Is time the real line?

This paper is devoted to discussing the topological structure of the arrow of time. In the literature, it is often accepted that its algebraic and topological structures are that of a one-dimensional Euclidean space $\mathbb{E}^1$, although a critical review on the subject is not easy to be found. Hence, leveraging on an operational approach, we collect evidences to identify it structurally as a normed vector space $(\mathbb{Q}, |\cdot|)$, and take a leap of abstraction to complete it, up to isometries, to the real line. During the development of the paper, the space-time is recognized as a fibration, with the fibers being the sets of simultaneous events. The corresponding topology is also exposed: open sets naturally arise within our construction, showing that the classical space-time is non-Hausdorff. The transition from relativistic to classical regimes is explored too.Comment: 26 pages, 9 figures. Misprints corrected and minor adjustments according to the review proces

Production Capacity and Queues in a Bookstore at Porto Velho, Brazil

The objective of this work was to study the productive capacity and queues in the services of a bookstore in Porto Velho city, Brazil. To do this, the specific objectives were: (1) to study the productive capacity in the operation units of the bookstore; (2) to carry out an analysis of queuing and flow management in the operation units of the bookstore; and (3) to suggest prospects for the development using the SWOT Matrix analysis tool

Explanation-by-Example Based on Item Response Theory

Intelligent systems that use Machine Learning classification algorithms are increasingly common in everyday society. However, many systems use black-box models that do not have characteristics that allow for self-explanation of their predictions. This situation leads researchers in the field and society to the following question: How can I trust the prediction of a model I cannot understand? In this sense, XAI emerges as a field of AI that aims to create techniques capable of explaining the decisions of the classifier to the end-user. As a result, several techniques have emerged, such as Explanation-by-Example, which has a few initiatives consolidated by the community currently working with XAI. This research explores the Item Response Theory (IRT) as a tool to explaining the models and measuring the level of reliability of the Explanation-by-Example approach. To this end, four datasets with different levels of complexity were used, and the Random Forest model was used as a hypothesis test. From the test set, 83.8% of the errors are from instances in which the IRT points out the model as unreliable.Comment: 15 pages, 5 figures, 3 tables, submitted for the BRACIS'22 conferenc

The discovery of a T6.5 subdwarf

We report the discovery of ULAS J131610.28+075553.0, an sdT6.5 dwarf in the UKIDSS Large Area Survey 2 epoch proper motion catalogue. This object displays significant spectral peculiarity, with the largest yet seen deviations from T6 and T7 templates in the Y and K bands for this subtype. Its large, similar to 1 arcsec yr(-1), proper motion suggests a large tangential velocity of V-tan approximate to 240-340 km s(-1), if we assume its M-J lies within the typical range for T6.5 dwarfs. This makes it a candidate for membership of the Galactic halo population. However, other metal-poor T dwarfs exhibit significant under luminosity both in specific bands and bolometrically. As a result, it is likely that its velocity is somewhat smaller, and we conclude it is a likely thick disc or halo member. This object represents the only T dwarf earlier than T8 to be classified as a subdwarf, and is a significant addition to the currently small number of known unambiguously substellar subdwarfs.Peer reviewe

Intake and Digestibility of Nutrients of Corn and \u3cem\u3eStylosanthes\u3c/em\u3e Silages in Diets for Sheep

The low concentration of water soluble carbohydrates, the high buffering capacity and the low autochthonous population of lactic acid bacteria are limiting factors to legume ensiling. However, recent research with tropical legumes has shown that the silages presented an adequate fermentation profile (Liu et al. 2012; Silva et al. 2012; Pereira et al. 2012). Nevertheless, there are few studies on the use of stylosanthes silages cv. Campo Grande (Stylosanthes capitata + Stylosantes macrocephala) for sheep feeding. The objective of this study was to evaluate the intake and digestibility of nutrients of stylosanthes and corn silages in sheep diets

Thermographic inspection of impact damage in carbon fiber-reinforcing polymer matrix laminates

