156 research outputs found

    MACOP modular architecture with control primitives

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    Walking, catching a ball and reaching are all tasks in which humans and animals exhibit advanced motor skills. Findings in biological research concerning motor control suggest a modular control hierarchy which combines movement/motor primitives into complex and natural movements. Engineers inspire their research on these findings in the quest for adaptive and skillful control for robots. In this work we propose a modular architecture with control primitives (MACOP) which uses a set of controllers, where each controller becomes specialized in a subregion of its joint and task-space. Instead of having a single controller being used in this subregion (such as MOSAIC on which MACOP is inspired), MACOP relates more to the idea of continuously mixing a limited set of primitive controllers. By enforcing a set of desired properties on the mixing mechanism, a mixture of primitives emerges unsupervised which successfully solves the control task. We evaluate MACOP on a numerical model of a robot arm by training it to generate desired trajectories. We investigate how the tracking performance is affected by the number of controllers in MACOP and examine how the individual controllers and their generated control primitives contribute to solving the task. Furthermore, we show how MACOP compensates for the dynamic effects caused by a fixed control rate and the inertia of the robot

    The effect of wind turbines alongside motorways on drivers’ behaviour

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    This paper presents the results of a first study aimed at investigating whether the presence of wind turbines in close proximity to motorways leads to behavioural adaptations among passing drivers. Empirical data from loop detectors and temporary video cameras were analysed in a study employing a before-and-after design at a site near Rotterdam, The Netherlands. Analyses of driving speed and standard deviation of speed (corrected for trend effects through the use of control sites) were performed as well as analyses of the lateral position and standard deviation of the lateral position and an observation of serious traffic conflicts. The results showed that constructing wind turbines alongside a motorway led to some clearly observable effects on drivers’ behaviour. The analyses of the speed data showed that the mean speed was lowered by 2.24km/h (corrected for trend effects) after the construction of the wind turbines while the standard deviation of the speed significantly increased. After the construction of the wind turbines, drivers took a lateral position somewhat more to the left-hand side in their driving lane. There was an indication close to the 0.05 significance level (p=0.057) that the standard deviation of the lateral position slightly increased when the rotor blades were in transversal position. In the before period as well as in the after period, no serious traffic conflicts were registered. The increase in standard deviation of speed and in lateral position are two factors that intrinsically can have an unfavourable effect on road safety. However, the observed order of magnitude of the change was shown to be quite limited. Earlier research suggests that negative effects on road safety are only expected for changes substantially greater than the ones that were observed in this study. On the other hand, there was a significant reduction in driving speed, which might have a favourable effect on the expected number and severity of crashes, although it could also be a compensatory mechanism that indirectly indicates a reduced driving performance. From these findings, it can be concluded that, based on the observed variables, no substantial negative effects for road safety were found in the present study. The authors recommend continuous monitoring and further research on the topic

    Autobiographical Memory Specificity and Emotional Disorder

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    The authors review research showing that when recalling autobiographical events, many emotionally disturbed patients summarize categories of events rather than retrieving a single episode. The mechanisms underlying such overgeneral memory are examined, with a focus on M. A. Conway and C. W. Pleydell-Pearce's (2000) hierarchical search model of personal event retrieval. An elaboration of this model is proposed to account for overgeneral memory, focusing on how memory search can be affected by (a) capture and rumination processes, when mnemonic information used in retrieval activates ruminative thinking; (b) functional avoidance, when episodic material threatens to cause affective disturbance; and (c) impairment in executive capacity and control that limits an individual's ability to remain focused on retrieval in the face of distraction

    Hyperadrenocorticisme bij de fret: een overzicht van de huidige kennis aan de hand van twee klinische cases

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    Hyperadrenocorticism is a frequently occurring disease in middle-aged ferrets. It is caused by a neoplasm of the adrenal cortex. Otherwise than in dogs and cats, hyperadrenocorticism in the ferret is always independent of adrenocorticotropic hormone (ACTH). The tumor of the adrenal cortex can be removed surgically, mostly with satisfying results. After surgery, a regression of symptoms occurs after two to eight weeks, and the animals are without symptoms after five to eight months. In recent years, there has been a growing interest in using a chemical therapy aimed at decreasing hormone production through the administration of GnRH agonists. These agonists initially cause a temporary increase of the sex steroids, and then a long-term decrease of them through desensitization of the GnRH receptors. A deslorelin implant seems to be a promising alternative for the surgical treatment of hyperadrenocorticism in ferrets. Some authors even recommend it as a standard preventive treatment after neutering in both genders and for every ferret over four years of age. Moreover, it is an excellent alternative for surgical castration

    Potato protein ingestion increases muscle protein synthesis rates at rest and during recovery from exercise in humans

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    Introduction Plant-derived proteins have received considerable attention as an alternative to animal-based proteins and are now frequently used in both plant-based diets and sports nutrition products. However, little information is available on the anabolic properties of potato-derived protein. This study compares muscle protein synthesis rates after the ingestion of 30 g potato protein versus 30 g milk protein at rest and during recovery from a single bout of resistance exercise in healthy, young males. Methods In a randomized, double-blind, parallel-group design, 24 healthy young males (24 ± 4 yr) received primed continuous l-[ring-13C6]-phenylalanine infusions while ingesting 30 g potato-derived protein or 30 g milk protein after a single bout of unilateral resistance exercise. Blood and muscle biopsies were collected for 5 h after protein ingestion to assess postprandial plasma amino acid profiles and mixed muscle protein synthesis rates at rest and during recovery from exercise. Results Ingestion of both potato and milk protein increased mixed muscle protein synthesis rates when compared with basal postabsorptive values (from 0.020% ± 0.011% to 0.053% ± 0.017%·h−1 and from 0.021% ± 0.014% to 0.050% ± 0.012%·h−1, respectively; P < 0.001), with no differences between treatments (P = 0.54). In the exercised leg, mixed muscle protein synthesis rates increased to 0.069% ± 0.019% and 0.064% ± 0.015%·h−1 after ingesting potato and milk protein, respectively (P < 0.001), with no differences between treatments (P = 0.52). The muscle protein synthetic response was greater in the exercised compared with the resting leg (P < 0.05). Conclusions Ingestion of 30 g potato protein concentrate increases muscle protein synthesis rates at rest and during recovery from exercise in healthy, young males. Muscle protein synthesis rates after the ingestion of 30 g potato protein do not differ from rates observed after ingesting an equivalent amount of milk protein

