A Gedanken spacecraft that operates using the quantum vacuum (Dynamic Casimir effect)

Conventional rockets are not a suitable technology for deep space missions. Chemical rockets require a very large weight of propellant, travel very slowly compared to light speed, and require significant energy to maintain operation over periods of years. For example, the 722 kg Voyager spacecraft required 13,600 kg of propellant to launch and would take about 80,000 years to reach the nearest star, Proxima Centauri, about 4.3 light years away. There have been various attempts at developing ideas on which one might base a spacecraft that would permit deep space travel, such as spacewarps. In this paper we consider another suggestion from science fiction and explore how the quantum vacuum might be utilized in the creation of a novel spacecraft. The spacecraft is based on the dynamic Casimir effect, in which electromagnetic radiation is emitted when an uncharged mirror is properly accelerated in the vacuum. The radiative reaction produces a dissipative force on the mirror that tends to resist the acceleration of the mirror. This force can be used to accelerate a spacecraft attached to the mirror. We also show that, in principal, one could obtain the power to operate the accelerated mirror in such a spacecraft using energy extracted from the quantum vacuum using the standard Casimir effect witha parallel plate geometry. Unfortunately the method as currently conceived generates a miniscule thrust, and is no more practical than a spacewarp, yet it does provide an interesting demonstration of our current understanding of the physics of the quantized electromagnetic field in vacuum.Comment: 18 pages, 3 figure

MASTER\u27S PROJECT: FRIENDS OF THE SOUL: A STUDY IN INTENTIONAL OPENING AND MUSIC

This capstone reflects the beginning of a livelong practice of intentional vulnerability and opening to spirit and connection. I built on learnings from my instructors at the University of Vermont (UVM) about relationship protocols, including listening, vulnerability, and honest introductions. I began with a question about how my leadership practices might shift away from unacknowledged privilege in relationships and emotional disengagement to embodied connection, openness to teachers and friends, and creative presence. The methods I used were creative harp music making, sharing harp music with others, mindfulness through harp, emotional awareness training with harp, and harp repair as a practice of exquisite attention and care for non-humans. I began a Vermont Harp Center and have been present to the community who have been drawn to that center. I have tried to listen to their needs and ideas and to hold the space of that community to look any way and to learn from my observation of the growth and movement of that community. I took harp lessons from a master harpist, I gave private lessons and group lessons for the first time in my life, I organized several harp community events, and I did harp repair work. I’ve also had many conversations with harpists and my broader community about presence, music, emotional connection, creative process, and love. I asked for feedback in those conversations, especially in those where I would previously have held an unspoken amount of power (such as when I am a professional helper or music teacher). I practiced noticing shifts in my emotional state and I recorded those shifts. I engaged with feelings of joy or upset with creativity and I practiced using harp playing to increase emotional regulation and awareness. I have been totally amazed, overwhelmed, and humbled by this capstone. It has transformed my understanding of my role as a leader from envisioning power and expertise to envisioning presence and patience. It has transformed my vision of myself as a helper and teacher into a vision where teachers and helpers are available to me everywhere, in every relationship to which I open myself

Leadership, Communication and Religiosity in Higher Education Administration: Distinctions That Make a Difference

This project investigated the communicative and religious components of transformational leadership and job satisfaction in the context of higher education. Specifically, 224 CAO members of the Council of Independent Colleges completed a survey assessing their own leadership style, communication behavior, and religiosity. A stepwise multiple regression procedure revealed seven significant predictors of transformational leadership. The most important variables included attentiveness, openness, role negotiation, and intrinsic religious orientation. Additionally, a t-test compared a subset of CAOs from institutions affiliated with the Council of Christian Colleges and Universities with CAOs in non-affiliated institutions. Results revealed statistically significant differences in attentiveness, information support, exercise of transformational leadership, and religious identity, practice, and orientation. Lastly, a second stepwise regression procedure revealed five significant predictors of CAO job satisfaction including availability of emotional support, level of commitment to the job, and amount of religious activity. The paper concludes with a discussion of implications for conducting higher education administration in ways that best reflect religious ideals

