4,394 research outputs found
PRODUCTION PLANNING AND CONTROL COMPLEMENTARITY ARCHITECTURE IN SELECTED MANUFACTURING FIRMS IN PORT HARCOURT, NIGERIA
The strategic objective of this study is to empirically have an objective grasp of production planning and control complementarity architecture of five selected manufacturing firms and relevant areas of cost control. The paper empirically explores some facets of production planning and processing analysis in different machines and periods; production divisions and types, scheduling and sequencing of production planning. Capacity planning levels including potential capacity, immediate capacity and effective capacity were strategically discussed. Aspects of production control architecture such as dispatching and functions of the dispatcher were also evaluated. Other related areas of production control examined include: expediting (follow-up) and progressing, and the activities in these production and control elements were objectively handled. The study arrived at the fact that, production planning and control functions complement each other in their functionality. Effective scheduling and sequencing are revealed to be a panacea that help the handling of time, space constraints and associated cost elements in production operations management. It is therefore recommended that, production and control operations functions should complement, and be jealously guided in manufacturing operations.
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Visual suppression of the vestibulo-ocular reflex during space flight
Visual suppression of the vestibulo-ocular reflex was studied in 16 subjects on 4 Space Shuttle missions. Eye movements were recorded by electro-oculography while subjects fixated a head mounted target during active sinusoidal head oscillation at 0.3 Hz. Adequacy of suppression was evaluated by the number of nystagmus beats, the mean amplitude of each beat, and the cumulative amplitude of nystagmus during two head oscillation cycles. Vestibulo-ocular reflex suppression was unaffected by space flight. Subjects with space motion sickness during flight had significantly more nystagmus beats than unaffected individuals. These susceptible subjects also tended to have more nystagmus beats before flight
Eye and head motion during head turns in spaceflight
Eye-head motion was studied pre-, in- and postflight during single voluntary head turns. A transient increase in vestibulo-ocular reflex (VOR) gain occurred early in the flight, but later trended toward normal. This increased gain was produced by a relative increase in eye counterrotation velocity. Asymmetries in gain with right and left turns also occurred, caused by asymmetries in eye counterrotation velocities. These findings were remarkably similar to those from Soviet primate studies using gaze fixation targets, except the human study trended more rapidly toward normal. These findings differ substantially from those measuring VOR gain by head oscillation, in which no significant changes were found inflight. No visual disturbances were noted in either test condition or in normal activities. These head turn studies are the only ones to date documenting any functional change in VOR in weightlessness
Regulating Access to Developmental Drugs for Terminally Ill Patients: Abigail Alliance v FDA
This amicus brief was filed in support of the Abigail Alliance for Better Access to Developmental Drugs in their lawsuit to force the Food and Drug Administration to provide patient access to drugs for cancer and other life-threatening illnesses after those drugs have passed through phase 1 clinical testing and have received FDA approval to enter additional clinical trials as a basis for eventual FDA approval for marketing. We make three arguments: (1) FDA staff face strong incentives to be too cautious in approving new drugs. As demonstrated by experience in cancer drug testing, patients often face a situation in which high-quality data from phase 1 clinical trials strongly indicate that a drug's benefits probably exceed its risks. (2) Permitting terminally-ill patients to access potentially life-saving post-phase-1 drugs still in testing will not unduly discourage patient participation in additional trials or inhibit post-phase- randomized clinical trials needed to obtain FDA approval. This is evident from the widespread and growing phenomenon of post-approval randomized clinical trials of approved drugs. (3) For similar reasons, it is clear that permitting terminally-ill patients to access potentially life-saving post-phase-1 drugs in testing will not discourage manufacturers from conducting additional randomized clinical trials.Health and Safety, Other Topics
Studies of the vestibulo-ocular reflex on STS 4, 5 and 6
The vestibulo-ocular reflex (VOR) may be altered by weightlessness. Since this reflex plays a large role in visual stabilization, it was important to document any changes caused by space flight. This is a report on findings on STS-4 through 6 and is part of a larger study of neurosensory adaptation done on STS-4 through 8. Voluntary horizontal head oscillations at 1/3 Hz with amplitude of 30 deg right and left of center were recorded by a potentiometer and compared to eye position recorded by electroculography under the following conditions: eyes open, head fixed, tracking horizontal targets switched 0, 15, and 30 degrees right and left (optokinetic reflex - OKR - and calibration); eyes open and fixed on static external target with oscillation, (vestibulo ocular reflex, eyes closed - VOR EC); eyes open and wearing opaque goggles with target fixed in imagination (vestibulo-ocular reflex, eyes shaded - VOR ES); and eyes open and fixed on a head synchronized target with head oscillation (VOR suppression). No significant changes were found in voluntary head oscillation frequency or amplitude in those with (n=5), and without (n=3), space motion sickness (SMS), with phase of flight or test condition. Variations in head oscillation were too small to have produced detectable changes in test results
Superfluid Helium Tanker (SFHT) study
