Causal Inference in Disease Spread across a Heterogeneous Social System

Diffusion processes are governed by external triggers and internal dynamics in complex systems. Timely and cost-effective control of infectious disease spread critically relies on uncovering the underlying diffusion mechanisms, which is challenging due to invisible causality between events and their time-evolving intensity. We infer causal relationships between infections and quantify the reflexivity of a meta-population, the level of feedback on event occurrences by its internal dynamics (likelihood of a regional outbreak triggered by previous cases). These are enabled by our new proposed model, the Latent Influence Point Process (LIPP) which models disease spread by incorporating macro-level internal dynamics of meta-populations based on human mobility. We analyse 15-year dengue cases in Queensland, Australia. From our causal inference, outbreaks are more likely driven by statewide global diffusion over time, leading to complex behavior of disease spread. In terms of reflexivity, precursory growth and symmetric decline in populous regions is attributed to slow but persistent feedback on preceding outbreaks via inter-group dynamics, while abrupt growth but sharp decline in peripheral areas is led by rapid but inconstant feedback via intra-group dynamics. Our proposed model reveals probabilistic causal relationships between discrete events based on intra- and inter-group dynamics and also covers direct and indirect diffusion processes (contact-based and vector-borne disease transmissions).Comment: arXiv admin note: substantial text overlap with arXiv:1711.0635

DETERMINATION OF ANTIOXIDANT CAPACITY IN PLUCHEA INDICA LESS LEAVES EXTRACT AND ITS FRACTIONS

Objective: This study was conducted to determine the DPPH free radical scavenging activity of pluchea extract (PE) and its fraction (ethyl acetate (EAF), n-butanol (BF) and aqueous (AF)) and comparing with the its activity of control antioxidant, such as green tea (GE) and rosemary extracts (RE), α-tocopherol succinate (ATS) and BHT.Methods: The antioxidant activity was evaluated by the decrease in absorbance as the result of DPPH˙ color change from purple to yellow at 517 nm by using a stopped-flow spectrometer UV-Vis. AE (antiradical efficiency) was a parameter more exactly used to measure the antioxidant power than EC50 (efficient concentration to reduce 50% of DPPH concentration). This parameter was determined by EC50 and TEC50 (the time needed to reach the steady state).Results: PE and its fraction had free radical-scavenging activity compared with control antioxidant. Based on EC50, the orders of ability to scavenging DPPH radicals was determined as the EAF~ GE>PE ~ ATS ~ RE ~ AF>BHT ~ BF. The results were not exactly because BHT and ATS were potentially as a synthetic antioxidant. Therefore AE parameter was used to determine scavenging activity. The classification order of scavenging activity based on AE was BHT>GE ~ ATS>EAF>RE~ BF~ PE~ AF.Conclusion: The PE and its fractions had DPPH free radical scavenging activity. Based on EC50 and AE parameters, the EAF showed the strongest DPPH free radical scavenging activity compared with PE and the other fractions

PENERAPAN STRATEGI PAIKEM DALAM TATANAN PEMBELAJARAN KOOPERATIF TIPE STUDENT TEAM ACHIEVEMENT DIVISION (STAD) UNTUK MENINGKATKANMOTIVASI BELAJAR MATEMATIKA SISWA KELAS VII DI SMP FATAHA KECAMATAN TUALANG KABUPATEN SIAK

Penelitian ini bertujuan mendeskripsikan penerapan strategi PAIKEM dalam tatanan pembelajan kooperatif tipe STAD untuk meningkatkan motivasi belajar matematika siswa kelas VII2 SMP FATAHA Kecamatan Tualang Kabupaten Siak setelah diterapkan strategi PAIKEM dalam tatanan pembelajaran kooperatif tipe STAD. Dalam penelitian ini rumusan masalahnya adalah “ Bagaimana penerapan strategi PAIKEM dalam tatanan pembelajaran kooperatif tipe STAD untuk meningkatkan motivasi belajar siswa kelas VII2 SMP FATAHA Kec.Tualang Kab.Siakpada pokok bahasan garis dan sudut?” Penelitian ini merupakan penelitian tindakan kelas. Dalam penelitian ini guru berkolaborasi dengan peneliti dalam proses pembelajaran. Subjek dalam penelitian ini adalah siswa kelas VII2 SMP FATAHA yang berjumlah 38 orang dan objek penelitian ini adalah strategi PAIKEM dalam tatanan pembelajaran kooperatif tipe STAD untuk meningkatkan motivasi siswa. Penelitian diawali dengan pertemuan awal (tanpa tindakan) dan tiga siklus (dengan tindakan). Teknik pengumpulan data pada penelitian ini, yaitu satu kali pertemuan sebelum tindakan, penelitian mengadakan observasi awal padamotivasi, selanjutnya peneliti menerapkan strategi PAIKEM dalam tatanan pembelajaran kooperatif tipe STAD, serta mengamati perkembangan motivasi siswa dengan mengisi lembar observasi. Adapun indikator keberhasilannya adalah 10 dan nilai yang harus dicapai semua indikator siswa tersebut. Berdasarkan hasil analisis dapat diperoleh data mulai dari tanpa tindakan sampai sesudah tindakan. Adapun data yang diperoleh yaitu 40.3% (tanpa tindakan), 64.4% (siklus I), 69.5% (siklus II) dan 76.5% (siklus III). Maka dapat diambil kesimpulan bahwa penerapan strategi PAIKEM dalam tatanan pembelajaran kooperatif tipe STAD dapat meningkatkan motivasi belajar matematika pada siswa

The acoustics of public square/places: a comparison between results from a computer simulation program and measurements in situ

http://www.odeon.dk/pdf/InterNoise2004.pd