Amplitude dependent frequency, desynchronization, and stabilization in noisy metapopulation dynamics

The enigmatic stability of population oscillations within ecological systems is analyzed. The underlying mechanism is presented in the framework of two interacting species free to migrate between two spatial patches. It is shown that that the combined effects of migration and noise cannot account for the stabilization. The missing ingredient is the dependence of the oscillations' frequency upon their amplitude; with that, noise-induced differences between patches are amplified due to the frequency gradient. Migration among desynchronized regions then stabilizes a "soft" limit cycle in the vicinity of the homogenous manifold. A simple model of diffusively coupled oscillators allows the derivation of quantitative results, like the functional dependence of the desynchronization upon diffusion strength and frequency differences. The oscillations' amplitude is shown to be (almost) noise independent. The results are compared with a numerical integration of the marginally stable Lotka-Volterra equations. An unstable system is extinction-prone for small noise, but stabilizes at larger noise intensity

Transition Phenomena Induced by Internal Noise and Quasi-absorbing State

We study a simple chemical reaction system and effects of the internal noise. The chemical reaction system causes the same transition phenomenon discussed by Togashi and Kaneko [Phys. Rev. Lett. 86 (2001) 2459; J. Phys. Soc. Jpn. 72 (2003) 62]. By using the simpler model than Togashi-Kaneko's one, we discuss the transition phenomenon by means of a random walk model and an effective model. The discussion makes it clear that quasi-absorbing states, which are produced by the change of the strength of the internal noise, play an important role in the transition phenomenon. Stabilizing the quasi-absorbing states causes bifurcation of the peaks in the stationary probability distribution discontinuously.Comment: 6 pages, 5 figure

A comparison of delayed SIR and SEIR epidemic models

In epidemiological research literatures, a latent or incubation period can be medelled by incorporating it as a delay effect (delayed SIR models), or by introducing an exposed class (SEIR models). In this paper we propose a comparison of a delayed SIR model and its corresponding SEIR model in terms of local stability. Also some numerical simulations are given to illustrate the theoretical results

Implementasi Metode Arima dalam Memprediksi Pertumbuhan Penduduk

Pertumbuhan penduduk terus meningkat tiap tahunnya dapat berdampak pada berbagai bidang. Untuk mengantisipasi dampak negatifnya, perlu dilakukannya prediksi jumlah penduduk pada waktu yang akan datang. Metode yang dapat digunakan dalam meramalkan pertumbuhan penduduk salah satunya metode ARIMA Box Jenkins. Penelitian ini bertujuan untuk mengetahui seberapa akuratnya penggunaan metode ARIMA dalam melakukan prediksi pertumbuhan penduduk di suatu wilayah. Metode yang digunakan dalam penelitian ini adalah deskriptif. Sumber data penelitian adalah data sekunder. Pengumpulan data menggunakan studi pustaka. Hasil dari penelitian yang dikaji menyatakan bahwa melakukan peramalan jumlah penduduk dengan menggunakan metode ARIMA memiliki tingkat ketepatan yang tidak stabil, ada beberapa penelitian yang memiliki tingkat ketepatan tinggi dan ada pula yang memiliki tingkat ketepatan rendah. Kesimpulan dari penelitian ini adalah metode ARIMA sudah banyak digunakan dalam memprediksi pertumbuhan penduduk dan tingkat keakuratan hasil peramalannya tidak jauh melenceng dari data sebenarnya

