694 research outputs found
Examining the Effects of Race on Human-AI Cooperation
Recent literature has shown that racism and implicit racial biases can affect oneâs actions in major ways, from the time it takes police to decide whether they shoot an armed suspect, to a decision on whether to trust a stranger. Given that race is a social/power construct, artifacts can also be racialized, and these racialized agents have also been found to be treated differently based on their perceived race. We explored whether peopleâs decision to cooperate with an AI agent during a task (a modified version of the Stag hunt task) is affected by the knowledge that the AI agent was trained on a population of a particular race (Black, White, or a non-racialized control condition). These data show that White participants performed the best when the agent was racialized as White and not racialized at all, while Black participants achieved the highest score when the agent was racialized as Black. Qualitative data indicated that White participants were less likely to report that they believed that the AI agent was attempting to cooperate during the task and were more likely to report that they doubted the intelligence of the AI agent. This work suggests that racialization of AI agents, even if superficial and not explicitly related to the behavior of that agent, may result in different cooperation behavior with that agent, showing potentially insidious and pervasive effects of racism on the way people interact with AI agents
Unbalanced reduction of nutrient loads has created an offshore gradient from phosphorus to nitrogen limitation in the North Sea
Measures to reduce eutrophication have often led to a more effective decline of phosphorus (P) than nitrogen(N) concentrations. The resultant changes in riverine nutrient loads can cause an increase in the N : Pratios of coastal waters. During four research cruises along a 450 km transect, we investigated how reductionsin nutrient inputs during the past 25 yr have affected nutrient limitation patterns in the North Sea. Thisrevealed a strong offshore gradient of dissolved inorganic N : P ratios in spring, from 375 : 1 nearshoretoward 1 : 1 in the central North Sea. This gradient was reflected in high nearshore N : P and C : P ratios ofparticulate organic matter (mainly phytoplankton), indicative of severe P deficiency of coastal phytoplankton,which may negatively affect higher trophic levels in the food web. Nutrient enrichment bioassays performedon-board showed P and Si limitation of phytoplankton growth nearshore, co-limitation of N and P ina transitional region, and N limitation in the outer-shore waters, confirming the existence of an offshore gradientfrom P to N limitation. Different species were limited by different nutrients, indicating that furtherreductions of P loads without concomitant reductions of N loads will suppress colonial Phaeocystis blooms,but will be less effective in diminishing harmful algal blooms by dino- and nanoflagellates. Hence, our resultsprovide evidence that de-eutrophication efforts in northwestern Europe have led to a large imbalance in theN : P stoichiometry of coastal waters of the North Sea, with major consequences for the growth, species composition,and nutritional quality of marine phytoplankton communities
Lesions of the paraventricular nucleus of the thalamus differentially affect signâ and goalâtracking conditioned responses
Recently, evidence has emerged suggesting a role for the paraventricular nucleus of the thalamus (PVT) in the processing of rewardâassociated cues. However, the specific role of the PVT in these processes has yet to be elucidated. Here we use an animal model that captures individual variation in response to discrete rewardâassociated cues to further assess the role of the PVT in stimulusâreward learning. When rats are exposed to a Pavlovian conditioning paradigm, wherein a discrete cue predicts food reward, two distinct conditioned responses emerge. Some rats, termed signâtrackers, approach and manipulate the cue, whereas others, termed goalâtrackers, approach the location of reward delivery upon cue presentation. For both signâ and goalâtrackers the cue is a predictor, but only for signâtrackers is it also an incentive stimulus. We investigated the role of the PVT in the acquisition and expression of these conditioned responses using an excitotoxic lesion. Results indicate that PVT lesions prior to acquisition amplify the differences between phenotypes â increasing signâtracking and attenuating goalâtracking behavior. Lesions of the PVT after rats had acquired their respective conditioned responses also attenuated the expression of the goalâtracking response, and increased the signâtracking response, but did so selectively in goalâtrackers. These results suggest that the PVT acts to suppress the attribution of incentive salience to reward cues, as disruption of the functional activity within this structure enhances the tendency to signâtrack.Here we utilized animal models that capture individual differences in the propensity to attribute incentive salience to reward cues (i.e. signâtrackers vs. goalâtrackers) to further elucidate the role of the PVT in cueâmotivated behaviors. We report that lesions of this structure increase the tendency for individuals to attribute incentive motivational value to reward cues. These findings suggest that the PVT is a critical part of the circuitry underlying maladaptive behavior, such as addiction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115973/1/ejn13031-sup-0001-TableS1-FigureS1-S5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115973/2/ejn13031.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115973/3/ejn13031_am.pd
Gender Specific Disruptions in Emotion Processing in Younger Adults with Depression
Background: One of the principal theories regarding the biological basis of major depressive disorder (MDD) implicates a dysregulation of emotion-processing circuitry. Gender differences in how emotions are processed and relative experience with emotion processing might help to explain some of the disparities in the prevalence of MDD between women and men. This study sought to explore how gender and depression status relate to emotion processing. Methods: This study employed a 2 (MDD status) Ă 2 (gender) factorial design to explore differences in classifications of posed facial emotional expressions (N=151). Results: For errors, there was an interaction between gender and depression status. Women with MDD made more errors than did nondepressed women and men with MDD, particularly for fearful and sad stimuli (Ps Ps P=.01). Men with MDD, conversely, performed similarly to control men (P=.61). Conclusions: These results provide novel and intriguing evidence that depression in younger adults (years) differentially disrupts emotion processing in women as compared to men. This interaction could be driven by neurobiological and social learning mechanisms, or interactions between them, and may underlie differences in the prevalence of depression in women and men. Depression and Anxiety, 2009. Published 2008 Wiley-Liss, Inc
