Estudo da longevidade de vacas zebu?nas

O Brasil ? um pa?s que se destaca pela produ??o de leite, ocupando a quinta posi??o mundial, segundo o Instituto Brasileiro de Geografia e Estat?stica (IBGE, 2015). O rebanho leiteiro brasileiro ? composto em sua maior parte por animais zebu?nos e mesti?os (cruzamento entre ra?as europeias e zebu?nas). Dentre as ra?as zebu?nas, o Gir e o Guzer? se destacam pela produ??o de carne ou leite, al?m de serem animais que se adaptam bem as condi??es do clima. Por muitos anos os programas de melhoramento gen?tico de gado de leite tinham como principal preocupa??o as caracter?sticas de produ??o. Todavia, o sucesso econ?mico da pecu?ria leiteira n?o est? associado apenas ? efici?ncia produtiva, mas tamb?m ? efici?ncia reprodutiva, sa?de e longevidade do rebanho. Contudo, os ganhos em produtividade levaram a redu??o na efici?ncia das caracter?sticas reprodutivas e ao decl?nio na longevidade. A longevidade ? uma caracter?stica altamente desej?vel em rebanhos leiteiros, em raz?o da sua rela??o com a lucratividade, pois em rebanhos com vacas mais longevas, tem-se uma redu??o com o custo de animais para reposi??o. Entretanto, a longevidade ? uma caracter?stica complexa influenciada por diversos fatores, como produ??o de leite, bem estar, endogamia e objetivos de cria??o. Al?m disso, a maioria das medidas de longevidade s?o obtidas tardiamente na vida da vaca ou at? mesmo ap?s a sua morte. Este fato, faz com que a sele??o direta para a longevidade seja impratic?vel devido ao tempo necess?rio para se obter a medida, bem como o longo intervalo de gera??es, sendo uma caracter?stica de baixa herdabilidade. Portanto, a sele??o indireta para longevidade tem sido utilizada por meio da sele??o de outras caracter?sticas de interesse econ?mico, expressas precocemente, como a idade ao primeiro parto, podendo contribuir para obten??o de ganhos gen?ticos. Sendo assim, o estudo das caracter?sticas de longevidade e as outras caracter?sticas de import?ncia econ?mica s?o indispens?veis para inclus?o da longevidade em programas de melhoramento gen?tico para produ??o de leite.Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016.Brazil is a country that stands out for milk production, ranking fifth in the world, according to the Brazilian Institute of Geography and Statistics (IBGE, 2015). The Brazilian dairy herd is mostly composed of zebu and mestizo animals (crossbreeding between European and zebu breeds). Among the zebu breeds, the Gir and Guzer? stand out for the production of meat or milk, besides being animals that adapt well the conditions of the climate. For many years the genetic improvement programs of dairy cattle had as main concern the production characteristics. However, the economic success of dairy farming is not only related to the productive efficiency, but also to the reproductive efficiency, health and longevity of the herd. However, gains in productivity led to a reduction in the efficiency of reproductive traits and a decline in longevity. Longevity is a highly desirable characteristic in dairy herds, because of its relation to profitability, since in livestock with longer cows, there is a reduction with the cost of replacement animals. However, longevity is a complex feature influenced by many factors, such as milk production, well-being, endogamy and creation goals. In addition, most longevity measures are obtained late in the life of the cow or even after death.This fact makes the direct selection for longevity impractical due to the time required to obtain the measure, as well as the long generation interval, being a characteristic of low heritability. Therefore, indirect selection for longevity has been used through the selection of other characteristics of economic interest, expressed early, such as age at first calving, and may contribute to obtain genetic gains. Thus, the study of longevity characteristics and other characteristics of economic importance are indispensable for inclusion of longevity in genetic breeding programs for milk production

Blood flow in a bifurcation and confluence microchannel: effect of the cell-free layer in velocity profiles

