6,057 research outputs found
Composite Data from Centrifugal Experimentation Regarding Human Information Processing
A cognitive model illustrating decrement in human performance as a function of increased G-forces has been highly sought after by the Department of Defense (DoD) for various reasons. The F-16 and other air combat platforms are super-agile aircraft that are easily capable of imposing G-forces on a pilot that are beyond human physiological limitations. Knowledge of these physiological limits and more importantly the resultant restrictions in cognitive function could prove invaluable to those who design and pilot such aircraft. The model may be utilized in the construction of improved flight simulators that incorporate more realistically performing enemy targets and therefore enhance the training of the air warfighter. Command and control functions may also benefit from a thorough understanding of the boundaries of human cognition in these dynamic environments. NTI is a research firm based in Fairborn, Ohio that has formulated just such a model. NTI has devised this model while contracted by the USAF Air Force Research Laboratory (AFRL) under a Phase II Small Business Innovation Research (SBIR) grant. The three primary principles that are employed in the NTI models\u27 construction are the T-matrix, a previously developed G-effective model and the G-Performance Assessment Simulation System (G-PASS) battery of tests. The T-Matrix concept has been developed emulating the Educational Testing Service (ETS) Q-Matrix with the exception that it is based on cognitive tests as an alternative to interview questions. The G-Effective Model is based on the fact that human performance is not decremented by increased G-Forces encountered by the air warfighter instantaneously. Rather, a decrease in performance is the result of a subsequent reduction in cerebral blood flow that is in turn affected by both the G-profile as well as the onset rate of imposed G-forces. The G-PASS battery of tests is intended to be performed in the Dynamic Environment Simulator (DES) human centrifuge at the Air Force Research Laboratories (AFRL) Human Effectiveness Protectorate-G (HEPG) located at Wright Patterson Air Force Base. These tests are utilized to probe critical cognitive functions that are essential to pilots of combat aircraft. Results of a descriptive comparison of the NTI model versus the composite data obtained from the DES experimental results are presented in this thesis. Results show that the decrement of cognitive function as a result of increased Gz forces obtained in the HEPG experiments is consistently lower than what is predicted by the NTI model. These results may be partially accounted for by the fact that the NTI model is based on relaxed G conditions, whereas the DES experimentation was performed utilizing G-suits, positive pressure breathing and straining maneuvers
‘The voice is the guide to the experience as well as the experience itself’: An interview with non zero one
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Since 2009, non zero one – a London-based collective of artists with a background and interest
in theatre but working across media and performance disciplines – has devised a series of
unexpected, challenging but also light-hearted and inviting experiences of immersion. Whilst
embracing a variety of techniques and contemporary media, one of the key features of the
company’s work is the exploration of audience interaction through the use of headphones,
typically in promenade and/or site-specific performance contexts. Following a first section that
questions the role of voice in (theatrical) sonic immersion, the text unfolds as a dialogue
between practitioner-scholar Konstantinos Thomaidis and non zero one artist and theatre
director Sarah Butcher. The interview lends an attentive ear to the role of voice in the
company’s work, from pre-recorded instruction to live audio interaction
A COMPARISON OF THREE RACKET SKILLS EXECUTED SY NOVICE AND EXPERIENCED PERFORMERS