Peptide F (pro-enkephalin fragment) : Radioimmunoassay, and stress-induced changes in adrenal
Utilizing a nine amino-acid (Asp-Glu-Leu-Tyr-Pro-Leu-Glu-Val-Glu) non-enkephalin containing fragment of Peptide F from the pro-enkephalin molecule, a radioimmunoassay was developed. Extraction of bovine, rat, and guinea pig adrenomedullary preparations demonstrated this fragment to be present and apparently partially conserved across species. In rats, acute inescapable foot-shock stress led to a significant decrease of the immunoreactive material in the adrenal medulla. Chronic daily stress for two weeks resulted in an inability of the adrenals to alter F levels upon subsequent stress. The existence of F-like immunoreactivity and its alteration by environmental manipulation, suggest that it may play a unique physiological role.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23838/1/0000077.pd
The Variable Vector Countermeasure Suit (V2Suit) for space habitation and exploration
The âVariable Vector Countermeasure Suit (V2Suit) for Space Habitation and Explorationâ is a novel system concept that provides a platform for integrating sensors and actuators with daily astronaut intravehicular activities to improve health and performance, while reducing the mass and volume of the physiologic adaptation countermeasure systems, as well as the required exercise time during long-duration space exploration missions. The V2Suit system leverages wearable kinematic monitoring technology and uses inertial measurement units (IMUs) and control moment gyroscopes (CMGs) within miniaturized modules placed on body segments to provide a âviscous resistanceâ during movements against a specified direction of âdownââinitially as a countermeasure to the sensorimotor adaptation performance decrements that manifest themselves while living and working in microgravity and during gravitational transitions during long-duration spaceflight, including post-flight recovery and rehabilitation. Several aspects of the V2Suit system concept were explored and simulated prior to developing a brassboard prototype for technology demonstration. This included a system architecture for identifying the key components and their interconnects, initial identification of key human-system integration challenges, development of a simulation architecture for CMG selection and parameter sizing, and the detailed mechanical design and fabrication of a module. The brassboard prototype demonstrates closed-loop control from âdownâ initialization through CMG actuation, and provides a research platform for human performance evaluations to mitigate sensorimotor adaptation, as well as a tool for determining the performance requirements when used as a musculoskeletal deconditioning countermeasure. This type of countermeasure system also has Earth benefits, particularly in gait or movement stabilization and rehabilitation.United States. National Aeronautics and Space Administration (Innovative Advanced Concepts Grant NNX11AR25G)United States. National Aeronautics and Space Administration (Innovative Advanced Concepts Grant NNX12AQ58G
Key Residues Defining the Î-Opioid Receptor Binding Pocket: A Site-Directed Mutagenesis Study
Structural elements of the rat Î-opioid receptor important in ligand receptor binding and selectivity were examined using a site-directed mutagenesis approach. Five single amino acid mutations were made, three that altered conserved residues in the Î, Î, and Î receptors (Asn 150 to Ala, His 297 to Ala, and Tyr 326 to Phe) and two designed to test for Î/Î selectivity (Ile 198 to Val and Val 202 to Ile). Mutation of His 297 in transmembrane domain 6 (TM6) resulted in no detectable binding with [ 3 H]DAMGO ( 3 H-labeled d-Ala 2 , N -Me-Phe 4 ,Gly-ol 5 -enkephalin), [ 3 H]bremazocine, or [ 3 H]ethylketocyclazocine. Mutation of Asn 150 in TM3 produces a three- to 20-fold increase in affinity for the opioid agonists morphine, DAMGO, fentanyl, Î-endorphin 1â31 , JOM-13, deltorphin II, dynorphin 1â13 , and U50,488, with no change in the binding of antagonists such as naloxone, naltrexone, naltrindole, and nor-binaltorphamine. In contrast, the Tyr 326 mutation in TM7 resulted in a decreased affinity for a wide spectrum of Î, Î, and Î agonists and antagonists. Altering Val 202 to Ile in TM4 produced no change on ligand affinity, but Ile 198 to Val resulted in a four- to fivefold decreased affinity for the Î agonists morphine and DAMGO, with no change in the binding affinities of Î and Î ligands.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65474/1/j.1471-4159.1997.68010344.x.pd
Tissue-specific calibration of extracellular matrix material properties by transforming growth factor-beta and Runx2 in bone is required for hearing
Publisher version: http://www.nature.com/embor/journal/v11/n10/full/embor2010135.htmlDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEPhysical cues, such as extracellular matrix stiffness, direct cell differentiation and support tissue-specific function. Perturbation of these cues underlies diverse pathologies, including osteoarthritis, cardiovascular disease and cancer. However, the molecular mechanisms that establish tissue-specific material properties and link them to healthy tissue function are unknown. We show that Runx2, a key lineage-specific transcription factor, regulates the material properties of bone matrix through the same transforming growth factor-beta (TGFbeta)-responsive pathway that controls osteoblast differentiation. Deregulated TGFbeta or Runx2 function compromises the distinctly hard cochlear bone matrix and causes hearing loss, as seen in human cleidocranial dysplasia. In Runx2(+/-) mice, inhibition of TGFbeta signalling rescues both the material properties of the defective matrix, and hearing. This study elucidates the unknown cause of hearing loss in cleidocranial dysplasia, and demonstrates that a molecular pathway controlling cell differentiation also defines material properties of extracellular matrix. Furthermore, our results suggest that the careful regulation of these properties is essential for healthy tissue functio
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