2,853 research outputs found

    Resting behavior of broilers reared with or without artificial brooders

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    Rest and sleep are important for the welfare of mammals and birds. A large part of the daily time budget of broiler chickens is taken up by resting behavior and the quality of resting is important. However, in intensive broiler production systems, disruptions of resting behaviors are common. These disruptions of resting behavior could be negative for the health and growth of the birds. This study investigated if artificial brooders that provide a delimited and darker resting place, away from active birds, reduce disruptions of resting behavior compared to a control situation without artificial brooders. Six pens of each treatment were used in the same building, keeping 60 chickens (Ross 308) per pen. The artificial brooders were removed at 21 days of age. Data on disturbances and duration of resting bouts and activity between resting bouts were collected on 20 and 34 days of age. Also, as an indicator of the quality of rest, the animals' cognitive performance was evaluated in a spatial learning test that was performed at 11 days of age. The results showed that birds housed in pens with access to brooders have longer resting bouts (260.7 +/- 5.2 vs. 132.8 +/- 5.3s, p < 0.001) and are less likely to be disturbed during resting by other individuals (0.15 vs. 0.48, p < 0.001). The effect of the artificial brooders on both the duration of resting bouts and the proportion of disturbances remained after the removal of the brooders at 21 days of age. The duration of activity between resting bouts was shorter if the resting bout was ended by a disturbance (9.98 +/- 1.0 vs. 61.0 +/- 2.4s, p < 0.001). Birds reared with brooders were more likely to solve the spatial learning task (0.5 vs. 0.27, p < 0.01), but those succeeding were not faster at solving it. Broilers may be exposed to disrupted rest due to the lack of a dedicated resting place separated from areas with high activity. Using artificial brooders reduces disturbances but does not eliminate them. Therefore, additional changes to the housing conditions or management will be needed to prevent disturbances

    Closed-Loop Targeted Memory Reactivation during Sleep Improves Spatial Navigation

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    Sounds associated with newly learned information that are replayed during non-rapid eye movement (NREM) sleep can improve recall in simple tasks. The mechanism for this improvement is presumed to be reactivation of the newly learned memory during sleep when consolidation takes place. We have developed an EEG-based closed-loop system to precisely deliver sensory stimulation at the time of down-state to up-state transitions during NREM sleep. Here, we demonstrate that applying this technology to participants performing a realistic navigation task in virtual reality results in a significant improvement in navigation efficiency after sleep that is accompanied by increases in the spectral power especially in the fast (12\u201315 Hz) sleep spindle band. Our results show promise for the application of sleep-based interventions to drive improvement in real-world tasks

    Principios básicos de resonancia magnética cardiovascular (RMC): secuencias, planos de adquisición y protocolo de estudio

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    ABSTRACT Evaluation of the cardiovascular system with magnetic resonance (CMR) has become one of the most relevant and up-to-the-minute clinical applications of this diagnostic technique, as CMR makes possible an exact and reproducible study of the anatomy and function of the heart and great vessels. The complexity of this technique is mainly due to the anatomical location and orientation of the cardiovascular structures, the specific CMR sequences that have to be used and a lack of familiarity amongst radiologists regarding cardiovascular pathology. In this report the most basic principles of CMR are described. The clinical usefulness of anatomical, functional, and flow quantification sequences are discussed, conventional CMR acquisition planes are described, and an easy CMR study protocol is proposed

    Tapping Environmental History to Recreate America’s Colonial Hydrology

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    To properly remediate, improve, or predict how hydrological systems behave, it is vital to establish their histories. However, modern-style records, assembled from instrumental data and remote sensing platforms, hardly exist back more than a few decades. As centuries of data is preferable given multidecadal fluxes of both meteorology/climatology and demographics, building such a history requires resources traditionally considered only useful in the social sciences and humanities. In this Feature, Pastore et al. discuss how they have undertaken the synthesis of historical records and modern techniques to understand the hydrology of the Northeastern U.S. from Colonial times to modern day. Such approaches could aid studies in other regions that may require heavier reliance on qualitative narratives. Further, a better insight as to how historical changes unfolded could provide a “past is prologue” methodology to increase the accuracy of predictive environmental models