INTRODUCTIONT he purpose of this investigation was to compare an adult novice (NOV) with an experienced (EXP) adult performing a badminton deep serve, a racquetball forehand, and a racquetball drive serve. Movements were videotaped by 4cameras at 120 Hz and the 3-D data were analyzed using the PEAK5 motion measurement system. Range of motion (ROM), sequence of motion, and temporal values were assessed on the following angular movements: absolute pelvic (P) and upper torso (UT) rotation, and relative humeral (H), elbow (E), and wist (W) rotation. RESULTS For each skill and performer, the segmental sequence and ROM are presented. This information is followed by the range of lag times (LT) between segments within the sequence and the total time (TT) (backswing to contact)over which the skill occurred. Badminton Serve EXP P(37.4"),UT(69.6"), H(76.3"), W(59.7"), E(16.0°).LT(.02-.I 8s). TT(.23s).NOV UT(30.4"), P(l 3.0°), H(67.0°),W(10.2"), E(34.2").LT(.OI -.14~)T. T(.2Os).Racquetball Forehand EXP H(68.8"),P(57.g0),U T(71. I") , W(ll .go), E(12.8").LT(.02-.1 0s). TT(. II S).NOV P(34.8"), UT(69.2"), W(59.4"),E(8.7"), H(10.7").LT(.03-. 1 3s). TT(.20s).Racquetball Serve U(P P(92.4"),UT(122.0°), H(154.0°), E(75.3"),W(41.8"). LT(.00-. 10s). TT(. 1 8s).NOV P(64.3"), UT(77.g0), W(81 .OO),H(87.0°), E (0.8").LT(.OI -. 14s). TT(. 194.CONCLUSIONS1) Results for the badminton serve indicated the EXP exhibited greater ROM than the NOV for all angles except E. The NOV constrained the W to possibly allow for the greater E movement.2) In the forehand and in the racquetball serve, the NOV constrained the elbow more than the EXP which was consistent with Southard's (1 987) results; however, the great W ROM was inconsistent and appeared to be a last resort to generatevelocity.3) The EXP was more compact performing the forehand than the racquetball serve. During the serve, the lack of initial ball velocity required greater ROM to achieve the goal.4) In all 3 tasks, the EXP displayed essentially the same sequence of propulsive segmental initiation (proximal to distal). The patterns exhibited by the NOV were more simultaneous and the sequences varied for each task. REFERENCES Bird, M., Hills, L., & Hudson, J. L.(1 991 ). Intersegmental coordination: an exploration of context. In C. Tant, P.Patterson, & S. York (Eds.),Biomechanics in Sworts IX: Proceedings of the 9th International Symposium on Biomechanics in Sports (pp. 233-237).Ames, IA: Iowa State University.Southard, D. & Higgins,T,. (1 987).Changing movement patterns: effects of demonstration and practice. Research Quarterlv for Exercise and Sport, 58(1),77-80
PCR for the detection of pathogens in neonatal early onset sepsis.
BACKGROUND: A large proportion of neonates are treated for presumed bacterial sepsis with broad spectrum antibiotics even though their blood cultures subsequently show no growth. This study aimed to investigate PCR-based methods to identify pathogens not detected by conventional culture. METHODS: Whole blood samples of 208 neonates with suspected early onset sepsis were tested using a panel of multiplexed bacterial PCRs targeting Streptococcus pneumoniae, Streptococcus agalactiae (GBS), Staphylococcus aureus, Streptococcus pyogenes (GAS), Enterobacteriaceae, Enterococcus faecalis, Enterococcus faecium, Ureaplasma parvum, Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma genitalium, a 16S rRNA gene broad-range PCR and a multiplexed PCR for Candida spp. RESULTS: Two-hundred and eight samples were processed. In five of those samples, organisms were detected by conventional culture; all of those were also identified by PCR. PCR detected bacteria in 91 (45%) of the 203 samples that did not show bacterial growth in culture. S. aureus, Enterobacteriaceae and S. pneumoniae were the most frequently detected pathogens. A higher bacterial load detected by PCR was correlated positively with the number of clinical signs at presentation. CONCLUSION: Real-time PCR has the potential to be a valuable additional tool for the diagnosis of neonatal sepsis
Non-user benefits emanating from enhanced water flow to the Yala Protected Area Complex
Water is a multiple use resource. Increasing scarcity and competition from various sectors is an important dimension to be considered in its management. Understanding the value of water to different water uses is, therefore, necessary to assist decision-making in water allocation among sectors. Although water used in agriculture can be valued using production function approaches, such direct valuation methods are not available for the environmental uses of water. This paper uses non-market valuation methods to estimate the economic value of a committed flow through a unique ecosystem, the Yala Protected Area Complex (YPC). The Yala Protected Area Complex is an important wildlife refuge situated in south-eastern Sri Lanka. Its large land extent, undisturbed nature, and abundance and diversity of fauna contribute to its uniqueness. The fact that the YPC is also the most visited national park in Sri Lanka is partially a result of this uniqueness. However, maintenance of the park’s ecosystem depends on the flow of the Menik Ganga. This flow is regulated by the Veheragala Reservoir Project, and there is now discussion of reducing flow into the park by about half of the current level. The proposed plan ensures dry season flow into the YPC