ◽  
Least Developed Countries ◽  
Control Food ◽  
Assay Precision

Vitamin A deficiency is still one of the major public health problems in least developed countries. Fortification of vegetable oils is a strategy implemented worldwide to prevent this deficiency. For a fortification program to be effective, regular monitoring is necessary to control food quality in the producing units. The reference methods for vitamin A quantification are expensive and time-consuming. A rapid method should be useful for regular assessment of vitamin A in the oil industry. A portable device was compared to high-performance liquid chromatography (HPLC) for three plant oils (rapeseed, groundnut, and soya). The device presented a good linearity from 3 to 30 mg retinol equivalents per kg (mg RE.kg- 1). Its limits of detection and quantification were 3 mg RE.kg- 1 for groundnut and rapeseed oils and 4 mg RE.kg- 1 for soya oil. The intra-assay precision ranged from 1.48 % to 3.98 %, considered satisfactory. Accuracy estimated by the root mean squares error ranged from 3.99 to 5.49 and revealed a lower precision than HPLC (0.4 to 2.25). Although it offers less precision than HPLC, the device estimates quickly the vitamin A content of the tested oils from 3 or 4 to 15 mg RE.kg- 1.

Research Recommendations for Applying Vitamin A-Labelled Isotope Dilution Techniques to Improve Human Vitamin A Nutrition

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 52-59 ◽  
Author(s):  
Sherry A. Tanumihardjo ◽  
Anura V. Kurpad ◽  
Janet R. Hunt
Keyword(s):  
Public Health ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Human Subjects ◽  
The Body ◽  
Pool Size ◽  
Serum Retinol ◽  
Vitamin A Status ◽  
Status Assessment ◽  
Total Body

The current use of serum retinol concentrations as a measurement of subclinical vitamin A deficiency is unsatisfactory for many reasons. The best technique available for vitamin A status assessment in humans is the measurement of total body pool size. Pool size is measured by the administration of retinol labelled with stable isotopes of carbon or hydrogen that are safe for human subjects, with subsequent measurement of the dilution of the labelled retinol within the body pool. However, the isotope techniques are time-consuming, technically challenging, and relatively expensive. There is also a need to assess different types of tracers and doses, and to establish clear guidelines for the use and interpretation of this method in different populations. Field-friendly improvements are desirable to encourage the application of this technique in developing countries where the need is greatest for monitoring the risk of vitamin A deficiency, the effectiveness of public health interventions, and the potential of hypervitaminosis due to combined supplement and fortification programs. These techniques should be applied to validate other less technical methods of assessing vitamin A deficiency. Another area of public health relevance for this technique is to understand the bioconversion of β-carotene to vitamin A, and its relation to existing vitamin A status, for future dietary diversification programs.

Vitamin A deficiency is associated with disease severity in patients with liver cirrhosis

2020 ◽  
Author(s):  
M Nagel ◽  
C Labenz ◽  
M Nguyen-Tat ◽  
N Cabezas Wallscheid ◽  
C Czauderna ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Vitamin A ◽  
Disease Severity ◽  
Vitamin A Deficiency

MANAGEMENT OF THE SUCCESS OF STUDENT’S LEARNING BASED ON THE MARKOV MODEL

2018 ◽  
pp. 4-11
Author(s):  
M. V. Noskov ◽  
M. V. Somova ◽  
I. M. Fedotova
Keyword(s):  
Information System ◽  
Markov Process ◽  
Continuous Time ◽  
Information Technologies ◽  
Educational Process ◽  
Automated Information System ◽  
The Subject ◽  
The University ◽  
Independent Work ◽  
Near Future

The article proposes a model for forecasting the success of student’s learning. The model is a Markov process with continuous time, such as the process of “death and reproduction”. As the parameters of the process, the intensities of the processes of obtaining and assimilating information are offered, and the intensity of the process of assimilating information takes into account the attitude of the student to the subject being studied. As a result of applying the model, it is possible for each student to determine the probability of a given formation of ownership of the material being studied in the near future. Thus, in the presence of an automated information system of the university, the implementation of the model is an element of the decision support system by all participants in the educational process. The examples given in the article are the results of an experiment conducted at the Institute of Space and Information Technologies of Siberian Federal University under conditions of blended learning, that is, under conditions when classroom work is accompanied by independent work with electronic resources.

Mitral Valve Replacement in an Adult with Left Pulmonary Agenesis

2015 ◽  
Vol 18 (3) ◽  
pp. 109
Author(s):  
Huseyin Saskin ◽  
Mustafa Idiz ◽  
Cagri Duzyol ◽  
Huseyin Macika ◽  
Rezan Aksoy
Keyword(s):  
Mitral Valve ◽  
Vitamin A ◽  
Valve Replacement ◽  
Viral Infections ◽  
Vitamin A Deficiency ◽  
Pulmonary Agenesis ◽  
Pulmonary Vessels ◽  
Live Births ◽  
Factors Associated ◽  
Female Predominance

Pulmonary agenesis is associated with the absence of pulmonary vessels, bronchi, or parenchyma. This condition usually occurs between the 4th and 5th week of gestation during the embryonic phase. Etiopathogenic factors associated with pulmonary agenesis are not fully understood. In the literature, genetic and teratogenic factors, viral infections, and vitamin-A deficiency are shown to be associated with pulmonary agenesis [Malcon 2012]. This condition may be seen unilaterally or bilaterally. Although the precise rate of incidence is unknown, it is estimated to occur in one of every 10,000 to 12,000 live births [Yetim 2011]. There is a 1.3:1 female predominance with unilateral agenesis [Halilbasic 2013]

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