A novel interplanetary communications relay

A case study of a potential Earth-Mars interplanetary communications relay, designed to ensure continuous communications, is detailed. The relay makes use of orbits based on artificial equilibrium points via the application of continuous low thrust, which allows a spacecraft to hover above the orbital plane of Mars and thus ensure communications when the planet is occulted with respect to the Earth. The artificial equilibria of two different low-thrust propulsion technologies are considered: solar electric propulsion, and a solar sail/solar electric propulsion hybrid. In the latter case it is shown that the combination of sail and solar electric propulsion may prove advantageous, but only under specific circumstances of the relay architecture suggested. The study takes into account factors such as the spacecraft's power requirements and communications band utilized to determine the mission and system architecture. A detailed contingency analysis is considered for recovering the relay after increasing periods of spacecraft motor failure, and combined with a consideration for how best to deploy the relay spacecraft to maximise propellant reserves and mission duration

Communication, Leadership, and Job Satisfaction: Perspectives on Supervisor-Subordinate Relationships

In an era when leadership is much studied and little understood (Tourish & Barge, 2010), and when job satisfaction has reached an all-time low (Gibbons, 2010), investigating factors that contribute to job and relationship satisfaction, as well as more effective leadership, becomes a critical task. This project asked 154 people employed fulltime to evaluate their work supervisor in terms of specific communication behaviors, perceived leader effectiveness, and their own levels of relational and job satisfaction. Gibb’s (1961) theory of supportive and defensive communication provided the conceptual lens used to explicate the impact of communication behaviors on specific personal and organizational outcomes. Statistical analysis highlighted the discursive nature of workplace interaction by uncovering strong, predictive relationships between the positive behaviors of spontaneity and empathy and worker perceptions of supervisor effectiveness, relational satisfaction, and employee job satisfaction. Likewise, perceptions of supervisor leadership style are instantiated in these same communication behaviors suggesting that leadership is indeed a communication phenomenon. Last, t-tests revealed that supervisors rated higher in effectiveness and higher in relational satisfaction utilized all six of Gibb’s supportive communication behaviors more, and all six defensive behaviors less, than their more negatively evaluated peers

Displaced geostationary orbit design using hybrid sail propulsion

Because of an increase in the number of geostationary spacecraft and the limits imposed by east–west spacing requirements, the geostationary orbit is becoming congested. To increase its capacity, this paper proposes to create new geostationary slots by displacing the geostationary orbit either out of or in the equatorial plane by means of hybrid solar sail and solar electric propulsion. To minimize propellant consumption, optimal steering laws for the solar sail and solar-electric-propulsion thrust vectors are derived and the performance in terms of mission lifetime is assessed. For comparison, similar analyses are performed for conventional propulsion, including impulsive and pure solar electric propulsion. It is shown that hybrid sails outperform these propulsion techniques and that out-of-plane displacements outperform in-plane displacements. The out-of-plane case is therefore further investigated in a spacecraft mass budget to determine the payload mass capacity. Finally, two transfers that enable a further improvement of the performance of hybrid sails for the out-of-plane case are optimized using a direct pseudospectral method: a seasonal transit between orbits displaced above and below the equatorial plane and a transit to a parking orbit when geostationary coverage is not needed. Both transfers are shown to require only a modest propellant budget, outweighing the improvements they can establish

“Children of a Lesser God:” The Effects of Communication and Interaction Patterns on Student Spiritual Identity at a Church-Related University

Social identity theory provides a frame for studying the relationship between communication and interaction patterns and college student spirituality. In this project we measured the self-perceived spirituality, personal attitudes toward self and others, and communication of a convenience sample of N=149 college students at a private, four-year, church-related institution in southern California. We found that traditionalism, a stable belief in the values and attitudes reflected in how one is raised, explained 60% of student spirituality scores. Gregariousness, the measure of connectedness a participant feels to a group or to the institution, explained an additional 5.2% of student spirituality. Additional post hoc analysis revealed a statistically significant negative association between rebelliousness and both traditionalism and spirituality scores. We also utilized two t-Tests to compare lower and upper class students, as well as females and males, on the variables of interest. Upper class students reported higher scores on spirituality, life satisfaction, gregariousness, positive attitude toward tradition, and self-disclosure whereas lower class members scored higher only in rebelliousness. In addition, females scored higher on all of the variables measured in comparison to males, with the exception of rebelliousness. Findings demonstrated that education at a private Christian institution did not erode student spirituality and may have strengthened spirituality over the four year period

