Characterization of ISF-VAT performance in weak magnetic nozzle

Vacuum arc thruster performance in a magnetic nozzle configuration is experimentally characterized. Measurements are performed on a miniature coaxial thruster with an anode inner diameter of $1.8$ mm. The magnetic field B is produced by a single air coil, $18$ mm in diameter. Direct measurement of thrust, mass consumption and arc current are performed. To obtain statistically viable results $\approx 6000$ arc pulses are analyzed at each operational point. Cathode mass erosion is measured using laser profilometry. To sustain thruster operation over several measurement cycles, an active cathode feeding system is used. For $0< B \leq 0.2$ T performance increase over the non-magnetic case is observed with the best thrust to arc power ratio $T/P \approx 9$ $\mu$N/W obtained at $B \approx 0.2$ T. A parametric model is provided that captures the performance enhancement based on beam collimation and acceleration by the magnetic nozzle. For $B > 0.2$ T the arc discharge is shown to be suppressed nullifying any additional gains by the nozzle effect

Abnormal Left-Sided Orbitomedial Prefrontal Cortical–Amygdala Connectivity during Happy and Fear Face Processing: A Potential Neural Mechanism of Female MDD

Background: Pathophysiologic processes supporting abnormal emotion regulation in major depressive disorder (MDD) are poorly understood. We previously found abnormal inverse left-sided ventromedial prefrontal cortical–amygdala effective connectivity to happy faces in females with MDD. We aimed to replicate and expand this previous finding in an independent participant sample, using a more inclusive neural model, and a novel emotion processing paradigm. Methods: Nineteen individuals with MDD in depressed episode (12 females), and 19 healthy individuals, age, and gender matched, performed an implicit emotion processing and automatic attentional control paradigm to examine abnormalities in prefrontal cortical–amygdala neural circuitry during happy, angry, fearful, and sad face processing measured with functional magnetic resonance imaging in a 3-T scanner. Effective connectivity was estimated with dynamic causal modeling in a trinodal neural model including two anatomically defined prefrontal cortical regions, ventromedial prefrontal cortex, and subgenual cingulate cortex (sgACC), and the amygdala. Results: We replicated our previous finding of abnormal inverse left-sided top-down ventromedial prefrontal cortical–amygdala connectivity to happy faces in females with MDD (p = 0.04), and also showed a similar pattern of abnormal inverse left-sided sgACC–amygdala connectivity to these stimuli (p = 0.03). These findings were paralleled by abnormally reduced positive left-sided ventromedial prefrontal cortical–sgACC connectivity to happy faces in females with MDD (p = 0.008), and abnormally increased positive left-sided sgACC–amygdala connectivity to fearful faces in females, and all individuals, with MDD (p = 0.008; p = 0.003). Conclusion: Different patterns of abnormal prefrontal cortical–amygdala connectivity to happy and fearful stimuli might represent neural mechanisms for the excessive self-reproach and comorbid anxiety that characterize female MDD

Innovative Vacuum Arc Thruster for CubeSat Constellations

Abstract: The University of the Federal Armed Forces (UniBwM) is currently developing an innovative electric propulsion system for small satellites with extremly low space, mass and power budget. Satellites with these characteristics were built by the JustusMaximilians-Universität Würzburg (JMUW) within the international CubeSat project. the Bavarian government UniBwM and JMUW are working together to equip the new pico satellite UWE-4 (Universität Würzburg Experimentalsatellit 4) with a sufficient propulsion system for fine positioning and attitude control. JMUW is responsible for the development of the satellite and the integration of the propulsion system which is currently under development at UniBwM based on the so called Vacuum Arc Thruster. To demonstrate the positioning ability of the system the mission of UWE-4 is to chase another CubeSat and to hold its relative position. Together with the strict restrictions of the CubeSat this gives some serious challenges to be solved

Age-Related Developmental and Individual Differences in the Influence of Social and Non-social Distractors on Cognitive Performance.

This study sought to examine age-related differences in the influences of social (neutral, emotional faces) and non-social/non-emotional (shapes) distractor stimuli in children, adolescents, and adults. To assess the degree to which distractor, or task-irrelevant, stimuli of varying social and emotional salience interfere with cognitive performance, children (N = 12; 8-12y), adolescents (N = 17; 13-17y), and adults (N = 17; 18-52y) completed the Emotional Identification and Dynamic Faces (EIDF) task. This task included three types of dynamically-changing distractors: (1) neutral-social (neutral face changing into another face); (2) emotional-social (face changing from 0% emotional to 100% emotional); and (3) non-social/non-emotional (shapes changing from small to large) to index the influence of task-irrelevant social and emotional information on cognition. Results yielded no age-related differences in accuracy but showed an age-related linear reduction in correct reaction times across distractor conditions. An age-related effect in interference was observed, such that children and adults showed slower response times on correct trials with socially-salient distractors; whereas adolescents exhibited faster responses on trials with distractors that included faces rather than shapes. A secondary study goal was to explore individual differences in cognitive interference. Results suggested that regardless of age, low trait anxiety and high effortful control were associated with interference to angry faces. Implications for developmental differences in affective processing, notably the importance of considering the contexts in which purportedly irrelevant social and emotional information might impair, vs. improve cognitive control, are discussed.NIMH R24 Research Network grant (MH67346, PI Ronald Dahl)

A Numerical Examination of the Performance of Small Magnetic Nozzle Thrusters

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143040/1/6.2017-4721.pd

The functional neuroanatomy of bipolar disorder:a consensus model

OBJECTIVES: Functional neuroimaging methods have proliferated in recent years, such that functional magnetic resonance imaging, in particular, is now widely used to study bipolar disorder. However, discrepant findings are common. A workgroup was organized by the Department of Psychiatry, University of Cincinnati (Cincinnati, OH, USA) to develop a consensus functional neuroanatomic model of bipolar I disorder based upon the participants' work as well as that of others. METHODS: Representatives from several leading bipolar disorder neuroimaging groups were organized to present an overview of their areas of expertise as well as focused reviews of existing data. The workgroup then developed a consensus model of the functional neuroanatomy of bipolar disorder based upon these data. RESULTS: Among the participants, a general consensus emerged that bipolar I disorder arises from abnormalities in the structure and function of key emotional control networks in the human brain. Namely, disruption in early development (e.g., white matter connectivity and prefrontal pruning) within brain networks that modulate emotional behavior leads to decreased connectivity among ventral prefrontal networks and limbic brain regions, especially the amygdala. This developmental failure to establish healthy ventral prefrontal-limbic modulation underlies the onset of mania and ultimately, with progressive changes throughout these networks over time and with affective episodes, a bipolar course of illness. CONCLUSIONS: This model provides a potential substrate to guide future investigations and areas needing additional focus are identified