This page has only limited features, please log in for full access.

Mr. Fillipe Georgiou
University of Newcastle (Australia)

Basic Info


Research Keywords & Expertise

0 Applied Mathematics
0 Biomedical Engineering
0 Electronics
0 Partial Differential Equations
0 Cells

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

PhD Student in applied mathematics at the University of Newcastle, Australia. Current research interests are Collective Behavior modelling and Biomedical Engineering.

Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Research article
Published: 07 July 2021 in PLOS Computational Biology
Reads 0
Downloads 0

Locusts are short horned grasshoppers that exhibit two behaviour types depending on their local population density. These are: solitarious, where they will actively avoid other locusts, and gregarious where they will seek them out. It is in this gregarious state that locusts can form massive and destructive flying swarms or plagues. However, these swarms are usually preceded by the aggregation of juvenile wingless locust nymphs. In this paper we attempt to understand how the distribution of food resources affect the group formation process. We do this by introducing a multi-population partial differential equation model that includes non-local locust interactions, local locust and food interactions, and gregarisation. Our results suggest that, food acts to increase the maximum density of locust groups, lowers the percentage of the population that needs to be gregarious for group formation, and decreases both the required density of locusts and time for group formation around an optimal food width. Finally, by looking at foraging efficiency within the numerical experiments we find that there exists a foraging advantage to being gregarious.

ACS Style

Fillipe Georgiou; Jerome Buhl; J. E. F. Green; Bishnu Lamichhane; Ngamta Thamwattana. Modelling locust foraging: How and why food affects group formation. PLOS Computational Biology 2021, 17, e1008353 .

AMA Style

Fillipe Georgiou, Jerome Buhl, J. E. F. Green, Bishnu Lamichhane, Ngamta Thamwattana. Modelling locust foraging: How and why food affects group formation. PLOS Computational Biology. 2021; 17 (7):e1008353.

Chicago/Turabian Style

Fillipe Georgiou; Jerome Buhl; J. E. F. Green; Bishnu Lamichhane; Ngamta Thamwattana. 2021. "Modelling locust foraging: How and why food affects group formation." PLOS Computational Biology 17, no. 7: e1008353.

Journal article
Published: 25 December 2020 in Animals
Reads 0
Downloads 0

Inappropriate leash reactivity is one of the most common problems in shelter dogs, which negatively affects the health of dogs and reduces their adoptability. We explored 370 human-dog interactions, involving 74 volunteers and 111 dogs, in an animal shelter when volunteers walked shelter dogs on a leash, considering the effects of canine demographics and the results of the shelter’s canine behavioural assessments. The interaction was video recorded and coded using ethograms, and a leash tension meter was used to measure the pull strength of dogs and handlers. Results showed that dogs that were more relaxed during the shelter assessment (i.e., when socialising with humans or being left alone in a new environment) were less reactive on the leash, with lower tension and pulling frequency. Moreover, socialised and relaxed dogs displayed more positive body language, such as tail in a high position, gazing at the handler, and exploring the environment. When walking with these dogs, volunteers utilised fewer verbal cues and body language during the walk. In addition to the canine behaviour assessment, there were correlations between canine demographics and the behavioural interaction and humans’ perception. Finally, volunteers perceived the walk as less satisfactory when they needed to pull the leash harder during the walk. This research suggests that the RSPCA behavioural assessment may be useful in predicting the behaviour of shelter dogs when walked by volunteers.

ACS Style

Hao-Yu Shih; Mandy B. A. Paterson; Fillipe Georgiou; Clive J. C. Phillips. Do Canine Behavioural Assessments and Characteristics Predict the Human-Dog Interaction When Walking on a Leash in a Shelter Setting? Animals 2020, 11, 26 .

AMA Style

Hao-Yu Shih, Mandy B. A. Paterson, Fillipe Georgiou, Clive J. C. Phillips. Do Canine Behavioural Assessments and Characteristics Predict the Human-Dog Interaction When Walking on a Leash in a Shelter Setting? Animals. 2020; 11 (1):26.

