Application of random survival forest for competing risks in prediction of cumulative incidence function for progression to AIDS

Objective: There has remained a need to better understanding of prognostic factors that affect the survival or risk in patients with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), particularly in developing countries. The aim of the present study aimed to identify the prognostic factors influencing AIDS progression in HIV positive patients in Hamadan province of Iran, using random survival forest in the presence of competing risks (death from causes not related to AIDS). This method considers all interactions between variables and their nonlinear effects. Method(s): A data set of 585 HIV-infected patients extracted from 1997 to 2011 was utilized. The effect of several prognostic factors on cumulative incidence function (probability) of AIDS progression and death were investigated. Result: The used model indicated that using antiretroviral therapy tuberculosis co-infection are two top most important variables in predicting cumulative incidence function for AIDS progression in the presence of competing risks, respectively. The patients with tuberculosis had much higher predicted cumulative incidence probability. Predicted cumulative incidence probability of AIDS progression was also higher for mother to child mode of HIV transmission. Moreover, transmission type and gender were two top most important variables for the competing event. Men and those patients with IDUS transmission mode had higher predicted risk compared to others. Conclusion: Considering nonlinear effects and interaction between variables, confection with tuberculosis was the most important variable in prediction of cumulative incidence probability of AIDS progression

Nanoporous Polyether Sulfone Membrane, Preparation and Characterization: Effect of Porosity and Mean Pore Size on Performance

Flat sheet membranes were prepared by phase inversion technique using polyether sulfone (PES) dissolved in dimethylacetamide (DMAc) with and without adding polyvinylpyrrolidone (PVP) or polyethyleneglycol (PEG). The characteristics of the prepared membranes were evaluated using Scanning Electron Microscope (SEM) images, Atomic Force Microscopy (AFM), and Optical Contact Angle (OCA) measurements, and porosity tests. The porosity test and SEM images show that increasing additives to a certain value increases the porosity of the membrane. Also, as the coagulation bath temperature is increased, the porosity of the membrane is increased. The roughness of the membrane is increased by increasing the additive concentration. The analysis of AFM images confirms the nanoporous structure of the prepared membranes, and that the membranes with appropriate pore size distribution can be prepared by the applied method. Permeability tests using single-layer membranes show that the direct relationship between porosity and the flux of pure water or salt solution is dominated by the effect of applied additive while the salt rejection shows an inverse relationship with the mean pore size regardless of the applied additive. The salt permeation flux is a function of total porosity while the salt rejection is a function of surface porosity. Pervaporation tests show that both permeation flux and enrichment factor depend on the total porosity of the support membrane

UK circulating strains of human parainfluenza 3: an amplicon based next generation sequencing method and phylogenetic analysis.

Background: Human parainfluenza viruses type 3 (HPIV3) are a prominent cause of respiratory infection with a significant impact in both pediatric and transplant patient cohorts.  Currently there is a paucity of whole genome sequence data that would allow for detailed epidemiological and phylogenetic analysis of circulating strains in the UK. Although it is known that HPIV3 peaks annually in the UK, to date there are no whole genome sequences of HPIV3 UK strains available.  Methods: Clinical strains were obtained from HPIV3 positive respiratory patient samples collected between 2011 and 2015.  These were then amplified using an amplicon based method, sequenced on the Illumina platform and assembled using a new robust bioinformatics pipeline. Phylogenetic analysis was carried out in the context of other epidemiological studies and whole genome sequence data currently available with stringent exclusion of significantly culture-adapted strains of HPIV3. Results: In the current paper we have presented twenty full genome sequences of UK circulating strains of HPIV3 and a detailed phylogenetic analysis thereof.  We have analysed the variability along the HPIV3 genome and identified a short hypervariable region in the non-coding segment between the M (matrix) and F (fusion) genes. The epidemiological classifications obtained by using this region and whole genome data were then compared and found to be identical. Conclusions: The majority of HPIV3 strains were observed at different geographical locations and with a wide temporal spread, reflecting the global distribution of HPIV3. Consistent with previous data, a particular subcluster or strain was not identified as specific to the UK, suggesting that a number of genetically diverse strains circulate at any one time. A small hypervariable region in the HPIV3 genome was identified and it was shown that, in the absence of full genome data, this region could be used for epidemiological surveillance of HPIV3.Wellcome Open Grant PHE PhD studentshi

Peningkatan Kemampuan Representasi Matematis Siswa SMP pada Materi Diagram Venn melalui Pendekatan Realistic Matematis Education

Penelitian eksperimen ini bertujuan untuk  mengetahui 1) kemampuan representasi matematis siswa kelas VII pada materi Diagram Venn melalui pendekatan matematika Realistik, 2) pendekatan matematika Realistik dapat  meningkatkan kemampuan reprsentasi matematis siswa dalam menyelesaikan Diagram Venn. Penelitian ini menggunakan desain penelitian One Group Pretest–Posttes Design dan menjadikan siswa kelas VII yang berjumlah 38 siswa sebagai sampel penelitian. Data penelitian dikumpulkan melalui teknik tes untuk mengetahui peningkatan kemampuan representasi matematis siswa terhadap penerapan model Realistic Mathematics Education (RME). Teknik analisis data menggunakan rumus PAP, N.Gain (g), uji Normalitas, dan uji Hipotesis. Hasil tes penelitian dianalisis untuk memperoleh tingkat kemampuan siswa dalam menyelesaikan soal dengan kualifikasi sebagai berikut: kualifikasi memuaskan sebesar 78,94% dan kualifikasi baik sebesar 21,05%. Pada taraf nyata α = 0,05 diperoleh thitung = 2,88 > ttabel = 1,684. Oleh karena itu hipotesis H0 ditolak, yang berarti bahwa terdapat peningkatan kemampuan representasi matematis siswa tergolong tinggi dengan nilai N Gain yang diperoleh yakni 0,88. Dengan demikian terdapat peningkatan kemampuan representasi matematis siswa melalui model pendekatan RME pada siswa SMP Negeri 4 Mangoli Selatan.Kata Kunci : Realistik Matematis Education, Kemampuan Representasi, Diagram Ven

