Drivers of pattern formation in a predator–prey model with defense in fearful prey

Existence of predator is routinely used to induce fear and anxiety in prey which is well known for shaping entire ecosystem. Fear of predation restricts the development of prey and promotes inducible defense in prey communities for the survival. Motivated by this fact, we investigate the dynamics of a Leslie–Gower predator prey model with group defense in a fearful prey. We obtain conditions under which system possess unique global-in-time solutions and determine all the biological feasible states of the system. Local stability is analyzed by linearization technique and Lyapunov direct method has been applied for global stability analysis of steady states. We show the occurrence of Hopf bifurcation and its direction at the vicinity of coexisting equilibrium point for temporal model. We consider random movement in species and establish conditions for the stability of the system in the presence of diffusion. We derive conditions for existence of non-constant steady states and Turing instability at coexisting population state of diffusive system. Incorporating indirect prey taxis with the assumption that the predator moves toward the smell of prey rather than random movement gives rise to taxis-driven inhomogeneous Hopf bifurcation in predator–prey model. Numerical simulations are intended to demonstrate the role of biological as well as physical drivers on pattern formation that go beyond analytical conclusions.

Absorbing Markov chains for analyzing COVID-19 infections

Recently, there are many works that proposed modeling approaches to describe the random movement of individuals for COVID-19 infection. However, these models have not taken into account some key aspects for disease such the prediction of expected time of patients remaining at certain health state before entering an absorption state (e.g., exit out of the system for ever such as death state or recovery). Therefore, we propose a dynamical model approach called the absorbing Markov chains for analyzing COVID-19 infections. From this modeling approach, we seek to focus and predict two states of absorption: recovery and death, as these two conditions are considered as important indicators in assessment of the health level. Based on the absorbing Markov model, the study suggested that there is a gradually increase in the predicted death number, while a decrease in the number of recovered individuals.

A Lattice Model for COVID-19 Epidemic

Susceptible, infective, recovered, and hospitalized/isolated individuals are placed on the cells of a nxn square lattice, where each cell is occupied by a single individual or is vacant. At discrete time units (typically one day each) all susceptibles and infectives execute a random movement and when a coincidence of the two types occurs the susceptible is converted to infective status according to some probability. Infectives are labelled by the number of days since originally infected. At each time increment the age label of the infectives is increased by one unit. When the label reaches a number like 15 or 20 days the susceptibles recover with some probability or become isolated/hospitalized. Upon reaching some age the latter types either recover or die. Probabilities for the movements and conversions from one status to another are implemented by random numbergeneration. Simulations were carried out to investigate the effect of several probability and age parameters, the size of population (proportional to nxn) and density (related to fraction of occupied cells), and the size of the movements. Mid-term gradual conversion of susceptibles to isolated was explored as intervention policy.

PERCOBAAN PENANDAAN LOBSTER PASIR (Panulirus homarus Linnaeus, 1758) DI TELUK PRIGI

Percobaan penebaran lobster pasir (Panulirus homarus) di Perairan Teluk Prigi, Kabupaten Trenggalek dilakukan pada 2015. Percobaan dilakukan dengan cara memberi tanda (tag) pada seluruh sampel lobster pasir yang ditebar, dikenal sebagai metode Capture-mark-recapture (CMR) dan sudah banyak digunakan untuk mempelajari populasi biota di alam. Penelitian bertujuan untuk mengetahui tingkat tertangkap kembali, laju pertumbuhan, dan pergerakan lobster pasir bertanda di Teluk Prigi. Penebaran lobster pasir bertanda dilakukan pada tiga lokasi yaitu Damas, Karanggongso dan Karangasem dengan jumlah 2.784 ekor dan diberi tanda jenis T-bar berwarna merah yang memiliki kode. Pengamatan lobster pasir bertanda yang tertangkap kembali dilakukan sepanjang tahun 2016 di Teluk Prigi (Februari-Desember). Tingkat tertangkap kembali lobster bertanda dihitung menggunakan proporsi antara lobster bertanda yang tertangkap dengan lobster bertanda yang ditebar. Laju pertumbuhan lobster bertanda yang tertangkap kembali dihitung berdasarkan pertumbuhan per satuan waktu yang sama dengan perubahan panjang dibagi dengan perubahan umur. Pergerakan lobster bertanda diukur melalui jarak dari lokasi tebar sampai dengan lokasi lobster bertanda yang tertangkap kembali. Tingkat tertangkap kembali lobster pasir (P. homarus) bertanda di Teluk Prigi sebanyak 4,7 %. Laju pertumbuhan lobster pasir yang tertangkap kembali rata-rata 0,09±0,05 mm/hari. Pergerakan lobster pasir bertanda yang tertangkap kembali di Teluk Prigi berkisar antara 0,1-11,36 km. Pergerakan lobster pasir bertanda memiliki kecenderungan acak dan tetap pada wilayah pantai.In 2015, restocking experiment of Scalloped spiny lobster (Panulirus homarus) was conducted in Gulf of Prigi, Trenggalek Regency and the lobsters were tagged. This methods is known as Capture-mark-recapture (CMR). CMR is widely used to study of biota populations in wild nature. The aims of this study are to determine the recapture rate, growth rate, and movement of tagged scalloped spiny lobster in Prigi Bay.The tagged spiny lobster release was realesed at three locations, namely Damas, Karanggongso and Karangasem with 2,784 lobsters and was tagged with a red T-bar type that has a code. Observations of tagged scalloped spiny lobsters were carried out again throughout 2016 in Prigi Bay (February-December). The recapture rate of tagged spiny lobster is calculated using the proportion between the tagged lobster with the tagged lobster released. The tagged tagged spiny lobster growth rate is calculated again based on growth per unit time which is equal to the change in length divided by the change in age. Tagged spiny lobster movements are measured by distance from the location of release to the location of the tagged tagged spiny lobster is capture again. The recapture rate of tagged spiny lobster (P. homarus) marked in Gulf of Prigi as much as 4.7%. The growth rate of tagged spiny lobster averaged 0.09 ± 0.05 mm/day. The movement of tagged spiny lobster in Gulf of Prigi ranges from 0.1 to 11.36 km. The movement of tagged spiny lobster has a random movement and remains in the coastal region.

Postcolonializing Practical Theological Methodology as Cartography of Boundary Dynamics

This paper conceptualizes a postcolonializing practical theological methodology that maps out the boundary dynamics of spectrality that often characterize the lived experiences on the margin of the empire. It draws from the mathematical understanding of Brownian motion that calculates the random movements of particles, as exposed by quantum mechanics, to construct an image for the postcolonializing practical theology. Then the random movement is explored through the concept of spectrality, which is engaged in dialogue with a 17th century Korean novel, Jangwha Hongryun Jeon, cultural theories and theologies.