A few detailed studies have been performed in complex in vitro microvascular networks composed by bifurcations and confluences. The main purpose of the present work is to numerically simulate the flow of two distinct fluids through bifurcation and confluence geometries, i. e red blood cells (RBCs)suspended in Dextran40 with about 14% of heamatocrit and pure water. The simulations of pure water and RBCs flows were performed resorting to the commercial finite volume software package FLUENT. A well known hemodynamic phenomenon, known as Fahraeus-Lindqvist effect, observed in both in vivo and in vitro studies, results in the formation of a marginal cell-free layer (CFL) at regions adjacent to the wall. Recently, studies have shown that the formation of the CFL is affected by the geometry of the microchannel and for the case of the confluences a CFL tend to appear in the middle of the microchannel after the apex of the confluence. By using the CFL experimental data, the main objective of this work is to implement a CFL in the numerical simulations in order to obtain a better understanding of the effect of this layer on the velocity profiles

Flow of red blood cells in microchannel networks: in vitro studies

Human blood is a multiphase biofluid primarily composed by the deformable red blood cells (RBCs) suspended in plasma. Because the complex structure of RBCs, blood exhibits unique flow characteristics on micro-scale level, due to their complex biochemical mechanisms and their response to both shear and extensional flow, which influence the rheological properties and flow behaviour of blood [1,2]. In the past years in vitro blood studies have been extensively performed and some important physiological phenomena, such as Fahraeus and Fahraeus-Lindqvist effect, were revealed [1,3]. This pioneer studies performed by Fahraeus and Fahraeus-Lindqvist in straight glass microchannels [4] revealed that for narrow tubes (diameter<300 μm), the apparent viscosity of blood declines with decreasing diameter. More recently, due to the developments in microscopy, computers and image analysis techniques, several researchers have used new measuring methods to obtain deeper quantitative understanding of the blood flow dynamics, in vitro [5-8] and in vivo experiments [9-10]. The increasing interest by the microfluidic and biomedical communities has also played a key role in several recent developments of lab-on-chip devices for blood sampling, analysis and cell culturing, aimed in a near future, the development of blood diagnostic devices, as an alternative tool to the traditional diagnostic strategies. However, the blood flow in microvascular networks phenomena remains incompletely understood. Thus, it is important to investigate in detail the behaviour of RBCs flow occurring in a microchannel network, such as, with divergent and convergent bifurcations, which mimics the irregular vessel segments linked by numerous diverging and converging bifurcations. Previously, we made in vitro studies in microchannels with a simple divergent and convergent bifurcation, that showed a pronounced cell-free layer (CFL) immediately downstream of the apex of the convergent bifurcation [1,4]. This interesting result led us to the present work, where the CFL in a microchannel network is investigated by using a high-speed video microscopy system in order to further understand the blood flow behaviour in microvessels networks

Visualization and measurement of red blood cells flowing in microfluidic devices

Several experimental techniques were performed in the past years using in vitro environments, in an attempt to not only understand the blood flow behaviour in microcirculation but also develop microfluidic devices as an alternative clinical methodology to detect blood diseases. Hence, the visualization and measurement of red blood cells (RBCs) flowing in a microfluidic device are important to provide not only essential information about hydrodynamic characteristics of the blood but also vital information to diagnose the initial symptoms of diseases during clinical investigations. For instance, RBC rigidity has been correlated with myocardial infarction, diabetes mellitus, hypertension, and also other haematological disorders and diseases that affect RBC deformation more directly, such as, hereditary spherocytosis, sickle cell anaemia and malaria. Regarding a better understanding of the RBCs deformation and motion, we present in this paper a compilation of studies made in our research group, using several microfluidic devices with different microchannel geometries and fabrication techniques (i.e., soft-lithography, xurography and hybrids) that focus in the shear and extensional flow behaviour, either in healthy or chemically stiffed RBCs.The authors acknowledge the financial support provided by 2007 Global COE Program “Global Nano-Biomedical Engineering Education and Research Network”, Japan and grant-in-Aid for Science and Technology, PTDC/SAU-BEB/105650/2008, PTDC/EME-MFE/099109/2008, PTDC/SAUENB/116929/2010, EXPL/EMS-SIS/2215/2013, scholarship SFRH/BD/91192/2012 and scholarship SFRH/BD/89077/2012 from FCT (Science and Technology Foundation), COMPETE, QREN and European Union (FEDER). The authors are also very grateful to Dr. Mónica Oliveira (Strathclyde University), Professor Takuji Ishikawa and Professor Takami Yamaguchi (Tohoku University) for their suggestions and support to this research work

