Shuttle/GPSPAC experimentation study

The utilization is discussed of the GPSPAC, which is presently being developed to be used on the low altitude host vehicle (LAHV), for possible use in the shuttle avionics system to evaluate shuttle/GPS navigation performance. Analysis and tradeoffs of the shuttle/GPS link, shuttle signal interface requirements, oscillator tradeoffs and GPSPAC mechanical modifications for shuttle are included. Only the on-orbit utilization of GPSPAC for the shuttle is discussed. Other phases are briefly touched upon. Recommendations are provided for using the present GPSPAC and the changes required to perform shuttle on-orbit navigation

Experiments on near-wall structure of three-dimensional boundary layers

Investigations of three-dimensional turbulent boundary layers have shown basic differences between two- and three-dimensional flows. These differences can significantly impact the modeling of three-dimensional flows since many flow models are based on results from two-dimensional boundary layers. In many cases the shear stress vector direction has been shown to lag relative to the direction of the mean velocity gradient as the cross flow grows downstream. Coincidence of these vectors is necessary for a scalar eddy viscosity modeling assumption. A second effect is a reduction in magnitude of the shear stress and/or the shear stress to turbulence energy ratio, a(sub 1). This reduction has been observed in several experiments. Recent numerical simulations also indicate wall-layer structural differences between two- and three-dimensional boundary layers. The differences in structure between two- and three-dimensional boundary layers was also addressed in the experiment of Littell & Eaton. The experiment used two-point correlations to investigate the vortical structures in a three dimensional boundary layer on a spinning disk. It was found that each sign of longitudinal vortex is equally likely to exist, but one sign of vorticity is associated with a structure which is better at producing ejections. The goal of the current investigation is to study the structure of the inner layers. Among other questions, the differences between the effects deduced from the three-dimensional flow simulations and the effects seen in experiments can be examined. The research concentrates on the structure of the wall-layer through flow visualization and direct turbulence measurements down to y(+) = 5

Characterising a tunable, pulsed atomic beam using matter-wave interferometry

We describe the creation and characterisation of a velocity tunable, spin-polarized beam of slow metastable argon atoms. We show that the beam velocity can be determined with a precision below 1% using matter-wave interferometry. The profile of the interference pattern was also used to determine the velocity spread of the beam, as well as the Van der Waals (VdW) co-efficient for the interaction between the metastable atoms and the multi-slit silicon nitride grating. The VdW co-efficient was determined to be C_{3} = 1.84 ± 0.17 a.u., in good agreement with values derived from spectroscopic data. Finally, the spin polarization of the beam produced during acceleration of the beam was also measured, demonstrating a spatially uniform spin polarization of 96% in the m = +2 state

True flesh: pilgrimage, measure, and perfecting the human in Dante’s 'Commedia'