PENERAPAN MODEL PEMBELAJARN KOOPERATIF TIPE STAD DALAM MENINGKATKAN HASIL BELAJAR SISWA PADA MATERI LUAS PERMUKAAN SISI DATAR BANGUN RUANG

Penelitian ini dilakukan dengan tujuan untuk: (1) Mengetahui penerapan model pembelajaran kooperatif tipe STAD dapat meningkatkan hasil belajar siswa pada materi luas permukaan sisi datar bangun ruang. (2) Mengetahui hasil belajar siswa pada materi luas permukaan sisi datar bangun ruang melalui pembelajaran kooperatif tipe STAD lebih baik dari hasil belajar siswa pada pembelajaran konvensional. Penelitian ini merupakan penelitian eksperimen dengan rancangan two groups pretest-posttest design, instrument yang digunakan berupa soal tes, LKS, lembar observasi guru dan siswa. Sampel yang diambil adalah siswa kelas VIII-2 berjumlah 30 siswa dan VIII-3 berjumlah 31 siswa. Teknik pengumpulan data dalam penelitian ini diperoleh dengan cara melihat skor yang diperoleh dari masing-masing kelas melalui tes soal matematika pada materi  luas permukaan sisi datar bangun ruang. Analisis data menggunakan chi-kuadrat untuk normalitas data dan statistik uji non parametrik yaitu uji tanda. Berdasarkan analisis data, disimpulkan bahwa: (i) setelah diberikan perlakuan dengan menerapkan model pembelajaran kooperatif tipe STAD, dapat dilihat bahwa, terdapat 18 siswa (60%) interpretasi tinggi, 11 siswa (36,67%) interpretasi sedang, dan 1 siswa (3,33%) interpretasi rendah. (ii) karena sebaran data pada salah satu sampel tidak berdistribusi normal, dalam hal ini statistik uji yang digunakan adalah statistik non parametrik, yaitu dengan menggunakan uji tanda. Hasil analisis uji tanda diperoleh h = 5 dengan taraf signifikansi 0,05, dari tabel nilai kritis h uji tanda, diperoleh h(0,05)(28) = 8, ini berarti h < htabel. Hasil ini berarti H0 ditolak, atau terima H1. Dengan demikian dapat disimpulkan bahwa hasil belajar siswa pada materi luas permukaan sisi datar bangun ruang dengan menggunakan model pembelajaran kooperatif tipe STAD lebih baik dari hasil belajar siswa dengan menggunakan pembelajaran konvensional

Pengaruh Model Pembelajaran Berbasis Masalah Terhadap Kemampuan Berpikir Kritis Matematis Siswa SMP Negeri 62 Halmahera Selatan Pada Materi Kubus

Penelitian ini merupakan penelitian eksperimen yang bertujuan untuk mengetahui, (1) Bagaimana kemampuan berpikir kritis matematis siswa setelah diterapkannya model pembelajaran berbasis masalah (2) Apakah model pembelajaran berbasis masalah berpengaruh terhadap kemampuan kerpikir  kritis matematis siswa. Populasi dalam penelitian ini adalah seluruh siswa kelas VIII SMP Negeri 62 Halmahera Selatan yang berjumlah 42 siswa yang kemudian tersebar pada dua kelas dan Sampel yang secara acak di ambil yaitu siswa kelas VIII1 yang berjumlah 20 siswa. Pengumpulan data dilakukan melalui tes kemampuan berpikir kritis matematis siswa dengan 6 butir soal sebagai instrumen yang telah divalidasi oleh validator. Analisis data yang digunakan adalah Kriteria kemampuan berpikir kritis, dan uji t. Hasil penelitian menunjukkan 60% yang sudah mencapai nilai di atas rata-rata, sehingga dikategorikan sebagai siswa yang sudah berpikir kritis,  40% siswa mencapai nilai di bawah rata-rata sehingga dikategorikan sebagai siswa yang  berpikir kritisnya kurang, Pengujian hipotesis dengan menggunakan uji t, dari hasil perhitungan diperoleh thitung = 2,21 dan ttabel = 2,09 karena thitung  ttabel maka H0 ditolak dan H1 diterima artinya bahwa data berdistribusi normal, dengan demikian model pembelajaran berbasis masalah berpengaruh terhadap kemampuan berpikir kritis matematis siswa.Kata kunci : Model Pembelajaran berbasis masalah, kemampuan berpikir kritis   matematis siswa

Increasing the reliability and the profit in a redundancy allocation problem

This paper proposes a new mathematical model for multi-objective redundancy allocation problem (RAP) without component mixing in each subsystem when the redundancy strategy can be chosen for individual subsystems. Majority of the mathematical model for the multi-objective redundancy allocation problems (MORAP) assume that the redundancy strategy for each subsystem is predetermined and fixed. In general, active redundancy has received more attention in the past. However, in practice both active and cold-standby redundancies may be used within a particular system design and the choice of the redundancy strategy becomes an additional decision variable. The proposed model for MORAP simultaneously maximizes the reliability and the net profit of the system. And finally, to clarify the proposed mathematical model a numerical example will be solved. Keywords: Redundancy Allocation Problem, Serial-Parallel System, Redundancy Strategies, MORAP