5,121 research outputs found

    Society of Gentlemen: Midshipman at the U.S. Naval Academy, 1845-1861

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    Exploring the First Years of the United States Naval Academy In October 1845, the United States Naval School began operations at Fort Severn in Annapolis, Maryland. Rechristened the United States Naval Academy in 1850, the Annapolis institution brought together young men from the far r...

    H-alpha Activity of Old M Dwarfs: Stellar Cycles and Mean Activity Levels For 93 Low-Mass Stars in the Solar Neighborhood

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    Through the McDonald Observatory M Dwarf Planet Search, we have acquired nearly 3,000 high-resolution spectra of 93 late-type (K5-M5) stars over more than a decade using HET/HRS. This sample provides a unique opportunity to investigate the occurrence of long-term stellar activity cycles for low-mass stars. In this paper, we examine the stellar activity of our targets as reflected in the H-alpha feature. We have identified periodic signals for 6 stars, with periods ranging from days to more than 10 years, and find long-term trends for 7 others. Stellar cycles with P > 1 year are present for at least 5% of our targets. Additionally, we present an analysis of the time-averaged activity levels of our sample, and search for correlations with other stellar properties. In particular, we find that more massive, earlier type (M0-M2) stars tend to be more active than later type dwarfs. Furthermore, high-metallicity stars tend to be more active at a given stellar mass. We also evaluate H-alpha variability as a tracer of activity-induced radial velocity (RV) variation. For the M dwarf GJ 1170, H-alpha variation reveals stellar activity patterns matching those seen in the RVs, mimicking the signal of a giant planet, and we find evidence that the previously identified stellar activity cycle of GJ 581 may be responsible for the recently retracted planet f (Vogt et al. 2012) in that system. In general, though, we find that H-alpha is not frequently correlated with RV at the precision (typically 6-7 m/s) of our measurements.Comment: Submitted to ApJ. Reflects comments from a positive refere

    Closed-drift thruster investigations

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    Recent data obtained from a second generation closed-drift thruster design, employing Hall current acceleration is outlined. This type device is emphasized for electric propulsion for geocentric mission applications. Because geocentric mission profiles are best achieved with a specific impulse range of 1000 to 2000 s, closed-drift thrusters are well suited for this application, permitting time payload compromises intermediate of those possible with either electrothermal or electrostatic devices. A discussion is presented of the potential advantages of using a 1000 to 2000 s device for one way orbit raising of nonpower payloads. Because closed-drift thruster operation is not space charge limited, and requires only one power circuit for steady state operation, their application is technically advantageous. Beam, plasma and thrust characteristics are detailed for a range of operating conditions

    Interpersonal cognitive self-focus as a function of neuroticism: Basal tendencies and priming effects

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    Self-focus is one mechanism that may account for the social-evaluative anxiety of individuals high in neuroticism. The present two studies (total N = 183) sought to cognitively model interpersonal self-focus. The cognitive task was a simple one in which participants simply categorized dyadic interpersonal pronouns, with reaction times as the dependent measure. When others engage us, the pronoun “me” refers to the other and the pronoun “you” refers to the self. Study 1 found a neuroticism by pronoun interaction on categorization time consistent with implicit interpersonal self-focus at high (but not low) levels of neuroticism establishing a basal tendency. Study 2 examined boundary conditions. Individuals high in neuroticism exhibited implicit self-focus particularly to the extent that they had been primed to think of themselves as submissive rather than dominant in their interpersonal interactions. Implications for understanding neuroticism, self-focus, and relationship functioning are discussed

    Do you use your head or follow your heart? Self-location predicts personality, emotion, decision making, and performance.

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    The head is thought to be rational and cold, whereas the heart is thought to be emotional and warm. In 8 studies (total N = 725), we pursued the idea that such body metaphors are widely consequential. Study 1 introduced a novel individual difference variable, one asking people to locate the self in the head or the heart. Irrespective of sex differences, head-locators characterized themselves as rational, logical, and interpersonally cold, whereas heart-locators characterized themselves as emotional, feminine, and interpersonally warm (Studies 1–3). Study 4 showed that head-locators were more accurate in answering general knowledge questions and had higher grade point averages, and Study 5 showed that heart-locators were more likely to favor emotional over rational considerations in moral decision making. Study 6 linked self-locations to reactivity phenomena in daily life—for example, heart-locators experienced greater negative emotion on high stressor days. In Study 7, we manipulated attention to the head versus the heart and found that head-pointing facilitated intellectual performance, whereas heart-pointing led to emotional decision making. Study 8 replicated Study 3’s findings with a nearly year-long delay between the self-location and outcome measures. The findings converge on the importance of head–heart metaphors for understanding individual differences in cognition, emotion, and performance

    Toward a metaphor-enriched personality psychology.

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    Conventional wisdom on metaphor suggests that it is the province of poets, metaphor is an optional way of thinking, or that metaphor merely serves communication purposes. In this chapter, we show that such wisdom is at variance with how human beings actually think and function. We first provide a brief overview of the metaphor representation perspective. We then make a case for the utility of this perspective in understanding how people differ from each other and do so within a broader context of how personality has traditionally been assessed. We then present four lines of personality research inspired by the metaphor representation perspective. We conclude with a discussion of the challenges and unanswered questions involved in translating the metaphor representation perspective to personality psychology

    Black and White as Valence Cues

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    Replication efforts involving large samples are recommended in helping to determine the reliability of an effect. This approach was taken for a study from Meier, Robinson, and Clore (2004) , one of the first papers in social cognition guided by conceptual metaphor theory, which reported that evaluations were faster when word valence metaphorically matched (e.g., a word with a negative meaning in black) rather than mismatched (e.g., a word with a negative meaning in white) font color. The present investigation was a direct large-scale replication attempt involving 980 participants who completed an experiment using web-based software and were diverse in terms of race, age, and geographical location. Words with a positive meaning were evaluated faster when font color was white rather than black and words with a negative meaning were evaluated faster when font color was black rather than white, replicating the main results of Meier et al. (2004) . </jats:p

    Hot Corrosion Test Facility at the NASA Lewis Special Projects Laboratory

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    The Hot Corrosion Test Facility (HCTF) at the NASA Lewis Special Projects Laboratory (SPL) is a high-velocity, pressurized burner rig currently used to evaluate the environmental durability of advanced ceramic materials such as SiC and Si3N4. The HCTF uses laboratory service air which is preheated, mixed with jet fuel, and ignited to simulate the conditions of a gas turbine engine. Air, fuel, and water systems are computer-controlled to maintain test conditions which include maximum air flows of 250 kg/hr (550 lbm/hr), pressures of 100-600 kPa (1-6 atm), and gas temperatures exceeding 1500 C (2732 F). The HCTF provides a relatively inexpensive, yet sophisticated means for researchers to study the high-temperature oxidation of advanced materials, and the injection of a salt solution provides the added capability of conducting hot corrosion studies
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