An Introduction to Hyperbolic Barycentric Coordinates and their Applications

Barycentric coordinates are commonly used in Euclidean geometry. The adaptation of barycentric coordinates for use in hyperbolic geometry gives rise to hyperbolic barycentric coordinates, known as gyrobarycentric coordinates. The aim of this article is to present the road from Einstein's velocity addition law of relativistically admissible velocities to hyperbolic barycentric coordinates along with applications.Comment: 66 pages, 3 figure

Assessing sustainable development goals attainment through energy-environmental efficiency: The case of Latin American and Caribbean countries

This study evaluates the attainment of sustainable development goals (SDGs) using energy-environmental efficiency as a principal driver. Hicks-Moorsteen Index, based on optimal targets, is utilized to estimate the performance of Latin America and the Caribbean (LAC) countries towards SDGs. Performance is decomposed into catch-up efficiency and technological progress. Results show that, compared to 2012, only 15% of the countries evaluated exhibit improved catch-up efficiency in 2020, while 74% of the countries evaluated showed technological progress in 2020 compared to 2012. Improvement in SDGs attainment in LAC results from technological advancement and not catch-up efficiency. Gross catch-up inefficiency appears to obstruct SDGs attainment. The regression elaborates the indirect extrinsic socio-economic dimension of the SDGs accomplishment. Specifically, the results of the fully modified ordinary least squares and generalized method of moments for the examined years support the desired prospects for green productivity among the cross-section of LAC. Moreover, in each of the upper years, the result suggests that environmental performance and renewable energy-induced economic progress are vital for the examined countries' sustainable green productivity. Notably, the result predicts a slow but progressive path toward achieving the SDGs, suggesting more intentional and inclusive effort by the respective economies.info:eu-repo/semantics/publishedVersio

Gyrations: The Missing Link Between Classical Mechanics with its Underlying Euclidean Geometry and Relativistic Mechanics with its Underlying Hyperbolic Geometry

Being neither commutative nor associative, Einstein velocity addition of relativistically admissible velocities gives rise to gyrations. Gyrations, in turn, measure the extent to which Einstein addition deviates from commutativity and from associativity. Gyrations are geometric automorphisms abstracted from the relativistic mechanical effect known as Thomas precession

3D Modelling of Large Urban Scenes from Diverse Sources of Information

The complex and extensive nature of urban environments creates difficulties to the task of generating virtual models. Thus a great effort in terms of human resources, time and money is needed. Nevertheless a large number of professionals and institutions devout efforts to gather and analyse data from these urban environments. As data is usually stored in a digital format, it becomes a valuable asset to incorporate it in the modelling process of virtual environments. This paper presents a three-dimensional modelling system with interoperable access to data in diverse formats and digital support, drived by an L-system based modelling process that automatically generates initial solutions for virtual environments, which can be incrementally improved

Sub-band-based transmission for mode-multiplexed optical systems

Mode-multiplexed optical transmission is subject to mode coupling and potentially large differential mode delays. In most recent implementations, these effects are compensated for at the receiver by complex adaptive MIMO equalizers. Although frequency-domain MIMO equalization requires a moderate complexity compared to time-domain equalization, the long required FFTs may face implementation issues and yield a relatively slow response to dynamic effects. In this paper, we evaluate an alternate transceiver architecture based on sub-band partitioning, implemented by filter banks, which enables concurrent time-domain equalization. The performance of sub-band and single-carrier schemes are compared using Monte-Carlo simulations

Dry matter and area partitioning, radiation interception and radiation-use efficiency in open-field bell pepper

The objective of this study was to determine some key components of a model for bell pepper growth and yield under non-limiting water and nutrient conditions using data from field trials conducted in Southern Portugal. DM partitioning, at least before fruiting, and specific area indices for leaves, stems and fruits were conservative in relation to normalized thermal time. The interception model had a good performance. It was based on the exponential extinction of radiation on the area covered by the plants, the ellipsoidal leaf-angle distributionmodel (X-parameter 2.48 and 2.89), and absorptivities of the leaves for PAR and NIR, 0.8 and 0.2, respectively. Radiation-use efficiency (RUE) was determined and presented in four different forms. RUE did not change substantially throughout the growing season. RUE of irrigated pepper crops grown in our experiments was around 1.6 g MJ 1 of intercepted PAR. The models and parameter values presented in this study may be useful to simulate the development and growth of fieldgrown pepper cro

