Agent Based Modeling in Land-Use and Land-Cover Change Studies

Agent based models (ABM) for land use and cover change (LUCC) holds the promise to provide new insight into the processes and patterns of the human and biophysical interactions in ways that have never been explored. Advances in computer technology make it possible to run almost infinite numbers of simulations with multiple heterogeneously shaped actors that reciprocally interact via vertical and horizontal power lines on various levels. Based upon an extensive literature review the basic components for such exercises are explored and discussed. This resulted in a systematic representation of these components consisting of: (1) Spatial static input data, (2) Actor and Actor-group static input data, (3) Spatial dynamic input, (4) Actor and Actor-group dynamic input data, (5) the model with the rules describing the rules, (6) Spatial static output, (7) Actor and Actor-group static output, (8) Dynamic output of Actor behaviour changes, (9) Dynamic output of actor-group behavioural changes, (10) Dynamic output of spatial patterns, (11) Dynamic output of temporal patterns. This representation proves to be epistemologically useful in the analysis of the relationships between the ABM LUCC components. In this paper, this representation is also used to enumerate the strengths and limitations of agent based modelling in LUCC

Territorialising homes: Prolonged and return burglaries in South Africa

This article draws on ethnographic data from South Africa to show that while burglaries may commonly be once-off incidents, many households are repeatedly victimised. In such situations, victims are retargeted and intimidated by the same burglars. Through two exemplary cases of middle- and lower-middle-income households, which are examples of ‘return’ and ‘prolonged’ burglaries, I illustrate that these burglaries are defined by four main characteristics: long duration, the targeted theft of possessions, remaining marks and the close proximity of burglars. I suggest that these burglaries are a way of laying claim to households through symbolic means, rather than physical confrontation. This has lasting social, emotional and financial repercussions for the victims. As relating to repeat-victimisation, burglaries deserve further attention from analysts

MANAGEMENT DECISIONS ON FARM-LEVEL AND THEIR LINK TO WEATHER REQUIREMENTS: A CASE STUDY FOR THE UPPER DANUBE RIVER BASIN

It is undeniable that the global warming has already affected the Earth’s biota, whereby the rise of air temperature is an important factor. Agricultural systems are also affected by climate change via the interrelated biophysical layers. Climate influences farmers` decisions in crop management. To simulate the interactions between climate/weather and the different crop management activities an agent based modelling approach is used, in which farmers` decision making is based on crop requirements from literature. To validate these decision algorithms on how farmers arrange their daily crop management decisions like planting, fertilizing, and harvesting due to changes of climate parameters, a statistical analysis of empirical data (1970-2003) on temperature and different crop growth stages, which represent different management activities, was carried out. Results show that every crop has to be considered separately and the requirements of the different crops on temperature have to be observed in different ways. There are crops which have a low germination temperature, for those the average daily temperature shows no relation with the planting day. In this case the temperature sum in a specific period is more precise. On the opposite side crops with a high germination temperature show significant correlation results with the average daily temperature of a period before the planting day.Crop management, heuristic decisions, regional climate change, Crop Production/Industries, Farm Management,

Gap formation in a self-gravitating disk and the associated migration of the embedded giant planet

