1,414 research outputs found

    Lying posture does not accurately indicate sleep stage in dairy cows

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    \ua9 2021 Elsevier B.V. Quality sleep is important for physical health and welfare in animals. However, we know little about dairy cow sleep, and how much they need. Practical techniques are needed to monitor sleep in cows to determine how different management practices affect their sleep and their welfare. It is impractical to use ‘gold standard’ electrophysiological - polysomnography (PSG) to identify sleep in cows. Previous work suggests lying postures are useful to identify sleep stages in calves, but the reliability of lying behaviour to identify these sleep stages in adult cows is uncertain. We compared the lying postures of adult dairy cows (deep bedded on straw or in a pasture) with PSG, to determine if lying postures could be used to accurately identify rapid eye movement (REM) and the different stages of non-REM (NREM) sleep. Lying in the typical “sleep” posture with the head turned and resting on the flank identified approximately 70 % of REM sleep in outdoor managed cows but was less accurate in indoor housed cows that showed REM sleep in numerous postures. Lying with the head still and low did not identify stages of NREM sleep in either group. Using the tucked ‘sleep posture’ to estimate total sleep would be an over estimation of REM sleep, but also an underestimation of total sleep as this posture would omit most NREM sleep. Lying postures are not useful indicators of sleep stages in dairy cows and additional research is required to identify efficacious alternative techniques

    Heart rate and heart rate variability change with sleep stage in dairy cows

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    \ua9 2021 by the authors. Licensee MDPI, Basel, Switzerland.Changes to the amount and patterns of sleep stages could be a useful tool to assess the effects of stress or changes to the environment in animal welfare research. However, the gold standard method, polysomnography PSG, is difficult to use with large animals such as dairy cows. Heart rate (HR) and heart rate variability (HRV) can be used to predict sleep stages in humans and could be useful as an easier method to identify sleep stages in cows. We compared the mean HR and HRV and lying posture of dairy cows at pasture and when housed, with sleep stages identified through PSG. HR and HRV were higher when cows were moving their heads or when lying flat on their side. Overall, mean HR decreased with depth of sleep. There was more variability in time between successive heart beats during REM sleep, and more variability in time between heart beats when cows were awake and in REM sleep. These shifts in HR measures between sleep stages followed similar patterns despite differences in mean HR between the groups. Our results show that HR and HRV measures could be a promising alternative method to PSG for assessing sleep in dairy cows

    Machine learning prediction of sleep stages in dairy cows from heart rate and muscle activity measures

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    \ua9 2021, The Author(s). Sleep is important for cow health and shows promise as a tool for assessing welfare, but methods to accurately distinguish between important sleep stages are difficult and impractical to use with cattle in typical farm environments. The objective of this study was to determine if data from more easily applied non-invasive devices assessing neck muscle activity and heart rate (HR) alone could be used to differentiate between sleep stages. We developed, trained, and compared two machine learning models using neural networks and random forest algorithms to predict sleep stages from 15 variables (features) of the muscle activity and HR data collected from 12 cows in two environments. Using k-fold cross validation we compared the success of the models to the gold standard, Polysomnography (PSG). Overall, both models learned from the data and were able to accurately predict sleep stages from HR and muscle activity alone with classification accuracy in the range of similar human models. Further research is required to validate the models with a larger sample size, but the proposed methodology appears to give an accurate representation of sleep stages in cattle and could consequentially enable future sleep research into conditions affecting cow sleep and welfare

    An electromagnetism-like metaheuristic for open-shop problems with no buffer

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    This paper considers open-shop scheduling with no intermediate buffer to minimize total tardiness. This problem occurs in many production settings, in the plastic molding, chemical, and food processing industries. The paper mathematically formulates the problem by a mixed integer linear program. The problem can be optimally solved by the model. The paper also develops a novel metaheuristic based on an electromagnetism algorithm to solve the large-sized problems. The paper conducts two computational experiments. The first includes small-sized instances by which the mathematical model and general performance of the proposed metaheuristic are evaluated. The second evaluates the metaheuristic for its performance to solve some large-sized instances. The results show that the model and algorithm are effective to deal with the problem

    Petroleomics by ion mobility mass spectrometry: resolution and characterization of contaminants and additives in crude oils and petrofuels

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ion mobility-mass spectrometry (IM-MS), performed with exceptional resolution and sensitivity in a new uniform-field drift tube ion mobility quadrupole time-of-flight (IM-QTOF) instrument, is shown to provide a useful tool for resolving and characterizing crude oils and their contaminants, as well as petrofuels and their additives. Whereas direct analysis of a crude oil sample contaminated with demulsifiers by the classical ESI(+/-)-FTICR-MS petroleomic approach was unsatisfactory since it responds only with abundance and m/z, and ionization is impaired due to suppression of polar compounds of crude oil by additives likely used in petroleum industry, IM-MS enables mobility separation of ions, particularly of double bond equivalent (DBE) series for a giving CnX class providing separated spectra which are typical obtained either for the crude oil or the contaminants, even suffering of ion suppression or low ionization efficiency. The combination of improved IM resolution and high mass resolving power (40,000@400) of the QTOF instrument provides useful information on class (N, NO, NS, etc.), carbon number (C-n), and unsaturation (DBE) levels for crude oils, allowing one to infer geochemical properties from DBE trends that can be compared with IM-MS data. As demonstrated by results of gasoline samples with additives, the IM-MS system also allows efficient separation and characterization of additives and contaminants in petrofuels.Ion mobility-mass spectrometry (IM-MS), performed with exceptional resolution and sensitivity in a new uniform-field drift tube ion mobility quadrupole time-of-flight (IM-QTOF) instrument, is shown to provide a useful tool for resolving and characterizing71144504463FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2013/19161-4]2013/19161-4sem informaçãosem informaçãoWe would like to thank the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) for the scholarship awarded to J.M.S. (process number 2013/19161-4), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Conselho Nacional de Des

