675 research outputs found
Design of a cooperative problem-solving system for enroute flight planning: An empirical study of its use by airline dispatchers
In a previous report, an empirical study of 30 pilots using the Flight Planning Testbed was reported. An identical experiment using the Flight Planning Testbed (FPT), except that 27 airline dispatchers were studied, is described. Five general questions were addressed in this study: (1) under what circumstances do the introduction of computer-generated suggestions (flight plans) influence the planning behavior of dispatchers (either in a beneficial or adverse manner); (2) what is the nature of such influences (i.e., how are the person's cognitive processes changed); (3) how beneficial are the general design concepts underlying FPT (use of a graphical interface, embedding graphics in a spreadsheet, etc.); (4) how effective are the specific implementation decisions made in realizing these general design concepts; and (5) how effectively do dispatchers evaluate situations requiring replanning, and how effectively do they identify appropriate solutions to these situations
Even Between-Lap Pacing Despite High Within-Lap Variation During Mountain Biking
Purpose: Given the paucity of research on pacing strategies during competitive events, this study examined
changes in dynamic high-resolution performance parameters to analyze pacing profiles during a multiple-lap
mountain-bike race over variable terrain. Methods: A global-positioning-system (GPS) unit (Garmin, Edge
305, USA) recorded velocity (m/s), distance (m), elevation (m), and heart rate at 1 Hz from 6 mountain-bike
riders (mean ± SD age = 27.2 ± 5.0 y, stature = 176.8 ± 8.1 cm, mass = 76.3 ± 11.7 kg, VO2max = 55.1 ± 6.0 mL
· kg–1 . min–1) competing in a multilap race. Lap-by-lap (interlap) pacing was analyzed using a 1-way ANOVA
for mean time and mean velocity. Velocity data were averaged every 100 m and plotted against race distance
and elevation to observe the presence of intralap variation. Results: There was no significant difference in lap times (P = .99) or lap velocity (P = .65) across the 5 laps. Within each lap, a high degree of oscillation in velocity was observed, which broadly reflected changes in terrain, but high-resolution data demonstrated additional
nonmonotonic variation not related to terrain. Conclusion: Participants adopted an even pace strategy across
the 5 laps despite rapid adjustments in velocity during each lap. While topographical and technical variations
of the course accounted for some of the variability in velocity, the additional rapid adjustments in velocity
may be associated with dynamic regulation of self-paced exercise
X-ray emission from isolated neutron stars
X-ray emission is a common feature of all varieties of isolated neutron stars
(INS) and, thanks to the advent of sensitive instruments with good
spectroscopic, timing, and imaging capabilities, X-ray observations have become
an essential tool in the study of these objects. Non-thermal X-rays from young,
energetic radio pulsars have been detected since the beginning of X-ray
astronomy, and the long-sought thermal emission from cooling neutron star's
surfaces can now be studied in detail in many pulsars spanning different ages,
magnetic fields, and, possibly, surface compositions. In addition, other
different manifestations of INS have been discovered with X-ray observations.
These new classes of high-energy sources, comprising the nearby X-ray Dim
Isolated Neutron Stars, the Central Compact Objects in supernova remnants, the
Anomalous X-ray Pulsars, and the Soft Gamma-ray Repeaters, now add up to
several tens of confirmed members, plus many candidates, and allow us to study
a variety of phenomena unobservable in "standard'' radio pulsars.Comment: Chapter to be published in the book of proceedings of the 1st Sant
Cugat Forum on Astrophysics, "ICREA Workshop on the high-energy emission from
pulsars and their systems", held in April, 201
Genome-wide association study of angioedema induced by angiotensin-converting enzyme inhibitor and angiotensin receptor blocker treatment
Angioedema in the mouth or upper airways is a feared adverse reaction to angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blocker (ARB) treatment, which is used for hypertension, heart failure and diabetes complications. This candidate gene and genome-wide association study aimed to identify genetic variants predisposing to angioedema induced by these drugs. The discovery cohort consisted of 173 cases and 4890 controls recruited in Sweden. In the candidate gene analysis, ETV6, BDKRB2, MME, and PRKCQ were nominally associated with angioedema (p < 0.05), but did not pass Bonferroni correction for multiple testing (p < 2.89 × 10−5). In the genome-wide analysis, intronic variants in the calcium-activated potassium channel subunit alpha-1 (KCNMA1) gene on chromosome 10 were significantly associated with angioedema (p < 5 × 10−8). Whilst the top KCNMA1 hit was not significant in the replication cohort (413 cases and 599 ACEi-exposed controls from the US and Northern Europe), a meta-analysis of the replication and discovery cohorts (in total 586 cases and 1944 ACEi-exposed controls) revealed that each variant allele increased the odds of experiencing angioedema 1.62 times (95% confidence interval 1.05–2.50, p = 0.030). Associated KCNMA1 variants are not known to be functional, but are in linkage disequilibrium with variants in transcription factor binding sites active in relevant tissues. In summary, our data suggest that common variation in KCNMA1 is associated with risk of angioedema induced by ACEi or ARB treatment. Future whole exome or genome sequencing studies will show whether rare variants in KCNMA1 or other genes contribute to the risk of ACEi- and ARB-induced angioedema
Magnetism, FeS colloids, and Origins of Life
A number of features of living systems: reversible interactions and weak
bonds underlying motor-dynamics; gel-sol transitions; cellular connected
fractal organization; asymmetry in interactions and organization; quantum
coherent phenomena; to name some, can have a natural accounting via
interactions, which we therefore seek to incorporate by expanding the horizons
of `chemistry-only' approaches to the origins of life. It is suggested that the
magnetic 'face' of the minerals from the inorganic world, recognized to have
played a pivotal role in initiating Life, may throw light on some of these
issues. A magnetic environment in the form of rocks in the Hadean Ocean could