We present the results of our recent study on the interactions between a giant planet and a self-gravitating gas disk. We investigate how the disk's self-gravity affects the gap formation process and the migration of the giant planet. Two series of 1-D and 2-D hydrodynamic simulations are performed. We select several surface densities and focus on the gravitationally stable region. To obtain more reliable gravity torques exerted on the planet, a refined treatment of disk's gravity is adopted in the vicinity of the planet. Our results indicate that the net effect of the disk's self-gravity on the gap formation process depends on the surface density of the disk. We notice that there are two critical values, \Sigma_I and \Sigma_II. When the surface density of the disk is lower than the first one, \Sigma_0 < \Sigma_I, the effect of self-gravity suppresses the formation of a gap. When \Sigma_0 > \Sigma_I, the self-gravity of the gas tends to benefit the gap formation process and enlarge the width/depth of the gap. According to our 1-D and 2-D simulations, we estimate the first critical surface density \Sigma_I \approx 0.8MMSN. This effect increases until the surface density reaches the second critical value \Sigma_II. When \Sigma_0 > \Sigma_II, the gravitational turbulence in the disk becomes dominant and the gap formation process is suppressed again. Our 2-D simulations show that this critical surface density is around 3.5MMSN. We also study the associated orbital evolution of a giant planet. Under the effect of the disk's self-gravity, the migration rate of the giant planet increases when the disk is dominated by gravitational turbulence. We show that the migration timescale associates with the effective viscosity and can be up to 10^4 yr.Comment: 24 pages, 13 figures, accepted by RA

The Potential of Detecting Nearby Terrestrial Planets in the HZ with Different Methods

Terrestrial planets in the habitable zone around nearby stars are of great interest and provide a good sample for further characteristics of their habitability. In this paper, we collect a nearby star catalog within 20 pc according to the Gaia Catalog of Nearby Stars, complete the physical parameters of the stars, and select stars that are not brown dwarfs or white dwarfs. After selection, a sample of 2234 main-sequence stars is used to estimate the extended HZ. Then we inject Earth-like planets into the extended HZ around each star and calculate the signals with four methods, i.e.; velocity amplitude for radial velocity, transit probability and depth for transit, stellar displacements for astrometry, and contrast and angular separation for imaging. Considering a typical noise model based on classic instruments, we predict the highest possible detection number of Earth-like planets via different methods in the best-case hypothetical scenario. According to this, we conclude that both astrometry and imaging have the potential to detect nearby Earth-like planets around G type stars, while radial velocity has the potential to detect 2% of nearby Earth-like planets around M stars under a precision of 0.2 m/s. Our work also provides the precision requirements for future missions to reveal the nearby Earth-like planet in the HZ.Comment: 22 pages, 16 figures, accepted 2023 September 7, published 2023 September 2

Non-Abelian gauge theories with composite fields in the background field method

Non-Abelian gauge theories with composite fields are examined in the background field method. Generating functionals of Green's functions for a Yang--Mills theory with composite and background fields are introduced, including the generating functional of vertex Green's functions (effective action). The corresponding Ward identities are obtained, and the issue of gauge dependence is investigated. A gauge variation of the effective action is found in terms of a nilpotent operator depending on the composite and background fields. On-shell independence from the choice of gauge fixing for the effective action is established. In the study of the Ward identities and gauge dependence, finite field-dependent BRST transformations with a background field are introduced and utilized on a systematic basis. On the other hand, the issue of gauge dependence is studied with reference to a finite variation of the gauge Fermion. The concept of a joint introduction of composite and background fields to non-Abelian gauge theories is exemplified by the Gribov--Zwanziger theory, including the case of a local BRST-invariant horizon, and by the Volovich--Katanaev model of two-dimensional gravity with dynamical torsion.Comment: 42 pages, presentation improved, Section 5 with Loop expansion added, subsection 6.3 with Local BRST Invariant Horizon Term with composite and background fields and 7 references added, summary improve

Repackaging East Indies Natural History in François Valentyn’s Oud en Nieuw Oost-Indiën

More than five hundred folio pages of François Valentyn’s multivolume description of the trading empire of the Dutch East India Company, Oud en Nieuw Oost-Indiën (Old and New East Indies, 1724-1726, five thousand pages in toto), are devoted to the natural history of Amboina. This essay contends that Valentyn’s nature description is not the work of a field naturalist, but rather of a scholar ordering and repackaging existing information, which was already available in a different textual format and in drawings. While the focus of this essay is on Valentyn’s compilation strategy, which targeted a non-expert readership of ‘liefhebbers’, the role of indigenous knowledge in his nature description is also discussed, arguing that it was generally subordinated to a European perspective in Valentyn’s book