    Generation Gap and the Impact of the Web on Goods Quality Perceptions

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    This study explores how age and general online shopping experience affect consumer perceptions on product quality uncertainty. Using the survey data collected from 549 consumers, we investigated how they perceive the uncertainty of product quality on six search, experience and credence goods. The ANOVA results show that age and the Web shopping experience of consumers are significant factors. A generation gap is indeed seen for all but one experience good. Web shopping experience is not a significant factor for search goods but is for experience and credence goods. There is an interaction effect between age and Web shopping experience for one credence good. Implications of these results are discussed

    A dynamical model reveals gene co-localizations in nucleus

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    Co-localization of networks of genes in the nucleus is thought to play an important role in determining gene expression patterns. Based upon experimental data, we built a dynamical model to test whether pure diffusion could account for the observed co-localization of genes within a defined subnuclear region. A simple standard Brownian motion model in two and three dimensions shows that preferential co-localization is possible for co-regulated genes without any direct interaction, and suggests the occurrence may be due to a limitation in the number of available transcription factors. Experimental data of chromatin movements demonstrates that fractional rather than standard Brownian motion is more appropriate to model gene mobilizations, and we tested our dynamical model against recent static experimental data, using a sub-diffusion process by which the genes tend to colocalize more easily. Moreover, in order to compare our model with recently obtained experimental data, we studied the association level between genes and factors, and presented data supporting the validation of this dynamic model. As further applications of our model, we applied it to test against more biological observations. We found that increasing transcription factor number, rather than factory number and nucleus size, might be the reason for decreasing gene co-localization. In the scenario of frequency-or amplitude-modulation of transcription factors, our model predicted that frequency-modulation may increase the co-localization between its targeted genes

    Lakeside Cemeteries in the Sahara: 5000 Years of Holocene Population and Environmental Change

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    Background: Approximately two hundred human burials were discovered on the edge of a paleolake in Niger that providea uniquely preserved record of human occupation in the Sahara during the Holocene (,8000 B.C.E. to the present). CalledGobero, this suite of closely spaced sites chronicles the rapid pace of biosocial change in the southern Sahara in response tosevere climatic fluctuation.Methodology/Principal Findings: Two main occupational phases are identified that correspond with humid intervals in theearly and mid-Holocene, based on 78 direct AMS radiocarbon dates on human remains, fauna and artifacts, as well as 9 OSLdates on paleodune sand. The older occupants have craniofacial dimensions that demonstrate similarities with mid-Holocene occupants of the southern Sahara and Late Pleistocene to early Holocene inhabitants of the Maghreb. Theirhyperflexed burials compose the earliest cemetery in the Sahara dating to ,7500 B.C.E. These early occupants abandon thearea under arid conditions and, when humid conditions return ,4600 B.C.E., are replaced by a more gracile people withelaborated grave goods including animal bone and ivory ornaments.Conclusions/Significance: The principal significance of Gobero lies in its extraordinary human, faunal, and archaeologicalrecord, from which we conclude the following:(1) The early Holocene occupants at Gobero (7700–6200 B.C.E.) were largely sedentary hunter-fisher-gatherers withlakeside funerary sites that include the earliest recorded cemetery in the Sahara.(2) Principal components analysis of craniometric variables closely allies the early Holocene occupants at Gobero with askeletally robust, trans-Saharan assemblage of Late Pleistocene to mid-Holocene human populations from the Maghreband southern Sahara.(3) Gobero was abandoned during a period of severe aridification possibly as long as one millennium (6200–5200 B.C.E).(4) More gracile humans arrived in the mid-Holocene (5200–2500 B.C.E.) employing a diversified subsistence economybased on clams, fish, and savanna vertebrates as well as some cattle husbandry.(5) Population replacement after a harsh arid hiatus is the most likely explanation for the occupational sequence at Gobero.(6) We are just beginnin

    Self-organising Thermoregulatory Huddling in a Model of Soft Deformable Littermates

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    Thermoregulatory huddling behaviours dominate the early experiences of developing rodents, and constrain the patterns of sensory and motor input that drive neural plasticity. Huddling is a complex emergent group behaviour, thought to provide an early template for the development of adult social systems, and to constrain natural selection on metabolic physiology. However, huddling behaviours are governed by simple rules of interaction between individuals, which can be described in terms of the thermodynamics of heat exchange, and can be easily controlled by manipulation of the environment temperature. Thermoregulatory huddling thus provides an opportunity to investigate the effects of early experience on brain development in a social, developmental, and evolutionary context, through controlled experimentation. This paper demonstrates that thermoregulatory huddling behaviours can self-organise in a simulation of rodent littermates modelled as soft-deformable bodies that exchange heat during contact. The paper presents a novel methodology, based on techniques in computer animation, for simulating the early sensory and motor experiences of the developing rodent
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