The effects of bed rest on crew performance during simulated shuttle reentry. Volume 1: Study overview and physiological results

A centrifuge study was carried out to measure physiological stress and control task performance during simulated space shuttle orbiter reentry. Jet pilots were tested with, and without, anti-g-suit protection. The pilots were exposed to simulated space shuttle reentry acceleration profiles before, and after, ten days of complete bed rest, which produced physiological deconditioning similar to that resulting from prolonged exposure to orbital zero g. Pilot performance in selected control tasks was determined during simulated reentry, and before and after each simulation. Physiological stress during reentry was determined by monitoring heart rate, blood pressure, and respiration rate. Study results indicate: (1) heart rate increased during the simulated reentry when no g protection was given, and remained at or below pre-bed rest values when g-suits were used; (2) pilots preferred the use of g-suits to muscular contraction for control of vision tunneling and grayout during reentry; (3) prolonged bed rest did not alter blood pressure or respiration rate during reentry, but the peak reentry acceleration level did; and (4) pilot performance was not affected by prolonged bed rest or simulated reentry

Formation of terrestrial planets in close binary systems: the case of Alpha Centauri A

At present the possible existence of planets around the stars of a close binary system is still matter of debate. Can planetary bodies form in spite of the strong gravitational perturbations of the companion star? We study in this paper via numerical simulation the last stage of planetary formation, from embryos to terrestrial planets in the Alpha Cen system, the prototype of close binary systems. We find that Earth class planets can grow around Alpha Cen A on a time-scale of 50 Myr. In some of our numerical models the planets form directly in the habitable zone of the star in low eccentric orbits. In one simulation two of the final planets are in a 2:1 mean motion resonance that, however, becomes unstable after 200 Myr. During the formation process some planetary embryos fall into the stars possibly altering their metallicity.Comment: accepted for pubblication in A&A, 13 pages, 9 figure

Opening the Treasure Chest in Carina

We have mapped the G287.84-0.82 cometary globule (with the Treasure Chest cluster embedded in it) in the South Pillars region of Carina (i) in [CII], 63micron [OI], and CO(11-10) using upGREAT on SOFIA and (ii) in J=2-1 transitions of CO, 13CO, C18O and J=3-2 transitions of H2CO using the APEX telescope in Chile. We probe the morphology, kinematics, and physical conditions of the molecular gas and the photon dominated regions (PDRs) in G287.84-0.82. The [CII] and [OI] emission suggest that the overall structure of the pillar (with red-shifted photo evaporating tails) is consistent with the effect of FUV radiation and winds from eta-Car and O stars in Trumpler 16. The gas in the head of the pillar is strongly influenced by the embedded cluster, whose brightest member is an O9.5V star, CPD-59 2661. The emission of the [CII] and [OI] lines peak at a position close to the embedded star, while all other tracers peak at another position lying to the north-east consistent with gas being compressed by the expanding PDR created by the embedded cluster. The molecular gas inside the globule is probed with the J=2-1 transitions of CO and isotopologues as well as H2CO, and analyzed using a non-LTE model (escape-probability approach), while we use PDR models to derive the physical conditions of the PDR. We identify at least two PDR gas components; the diffuse part (~10^4 cm^-3) is traced by [CII], while the dense (n~ 2-8x10^5 cm^-3) part is traced by [CII], [OI], CO(11-10). Using the F=2-1 transition of [13CII] detected at 50 positions in the region, we derive optical depths (0.9-5), excitation temperatures of [CII] (80-255 K), and N(C+) of 0.3-1x10^19 cm^-2. The total mass of the globule is ~1000 Msun, about half of which is traced by [CII]. The dense PDR gas has a thermal pressure of 10^7-10^8 K cm^-3, which is similar to the values observed in other regions.Comment: Accepted for publication in Astronomy and Astrophysics (abstract slightly abridged

The Relationship Between Secondary School Teachers\u27 Perceptions of Principal Ethical Leadership and Organizational Health

The purpose of this descriptive, correlational study was to determine if any significant relationships existed between secondary school teachers’ perceptions of principal leader integrity as measured by the Perceived Leadership Integrity Scale ([PLIS], Craig & Gustafson, 1998) and schools’ organizational health as perceived by secondary school teachers and gauged by the Organizational Health Inventory for Secondary Schools ([OHI-S], Hoy & Feldman, 1987). The study also explored the seven OHI-S dimensions: (1) Institutional Integrity, (2) Initiating Structure, (3) Consideration, (4) Principal Influence, (5) Resource Support, (6) Morale, and (7) Academic Emphasis—and their relationships with the demographics of the sample. The sample involved six hundred fifty (650) Tennessee secondary school teachers identified through a purposive sampling process. These teachers completed both surveys and the requested demographic questionnaire online. Pearson product correlations revealed statistically significant relationships between Perceived Leader Integrity (PLI) and the composite score calculated from the scores of the seven OHI-S dimensions—the Organizational Health Index (OH Index), as well as between PLI and each of the seven OHI-S dimensions. Multiple regression analysis provided closer scrutiny of the data. In terms of the seven dimensions on PLI, this analysis showed the OH Index to have a moderate direct relationship, Consideration to be the strongest indicator, and Institutional Integrity and Academic Emphasis to a have a smaller, but statistically significant relationships. Univariate and multivariate analysis of variance tests were conducted to determine differences between and among PLI, the OH Index, and the demographic variables. Subject taught was strongly significant in relation to the seven OHI-S dimensions. The Tukey HSD and the Bonferroni correction were performed to examine more closely the significant differences found to exist among educational level or total years of teaching experience and the OH Index, as well as each of its seven dimensions. These findings help broaden understanding of the relationship between leadership and ethics. Northouse (2004) suggests that clarification of this relationship can identify implications for policy and decision making. Future research should explore the use of longitudinal or qualitative research methodology to study PLI and organizational health in greater depth

Marxists, Mormons and Indoctrination in Schools

It is argued that when we call a set of activities, \u27indoctrination: we are talking about something that is a matter of degree and that the degree of the indoctrination will be determined by a complex interrelationship between the teachers intentions, the content of what he teaches and the methods he uses. The content of indoctrination has to do with doctrines, doctrines being complex set of interrelated beliefs such as Mormonism and Marxism, that cannot be demonstrated to be unquestionably true (or unquestionably false). So teachers should make clear the equivocal status of doctrines. It is suggested that although full-blown indoctrination may be difficult to achieve in Australian state schools, teachers certainly have the opportunity of exerting subtle influences and pressures on children

The changing epidemiology of Staphylococcus aureus?

Strains of methicillin-resistant Staphylococcus aureus (MRSA), which had been largely confined to hospitals and long-term care facilities, are emerging in the community. The changing epidemiology of MRSA bears striking similarity to the emergence of penicillinase-mediated resistance in S. aureus decades ago. Even though the origin (hospital or the community) of the emerging MRSA strains is not known, the prevalence of these strains in the community seems likely to increase substantially

Epistemic Authority, Rationality and the Fallacy of Educational Democracy

In any rational authority system, authority must be closely connected to point, purpose and function. The situation of authority in colleges and universities provides a special case of such point, purpose and function. The present paper tries to show the quite special features of the epistemic (knowledge) authority of academics that provide rational justification for their being in many positions of social authority in their institutions. To do this, (1) the particular aspects of the point, purpose and function of such epistemic authorities will be demonstrated, (2) the logical necessity of academic disciplines for rational endeavour will be pointed out, and (3) the mistakes involved in the common notion of educational democracy will be exposed