Replenishment of superfluid helium (SFHe) offers the potential of extending the on-orbit life of observatories, satellite instruments, sensors and laboratories which operate in the 2 K temperature regime. A reference set of resupply customers was identified as representing realistic helium servicing requirements and interfaces for the first 10 years of superfluid helium tanker (SFHT) operations. These included the Space Infrared Telescope Facility (SIRTF), the Advanced X-ray Astrophysics Facility (AXAF), the Particle Astrophysics Magnet Facility (Astromag), and the Microgravity and Materials Processing Sciences Facility (MMPS)/Critical Point Phenomena Facility (CPPF). A mixed-fleet approach to SFHT utilization was considered. The tanker permits servicing from the Shuttle cargo bay, in situ when attached to the OMV and carried to the user spacecraft, and as a depot at the Space Station. A SFHT Dewar ground servicing concept was developed which uses a dedicated ground cooling heat exchanger to convert all the liquid, after initial fill as normal fluid, to superfluid for launch. This concept permits the tanker to be filled to a near full condition, and then cooled without any loss of fluid. The final load condition can be saturated superfluid with any desired ullage volume, or the tank can be totally filed and pressurized. The SFHT Dewar and helium plumbing system design has sufficient component redundancy to meet fail-operational, fail-safe requirements, and is designed structurally to meet a 50 mission life usage requirement. Technology development recommendations were made for the selected SFHT concept, and a Program Plan and cost estimate prepared for a phase C/D program spanning 72 months from initiation through first launch in 1997
Studies of the horizontal vestibulo-ocular reflex on STS 7 and 8
Unpaced voluntary horizontal head oscillation was used to study the Vestibulo-Ocular Reflex (VOR) on Shuttle flights STS 7 and 8. Ten subjects performed head oscillations at 0.33 Hz + or - 30 deg amplitude under the followng conditions: VVOR (visual VOR), eyes open and fixed on a stationary target; VOR-EC, with eyes closed and fixed on the same target in imagination; and VOR-S (VOR suppression), with eyes open and fixed on a head-synchronized target. Effects of weightlessness, flight phase, and Space Motion Sickness (SMS) on head oscillation characteristics were examined. A significant increase in head oscillation frequency was noted inflight in subjects free from SMS. In subjects susceptible to SMS, frequency was reduced during their Symptomatic period. The data also suggest that the amplitude and peak velocity of head oscillation were reduced early inflight. No significant changes were noted in reflex gain or phase in any of the test conditions; however, there was a suggestion of an increase in VVOR and VOR-ES gain early inflight in asymptomatic subjects. A significant difference in VOR-S was found between SMS susceptible and non-susceptible subjects. There is no evidence that any changes in VOR characteristics contributed to SMS
Population Trends of Quails in North America
We used North American Breeding Bird Survey data (1966-91) to estimate distribution, relative abundance, and population trends of quails. Population trends in grassland/shrub birds sympatric with northern bobwhite (Colinus virginianus) were also examined. Northern bobwhite and scaled quail (Callipepl,a squamata) populations have declined since 1966. Rates of decline for these quails have increased during the past decade. California quail (C. califomica), Gambel\u27s quail (C. gambelii), and mountain quail (Oreortyx pictus) populations have been stable over the long-term (1966-91). However, the short-term (1982-91) trend for California quail is positive, whereas Gambel\u27s quail appear to be declining. Patterns in trends indicate similar factors may be negatively affecting breeding populations of grassland/shrub birds throughout the bobwhite\u27s range. We discuss plausible hypotheses to explain population trends and recommend future action
Saccadic eye movement during spaceflight
Saccadic eye movements were studied in six subjects during two Space Shuttle missions. Reaction time, peak velocity and accuracy of horizontal, visually-guided saccades were examined preflight, inflight and postflight. Conventional electro-oculography was used to record eye position, with the subjects responding to pseudo-randomly illuminated targets at 0 deg and + or - 10 deg and 20 deg visual angles. In all subjects, preflight measurements were within normal limits. Reaction time was significantly increased inflight, while peak velocity was significantly decreased. A tendency toward a greater proportion of hypometric saccades inflight was also noted. Possible explanations for these changes and possible correlations with space motion sickness are discussed
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UNCOVER: The Growth of the First Massive Black Holes from JWST/NIRSpec—Spectroscopic Redshift Confirmation of an X-Ray Luminous AGN at z = 10.1
The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from seeds to supermassive BHs. Recently, Bogdan et al. reported the detection of an X-ray luminous supermassive BH, UHZ-1, with a photometric redshift at z \u3e 10. Such an extreme source at this very high redshift provides new insights on seeding and growth models for BHs given the short time available for formation and growth. Harnessing the exquisite sensitivity of JWST/NIRSpec, here we report the spectroscopic confirmation of UHZ-1 at z = 10.073 ± 0.002. We find that the NIRSpec/Prism spectrum is typical of recently discovered z ≈ 10 galaxies, characterized primarily by star formation features. We see no clear evidence of the powerful X-ray source in the rest-frame UV/optical spectrum, which may suggest heavy obscuration of the central BH, in line with the Compton-thick column density measured in the X-rays. We perform a stellar population fit simultaneously to the new NIRSpec spectroscopy and previously available photometry. The fit yields a stellar-mass estimate for the host galaxy that is significantly better constrained than prior photometric estimates (�⋆∼1.4−0.4+0.3×108M⊙). Given the predicted BH mass (MBH ∼ 107–108M⊙), the resulting ratio of MBH/M⋆ remains 2 to 3 orders of magnitude higher than local values, thus lending support to the heavy seeding channel for the formation of supermassive BHs within the first billion years of cosmic evolution
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