Statistical Modeling of Count Data with Over-Dispersion or Zero-Inflation Problems

In this study, we will analyze a supply retailing company’s data to model the relationship between their customer’s past purchase behavior to predict their future online purchase behavior. The data was divided into time periods from 2016: P1-P6(January 31st to July 30th) and P7(July 31st to August 27th ). Based on customer’s past purchase information from the P1-P6 period, such as money spent, number of cart additions, transactions type, number of unique purchase dates, number of unique purchase skus, number of page views, number browse dates, company size, and number of products purchased, we aim to find if these information could predict the customer’s purchase behavior in the P7 period, which is the number of responses the customer responded to emails sent to them during P7. With the response variable as count data, we model the data in R with the Poisson distribution regression with an offset variable. We also model the number of responses out of the number of emails sent using a logistic regression model. For the Poisson model, since there are zero inflation or over-dispersion issues in the response, hurdle model, zero-inflated-poisson (ZIP) model and zero-inflated-negative-binomial (ZINB) model would be used to handle these issues. Model comparisons among the Poisson model with an offset, logistic regression model, hurdle model, ZIP, ZINB is conducted to select the best model to fit the data using the AIC criterion and the cross-validation criterion

Different Factors That Influence the Rise of India and Indonesia

India and Indonesia are among the largest economies in the world, and this was not something serious for China to pay attention to in the past. However, in this decade, these two countries have shown aggressive economic growth, compared to other developed and developing countries such as Russia and Mexico. India under the Modi administration launched the Digital India 2025 ambition in 2018 and a GDP target of 5 trillion USD, Indonesia under the Jokowi administration featured the Global Marine Fulcrum (GMF) and the target of becoming the 4th largest economy in the world by 2045. Both focus on many sectors, especially economic support infrastructures such as railroads, ports, and fast trains. In terms of military, India is already strong in the 4th position in the world, and Indonesia is still far below India, the 16th in the world. The current world situation is unstable, leading India to steps to strengthen ties with Western countries to stem China's growth. On the Indonesian side, it tends not to field close relations with the West and is still cooperating, both with the West and China to develop the country's potential and infrastructure. However, both of them still have the duty to become the foremost countries; India with the problem of unification, and adjusting its foreign policies to neighboring countries, and Indonesia need to finalize on innovation and domestic development. &nbsp

Does epigenetic polymorphism contribute to phenotypic variances in Jatropha curcas L.?

<p>Abstract</p> <p>Background</p> <p>There is a growing interest in <it>Jatropha curcas </it>L. (jatropha) as a biodiesel feedstock plant. Variations in its morphology and seed productivity have been well documented. However, there is the lack of systematic comparative evaluation of distinct collections under same climate and agronomic practices. With the several reports on low genetic diversity in jatropha collections, there is uncertainty on genetic contribution to jatropha morphology.</p> <p>Result</p> <p>In this study, five populations of jatropha plants collected from China (CN), Indonesia (MD), Suriname (SU), Tanzania (AF) and India (TN) were planted in one farm under the same agronomic practices. Their agronomic traits (branching pattern, height, diameter of canopy, time to first flowering, dormancy, accumulated seed yield and oil content) were observed and tracked for two years. Significant variations were found for all the agronomic traits studied. Genetic diversity and epigenetic diversity were evaluated using florescence Amplified Fragment Length Polymorphism (fAFLP) and methylation sensitive florescence AFLP (MfAFLP) methods. Very low level of genetic diversity was detected (polymorphic band <0.1%) within and among populations. In contrast, intermediate but significant epigenetic diversity was detected (25.3% of bands were polymorphic) within and among populations. More than half of CCGG sites surveyed by MfAFLP were methylated with significant difference in inner cytosine and double cytosine methylation among populations. Principal coordinates analysis (PCoA) based on Nei's epigenetic distance showed Tanzania/India group distinct from China/Indonesia/Suriname group. Inheritance of epigenetic markers was assessed in one F1 hybrid population between two morphologically distinct parent plants and one selfed population. 30 out of 39 polymorphic markers (77%) were found heritable and followed Mendelian segregation. One epiallele was further confirmed by bisulphite sequencing of its corresponding genomic region.</p> <p>Conclusion</p> <p>Our study confirmed climate and practice independent differences in agronomic performance among jatropha collections. Such agronomic trait variations, however, were matched by very low genetic diversity and medium level but significant epigenetic diversity. Significant difference in inner cytosine and double cytosine methylation at CCGG sites was also found among populations. Most epigenetic differential markers can be inherited as epialleles following Mendelian segregation. These results suggest possible involvement of epigenetics in jatropha development.</p