    Potato Protein Ingestion Increases Muscle Protein Synthesis Rates at Rest and during Recovery from Exercise in Humans

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    INTRODUCTION: Plant-derived proteins have received considerable attention as an alternative to animal-based proteins and are now frequently used in both plant-based diets and sports nutrition products. However, little information is available on the anabolic properties of potato-derived protein. This study compares muscle protein synthesis rates after the ingestion of 30 g potato protein versus 30 g milk protein at rest and during recovery from a single bout of resistance exercise in healthy, young males. METHODS: In a randomized, double-blind, parallel-group design, 24 healthy young males (24 ± 4 yr) received primed continuous l-[ring-(13)C(6)]-phenylalanine infusions while ingesting 30 g potato-derived protein or 30 g milk protein after a single bout of unilateral resistance exercise. Blood and muscle biopsies were collected for 5 h after protein ingestion to assess postprandial plasma amino acid profiles and mixed muscle protein synthesis rates at rest and during recovery from exercise. RESULTS: Ingestion of both potato and milk protein increased mixed muscle protein synthesis rates when compared with basal postabsorptive values (from 0.020% ± 0.011% to 0.053% ± 0.017%·h(−1) and from 0.021% ± 0.014% to 0.050% ± 0.012%·h(−1), respectively; P < 0.001), with no differences between treatments (P = 0.54). In the exercised leg, mixed muscle protein synthesis rates increased to 0.069% ± 0.019% and 0.064% ± 0.015%·h(−1) after ingesting potato and milk protein, respectively (P < 0.001), with no differences between treatments (P = 0.52). The muscle protein synthetic response was greater in the exercised compared with the resting leg (P < 0.05). CONCLUSIONS: Ingestion of 30 g potato protein concentrate increases muscle protein synthesis rates at rest and during recovery from exercise in healthy, young males. Muscle protein synthesis rates after the ingestion of 30 g potato protein do not differ from rates observed after ingesting an equivalent amount of milk protein

    Design and characterisation of food grade powders and inks for microstructure control using 3D printing

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    Additive Manufacturing techniques have been previously applied to food materials with direct consumption in mind, as opposed to creating structural ingredients as shown in this study. First, semi-crystalline cellulose was mechanically treated by ball milling to render an amorphous powder, which has been characterised. Requirements for the subsequent recrystallization of this powder with a view to structuring have been determined through the control of moisture and thermal energy. Food inks based on xanthan gum have been formulated to enable successful jetting with a FujiFilm Dimatix ink jet printer. The polymer inks were subsequently jetted onto the amorphous cellulose powder to observe powder-binder interactions. Material combinations and parameters were optimised to produce cohesive geometric structures. The results of this study are promising when looking towards using these materials in a binder jetting additive manufacturing technique using designer particles and inks to create structures for use in food products

    Associations between branched chain amino acid intake and biomarkers of adiposity and cardiometabolic health independent of genetic factors: a twin study

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    Background: Conflicting data exist on the impact of dietary and circulating levels of branched chain amino acids (BCAA) on cardiometabolic health and it is unclear to what extent these relations are mediated by genetics.  Methods: In a cross-sectional study of 1997 female twins we examined associations between BCAA intake, measured using food frequency-questionnaires, and a range of markers of cardiometabolic health, including DXA-measured body fat, blood pressure, HOMA-IR, highsensitivity C-reactive protein (hs-CRP) and lipids. We also measured plasma concentrations of BCAA and known metabolites of amino acid metabolism using untargeted mass spectrometry. Using a within-twin design, multivariable analyses were used to compare the associations between BCAA intake and endpoints of cardiometabolic health, independently of genetic confounding.  Results: Higher BCAA intake was significantly associated with lower HOMA-IR (-0.1, Ptrend 0.02), insulin (-0.5 ”U/mL, P-trend 0.03), hs-CRP -0.3 mg/L, P-trend 0.01), systolic blood pressure (-2.3 mm Hg, P-trend 0.01) and waist-to-height ratio (-0.01, P-trend 0.04), comparing extreme quintiles of intake. These associations persisted in within-pair analysis for monozygotic twins for insulin resistance (P<0.01), inflammation (P=0.03), and blood pressure (P=0.04) suggesting independence from genetic confounding. There were no association between BCAA intake and plasma concentrations, although two metabolitespreviously associated with obesity were inversely associated with BCAA intake (alphahydroxyisovalerate and trans-4-hydroxyproline).  Conclusions: Higher intakes of BCAA were associated, independently of genetics, with lower insulin resistance, inflammation, blood pressure and adiposity-related metabolites. The BCAA intake associated with our findings are easily achievable in the habitual diet.  Abbreviations: BCAA, branched chain amino acids; DBP, diastolic blood pressure; DZ, dizygotic; FFQ, food frequency questionnaire; HDL-C, high density lipoprotein cholesterol; hs-CRP, high sensitivity C-reactive protein; MZ, monozygotic; SBP, systolic blood pressure; T2DM, type 2 diabetes; SBP, systolic blood pressure; WHtR, waist to height rati
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