21,070 research outputs found
Survey of projected growth and problems facing air transportation, 1975 - 1985
Results are presented of a survey conducted to determine the current opinion of people working in air transportation demand forecasting on the future of air transportation over the next ten years. In particular, the survey included questions on future demand growth, load factor, fuel prices, introduction date for the next new aircraft, the priorities of problems facing air transportation, and the probability of a substantial change in air transportation regulation. The survey participants included: airlines, manufacturers, universities, government agencies, and other organizations (financial institutions, private research companies, etc.). The results are shown for the average responses within the organization represented as well as the overall averages
Constrained action selection in children with developmental coordination disorder
The effect of advance (‘precue’) information on short aiming movements was explored in adults, high school children, and primary school children with and without developmental coordination disorder (n = 10, 14, 16, 10, respectively). Reaction times in the DCD group were longer than in the other groups and were more influenced by the extent to which the precue constrained the possible action space. In contrast, reaction time did not alter as a function of precue condition in adults. Children with DCD showed greater inaccuracy of response (despite the increased RT). We suggest that the different precue effects reflect differences in the relative benefits of priming an action prior to definitive information about the movement goal. The benefits are an interacting function of the task and the skill level of the individual. Our experiment shows that children with DCD gain a benefit from advance preparation in simple aiming movements, highlighting their low skill levels. This result suggests that goal-directed RTs may have diagnostic potential within the clinic
Origin binding by a 100,000-dalton super-T antigen from SVT2 cells.
The SVT2 line of simian virus 40-transformed mouse cells expresses little or no wild-type-size A protein (T antigen). Instead, a variant form is produced in these cells that is larger than normal-size A protein. This variant form has an Mr of 100,000 (100K super-T antigen) and is found primarily in complexes with the host-cell-coded p53 protein. Binding of the 100K super-T antigen to simian virus 40 origin region DNA was assayed by immunoprecipitation of super-T antigen-DNA complexes and then digestion with DNase I. DNA sequences associated with super-T antigen were protected from digestion and retained in the immune complex, while unprotected sequences were digested and released. The 100K super-T antigen efficiently protects DNA sequences in the previously defined regions I and II (P. Tegtmeyer, B. A. Lewton, A. L. DeLucia, V. G. Wilson, and K. Ryder, J. Virol. 46:151-161, 1983). Within region II (the origin of replication), the pattern and size of protected fragments are identical for super-T antigen and purified wild-type A protein. Thus, even though super-T antigen is larger than wild-type A protein, both must bind with the same alignment on origin DNA. Furthermore, complexes between the host-cell-coded p53 protein and the 100K super-T antigen also retain the ability to bind in regions I and II
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Scolecophis, S. atrocinctus
Number of Pages: 3Integrative BiologyGeological Science
A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: The Group Catalog
With a large, unique spectroscopic survey in the fields of 28 galaxy-scale
strong gravitational lenses, we identify groups of galaxies in the 26
adequately-sampled fields. Using a group finding algorithm, we find 210 groups
with at least five member galaxies; the median number of members is eight. Our
sample spans redshifts of 0.04 0.76 with a median of 0.31,
including 174 groups with . Groups have radial velocity
dispersions of 60 1200 km s with a median of 350
km s. We also discover a supergroup in field B0712+472 at 0.29
consisting of three main groups. We recover groups similar to 85% of
those previously reported in these fields within our redshift range of
sensitivity and find 187 new groups with at least five members. The properties
of our group catalog, specifically 1) the distribution of , 2)
the fraction of all sample galaxies that are group members, and 3) the fraction
of groups with significant substructure, are consistent with those for other
catalogs. The distribution of group virial masses agrees well with theoretical
expectations. Of the lens galaxies, 12 of 26 (46%) (B1422+231, B1600+434,
B2114+022, FBQS J0951+2635, HE0435-1223, HST J14113+5211, MG0751+2716,
MGJ1654+1346, PG 1115+080, Q ER 0047-2808, RXJ1131-1231, and WFI J2033-4723)
are members of groups with at least five galaxies, and one more (B0712+472)
belongs to an additional, visually identified group candidate. There are groups
not associated with the lens that still are likely to affect the lens model; in
six of 25 (24%) fields (excluding the supergroup), there is at least one
massive ( 500 km s) group or group candidate projected
within 2 of the lens.Comment: 87 pages, 8 figures, a version of this was published in Ap
A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for
Strong gravitational lensing provides an independent measurement of the
Hubble parameter (). One remaining systematic is a bias from the
additional mass due to a galaxy group at the lens redshift or along the
sightline. We quantify this bias for more than 20 strong lenses that have
well-sampled sightline mass distributions, focusing on the convergence
and shear . In 23% of these fields, a lens group contributes a 1%
convergence bias; in 57%, there is a similarly significant line-of-sight group.
For the nine time delay lens systems, is overestimated by 11%
on average when groups are ignored. In 67% of fields with total
0.01, line-of-sight groups contribute more convergence than
do lens groups, indicating that the lens group is not the only important mass.
Lens environment affects the ratio of four (quad) to two (double) image
systems; all seven quads have lens groups while only three of 10 doubles do,
and the highest convergences due to lens groups are in quads. We calibrate the
- relation: with a rms scatter of 0.34 dex.