HUBUNGAN ANTARA PERSEPSI BAHAYA MEROKOK DAN KONFORMITAS TEMAN SEBAYA DENGAN PERILAKU MEROKOK PADA MAHASISWA

Penelitianinibertujuanuntukmengetahuisecara empiris hubungan antara persepsibahayamerokokdan konformitastemansebaya dengan perilakumerokok.PopulasidalampenelitianiniadalahseluruhmahasiswaUniversitasMuria Kudus yang merokok.Pengambilansampelmenggunakanteknikquota samplingyaitu 100 mahasiswa.Alatpengumpul data menggunakanskalapersepsibahayamerokok, skalakonformitastemansebayadanskalaperilakumerokok.Ketigaskalatersebutmenggunakanskalalikert yang dimodifikasimenjadi 4 alternatifpilihanjawaban.Adapunmetodeanalisis data menggunakananalisisregeresiduapredictors (regresiberganda).Hasilhipotesis mayor diperoleh rx12y = 0,589; p = 0,00 (p < 0,01) berartiadahubungan yang sangatsignifikanantarapersepsibahayamerokokdankonformitastemansebayaterhadapperilakumerokokdengansumbanganefektif(34,7%). Hipotesis minor pertamadiperoleh rx1y = -0,588; p = 0,00 (p < 0,01) berartiadanyahubungannegatif yang sangatsignifikanantarapersepsibahayamerokokdanperilakumerokokdengansumbanganefektif(34,6%). Sedangkanhipotesis minor keduadiperoleh rx2y = 0,566; p = 0,00 (p < 0,01) berartiadahubunganpositif yang sangatsignifikanantarakonformitastemansebayadanperilakumerokokdengansumbanganefektif(32,0%)

Design of flood warning prototype using ESP32 module-based ultrasonic sensors

Natural disasters such as floods can cause many losses to humans, such as material losses, trauma for the victims, and loss of life. Floods that occur can be caused by various factors such as human activity itself which results in changes in natural spatial planning, so the arrival of floods is also difficult to detect with certainty. Based on this, it is necessary to develop a technological innovation that helps provide a warning of the arrival of a natural disaster. The ESP32 microcontroller is one of the technologies that can be used to create an early warning system for the arrival of floods. The design and manufacture of this technology certainly involves modeling, algorithm planning, assembly of the components of the tools used, including wiring and mechanics as needed. This tool uses an internet of things (IoT) system with the help of an ESP32 microcontroller that supports integration via Wi-Fi and Bluetooth so that it can be connected to a smartphone device as a notification receiver in real time and accurately by notifying the water level which will be an indicator of potential flooding, so that people are more alert in the face of flooding to prevent and minimize the losses that will be experienced

PENGOLAHAN KOPI BUBUK “NDARUNGAN” SEBAGAI PEMANFAATAN TANAMAN KOPI DI DESA GAJAHREJO, KECAMATAN GAJAHREJO, KAB. MALANG

Abstrak: Desa Gajahrejo, Kecamatan Gedangan, Kabupaten Malang merupakan lokasi pengabdian masyarakat yang memiliki potensi produk kopi bubuk yang cukup baik. Namun, dalam produksi bubuk kopi masyarakat menghadapi permasalahan yaitu proses produksi yang kurang efisien karena masih manual, pengemasan yang kurang menarik bagi konsumen, ketidaktahuan mengenai prosedur memperoleh ijin edar produk dari Dinas Kesehatan. Dari permasalahan tersebut, maka ditawarkan beberapa solusi kepada petani kopi berupa kemasan sachet dengan filter drip bag dan pengurusan perijinan edar produk sebagai solusi yang ditawarkan dengan harap dapat membantu masyarakat desa Gajahrejo dalam mengembangkan usaha kopi bubuk “Ndarungan”. Abstract: Gajahrejo village, Gedangan District, Malang Regency is a community service location that has quite good potential for ground coffee products. However, in the production of coffee powder, the community faces problems, namely inefficient production processes because it is still manual, packaging that is not attractive to consumers, and ignorance of the procedure for obtaining a product distribution permit from the Health Office. From these problems, several solutions are offered to coffee farmers in the form of sachet packaging with drip bag filters and product distribution licensing management as solutions offered with the hope of helping the community of Gajahrejo village in developing the “Ndarungan” ground coffee business

Local enrichment and its nonlocal consequences for victim-exploiter metapopulations

The stabilizing effects of local enrichment are revisited. Diffusively coupled host-parasitoid and predator-prey metapopulations are shown to admit a stable fixed point, limit cycle or stable torus with a rich bifurcation structure. A linear toy model that yields many of the basic qualitative features of this system is presented. The further nonlinear complications are analyzed in the framework of the marginally stable Lotka-Volterra model, and the continuous time analog of the unstable, host-parasitoid Nicholson-Bailey model. The dependence of the results on the migration rate and level of spatial variations is examined, and the possibility of "nonlocal" effect of enrichment, where local enrichment induces stable oscillations at a distance, is studied. A simple method for basic estimation of the relative importance of this effect in experimental systems is presented and exemplified.Comment: 25 pages, 13 figures, to appear physica D 200