    Fabrication of Metal and Alloy Components by Additive Manufacturing: Examples of 3D Materials Science

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    ObjectiveThis paper provides a brief review of relatively new additive manufacturing technologies for the fabrication of unusual and complex metal and alloy products by laser and electron beam melting. A number of process features and product microstructures are illustrated utilizing 3D optical and transmission electron microscope image compositions representing examples of 3D materials science.MethodsProcessing methods involving electron beam melting (EBM) and a process referred to as direct metal laser sintering (DMLS), often called selective laser melting (SLM) are described along with the use of light (optical) microscopy (OM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to elucidate microstructural phenomena.ResultsExamples of EBM and SLM studies are presented in 3D image compositions. These include EBM of Ti-6Al-4V, Cu, Co-base superalloy and Inconel 625; and SLM of 17-4 PH stainless steel, Inconel 718 and Inconel 625.Conclusions3D image compositions constituting 3D materials science provide effective visualization for directional solidification-related phenomena associated with the EBM and SLM fabrication of a range of metals and alloys, especially microstructures and microstructural architectures

    Resting behavior of broilers reared with or without artificial brooders

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    Rest and sleep are important for the welfare of mammals and birds. A large part of the daily time budget of broiler chickens is taken up by resting behavior and the quality of resting is important. However, in intensive broiler production systems, disruptions of resting behaviors are common. These disruptions of resting behavior could be negative for the health and growth of the birds. This study investigated if artificial brooders that provide a delimited and darker resting place, away from active birds, reduce disruptions of resting behavior compared to a control situation without artificial brooders. Six pens of each treatment were used in the same building, keeping 60 chickens (Ross 308) per pen. The artificial brooders were removed at 21 days of age. Data on disturbances and duration of resting bouts and activity between resting bouts were collected on 20 and 34 days of age. Also, as an indicator of the quality of rest, the animals' cognitive performance was evaluated in a spatial learning test that was performed at 11 days of age. The results showed that birds housed in pens with access to brooders have longer resting bouts (260.7 ± 5.2 vs. 132.8 ± 5.3s, p &lt; 0.001) and are less likely to be disturbed during resting by other individuals (0.15 vs. 0.48, p &lt; 0.001). The effect of the artificial brooders on both the duration of resting bouts and the proportion of disturbances remained after the removal of the brooders at 21 days of age. The duration of activity between resting bouts was shorter if the resting bout was ended by a disturbance (9.98 ± 1.0 vs. 61.0 ± 2.4s, p &lt; 0.001). Birds reared with brooders were more likely to solve the spatial learning task (0.5 vs. 0.27, p &lt; 0.01), but those succeeding were not faster at solving it. Broilers may be exposed to disrupted rest due to the lack of a dedicated resting place separated from areas with high activity. Using artificial brooders reduces disturbances but does not eliminate them. Therefore, additional changes to the housing conditions or management will be needed to prevent disturbances

    Changes in Muscle Metabolism are Associated with Phenotypic Variability in Golden Retriever Muscular Dystrophy

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    Duchenne muscular dystrophy (DMD) is an X-chromosome-linked disorder and the most common monogenic disease in people. Affected boys are diagnosed at a young age, become non-ambulatory by their early teens, and succumb to cardiorespiratory failure by their thirties. Despite being a monogenic condition resulting from mutations in the DMD gene, affected boys have noteworthy phenotypic variability. Efforts have identified genetic modifiers that could modify disease progression and be pharmacologic targets. Dogs affected with golden retriever muscular dystrophy (GRMD) have absent dystrophin and demonstrate phenotypic variability at the functional, histopathological, and molecular level. Our laboratory is particularly interested in muscle metabolism changes in dystrophin-deficient muscle. We identified several metabolic alterations, including myofiber type switching from fast (type II) to slow (type I), reduced glycolytic enzyme expression, reduced and morphologically abnormal mitochondria, and differential AMP-kinase phosphorylation (activation) between hypertrophied and wasted muscle. We hypothesize that muscle metabolism changes are, in part, responsible for phenotypic variability in GRMD. Pharmacological therapies aimed at modulating muscle metabolism can be tested in GRMD dogs for efficacy
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