Filter Bank Multi-Sub-Band Transmission for Optical Systems with Mode Multiplexing

Mode-multiplexed optical transmission is subject to mode coupling and potentially large differential mode delays. In most recent implementations, these effects are compensated for at the receiver by complex adaptive multiple-input multiple-output (MIMO) equalizers. Although frequency-domain MIMO equalization requires a moderate complexity compared to time-domain equalization, the long required fast Fourier transforms may face implementation issues. In this paper, we evaluate an alternative transceiver architecture based on sub-band partitioning, implemented by filter banks, which enables concurrent time-domain equalization. Single-carrier (SC) and multi-sub-band (MSB) mode division multiplexing transmission are simulated using frequency-domain equalization and time-domain equalization, respectively. Their performance is compared in terms of static transmission performance, channel tracking capability, phase noise tolerance, and computational complexity. The results indicate that compared with an equivalent SC solution, the MSB architecture provides a high degree of parallelism at the cost of a penalty of 0.7-1.3 dB for a laser linewidth of 25-100 kHz and a moderate increase in complexity

Displasia renal em um bezerro Limousin

Descreve-se um caso de displasia renal em um bezerro Limousin, macho, de quatro meses. O animal apresentava perda de peso, baixa taxa de crescimento, anorexia, apatia, diarréia escura fétida e uremia, sem melhora apesar de tratamento. O bezerro foi sacrificado para interromper o sofrimento adicional e submetido à necropsia. Ao exame foi observado que os rins estavam pequenos, firmes, pálidos e com superfície rugosa. A cápsula estava aderida à uma superfície subcapsular irregular. O córtex tinha aparência difusamente pálida e fibrosa e apresentava múltiplos focos brancos de fibrose. A junção córtico-medular estava indistinta. O exame histologico dos rins revelou múltiplos glomérulos imaturos com núcleo periférico, capilares inaparentes e padrão arbóreo. O córtex renal apresentou túbulos primitivos com epitélio cubóide ou cilíndrico envolvido por mesênquima corado somente pelo alcian blue e não pelo tricrômico de Masson. Foi também observada leve fibrose intersticial na medula renal. Os rins mostravam estruturas em estágio inapropriado de desenvolvimento ou anômalas

O epitélio respiratório em ratos Wistar após 48 horas de exposição contínua ao ruído de baixa frequência

ABSTRACTPrevious studies show that exposure to low frequency noise (LFN) (≤500Hz, including infrasound) produces irreversible lesions in Wistar rat respiratory epithelia. Recovery periods for LFN-induced lesions have thus become an object of interest. Changes in the respiratory epithelia of Wistar rats after continuous short-term exposure to LFN are described. Twelve rats were exposed to continuous LFN for 48hrs, and 10 age-matched rats were kept in silence. Animals were treated in accordance with 86/609/CE. After exposure ceased, two rodents were sacrificed immediately, and another two after 6, 12, 24, 48hrs, and 7 days of post-exposure silence. Respiratory epithelial fragments were prepared for light and scanning/ transmission electron microscopy. Six hours after exposure, intense and irregular cellular tumefaction was visible and rosetta structures, formed by secretory cells (SC) centered on a brush cell (BC), were identifiable. Cilia were shorter and shaggy. BC microvilli tended to group, losing the uniform distribution seen in controls. Twelve hours after exposure, cell balooning was still present, BC shape was highly irregular and microvilli were grouped. SC microvilli were still shorter than controls. Seven days after exposure, controls and exposed were indistinguishable. LFN-induced epithelial lesions seem to be reversible if recovery periods are respected.REV PORT PNEUMOL 2003; IX (6): 473-47