Critics of Dante’s Commedia have frequently maintained that the 14th-century poem depicts a “pilgrimage” in the sense of a journey to God, undertaken both in imitation of the actual practice of pilgrimage to holy sites such as Jerusalem and Santiago de Compostela, as well as of the Biblical Exodus, a journey from the exile of earthly life to the true patria of Heaven. Yet, since the middle of the 20th century, this label has been taken for granted, without acknowledging a pivotal characteristic that determines both these historical precedents which is mirrored in Dante’s text: the human body. This study maintains that the Commedia should be read according to Dante’s understanding of the term “peregrinatio,” the Latin word from which our English “pilgrimage” derives. Properly speaking, while the human body was considered the source of man’s alienation from God, it is conversely also its source of potential inclusion through the figure of Christ, who, through the Incarnation, partook of both human and divine natures. Peregrinatio manifests this process of salvation through movement in imitation of Christ, allowing for the proper reintegration of humanity in the order of the universe and for the true revelation of man’s resemblance to Christ that is revealed in the poem’s final vision of God. Chapters 1-3 contextualize Dante’s understanding of peregrinatio in both his works and broader medieval thought. Chapter 1 reveals how the entire journey of the Commedia is framed by the experience of Christ and how the reflection of the Incarnation in the character Dante enables the potential for salvation. By analyzing the etymology and history of the term—originally denoting exile and travel in Roman culture, but then theologized to humanity’s ontological state by the Church Fathers—we can see how Dante’s understanding of the process was more nuanced than critics typically attest in their use of the labels “pilgrim” or “pilgrimage.” Dante utilizes the polysemic nature of the word to portray the Commedia as the praxis of peregrinatio, a process of recognizing one’s resemblance to Christ. Chapter 2 continues by focusing on how the above process manifests as the journey of physical movement presented in the poem. Classical usage of peregrinatio often indicated motion in space, a meaning that was transferred to the historical phenomenon of pilgrimage. Dante considered pilgrimage as travel to a holy place in order to access the sacred, which was done, as the cult of relics indicates, through the body and the sense of touch. Dante’s understanding of this action is then contextualized by reading the relationship constructed between the body and sacred space in pilgrimage literature. These accounts reveal that people in the Middle Ages understood space through a sense of personal interaction and physical presence, emerging from primarily walking around and the absence of maps. This, connected with the practice of measuring holy spaces and relics, demonstrates that the body was thought to be necessary in order to access the sacred and reveal one’s resemblance to God. Chapter 3 utilizes the understanding of peregrinatio furnished by the first two chapters to look specifically at the Commedia. The Christological dimension of this process informs Dante’s journey from the first verses of the Inferno, where Dante repeatedly encounters signs of salvation through Christ much as pilgrims who journeyed to the Holy Land. The presence of these factors reveals that Dante recognized his journey as having to be carried out in imitation of Christ, and that this informs the potential of his text to lead its readers to salvation as well. The peculiarity of this conception emerges in the fact that Dante, through the presence of his human body, permanently alters the landscape of Hell, something that no one before or after has done, with the sole exception of Christ. Chapter 4-6 turn their focus to the end point of this process of peregrinatio experienced in the final vision of God at the end of the Commedia and the identification of man’s image in God through the Incarnation. Dante expresses this relationality through a simile of a geometer trying to measure a circle. While it is typically argued that this is merely a reference to the impossible geometric problem of squaring the circle, that reading does not attend to the use of “measure” and its precedents in Dante’s other works. Instead, measure was understood through a complex set of dynamics that permeated various aspects of medieval life, from intellectual activity to trade. In this regard, Dante utilizes the term to express how the imitation of Christ central to the process of peregrinatio actually takes place: by establishing an intertwined metaphysical and ethical understanding of humanity. Chapter 4 examines the history of the idea of measure as it would have been known to Dante, from: the Bible, Greek philosophy, Christian theology, courtly ethics, and material culture. While each thinker and tradition expresses different aims, measure is universally used to denote a sense of a larger order to which man wishes to belong. Specifically in the Christian tradition, this manifests through a history of interpretation around Wisdom 11:21’s statement of the universe being ordered by God in “measure, number, and weight.” This reveals itself to operate by the same mechanics of peregrinatio, as this triad was seen as a trace of Trinity in all creation and as dictating the ways in which ethical behavior can comport oneself to Christ. Chapter 5 utilizes these precedents to examine Dante’s complex use of the term measure in his works outside of the Commedia. Particularly in his growing education after his exile in 1301, Dante became increasingly aware of the intellectual richness behind the concept, which he seeks to ground specifically in Aristotelian thought and scholastic theology, predominantly in the Convivio and the Monarchia. The use of measure in both these texts displays Dante’s grasp of its Christological richness, where proper ethical action “measured” by the standard of Christ can induce the ontological change that was the goal of peregrinatio, allowing for participation in the divine order. Chapter 6 returns to the Commedia and the simile of the geometer to contextualize the 20 uses of forms of misura (measure) in the poem according to Dante’s previous utilization of the term and the intellectual inheritance discussed in chapter 4. This reading reveals that, contrary to typical scholarship on the word, Dante does not use it as an Italian rendering of the Aristotelian mean—the conception of virtue as the middle ground between the extremes of vice—but rather views misura as an active process conceived through Christ. Through a series of uses of the verb “to measure,” Dante depicts the culmination of the process of peregrinatio to express the goal of full personhood, body and soul, in the image of Christ, and thereby as a return to the full potential for which humanity was created

