A prediction model of specific productivity index using least square support vector machine method

In the design of oilfield development plans, specific productivity index plays a vital role. Especially for offshore oilfields, affected by development costs and time limits, there are shortcomings of shorter test time and fewer test sampling points. Therefore, it is very necessary to predict specific productivity index. In this study, a prediction model of the specific productivity index is established by combining the principle of least squares support vector machine (LS-SVM) with the calculation method of the specific productivity index. The model uses logging parameters, crude oil experimental parameters and the specific productivity index of a large number of test well samples as input and output items respectively, and finally predicts the specific productivity index of non-test wells. It reduces the errors caused by short training time, randomness of training results and insufficient learning. A large number of sample data from the Huanghekou Sag in Bohai Oilfield were used to verify the prediction model. Comparing the specific productivity index prediction results of LS-SVM and artificial neural networks (ANNs) with actual well data respectively, the LS-SVM model has a better fitting effect, with an error of only 3.2%, which is 12.1% lower than ANNs. This study can better reflect the impact of different factors on specific productivity index, and it has important guiding significance for the evaluation of offshore oilfield productivity.Cited as: Wu, C., Wang, S., Yuan, J., Li, C., Zhang, Q. A prediction model of specific productivity index using least square support vector machine method. Advances in Geo-Energy Research, 2020, 4(4): 460-467, doi: 10.46690/ager.2020.04.1

Privacy-Preserving Health Data Collection for Preschool Children

With the development of network technology, more and more data are transmitted over the network and privacy issues have become a research focus. In this paper, we study the privacy in health data collection of preschool children and present a new identity-based encryption protocol for privacy protection. The background of the protocol is as follows. A physical examination for preschool children is needed every year out of consideration for the children's health. After the examination, data are transmitted through the Internet to the education authorities for analysis. In the process of data collection, it is unnecessary for the education authorities to know the identities of the children. Based on this, we designed a privacy-preserving protocol, which delinks the children’s identities from the examination data. Thus, the privacy of the children is preserved during data collection. We present the protocol in detail and prove the correctness of the protocol

Multiple metrics of diversity have different effects on temperate forest functioning over succession.

Manuscript. Published version available in Oecologia, Dec. 2016, vol. 182, issue 4, pp 1175–1185Biodiversity can be measured by taxonomic, phylogenetic, and functional diversity. How ecosystem functioning depends on these measures of diversity can vary from site to site and depends on successional stage. Here, we measured taxonomic, phylogenetic, and functional diversity, and examined their relationship with biomass in two successional stages of the broad-leaved Korean pine forest in northeastern China. Functional diversity was calculated from six plant traits, and aboveground biomass (AGB) and coarse woody productivity (CWP) were estimated using data from three forest censuses (10 years) in two large fully mapped forest plots (25 and 5 ha). 11 of the 12 regressions between biomass variables (AGB and CWP) and indices of diversity showed significant positive relationships, especially those with phylogenetic diversity. The mean tree diversity-biomass regressions increased from 0.11 in secondary forest to 0.31 in old-growth forest, implying a stronger biodiversity effect in more mature forest. Multi-model selection results showed that models including species richness, phylogenetic diversity, and single functional traits explained more variation in forest biomass than other candidate models. The models with a single functional trait, i.e., leaf area in secondary forest and wood density in mature forest, provided better explanations for forest biomass than models that combined all six functional traits. This finding may reflect different strategies in growth and resource acquisition in secondary and old-growth forests

14-Year Outcome of Angle-Closure Prevention with Laser Iridotomy in the Zhongshan Angle Closure Prevention Study: Extended Follow-Up of a Randomized Controlled Trial