Chicago/Turabian Style

Hao-Yu Shih; Mandy B. A. Paterson; Fillipe Georgiou; Clive J. C. Phillips. 2020. "Do Canine Behavioural Assessments and Characteristics Predict the Human-Dog Interaction When Walking on a Leash in a Shelter Setting?" Animals 11, no. 1: 26.

Journal article
Published: 16 October 2020 in Animals
Reads 0
Downloads 0

Previous studies have indicated that human gender and canine sex influences human–dog interactions. However, the majority of studies have considered the interaction when dogs were off-leash and the behavioural interactions when dogs are walked on a leash have not been addressed. This study investigated human–dog interactions when shelter volunteers take shelter dogs for an on-leash walk. Video records were made of 370 walks, involving 74 volunteers and 111 shelter dogs, and a leash tension meter was used to determine the pull strength of dogs and walkers. Human gender and canine sex had dyadic effects during the walk. Male dogs tended to pull more frequently and created increased leash tensions. Dogs displayed more stress related behaviours when interacting with men than women, with the signs being spending less time holding the tail in the high position, and more frequent gazing and lip-licking behaviours. Finally, there was a greater pre-disposition in women to use verbal commands, and language typically used with babies, while men were more inclined to have physical contact with dogs. This study’s results may be used to match shelter dogs with appropriate men and women volunteers for walking exercise of the dog, and to improve potential dog socialisation efforts by shelters.

ACS Style

Hao-Yu Shih; Mandy B. A. Paterson; Fillipe Georgiou; Nancy A. Pachana; Clive J. C. Phillips. Who Is Pulling the Leash? Effects of Human Gender and Dog Sex on Human–Dog Dyads When Walking On-Leash. Animals 2020, 10, 1894 .

AMA Style

Hao-Yu Shih, Mandy B. A. Paterson, Fillipe Georgiou, Nancy A. Pachana, Clive J. C. Phillips. Who Is Pulling the Leash? Effects of Human Gender and Dog Sex on Human–Dog Dyads When Walking On-Leash. Animals. 2020; 10 (10):1894.

Chicago/Turabian Style

Hao-Yu Shih; Mandy B. A. Paterson; Fillipe Georgiou; Nancy A. Pachana; Clive J. C. Phillips. 2020. "Who Is Pulling the Leash? Effects of Human Gender and Dog Sex on Human–Dog Dyads When Walking On-Leash." Animals 10, no. 10: 1894.

Preprint content
Published: 21 September 2020
Reads 0
Downloads 0

Locust swarms are a major threat to agriculture, affecting every continent except Antarctica and impacting the lives of 1 in 10 people. Locusts are short horned grasshoppers that exhibit two behaviour types depending on their local population density. These are; solitarious, where they will actively avoid other locusts, and gregarious where they will seek them out. It is in this gregarious state that locusts can form massive and destructive flying swarms or plagues. However, these swarms are usually preceded by the formation of hopper bands by the juvenile wingless locust nymphs. It is thus important to understand the hopper band formation process to control locust outbreaks.On longer time-scales, environmental conditions such as rain events synchronize locust lifecycles and can lead to repeated outbreaks. On shorter time-scales, changes in resource distributions at both small and large spatial scales have an effect on locust gregarisation. It is these short time-scale locust-resource relationships and their effect on hopper band formation that are of interest.In this paper we investigate not only the effect of food on both the formation and characteristics of locust hopper bands but also a possible evolutionary explanation for gregarisation in this context. We do this by deriving a multi-population aggregation equation that includes non-local inter-individual interactions and local inter-individual and food interactions. By performing a series of numerical experiments we find that there exists an optimal food width for locust hopper band formation, and by looking at foraging efficiency within the model framework we uncover a possible evolutionary reason for gregarisation.Author summaryLocusts are short horned grass hoppers that live in two diametrically opposed behavioural states. In the first, solitarious, they will actively avoid other locusts, whereas the second, gregarious, they will actively seek them out. It is in this gregarious state that locusts form the recognisable and destructive flying adult swarms. However, prior to swarm formation juvenile flightless locusts will form marching hopper bands and make their way from food source to food source. Predicting where these hopper bands might form is key to controlling locust outbreaks.Research has shown that changes in food distributions can affect the transition from solitarious to gregarious. In this paper we construct a mathematical model of locust-locust and locust-food interactions to investigate how and why isolated food distributions affect hopper band formation. Our findings suggest that there is an optimal food width for hopper band formation and that being gregarious increases a locusts ability to forage when food width decreases.