Clinical presentation, diagnostic findings and outcome of dogs undergoing surgical resection for intracranial meningioma: 101 dogs

Background: Meningioma is the most common primary brain neoplasm in dogs. Further information is required regarding the expected long-term prognosis of dogs following the surgical resection of an intracranial meningioma together with the influence of adjunctive therapies. Whilst there have been several studies reporting the long-term outcome of intracranial meningioma resection following surgery alone, surgery with the use of an ultrasonic aspirator, surgery combined with radiotherapy and surgery combined with the addition of hydroxyurea, it is currently unclear which type of adjunctive therapy is associated with the most favourable outcomes. The objective of this study is to describe the presentation and outcome of dogs undergoing surgery for the resection of an intracranial meningioma and the effect of clinical factors, adjunctive therapies and meningioma histopathological subtype on the long-term outcome. Results: A hundred and one dogs that had intracranial surgery for meningioma resection were investigated from four referral centres. 94% of dogs survived to hospital discharge with a median survival time of 386 days. Approximately 50% of dogs survived for less than a year, 25% survived between 1 and 2 years, 15% survived between 2 and 3 years and 10% survived for greater than 3 years following discharge from hospital. One or more adjunctive therapies were used in 75 dogs and the analysis of the data did not reveal a clear benefit of a specific type of adjunctive therapy. Those dogs that had a transfrontal approach had a significantly reduced survival time (MST 184 days) compared to those dogs that had a rostrotentorial approach (MST 646 days; p < 0.05). There was no association between meningioma subtype and survival time. Conclusions: This study did not identify a clear benefit of a specific type of adjunctive therapy on the survival time. Dogs that had a transfrontal approach had a significantly reduced survival time. Intracranial surgery for meningioma resection offers an excellent prognosis for survival to discharge from hospital with a median long term survival time of 386 days

Natural and sail-displaced doubly-symmetric Lagrange point orbits for polar coverage

This paper proposes the use of doubly-symmetric, eight-shaped orbits in the circular restricted three-body problem for continuous coverage of the high-latitude regions of the Earth. These orbits, for a range of amplitudes, spend a large fraction of their period above either pole of the Earth. It is shown that they complement Sun-synchronous polar and highly eccentric Molniya orbits, and present a possible alternative to low thrust pole-sitter orbits. Both natural and solar-sail displaced orbits are considered. Continuation methods are described and used to generate families of these orbits. Starting from ballistic orbits, other families are created either by increasing the sail lightness number, varying the period or changing the sail attitude. Some representative orbits are then chosen to demonstrate the visibility of high-latitude regions throughout the year. A stability analysis is also performed, revealing that the orbits are unstable: it is found that for particular orbits, a solar sail can reduce their instability. A preliminary design of a linear quadratic regulator is presented as a solution to stabilize the system by using the solar sail only. Finally, invariant manifolds are exploited to identify orbits that present the opportunity of a ballistic transfer directly from low Earth orbit

Formation of antihydrogen in antiproton - positron collision

A quantum mechanical approach is proposed for the formation of antihydrogen in the ground and excited states (2s, 2p) via the mechanism of three body recombination (TBR) inside a trapped plasma of anti proton and positron or in the collision between the two beams of them. Variations of the differential (DCS) as well as the total (TCS) formation cross sections are studied as a function of the incident energies of both the active and the spectator positrons. Significantly large cross sections are found at very low incident energies in the TBR process as compared to other processes leading to antihydrogen. The present formation cross section decreases with increasing positron energy (temperature) but no simple power law could be predicted for it covering the entire energy range, corroborating the experimental findings qualitatively. The formation cross sections are found to be much higher for unequal energies of the two positrons than for equal energies, as expected physically.Comment: 14 pages, 13 figure