Purpose: This study aimed to evaluate the efficacy of laser peripheral iridotomy (LPI) prophylaxis for primary angle closure suspects (PACS) after 14 years and to identify risk factors for the conversion from PACS to primary angle closure (PAC)./ Design: An extended follow-up of Zhongshan Angle Closure Prevention (ZAP) study./ Participants: A total of 889 Chinese patients aged 50 to 70 years with bilateral PACS./ Methods: Each patient received LPI in one randomly selected eye, with the fellow untreated eye serving as a control. Since the risk of glaucoma was low and acute angle closure (AAC) only occurred in rare cases, the follow-up was extended to 14 years despite substantial benefits of LPI reported after the 6-year visit./ Main Outcome Measures: The primary outcome was incidence of PAC, a composite endpoint including peripheral anterior synechiae (PAS), intraocular pressure (IOP) > 24 mmHg, or AAC. Results During the 14 years, 390 LPI-treated eyes and 388 control eyes were lost to the follow-up. A total of 33 LPI-treated eyes and 105 control eyes reached primary endpoints (P <0.01). Within them, twelve eyes developed AAC or primary angle closure glaucoma (AAC: five control eyes and one LPI-treated eye; PACG: four control eyes and two LPI-treated eyes). The hazard ratio for progression to PAC was 0.31 (95% confidence interval, 0.21–0.46) in LPI-treated eyes compared with control eyes. At the 14-year visit, LPI-treated eyes had severer nuclear cataract, higher IOP, larger angle width and limbal anterior chamber depth (LACD) than control eyes. Higher IOP, shallower LACD, and central anterior chamber depth (CACD) were associated with an increased risk of developing endpoints in control eyes. In the treated group, eyes with higher IOP, shallower LACD, or less IOP elevation after dark room–prone provocative tests (DRPPT) were more likely to develop PAC after LPI./ Conclusions: Despite a two-third decrease in PAC incidence after LPI, the cumulative risk of PAC was relatively low in the community-based PACS population over 14 years. Apart from IOP, IOP elevation after DRPPT, CACD, and LACD, more risk factors are needed to achieve precise prediction of PAC occurrence and guide clinical practice

Ras Drives Malignancy Through Stem Cell Crosstalk with the Microenvironment

Squamous cell carcinomas (SCCs) are triggered by marked elevation of RAS/MAPK signaling and progression from benign papilloma to invasive malignancy. A subset of tumor-initiating basal progenitors, the cancer stem cells, obtain increased resistance to chemo and immunotherapy along this path. However, the distribution and changes in cancer stem cells during progression from a benign state to an invasive SCC remain elusive. Here we show that following HRASG12V activation, cancer stem cells rewire their gene expression program and trigger self-propelling, aberrant signaling crosstalk with their tissue microenvironment that drives their malignant progression. Surprisingly, the non-genetic, dynamic cascade of crosstalk involves pathways often mutated in advanced metastatic SCCs with a high mutational burden. Coupling our clonal skin HRASG12V model with single-cell transcriptomics, chromatin-landscaping, lentiviral reporters and lineage-tracing, we show that the aberrant cancer stem cell-microenvironment crosstalk creates conditions ripe for hijacking leptin receptor (LEPR)-signaling, which in turn launches downstream PI3K-AKT-mTOR signaling at the benign-malignant transition. By functionally interrogating each step in this pathway, we unravel how dynamic temporal crosstalk with the microenvironment and orchestrated by the stem cells, profoundly fuels this path to malignancy. This discovery provides new insights into the path to malignancy and suggests broad implications for cancer therapeutics

Research on the Effect of Particle Size on the Interface Friction between Geogrid Reinforcement and Soil

For projects such as roads and railways, different fillers are often selected, and these also relate to the area where the project is located, so the characteristics of the filling soil should be considered in the design. However, the characteristics of the soil used in geosynthetic-reinforced soil (GRS) structure design are routinely simple soil properties and are not based on testing of soil with reinforcement. In order to study the influence of fillers with different particle sizes on the interface friction characteristics between the geogrid and soil, a self-developed large-scale pull-out testing machine was used. Under the action of a normal static load, pull-out tests were carried out with different fillers, such as sand, silt and gravel. According to the test results, the greater the stress applied in the normal direction, the greater the maximum pull-out force. As for the different fillers, shear stress from material with a larger particle size, such as gravel, was larger than that of sand and silt. Finally, to reveal the pattern of how the soil particles moved during the pull-out test, from a microscopic point of view, and the effect on particle–mesh size ratio, a series of discrete element method (DEM) analyses were conducted by PFC2D. The results indicated that a larger particle is more likely to rotate and move during the test, and this makes the interlocking effect greater between the geogrid and the soil, which leads to a larger pull-out force in the laboratory test