Prediksi Kedalaman Terbentuknya Wax Pada Sumur X Lapangan Y

Ketika temperatur crude oil berkurang, komponen-komponen berat seperti paraffin/wax (C18 – C60) akan terpresipitasi dan mengendap pada dinding pipa. Pengendapan wax dapat menyebabkan diameter internal pipa berkurang dan pipa tersumbat. Laju produksi yang rendah dapat mempengaruhi terjadinya deposit wax karena waktu tinggal (residence time) minyak yang lama di pipa. Residence time minyak yang lama, menyebabkan adanya heat loss dari fluida, sehingga menurunkan temperatur minyak saat mengalir. Penelitian ini dilakukan dengan tujuan untuk memprediksi kedalaman terbentuknya wax pada sumur X. Untuk mengetahui kedalaman terbentuknya wax pada sumur X, yaitu dengan memplot hasil prediksi distribusi tekanan dan temperatur per kedalaman kedalam kurva wax deposition envelope. Fase wax pada sumur X akan muncul pada temperatur 131 °F dan tekanan 343 psi di kedalaman 300 ft dari kepala sumur dan pada saat tekanan statis reservoir mencapai 1752 psi

Komunikasi Pendek* Studi Floristik Jenis-jenis Anggrek (Orchidaceae) Di Taman Nasional Gunung Halimun, Jawabarat

Lokasi Taman Nasional Gunung Halimun secara administratif termasuk dalam tiga wilayah Kabupaten, yaitu Bogor, Sukabumi dan Lebak.Kawasan ini diresmikan sebagai Taman Nasional pada tahun 1992 yang meliputi luasan 40.000 ha.(Anonim. 1999.Gunung Halimun National Park Mesh Map. Biodiversity Conservation Project. Bogor. 53 pp.). Taman Nasional Gunung Halimun terbagi dalam sembilan daerah kerja (Resort). Lima resort di antaranya, yaitu kawasan resort Citorek,Cikelat, Kabandungan, Cisangku dan Cigudeg telah dikunjungi dan diamati keragaman jenis anggreknya. Tujuan penelitian ini adalah untuk mengetahui keragaman jenis anggrek dan mengevaluasi status populasinya di alam

Risk of Pseudotumor Cerebri Syndrome (PTCS) with hormonal contraceptive use

Background: Hormonal contraceptives (HC), one of the most prescribed classes of medication in women, have been linked with pseudotumor cerebri syndrome (PTCS). To date, no large epidemiologic study has examined this association.Methods: A case-control study using the IMS LifeLink Pharmetrics Plus database was conducted. Cases had an ICD-9-CM code for benign intracranial hypertension as well as a procedural code for a CT or MRI and a code for lumbar puncture procedure within 15 days of the PTCS code. Controls were selected from the cohort using density-based sampling.Results: From a cohort of 9,053,240 subjects, there were 288 cases of PTCS corresponding to 2,880 controls. The adjusted RRs for two or more prescriptions of oral combined contraceptive was 0.62 (95% confidence interval 0.39-0.99). RRs for overall HC use was 0.91 (95% CI 0.39-2.12) for one prescription of HCs and 0.69 (95% CI 0.45-1.05) for two or more prescriptions. The RRs for one and two or more prescriptions of progestin only HCs were 0.75 (95% CI 0.08-7.46) and 1.06 (95% CI 0.42-2.69), respectively.Conclusions: Overall HC use does not have a significant effect on incidence of PTCS, however harm associated with progestin-only contraceptives cannot be excluded

Correlation between serum vitamin D level and neonatal indirect hyperbilirubinemia

Background: Considering the significant prevalence of Neonatal Indirect Hyperbilirubinemia (NIH) and its irreversible neurological complications, identifying the factors involved in the prevalence of neonatal jaundice is essential. The present study was conducted to determine the relationship between serum vitamin D levels and the prevalence of NIH in infants admitted to Qods Hospital of Qazvin in Iran in 2015-16. Methods: In this case-control study, 30 term infants with NIH (the case group) were compared with 30 healthy, non- icteric, term infants (the control group) in terms of serum levels of 25-hydroxyvitamin D. The results were analyzed and compared between the two groups using t-test and the Chi-square test. Results: The mean and standard deviation of serum 25-hydroxyvitamin D levels were 10.76±8.6 ng/dl in the case group and 14.88±11.38 ng/dl in the control group. There were no significant differences between the two groups (P=0.11). Conclusion: The results suggest the lack of a relationship between vitamin D levels and NIH. However, further prospective studies are needed to conclude that vitamin D has no role in the pathogenesis of NIH. © 2018 The Author(s)

Correlation between serum vitamin D level and neonatal indirect hyperbilirubinemia