ACS Style

Fillipe Georgiou; Jerome Buhl; J.E.F. Green; Bishnu Lamichhane; Natalie Thamwattana. Modelling locust foraging: How and why food affects hopper band formation. 2020, 1 .

AMA Style

Fillipe Georgiou, Jerome Buhl, J.E.F. Green, Bishnu Lamichhane, Natalie Thamwattana. Modelling locust foraging: How and why food affects hopper band formation. . 2020; ():1.

Chicago/Turabian Style

Fillipe Georgiou; Jerome Buhl; J.E.F. Green; Bishnu Lamichhane; Natalie Thamwattana. 2020. "Modelling locust foraging: How and why food affects hopper band formation." , no. : 1.

Journal article
Published: 10 August 2020 in Animals
Reads 0
Downloads 0

Leash tension forces exerted by dog and handler during walks affect their welfare. We developed a novel ambulatory measurement device using a load cell and a tri-axial accelerometer to record both the tension and direction of forces exerted on the leashes. Data were relayed telemetrically to a laptop for real time viewing and recording. Larger and heavier dogs exerted higher leash tension but had a lower pulling frequency than their smaller and lighter conspecifics. This pattern was observed in the reactional forces of handlers. Young dogs pulled more frequently during walks, which was also mirrored in handlers’ pulling. Well-behaved dogs created lower leash tension, but handlers did not respond with lower forces. This novel method of recording leash tension will facilitate real-time monitoring of the behaviour of dogs and their handlers during walks.

ACS Style

Hao-Yu Shih; Fillipe Georgiou; Robert A. Curtis; Mandy B. A. Paterson; Clive J. C. Phillips. Behavioural Evaluation of a Leash Tension Meter Which Measures Pull Direction and Force during Human–Dog On-Leash Walks. Animals 2020, 10, 1382 .

AMA Style

Hao-Yu Shih, Fillipe Georgiou, Robert A. Curtis, Mandy B. A. Paterson, Clive J. C. Phillips. Behavioural Evaluation of a Leash Tension Meter Which Measures Pull Direction and Force during Human–Dog On-Leash Walks. Animals. 2020; 10 (8):1382.

Chicago/Turabian Style

Hao-Yu Shih; Fillipe Georgiou; Robert A. Curtis; Mandy B. A. Paterson; Clive J. C. Phillips. 2020. "Behavioural Evaluation of a Leash Tension Meter Which Measures Pull Direction and Force during Human–Dog On-Leash Walks." Animals 10, no. 8: 1382.