Preparation of ZrB2-ZrC-SiC-ZrO2 nanopowders with in-situ grown homogeneously dispersed SiC nanowires

To explore the application of SiC nanowires (SiCnws) in ZrB2 based ceramic materials, a facile approach is reported to in situ synthesize homogeneously dispersed SiCnws in ZrB2-ZrC-SiC-ZrO2 nanopowders by pyrolyzing a B-Si-Zr containing sol precursor impregnated in polyurethane sponge. The sponge was used to provide porous skeletons for the growth of SiC nanowires and facilitate their uniform distribution in the powders. After heat-treatment of the precursor with a Si/Zr atomic ratio of 10 at 1500 °C for 2 h, ZrB2-ZrC-SiC-ZrO2 ceramic powders were obtained with an even and fine particle size of ~100 nm. The SiCnws were in a diameter of ~100 nm with a controllable length varying from tens to hundreds of microns by increasing the silicon content in the precursor. Moreover, the produced SiCnws were in high purity, and homogeneously dispersed in the hybrid nanopowders. The study can open up a feasible route to overcome the critical fabrication process in SiCnws reinforced ceramic matrix composites

Risk prediction for <1 cm lateral lymph node metastasis in papillary thyroid microcarcinoma

BackgroundBecause the diameter of the suspicious lymph nodes is less than 1 cm and adjacent to important structures in the neck, the diagnosis of small LLNM is important but difficult without the help of fine needle aspiration (FNA). There are no relevant reports of risk factors that predict the risk of suspicious &lt;1 cm LLNM.MethodsA total of 159 PTMC patients with suspicious &lt;1 cm LLNM were included in the study. Multivariate logistic regression analysis was used to identify ultrasound independent predictors of LLNM. A predictive model was developed according to multivariate logistic regression and evaluated by Hosmer-Lemeshow fit test.ResultsAge ≤ 38 years old, the largest PTMC was located in the upper part, and the presence of liquefaction or microcalcification in suspicious lymph nodes were independent risk factors for LLNM (univariate analysis P = 0.00, 0.00, 0.00; multivariate analysis P = 0.00, 0.02, 0.00. OR = 4.66 [CI: 1.78-12.21], 3.04 [CI: 1.24-7.46], 6.39 [CI: 1.85-22.00]). The predictive model for the diagnosis of suspicious &lt;1 cm lymph nodes was established as: P = ex/(1 + ex). X = -1.29 + (1.11 × whether the largest tumor is located in the upper part) + (1.54 × whether the age is ≤ 38 years) + (1.85 × whether the suspicious lymph nodes have liquefaction/microcalcification). The Hosmer-Lemeshow fit test was used to test the predicted ability, and it found that the predictive model had a good fit and prediction accuracy (X2 = 6.214, P = 0.623 &gt; 0.05). Chi squared trend analysis showed that the increase in the number of risk factors gradually increased the malignancy possibility of suspicious &lt;1 cm lymph nodes (chi squared trend test, P = 0.00).ConclusionsAge ≤ 38 years old, the largest PTMC located in the upper part, and the presence of liquefaction or microcalcification in suspicious lymph nodes were independent risk factors for suspicious &lt;1 cm LLNM in PTMC patients. Our result show that it is feasible to evaluate the malignant possibility of these lymph nodes using the number of risk factors

MONITORING DYNAMIC GLOBAL DEFLECTION OF A BRIDGE BY MONOCULAR DIGITAL PHOTOGRAPHY

This study uses MDP (monocular digital photography) to monitor the dynamic global deflection of a bridge with the PST-TBP (Photographing scale transformation-time baseline parallax) method in which the reference system set near the camera is perpendicular to the photographing direction and does not need parallel to the bridge plane. A SONY350 camera was used to shoot the bridge every two seconds when the excavator was moving on the bridge and produced ten image sequences. Results show that the PST-TBP method is effective in solving the problem of the photographing direction being perpendicular to the bridge plane in monitoring the bridge by MDP. The PST-TBP method can achieve sub-pixel matching accuracy (0.3 pixels). The maximal deflection of the bridge is 55.34 mm which is within the bridge’s allowed value of 75mm. The MDPS (monocular digital photography system) depicts deflection trends of the bridge in real time, which can warn the possible danger of the bridge in time. It provides key information to assess the bridge health on site and to study the dynamic global deformation mechanism of a bridge caused by dynamic vehicle load. MDP is expected to be applied to monitor the dynamic global deflection of a bridge