Background: Considering the significant prevalence of Neonatal Indirect Hyperbilirubinemia (NIH) and its irreversible neurological complications, identifying the factors involved in the prevalence of neonatal jaundice is essential. The present study was conducted to determine the relationship between serum vitamin D levels and the prevalence of NIH in infants admitted to Qods Hospital of Qazvin in Iran in 2015-16. Methods: In this case-control study, 30 term infants with NIH (the case group) were compared with 30 healthy, non- icteric, term infants (the control group) in terms of serum levels of 25-hydroxyvitamin D. The results were analyzed and compared between the two groups using t-test and the Chi-square test. Results: The mean and standard deviation of serum 25-hydroxyvitamin D levels were 10.76±8.6 ng/dl in the case group and 14.88±11.38 ng/dl in the control group. There were no significant differences between the two groups (P=0.11). Conclusion: The results suggest the lack of a relationship between vitamin D levels and NIH. However, further prospective studies are needed to conclude that vitamin D has no role in the pathogenesis of NIH. © 2018 The Author(s)

The synthetic triterpenoid RTA dh404 (CDDO-dhTFEA) restores endothelial function impaired by reduced Nrf2 activity in chronic kidney disease

AbstractChronic kidney disease (CKD) is associated with endothelial dysfunction and accelerated cardiovascular disease, which are largely driven by systemic oxidative stress and inflammation. Oxidative stress and inflammation in CKD are associated with and, in part, due to impaired activity of the cytoprotective transcription factor Nrf2. RTA dh404 is a synthetic oleanane triterpenoid compound which potently activates Nrf2 and inhibits the pro-inflammatory transcription factor NF-κB. This study was designed to test the effects of RTA dh404 on endothelial function, inflammation, and the Nrf2-mediated antioxidative system in the aorta of rats with CKD induced by 5/6 nephrectomy. Sham-operated rats served as controls. Subgroups of CKD rats were treated orally with RTA dh404 (2mg/kg/day) or vehicle for 12 weeks. The aortic rings from untreated CKD rats exhibited a significant reduction in the acetylcholine-induced relaxation response which was restored by RTA dh404 administration. Impaired endothelial function in the untreated CKD rats was accompanied by significant reduction of Nrf2 activity (nuclear translocation) and expression of its cytoprotective target genes, as well as accumulation of nitrotyrosine and upregulation of NAD(P)H oxidases, 12-lipoxygenase, MCP-1, and angiotensin II receptors in the aorta. These abnormalities were ameliorated by RTA dh404 administration, as demonstrated by the full or partial restoration of the expression of all the above analytes to sham control levels. Collectively, the data demonstrate that endothelial dysfunction in rats with CKD induced by 5/6 nephrectomy is associated with impaired Nrf2 activity in arterial tissue, which can be reversed with long term administration of RTA dh404

Improving the efficiency of Monte Carlo Bayesian calibration of hydrologic models via model pre-emption

Final published version available at: Shafii, M., Tolson, B., & Shawn Matott, L. (2015). Improving the efficiency of Monte Carlo Bayesian calibration of hydrologic models via model pre-emption. Journal of Hydroinformatics, 17(5), 763–770. https://doi.org/10.2166/hydro.2015.043Bayesian inference via Markov Chain Monte Carlo (MCMC) sampling and sequential Monte Carlo (SMC) sampling are popular methods for uncertainty analysis in hydrological modelling. However, application of these methodologies can incur significant computational costs. This study investigated using model pre-emption for improving the computational efficiency of MCMC and SMC samplers in the context of hydrological modelling. The proposed pre-emption strategy facilitates early termination of low-likelihood simulations and results in reduction of unnecessary simulation time steps. The proposed approach is incorporated into two samplers and applied to the calibration of three rainfall-runoff models. Results show that overall pre-emption savings range from 5 to 21%. Furthermore, results indicate that pre-emption savings are greatest during the pre-convergence 'burn-in' period (i.e., between 8 and 39%) and decrease as the algorithms converge towards high likelihood regions of parameter space. The observed savings are achieved with absolutely no change in the posterior set of parameters.Bryan Tolson's NSERC Discovery Gran

Uncertainty-based multi-criteria calibration of rainfall-runoff models: a comparative study

The final publication is available at Springer via http://dx.doi.org/10.1007/s00477-014-0855-xThis study compares formal Bayesian inference to the informal generalized likelihood uncertainty estimation (GLUE) approach for uncertainty-based calibration of rainfall-runoff models in a multi-criteria context. Bayesian inference is accomplished through Markov Chain Monte Carlo (MCMC) sampling based on an auto-regressive multi-criteria likelihood formulation. Non-converged MCMC sampling is also considered as an alternative method. These methods are compared along multiple comparative measures calculated over the calibration and validation periods of two case studies. Results demonstrate that there can be considerable differences in hydrograph prediction intervals generated by formal and informal strategies for uncertainty-based multi-criteria calibration. Also, the formal approach generates definitely preferable validation period results compared to GLUE (i.e., tighter prediction intervals that show higher reliability) considering identical computational budgets. Moreover, non-converged MCMC (based on the standard Gelman-Rubin metric) performance is reasonably consistent with those given by a formal and fully-converged Bayesian approach even though fully-converged results requires significantly larger number of samples (model evaluations) for the two case studies. Therefore, research to define alternative and more practical convergence criteria for MCMC applications to computationally intensive hydrologic models may be warranted.NSERC Discovery Gran