Análise do escoamento sanguíneo em microcanais com bifurcações

In vitro experiments allow precise measurement and control over relevant physiological variables. Thus, in the present study we have used a lithography technique to fabricate a rectangular PDMS microchannel with a bifurcation. By using a confocal micro-PTV system, we have measured the effect of bifurcation on the flow behaviour of both fluorescent particles diluted in pure water and red blood cells (RBCs) in concentrated suspensions. After performing simulations with the commercial finite element software package POLYFLOW®, some experimental results were compared with the numerical results. Our preliminary results suggest that the RBC paths may suffer fluctuations on the transversal direction caused by RBCs obstruction around the neighbourhood of the diverging point of the bifurcation

Motions of particles and red blood cells in a bifurcation: comparison between experiments and numerical simulations

The blood flow dynamics in microcirculation depends strongly on the microvascular networks composed with short irregular vessel segments which are linked by numerous bifurcations. This paper presents the application of a confocal micro-PTV system to track RBCs through a rectangular polydimethysiloxane (PDMS) microchannel with a bifurcation. By using a confocal micro-PTV system, we have measured the effect of bifurcation on the flow behaviour of both fluorescent particles diluted in pure water and RBCs in concentrated suspensions. After performing simulations with the commercial finite element software package POLYFLOW®, some experimental results were compared with the numerical results. Our preliminary qualitative results suggest that the in vitro blood flowing (Re = 0.007) through a bifurcation seems to have a tendency to behave more closely as a Power law model than as a Carreau or Newtonian model.This study was supported in part by the Portuguese Government by a grant of the Science and Technology Foundation (BII/UNI/0532/EME/2008)

Perdas reprodutivas e reconcepção em fêmeas bovinas de corte submetidas a inseminação artificial em tempo fixo

O objetivo deste estudo foi avaliar as perdas gestacionais entre 30 e 120 dias de gestação e reconcepção em vacas de corte submetidas à inseminação artificial em tempo fixo (IATF). Foram analisadas 18.462 informações do arquivo zootécnico de animais submetidos a IATF no período da estação de monta de novembro de 2019 a abril de 2020 na região do semiárido de Minas Gerais. Os parâmetros avaliados foram perda gestacional, categoria animal, presença do bezerro ao pé da vaca, escore de condição corporal (ECC) e situação final da estação de monta das fêmeas que perderam gestação após a IATF, os dados foram analisados pelo teste qui-quadrado de Person (χ²) e teste de Kruskal-Wallis, com nível de significância de 5% com uso do programa SPSS. A taxa de prenhez final foi de 58,52%. A taxa de perdas entre o primeiro e segundo diagnóstico gestacional foi de 3,6%. Observou-se dependência entre as variáveis categoria e perda gestacional (χ²= 12,374, p0,05). A diferença do ECC entre as categorias foi significativa (p<0,05). A situação final foi influenciada (p<0,05) pela categoria animal. A ordem de parição e o escore de condição corporal influenciam significativamente a taxa de perda gestacional. Palavras-chaves: Bovinocultura; Desempenho reprodutivo; Perdas gestacionai

School environment associates with lung function and autonomic nervous system activity in children : a cross-sectional study