Laminados compósitos com matrizes poliméricas, respectivamente termorrígida e termoplástica, fortalecidas com fibras contínuas de carbono foram submetidos a impacto único transversal com diferentes níveis de energia. Os danos impingidos aos materiais estruturais foram avaliados por termografia ativa infravermelha na modalidade transmissão. Em geral, os termogramas do laminado termoplástico apresentaram indicações mais claras e bem definidas dos danos causados por impacto, se comparados aos do compósito termorrígido. O aquecimento convectivo das amostras por fluxo controlado de ar quente se mostrou mais eficaz que o realizado por irradiação, empregando-se lâmpada de filamento. Observou-se também que tempos mais longos de aquecimento favoreceram a visualização dos danos. O posicionamento da face impactada do espécime, relativamente à câmera infravermelha e à fonte de calor, não afetou a qualidade dos termogramas no caso do laminado termorrígido, enquanto que influenciou significativamente os termogramas do compósito termoplástico. Os resultados permitiram concluir que a termografia infravermelha é um método de ensaio não-destrutivo simples, robusto e confiável para a detecção de danos por impacto tão leve quanto 5 J em laminados compósitos poliméricos reforçados com fibras de carbono.Continuous carbon fiber reinforced thermoset and thermoplastic composite laminates were exposed to single transversal impact with different energy levels. The damages impinged to the structural materials were evaluated by active infrared thermography in the transmission mode. In general, the thermoplastic laminate thermograms showed clearer damage indications than those from the thermosetting composite. The convective heating of the samples by controlled hot air flow was more efficient than via irradiation using a filament lamp. It was also observed that longer heating times improved the damage visualization. The positioning of the specimen's impacted face regarding the infrared camera and the heating source did not affect the thermo-imaging of thermosetting specimens, whereas it substantially influenced the thermograms of thermoplastic laminates. The results obtained allow concluding that infrared thermography is a simple, robust and trustworthy methodology for detecting impact damages as slight as 5 J in carbon fiber composite laminates.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNPqMaterials Institute of Brazi

76 T dwarfs from the UKIDSS LAS : benchmarks, kinematics and an updated space density

We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Near-infrared broad- and narrow-band photometry and spectroscopy are presented for the new objects, along with Wide-field Infrared Survey Explorer (WISE) and warm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H - [4.5] and J - W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in T-eff when considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.Peer reviewe

Chemical Composition and Evaluation of Antitumoral Activity of Leaf and Root Essential Oils of Conyza canadensis (Asteraceae)

The leaf and root oils of Conyza canadensis were studied for chemical composition and antitumor activity. The results showed that there is great variation in the composition of the oils obtained from different parts. The main components in the leaf oil were limonene, caryophyllene oxide and espatulenol. In the root oil the major component was the acetylenic ester lachnophyllum methyl ester. It was observed that according to the collection time (6 and 16 hours), significant variations in the content of the main components of this essential oil of leaves can occur. Limonene, spatulenol and caryophyllene oxide presented a distribution of 61% / 5.4% / 12.5% ​​and 38% / 10.7% / 22.3% in oils obtained from plants collected at 6 and 16 hours, respectively. The antitumor activity of the oils showed that leaf oil had a greater potential for inhibition, and this oil was distinguished by the activity against neoplastic cell lines K562 (leukemia) and NCI-ADR / RES (ovary with multidrug resistance phenotype ) with TGI values ​​of 16.8 and 19.0 mg.mL-1, respectively. Comparing the leaf oils and their tumor cell inhibition potentials, it was noted that this activity is higher in the oil with higher contents of monoterpene limonene. DOI: http://dx.doi.org/10.17807/orbital.v11i5.137

Rutin-functionalized multi-walled carbon nanotubes: molecular docking, physicochemistry and cytotoxicity in fibroblasts

Multi-Walled Carbon Nanotubes (MWCNT) have been functionalized with rutin through three steps (i. reaction step; ii. purification step; iii. drying step) and their physicochemical properties investigated with respect to morphological structure, thermal analysis, Fourier Transform Infrared Spectroscopy (FTIR), and cytotoxicity. The molecular docking suggested the rutin-functionalized MWCNT occurred by hydrogen bonds, which was confirmed by FTIR assays, corroborating the results obtained by thermal analyses. A tubular shape, arranged in a three-dimensional structure, could be observed. Mild cytotoxicity observed in 3T3 fibroblasts suggested a doseeffect relationship after exposure. These findings suggest the formation of aggregates of filamentous structures on the cells favoring the cell penetration.The authors acknowledge Classius Ferreira da Silva, from the Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, for the scanning electron microscopy analyses.info:eu-repo/semantics/publishedVersio