Shear, which, unlike convergence, can be measured directly from lensed images,
can be a poor predictor of ; for 19% of our fields, is
. Thus, accurate cosmology using strong gravitational lenses
requires precise measurement and correction for all significant structures in
each lens field.Comment: 34 pages, 11 figures, accepted for publication in Ap
Depolarization of sperm membrane potential is a common feature of men with subfertility and is associated with low fertilization rate at IVF
STUDY QUESTION. Are significant abnormalities in outward (K+) conductance and resting membrane potential (Vm) present in the spermatozoa of patients undertaking IVF and ICSI and if so, what is their functional effect on fertilization success? SUMMARY ANSWER. Negligible outward conductance (≈5% of patients) or an enhanced inward conductance (≈4% of patients), both of which caused depolarization of Vm, were associated with a low rate of fertilization following IVF. WHAT IS KNOWN ALREADY. Sperm-specific potassium channel knockout mice are infertile with defects in sperm function, suggesting that these channels are essential for fertility. These observations suggest that malfunction of K+ channels in human spermatozoa might contribute significantly to the occurrence of subfertility in men. However, remarkably little is known of the nature of K+ channels in human spermatozoa or the incidence and functional consequences of K+ channel defects. STUDY DESIGN, SIZE AND DURATION. Spermatozoa were obtained from healthy volunteer research donors and subfertile IVF and ICSI patients attending a hospital assisted reproductive techniques clinic between May 2013 and December 2015. In total, 40 IVF patients, 41 ICSI patients and 26 normozoospermic donors took part in the study. PARTICIPANTS/MATERIALS, SETTING, METHODS. Samples were examined using electrophysiology (whole-cell patch clamping). Where abnormal electrophysiological characteristics were identified, spermatozoa were further examined for Ca2+ influx induced by progesterone and penetration into viscous media if sufficient sample was available. Full exome sequencing was performed to specifically evaluate potassium calcium-activated channel subfamily M α 1 (KCNMA1), potassium calcium-activated channel subfamily U member 1 (KCNU1) and leucine-rich repeat containing 52 (LRRC52) genes and others associated with K+ signalling. In IVF patients, comparison with fertilization rates was done to assess the functional significance of the electrophysiological abnormalities. MAIN RESULTS AND THE ROLE OF CHANCE. Patch clamp electrophysiology was used to assess outward (K+) conductance and resting membrane potential (Vm) and signalling/motility assays were used to assess functional characteristics of sperm from IVF and ICSI patient samples. The mean Vm and outward membrane conductance in sperm from IVF and ICSI patients were not significantly different from those of control (donor) sperm prepared under the same conditions, but variation between individuals was significantly greater (P< 0.02) with a large number of outliers (>25%). In particular, in ≈10% of patients (7/81), we observed either a negligible outward conductance (4 patients) or an enhanced inward current (3 patients), both of which caused depolarization of Vm. Analysis of clinical data from the IVF patients showed significant association of depolarized Vm (≥0 mV) with low fertilization rate (P= 0.012). Spermatozoa with electrophysiological abnormities (conductance and Vm) responded normally to progesterone with elevation of [Ca2+]i and penetration of viscous medium, indicating retention of cation channel of sperm (CatSper) channel function. LIMITATIONS, REASONS FOR CAUTION. For practical, technical, ethical and logistical reasons, we could not obtain sufficient additional semen samples from men with conductance abnormalities to establish the cause of the conductance defects. Full exome sequencing was only available in two men with conductance defects. WIDER IMPLICATIONS OF THE FINDINGS. These data add significantly to the understanding of the role of ion channels in human sperm function and its impact on male fertility. Impaired potassium channel conductance (Gm) and/or Vm regulation is both common and complex in human spermatozoa and importantly is associated with impaired fertilization capacity when the Vm of cells is completely depolarized
The Nature of Nearby Counterparts to Intermediate Redshift Luminous Compact Blue Galaxies II. CO Observations
We present the results of a single-dish beam-matched survey of the three
lowest rotational transitions of CO in a sample of 20 local (D < 70 Mpc)
Luminous Compact Blue Galaxies (LCBGs). These ~L*, blue, high surface
brightness, starbursting galaxies were selected with the same criteria used to
define LCBGs at higher redshifts. Our detection rate was 70%, with those
galaxies having Lblue<7e9 Lsun no detected. We find the H2 masses of local
LCBGs range from 6.6e6 to 2.7e9 Msun, assuming a Galactic CO-to-H2 conversion
factor. Combining these results with our earlier HI survey of the same sample,
we find that the ratio of molecular to atomic gas mass is low, typically 5-10%.
Using a Large Velocity Gradient model, we find that the average gas conditions
of the entire ISM in local LCBGs are similar to those found in the centers of
star forming regions in our Galaxy, and nuclear regions of other galaxies. Star
formation rates, determined from IRAS fluxes, are a few solar masses per year,
much higher per unit dynamical mass than normal spirals. If this rate remains
constant, the molecular hydrogen depletion time scales are short, 10-200 Myr.Comment: accepted for publication in the ApJ (vol 625
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