Project Spraoi: Dietary Intake, Nutritional Knowledge, Cardiorespiratory Fitness and Health Markers of Irish Primary School Children

Objective: Examine dietary intake (DI), anthropometric measures, cardiorespiratory fitness (CRF) and nutritional knowledge (NK) of school children.Design: Cross-sectional study. Food Diary, NK questionnaire and 550m walk/run test were used to assess DI, NK and CRF respectively. Blood pressure (BP) was also taken and body mass index (BMI) and waist to height ratio (WHtR) were calculated.Setting: Two primary schools, Cork, Ireland. Subjects: Six (n = 49, age 5.9 ± 0.6 years) and ten (n = 52, age 9.8 ± 0.5 years) year olds.Results: Intakes of fruit and vegetables, fibre, calcium and iron were sub-optimal. Unhealthy snacks and saturated fat intakes were higher than recommended. A total of 24.4% of six year olds and 35.4% of ten year olds were classified as ‘fast’. Furthermore, 45.9% of six and ten year olds had high-normal BP and 27.9% had high BP. NK was negatively correlated with sugar intake (r = -0.321, p = 0.044) in ten year olds. WHtR was negatively correlated with servings of vegetables in six year olds (r = -0.377, p = 0.014). For ten year olds, there was a positive correlation between WHtR and run score (r = 0.350, p = 0.014) and BMI and run score (r = 0.482, p = 0.001).Conclusion: This study highlights, for the first time, DI, NK, CRF, BP and anthropometric data for Irish children and their potential combined effect on overall health. Study results suggest preventive initiatives are needed, in children as young as 6 years of age

Bis[4-(dimethyl­amino)phen­yl]diazene oxide

The asymmetric unit of the title compound, C16H20N4O, contains six independent approximately planar mol­ecules and is best described as a commensurate modulation of a P21/c parent. Two sets of disordered mol­ecules share almost the same locations (related by an in-plane translation), ensuring that the c-glide plane condition is not attained. C—H⋯O inter­actions provide structural cohesion. The site occupancy factors of the disordered molecules are ca 0.72/0.28 and 0.67/0.33

Evidence of strategic periodicities in collective conflict dynamics

We analyze the timescales of conflict decision-making in a primate society. We present evidence for multiple, periodic timescales associated with social decision-making and behavioral patterns. We demonstrate the existence of periodicities that are not directly coupled to environmental cycles or known ultraridian mechanisms. Among specific biological and socially-defined demographic classes, periodicities span timescales between hours and days, and many are not driven by exogenous or internal regularities. Our results indicate that they are instead driven by strategic responses to social interaction patterns. Analyses also reveal that a class of individuals, playing a critical functional role, policing, have a signature timescale on the order of one hour. We propose a classification of behavioral timescales analogous to those of the nervous system, with high-frequency, or $\alpha$-scale, behavior occurring on hour-long scales, through to multi-hour, or $\beta$-scale, behavior, and, finally $\gamma$ periodicities observed on a timescale of days.Comment: 22 pages, 7 figures, 1 table. Accepted for publication in Journal of the Royal Society Interfac

Achirality in the low temperature structure and lattice modes of tris(acetylacetonate)iron(iii)

Tris(acetylacteonate) iron(III) is a relatively ubiquitous mononuclear inorganic coordination complex. The bidentate nature of the three acetylacteonate ligands coordinating around a single centre inevitably leads to structural isomeric forms, however whether or not this relates to chirality in the solid state has been questioned in the literature. Variable temperature neutron diffraction data down to T = 3 K, highlights the dynamic nature of the ligand environment, including the motions of the hydrogen atoms. The Fourier transform of the molecular dynamics simulation based on the experimentally determined structure was shown to closely reproduce the low temperature vibrational density of states obtained using inelastic neutron scattering