and, therefore, has been deemed acceptable. However, there is a possibility that farmers will demand further water releases during the dry season which could in turn endanger the planned downstream water releases. So there is a potential trade-off between environmental and irrigation uses of water. A willingness to pay (WTP) survey was conducted in ten districts in Sri Lanka during the fourth quarter of 2008 to estimate the WTP of the general population of the country towards maintaining this important environmental resource. In the hypothetical market presented, participants were told of the need for financial contributions from the general public to ensure the release of a minimum downstream flow commitment of 50 MCM. Participants were also informed of how this flow would enhance the ecosystem of the YPC. A single bound dichotomous choice contingent valuation approach was used as the elicitation format. Nonobligatory voluntary contributions were solicited towards a trust fund that could be used to ensure release of the required quantity of water downstream during dry months. According to the results of a binary logistic regression, income, age, and religious attachments are important factors affecting the decision to contribute to environmental flow maintenance to the YPC. Sixty-five percent of respondents were willing to pay something to ensure the maintenance of an adequate environmental flow in the YPC. The estimated mean WTP for water releases to enhance the YPC is Sri Lankan Rupees (SLR) 435 per year. Over the requested payment horizon of 10 years, the present value of aggregate WTP from the Sri Lankan population to enhance the ecosystem of the YPC is SLR 12 billion. This quantity greatly surpasses the present value of net benefits from rice farming estimated at SLR 0.64 billion, which would be generated if the same quantity of water was used for irrigation for 10 years (assuming current prices and input intensities). Thus, there is a clear opportunity for national welfare gain by ensuring adequate flow in YPC.Length: pp.37-47Water useMultiple useWildlifeHabitatsEcosystemsIrrigation waterWater allocation
Non-user benefits emanating from enhanced water flow to Yala Protected Area Complex. Abstract only
EcosystemsWater resource managementMultiple useDecision makingWater allocationEnvironmental flows
Multiadaptive Galerkin Methods for ODEs III: A Priori Error Estimates
The multiadaptive continuous/discontinuous Galerkin methods mcG(q) and mdG(q)
for the numerical solution of initial value problems for ordinary differential
equations are based on piecewise polynomial approximation of degree q on
partitions in time with time steps which may vary for different components of
the computed solution. In this paper, we prove general order a priori error
estimates for the mcG(q) and mdG(q) methods. To prove the error estimates, we
represent the error in terms of a discrete dual solution and the residual of an
interpolant of the exact solution. The estimates then follow from interpolation
estimates, together with stability estimates for the discrete dual solution
(1E,4E)-1-(3-Nitrophenyl)-5-phenylpenta-1,4-dien-3-one
In the title compound, C17H13NO3, the dihedral angle between the benzene rings is 31.21 (5)°. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds occur. A C—H⋯π interaction is also indicated
Stochastic B-series analysis of iterated Taylor methods
For stochastic implicit Taylor methods that use an iterative scheme to
compute their numerical solution, stochastic B--series and corresponding growth
functions are constructed. From these, convergence results based on the order
of the underlying Taylor method, the choice of the iteration method, the
predictor and the number of iterations, for It\^o and Stratonovich SDEs, and
for weak as well as strong convergence are derived. As special case, also the
application of Taylor methods to ODEs is considered. The theory is supported by
numerical experiments
DIRK Schemes with High Weak Stage Order
Runge-Kutta time-stepping methods in general suffer from order reduction: the
observed order of convergence may be less than the formal order when applied to
certain stiff problems. Order reduction can be avoided by using methods with
high stage order. However, diagonally-implicit Runge-Kutta (DIRK) schemes are
limited to low stage order. In this paper we explore a weak stage order
criterion, which for initial boundary value problems also serves to avoid order
reduction, and which is compatible with a DIRK structure. We provide specific
DIRK schemes of weak stage order up to 3, and demonstrate their performance in
various examples.Comment: 10 pages, 5 figure
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