Children are in contact with local environments, which may affect respiratory symptoms and allergic sensitization. We aimed to assess the effect of the environment and the walkability surrounding schools on lung function, airway inflammation and autonomic nervous system activity. Data on 701 children from 20 primary schools were analysed. Lung function, airway inflammation and pH from exhaled breath condensate were measured. Pupillometry was performed to evaluate autonomic activity. Land use composition and walkability index were quantified within a 500 m buffer zone around schools. The proportion of effects explained by the school environment was measured by mixed-effect models. We found that green school areas tended to be associated with higher lung volumes (FVC, FEV1 and FEF25-75%) compared with built areas. FVC was significantly lower in-built than in green areas. After adjustment, the school environment explained 23%, 34% and 99.9% of the school effect on FVC, FEV1, and FEF25-75%, respectively. The walkability of school neighbourhoods was negatively associated with both pupil constriction amplitude and redilatation time, explaining -16% to 18% of parasympathetic and 8% to 29% of sympathetic activity. Our findings suggest that the environment surrounding schools has an effect on the lung function of its students. This effect may be partially mediated by the autonomic nervous system.Peer reviewe

práticas artísticas no ensino básico e secundário

Educação Artística: integrar a inovação. A educação artística apresenta-se como um território a re-cartografar, numa atualização tão rápida quanto aquela que ocorre no campo artístico. As propostas publicadas neste número 11 da Revista Matéria-Prima trazem essa diversidade de abordagens, com novidades conceptuais que estabelecem as devidas relações entre educação e cidadania, participação, sustentabilidade, cultura visual, e também com alguma atenção sobre os debates pós-coloniais e as questões de género. Os 16 artigos reunidos neste 11º número da Revista Matéria-Prima trazem a realidade operativa quer na formação de professores e quer na formulação dos discursos pedagógicos, suas justificações e suas propostas alternativas.As propostas apresentadas devolvem o debate ao terreno, e alargam-no. Provocam as periferias, convocam abordagens diferenciadas sobre o tema da arte e da educação. Em todas elas a proposta de crescimento através da arte, que hoje implica cada vez mais cidadania, crítica, criatividade, interligação, comprometimento, participação.info:eu-repo/semantics/publishedVersio

MAMMALS IN PORTUGAL : A data set of terrestrial, volant, and marine mammal occurrences in P ortugal

Mammals are threatened worldwide, with 26% of all species being includedin the IUCN threatened categories. This overall pattern is primarily associatedwith habitat loss or degradation, and human persecution for terrestrial mam-mals, and pollution, open net fishing, climate change, and prey depletion formarine mammals. Mammals play a key role in maintaining ecosystems func-tionality and resilience, and therefore information on their distribution is cru-cial to delineate and support conservation actions. MAMMALS INPORTUGAL is a publicly available data set compiling unpublishedgeoreferenced occurrence records of 92 terrestrial, volant, and marine mam-mals in mainland Portugal and archipelagos of the Azores and Madeira thatincludes 105,026 data entries between 1873 and 2021 (72% of the data occur-ring in 2000 and 2021). The methods used to collect the data were: live obser-vations/captures (43%), sign surveys (35%), camera trapping (16%),bioacoustics surveys (4%) and radiotracking, and inquiries that represent lessthan 1% of the records. The data set includes 13 types of records: (1) burrowsjsoil moundsjtunnel, (2) capture, (3) colony, (4) dead animaljhairjskullsjjaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8),observation in shelters, (9) photo trappingjvideo, (10) predators dietjpelletsjpine cones/nuts, (11) scatjtrackjditch, (12) telemetry and (13) vocalizationjecholocation. The spatial uncertainty of most records ranges between 0 and100 m (76%). Rodentia (n=31,573) has the highest number of records followedby Chiroptera (n=18,857), Carnivora (n=18,594), Lagomorpha (n=17,496),Cetartiodactyla (n=11,568) and Eulipotyphla (n=7008). The data setincludes records of species classified by the IUCN as threatened(e.g.,Oryctolagus cuniculus[n=12,159],Monachus monachus[n=1,512],andLynx pardinus[n=197]). We believe that this data set may stimulate thepublication of other European countries data sets that would certainly contrib-ute to ecology and conservation-related research, and therefore assisting onthe development of more accurate and tailored conservation managementstrategies for each species. There are no copyright restrictions; please cite thisdata paper when the data are used in publications.info:eu-repo/semantics/publishedVersio