Identification of morphofunctional traits in Mangalarga Marchador horse using principal component analysis

Dados de 14.288 animais da ra?a Mangalarga Marchador, nascidos de 1990 a 2005, foram utilizados para avaliar a redu??o da dimensionalidade do espa?o multivariado para caracter?sticas morfofuncionais, por meio da an?lise de componentes principais. Foram consideradas as caracter?sticas: altura na cernelha, altura na garupa, comprimento da cabe?a, comprimento do pesco?o, comprimento do dorso, comprimento da garupa, comprimento da esp?dua, comprimento do corpo, largura da cabe?a, largura das ancas, per?metro do t?rax, per?metro da canela e a pontua??o da marcha. Para tais caracter?sticas, obtiveram-se sete componentes principais, a partir da matriz de correla??o, que apresentaram vari?ncia inferior a 0,7 (autovalor inferior a 0,7). Isso sugere sete vari?veis para descarte, por apresentarem maiores coeficientes de pondera??o, em valor absoluto, a partir do ?ltimo componente principal. A raz?o para isso ? que vari?veis altamente correlacionadas com os componentes de menor vari?ncia representam varia??o praticamente insignificante. Com base nesses resultados, recomendam-se as seguintes caracter?sticas para serem mantidas em trabalhos futuros com esta base de dados: pontua??o da marcha, altura na garupa, comprimento do dorso, comprimento da garupa, largura da cabe?a e per?metro da canela.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Records from 14,288 animals of the Mangalarga Marchador breed, born from 1990 to 2005, were used to discard morphofunctional traits in a principal component analysis. The following traits were used: height at withers, height at croup, lengths of head, neck, back, croup, hip length and body, widths of head, hip width, thorax perimeter, cannon bone circumference and gait score. For the traits considered it was observed that 7 principal components showed variation lower than 0.7; suggesting that seven variables could be discarded. The reason is that when variable are highly correlated with the principal components of smaller variance, their variation is practically insignificant. Based on those results the recommendation is to maintain the following traits for future research with this database: gait score, height at croup, length of back, length of croup, width of head and cannon bone circumference

Slow-wave sleep and androgens : selective slow-wave sleep suppression affects testosterone and 17α-hydroxyprogesterone secretion

© 2018 Elsevier B.V. All rights reserved.Objectives: Levels of steroid hormones such as androgens and cortisol exhibit circadian variation, and their fluctuations are related to the sleep-wake cycle. Currently, the functional role of different stages of sleep in steroid hormone secretion remains unclear. The present study aims to explore the effect of slow-wave sleep (SWS) suppression on morning levels of cortisol and androgens. Methods: Twelve healthy male volunteers participated in two experimental sessions: a session with selective SWS suppression during night sleep and a session with regular night sleep (control). SWS suppression was achieved by stimulation using an acoustic tone. Salivary samples were collected in the morning immediately after awakening and again 40 min later. The samples were analysed by liquid chromatography-tandem mass spectrometry for testosterone, androstenedione (Ad), dehydroepian-drosterone (DHEA), 17a-hydroxyprogesterone (17-OHP), and cortisol. Results: SWS suppression reduced overall SWS duration by 54.2% without significant changes in total sleep time and sleep efficiency. In the session with selective SWS suppression, the average level of morning testosterone was lower than in the control session (p¼0.017). Likewise, 17-OHP was lower in the SWS suppression condition (p¼0.011) whereas the ratio of DHEA/Ad was higher (p¼0.025). There were no significant differences between sessions in cortisol, Ad, or DHEA concentrations.Conclusions:The effect of selective SWS suppression on morning levels of testosterone and 17-OHP points to the importance of SWS for the synthesis and secretion of androgens. These results suggest that chronic sleep problems, which lead to reduced SWS, increase the risk for the development of androgen deficiency in the long term.This work was supported by the Russian Foundation for Basic Research (RFBR grant number 18-013-01187А). M.O.V. was sup-ported within the framework of the Basic Research Program at the National Research University Higher School of Economics (HSE) and subsidy by the Russian Academic Excellence Project '5-100'. The supporting agencies had no role in the design or conduct of the study; the collection, analysis, or interpretation of the data; or the writing or approval of the manuscript.info:eu-repo/semantics/publishedVersio