13 research outputs found

    Learning new sensorimotor contingencies:Effects of long-term use of sensory augmentation on the brain and conscious perception

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    Theories of embodied cognition propose that perception is shaped by sensory stimuli and by the actions of the organism. Following sensorimotor contingency theory, the mastery of lawful relations between own behavior and resulting changes in sensory signals, called sensorimotor contingencies, is constitutive of conscious perception. Sensorimotor contingency theory predicts that, after training, knowledge relating to new sensorimotor contingencies develops, leading to changes in the activation of sensorimotor systems, and concomitant changes in perception. In the present study, we spell out this hypothesis in detail and investigate whether it is possible to learn new sensorimotor contingencies by sensory augmentation. Specifically, we designed an fMRI compatible sensory augmentation device, the feelSpace belt, which gives orientation information about the direction of magnetic north via vibrotactile stimulation on the waist of participants. In a longitudinal study, participants trained with this belt for seven weeks in natural environment. Our EEG results indicate that training with the belt leads to changes in sleep architecture early in the training phase, compatible with the consolidation of procedural learning as well as increased sensorimotor processing and motor programming. The fMRI results suggest that training entails activity in sensory as well as higher motor centers and brain areas known to be involved in navigation. These neural changes are accompanied with changes in how space and the belt signal are perceived, as well as with increased trust in navigational ability. Thus, our data on physiological processes and subjective experiences are compatible with the hypothesis that new sensorimotor contingencies can be acquired using sensory augmentation

    Wolf (Canis lupus) Predation Impacts on Livestock Production: Direct Effects, Indirect Effects, and Implications for Compensation Ratios

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    Growing wolf (Canis lupus L.) populations in the US Rocky Mountain Region have increased conflicts between livestock production and wolf conservation. Given that the costs of large carnivore conservation are disproportionately borne by local livestock producers, the United States uses compensation for wolf damage to reduce conflicts and mediate negative attitudes toward the predators. Current compensation programs, however, only consider the direct effects of wolf predation. Indirect effects, such as wolf effects on weaning weights, and conception rates, may also reduce profitability. By not including indirect wolf effects, compensation programs may systematically undercompensate ranchers. We use a stochastic budget model of a representative cow-calf ranch in northwest Wyoming to estimate the economic impact of both direct (death loss and injured calves) and indirect effects (decreased weaning weights, decreased conception rates, and increased cattle sickness) of wolf predation. Our results suggest that short-run (i.e., year-to-year) financial impacts of wolf indirect effects may be as large as or larger than the direct effects. Including indirect effects implies that the compensation ratio (i.e., number of calves compensated per confirmed depredation) necessary to fully offset the financial impacts of wolves would need to be two to three times larger than current 7:1 compensation ratio used in Wyoming.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

    Do Blood Tests Cause Anemia in Hospitalized Patients?: The Effect of Diagnostic Phlebotomy on Hemoglobin and Hematocrit Levels

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    OBJECTIVE: To determine whether phlebotomy contributes to changes in hemoglobin and hematocrit levels in hospitalized general internal medicine patients. DESIGN: Retrospective cohort study. SETTING: General internal medicine inpatient service at a tertiary care hospital. PARTICIPANTS: All adult patients discharged from the Toronto General Hospital's internal medicine service between January 1 and June 30, 2001. A total of 989 hospitalizations were reviewed and 404 hospitalizations were included in our analysis. MEASUREMENTS AND MAIN RESULTS: Mean (SD) hemoglobin and hematocrit changes during hospitalization were 7.9 (12.6) g/L (P<.0001) and 2.1% (3.8%) (P<.0001), respectively. The mean (SD) volume of phlebotomy during hospital stay was 74.6 (52.1) mL. On univariate analysis, changes in hemoglobin and hematocrit were predicted by the volume of phlebotomy, length of hospital stay, admission hemoglobin/hematocrit value, age, Charlson comorbidity index, and admission intravascular volume status. The volume of phlebotomy remained a strong predictor of drop in hemoglobin and hematocrit after adjusting for other predictors using multivariate analysis (P<.0001). On average, every 100 mL of phlebotomy was associated with a decrease in hemoglobin and hematocrit of 7.0 g/L and 1.9%, respectively. CONCLUSIONS: Phlebotomy is highly associated with changes in hemoglobin and hematocrit levels for patients admitted to an internal medicine service and can contribute to anemia. This anemia, in turn, may have significant consequences, especially for patients with cardiorespiratory diseases. Knowing the expected changes in hemoglobin and hematocrit due to diagnostic phlebotomy will help guide when to investigate anemia in hospitalized patients

    Thioesterase Domains of Fungal Nonreducing Polyketide Synthases Act as Decision Gates during Combinatorial Biosynthesis

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    A crucial step during the programmed biosynthesis of fungal polyketide natural products is the release of the final polyketide intermediate from the iterative polyketide synthases (iPKSs), most frequently by a thioesterase (TE) domain. Realization of combinatorial biosynthesis with iPKSs requires TE domains that can accept altered polyketide intermediates generated by hybrid synthase enzymes and successfully release “unnatural products” with the desired structure. Achieving precise control over product release is of paramount importance with O—C bond-forming TE domains capable of macrocyclization, hydrolysis, transesterification and pyrone formation that channel reactive, pluripotent polyketide intermediates to defined structural classes of bioactive secondary metabolites. By exploiting chimeric iPKS enzymes to offer substrates with controlled structural variety to two orthologous O—C bond-forming TE domains in situ, we show that these enzymes act as non-equivalent decision gates, determining context-dependent release mechanisms and overall product flux. Inappropriate choice of a TE could eradicate product formation in an otherwise highly productive chassis. Conversely, a judicious choice of a TE may allow the production of a desired hybrid metabolite. Finally, a serendipitous choice of a TE may reveal the unexpected productivity of some chassis. The ultimate decision gating role of TE domains influences the observable outcome of combinatorial domain swaps, emphasizing that the deduced programming rules are context dependent. These factors may complicate engineering the biosynthesis of a desired “unnatural product”, but may also open additional avenues to create biosynthetic novelty based on fungal nonreduced polyketides
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