have enabled the accretion and therefore an ordered confinement of
super-paramagnetic colloids within a structured phase. A moderate H-field can
help magnetic nano-particles to not only overcome thermal fluctuations but also
harness them. Such controlled dynamics brings in the possibility of accessing
quantum effects, which together with frustrations in magnetic ordering and
hysteresis (a natural mechanism for a primitive memory) could throw light on
the birth of biological information which, as Abel argues, requires a
combination of order and complexity. This scenario gains strength from
observations of scale-free framboidal forms of the greigite mineral, with a
magnetic basis of assembly. And greigite's metabolic potential plays a key role
in the mound scenario of Russell and coworkers-an expansion of which is
suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed
Krishnaswami Alladi, Springer 201
Widespread horizontal transfer of mitochondrial genes in flowering plants
Horizontal gene transfer - the exchange of genes across mating barriers - is recognized as a major force in bacterial evolution(1,2). However, in eukaryotes it is prevalent only in certain phagotrophic protists and limited largely to the ancient acquisition of bacterial genes(3-5). Although the human genome was initially reported(6) to contain over 100 genes acquired during vertebrate evolution from bacteria, this claim was immediately and repeatedly rebutted(7,8). Moreover, horizontal transfer is unknown within the evolution of animals, plants and fungi except in the special context of mobile genetic elements(9-12). Here we show, however, that standard mitochondrial genes, encoding ribosomal and respiratory proteins, are subject to evolutionarily frequent horizontal transfer between distantly related flowering plants. These transfers have created a variety of genomic outcomes, including gene duplication, recapture of genes lost through transfer to the nucleus, and chimaeric, half-monocot, half-dicot genes. These results imply the existence of mechanisms for the delivery of DNA between unrelated plants, indicate that horizontal transfer is also a force in plant nuclear genomes, and are discussed in the contexts of plant molecular phylogeny and genetically modified plants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62688/1/nature01743.pd
Recent cadmium exposure among male partners may affect oocyte fertilization during in vitro fertilization (IVF)
We recently reported evidence suggesting associations between urine cadmium concentrations, reflecting long-term exposure, measured in 25 female patients (relative risk = 1.41, P = 0.412) and 15 of their male partners (relative risk = 0.19, P = 0.097) and oocyte fertilization in vitro. Blood cadmium concentrations reflect more recent exposure.
We here incorporate those measures into our prior data set and employ multivariable log-binomial regression models to generate hypotheses concerning the relative effects of long-term and recent cadmium exposure on oocyte fertilization in vitro.
No association is indicated for blood cadmium from women and oocyte fertilization, adjusted for urine cadmium and creatinine, blood lead and mercury, age, race/ethnicity and cigarette smoking (relative risk = 0.88, P = 0.828). However, we suggest an inverse adjusted association between blood cadmium from men and oocyte fertilization (relative risk = 0.66, P = 0.143).
These results suggest that consideration of long-term and recent exposures are both important for assessing the effect of partner cadmium levels on oocyte fertilization in vitro
Nobody Is Perfect: ERP Effects Prior to Performance Errors in Musicians Indicate Fast Monitoring Processes
Background: One central question in the context of motor control and action monitoring is at what point in time errors can be detected. Previous electrophysiological studies investigating this issue focused on brain potentials elicited after erroneous responses, mainly in simple speeded response tasks. In the present study, we investigated brain potentials before the commission of errors in a natural and complex situation. Methodology/Principal Findings: Expert pianists bimanually played scales and patterns while the electroencephalogram (EEG) was recorded. Event-related potentials (ERPs) were computed for correct and incorrect performances. Results revealed differences already 100 ms prior to the onset of a note (i.e., prior to auditory feedback). We further observed that erroneous keystrokes were delayed in time and pressed more slowly. Conclusions: Our data reveal neural mechanisms in musicians that are able to detect errors prior to the execution of erroneous movements. The underlying mechanism probably relies on predictive control processes that compare the predicted outcome of an action with the action goal
Strongly magnetized pulsars: explosive events and evolution
Well before the radio discovery of pulsars offered the first observational
confirmation for their existence (Hewish et al., 1968), it had been suggested
that neutron stars might be endowed with very strong magnetic fields of
-G (Hoyle et al., 1964; Pacini, 1967). It is because of their
magnetic fields that these otherwise small ed inert, cooling dead stars emit
radio pulses and shine in various part of the electromagnetic spectrum. But the
presence of a strong magnetic field has more subtle and sometimes dramatic
consequences: In the last decades of observations indeed, evidence mounted that
it is likely the magnetic field that makes of an isolated neutron star what it
is among the different observational manifestations in which they come. The
contribution of the magnetic field to the energy budget of the neutron star can
be comparable or even exceed the available kinetic energy. The most magnetised
neutron stars in particular, the magnetars, exhibit an amazing assortment of
explosive events, underlining the importance of their magnetic field in their
lives. In this chapter we review the recent observational and theoretical
achievements, which not only confirmed the importance of the magnetic field in
the evolution of neutron stars, but also provide a promising unification scheme
for the different observational manifestations in which they appear. We focus
on the role of their magnetic field as an energy source behind their persistent
emission, but also its critical role in explosive events.Comment: Review commissioned for publication in the White Book of
"NewCompStar" European COST Action MP1304, 43 pages, 8 figure
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