Journal article
Published: 09 October 2019 in ANZIAM Journal
Reads 0
Downloads 0

One method of modelling cell-cell adhesion gives rise to a partial integro-differential equation. While non-adaptive techniques work in the numerical modelling of such an equation, there are also many opportunities for optimisation. The studied partial integro-differential equation has a tendency to produce aggregations leaving large regions where both the function value and derivative are equal to zero, leading to a higher resolution than needed and lower than desired resolution where the aggregations form. In order to overcome this we develop an adaptive scheme in both space and time using a modified form of Matlab's ode45 and finite volume methods to more efficiently simulate the studied partial integro-differential equation. We use our numerical scheme to simulate the problem presented by Armstrong et al. [J. Theor. Biol. 243 (2006), pp. 98--113] and compare results. References N. J. Armstrong, K. J. Painter, and J. A. Sherratt. A continuum approach to modelling cell-cell adhesion. J. Theor. Biol., 243:98113, 2006. doi:10.1016/j.jtbi.2006.05.030. R. J. LeVeque. Finite volume methods for hyperbolic problems. Cambridge Texts in Applied Mathematics. Cambridge University Press, 2002. doi:10.1017/CBO9780511791253. C. F. Van Loan. Introduction to scientific computing: A matrix vector approach using MATLAB. MATLAB Curriculum. Prentise Hall, 1997. J. A. Sheratt, S. A. Gourley, N. J. Armstrong, and K. J. Painter. Boundedness of solutions of a non-local reaction-diffusion model for adhesion in cell aggregation and cancer invasion. Eur. J. Appl. Math., 20(1):123144, 2009. doi:10.1017/S0956792508007742. M. S. Steinberg. On the mechanism of tissue reconstruction by dissociated cells, I. Population kinetics, differential adhesiveness and the absence of directed migration. P. Natl Acad. Sci. USA, 48(9):15771582, 1962a. doi:10.1073/pnas.48.9.1577. M. S. Steinberg. Mechanism of tissue reconstruction by dissociated cells, II: Time-course of events. Science, 137(3532):762763, 1962b. doi:10.1126/science.137.3532.762. M. S. Steinberg. On the mechanism of tissue reconstruction by dissociated cells, III. Free energy relations and the reorganisation of fused, heteronomic tissue fragments. P. Natl Acad. Sci. USA, 48(10):17691776, 1962c. doi:10.1073/pnas.48.10.1769. P. L. Townes and J. Holtfreter. Directed movements and selective adhesion of embryonic amphibian cells. J. Exp. Zool., 128(1):53120, 1955. doi:10.1002/jez.1401280105.

ACS Style

Fillipe Georgiou; B. Lamichhane; N. Thamwattana. An adaptive numerical scheme for a partial integro-differential equation. ANZIAM Journal 2019, 60, C187 -C200.

AMA Style

Fillipe Georgiou, B. Lamichhane, N. Thamwattana. An adaptive numerical scheme for a partial integro-differential equation. ANZIAM Journal. 2019; 60 ():C187-C200.

Chicago/Turabian Style

Fillipe Georgiou; B. Lamichhane; N. Thamwattana. 2019. "An adaptive numerical scheme for a partial integro-differential equation." ANZIAM Journal 60, no. : C187-C200.

Journal article
Published: 01 October 2019 in Mathematics and Computers in Simulation
Reads 0
Downloads 0

Phagocytosis refers to a process in which one cell type fully encloses and consumes unwanted cells, debris or particulate matter. It has an important role in immune systems through the destruction of pathogens and the inhibiting of cancerous cells. In this paper, we combine cell–cell adhesion and predator–prey modelling to generate a new model for phagocytosis that can relate the interaction between cells in both space and time. Stability analysis for both homogeneous and non-homogeneous steady states is provided for one-dimensional model indicating the range of parameters that leads to phagocytosis. Finally, the paper presents numerical results for both one and two-dimensional models, which show excellent agreement with a real phenomenon of bacteria phagocytized by neutrophil cell.

ACS Style

Fillipe Georgiou; N. Thamwattana. Modelling phagocytosis based on cell–cell adhesion and prey–predator relationship. Mathematics and Computers in Simulation 2019, 171, 52 -64.

AMA Style

Fillipe Georgiou, N. Thamwattana. Modelling phagocytosis based on cell–cell adhesion and prey–predator relationship. Mathematics and Computers in Simulation. 2019; 171 ():52-64.

Chicago/Turabian Style

Fillipe Georgiou; N. Thamwattana. 2019. "Modelling phagocytosis based on cell–cell adhesion and prey–predator relationship." Mathematics and Computers in Simulation 171, no. : 52-64.