When Shape Matters: Using a Simple Mathematical Model to Estimate Critical Area Sizes in Conservation

In the analysis of anthropogenic impact on the environment arises the question of whether the shapes of preserved habitat fragments play an important role in the conservation of wild species. In this work we use a very simple mathematical model based on a reaction-diffusion equation to analyze the effects of geometric shape and area on the permanence of populations in habitat fragments. Our results indicate that a dimensionless quantity calculated from a combination of biological variables is the main component that determines if the species survives in the preserved fragment and whether its geometric shape is important. We provide a methodology to calculate critical area sizes for which population size is most affected by fragment shape. The calculation is based on four quantitative variables: maximum per capita reproduction rate, per capita mortality rate outside the fragment, carrying capacity in the conserved environment and mobility in the disturbed environment. The methodology is illustrated by a preliminary study, in which the model is used to estimate threshold area sizes for habitat fragments for the threatened species Sapajus xanthosternos .

The Rock Art in Kinta Valley, West Malaysia: A synthesis Lukisan Gua di Lembah Kinta, Semenanjung Malaysia: Satu sintesis

This paper presents a synthesis of the new rock art mapping project in the Kinta Valley of West Malaysia. Through our collaboration with Kinta Valley Watch, we have successfully located more than 30 new rock art sites between 2019 and June 2021. The rock art is represented by both red and black paintings, with a wide variety of motifs including anthropomorph, zoomorph, botanic, watercraft, weapon, animal rider, handprint, geometric shape, line art, and other abstract design. This discovery is instrumental to the contemporary rock art research in Malaysia and demonstrated a collective effort in rock art research through long-term collaboration with the local stakeholders. Kertas kerja ini merupakan satu sintesis hasil daripada projek pemetaan lukisan gua di Lembah Kinta, Semenanjung Malaysia. Melalui kolaborasi dengan organisasi tempatan iaitu Kinta Valley Watch, kami telah mengenalpasti lebih daripada 30 lokasi lukisan gua antara tahun 2019 dan 2021. Antara bentuk lukisan gua yang dijumpai termasuklah antropomor ik ( igura manusia), zoomor ik ( igura haiwan), tumbuh-tumbuhan, perahu, senjata, penunggang haiwan, gambar tangan, geometrik, seni garisan dan simbol abstrak. Jumpaan ini amat berharga untuk kajian lukisan gua di Malaysia dan memaparkan satu usaha bersama demi kajian lukisan gua melalui kolaborasi jangka panjang dengan komuniti tempatan.

Theory of Geometric Shape Conversion

In this paper we have proposed a new theory about geometric shape conversion. Through a particular process where the number of steps of the process tends to infinity, keeping one or more shapes of two or more shapes the same throughout the whole process and by gradually changing its size, shifting another shape toward another specific new size or new shape is the main topic of discussion of the theory. Again, if the shape that changes its size does not shift toward another specific new size or new shape then it is considered as error and this theory also discussed the properties of that error.

KHAT NASKHI'S WRITING AND ARTISTIC TECHNIQUES IN CALLIGRAPHY LEARNING

The research examines the procedures for writing khat naskhi and the beauty of writing in calligraphy learning. This research is library research, the data collected is based on a critical and in-depth assessment of the relevant library materials. Primary data sources are Mushaf, calligraphy books, rasm, khat and imla. Data collection techniques are carried out by; read, recording, identifying, tabulating, analyze and conclude. The results of this study indicate that the technique of writing khat naskhi is very easy for beginners, because it has a simple cursive geometric shape, and does not highlight variations other than letters and diacritical marks. This type of khat is also very familiar to use in writing manuscripts so that it is in great demand by Arabs and non-Arabs because its shape can be distinguished by several signs, namely, the writing is easy to read, has a horizontal line reference, has simple punctuation marks and has four styles, namely: 1) Tarsif, 2) Ta'lif, 3) Tastir and 4) Tanshil.

Experimental verification of new features of bearing operation under combined loading conditions

Bearing units of lifting machines, products of construction, road, aviation, space and other branches of technology are very important structural elements, since the failure of even one bearing can cause the failure of the entire product. The results of experimental verification of the theoretical model of bearing operation under combined loading conditions are presented. The behavior under load of bearing units in the most general case can be represented by a sequence of five design schemes, expressed in the form of five statically indeterminate beams. The purpose of the experiments was to test this model under real loading conditions. The experiments were based on the analysis of the geometric shape of the curved elastic line, which the shaft of the bearing assembly acquires under load. The experimental results confirmed the validity of the model and showed that the previously generally accepted model of a two-support beam is not implemented. The conclusion is confirmed that in responsible lifting machines, as well as in responsible products of construction, road, aviation, space and other branches of technology, it is impractical to calculate bearings according to the traditional method, since an erroneous value of bearing durability can be obtained, overestimated from 28.37 to 26.663.9 times.

The structure of the modules of the search system by geometric shape based on the repeated use of design knowledge

The development of a diagram of the components of a search system by geometric form and a class diagram of obtaining design knowledge using Hu-moments is considered. Keywords: 3D model, PLM, Hu-moments, design knowledge, component diagram. [email protected]

The Aerodynamics of a Diabolo

Diabolo is a popular game in which the object can be spun at up to speeds of 5000 rpm. This high spin velocity gives the diabolo the necessary angular momentum to remain stable. The shape of the diabolo generates an interesting air flow pattern. The viscous air applies a resistive torque on the fast spinning diabolo. Through computational fluid dynamics (CFD) simulations it's shown that the resistive torque has an interesting dependence on the angular speed of the diabolo. Further, the geometric shape of the diabolo affects the dependence of torque on angular speed.