672 research outputs found
The Hipparcos Transit Data: What, why and how?
The Hipparcos Transit Data are a collection of partially reduced, fully
calibrated observations of (mostly) double and multiple stars obtained with the
ESA Hipparcos astrometry satellite. The data are publicly available, as part of
the CD-ROM set distributed with the Hipparcos and Tycho Catalogues (ESA
SP--1200, 1997), for about a third of the Hipparcos Catalogue entries including
all confirmed or suspected non-single stars. The Transit Data consist of signal
modulation parameters derived from the individual transits of the targets
across the Hipparcos focal grid. The Transit Data permit re-reduction of the
satellite data for individual objects, using arbitrarily complex object models
in which time-variable photometric as well as geometric characteristics may be
taken into account. We describe the structure and contents of the Transit Data
files and give examples of how the data can be used. Some of the applications
use standard astronomical software: Difmap or AIPS for aperture synthesis
imaging, and GaussFit for detailed model fitting. Fortran code converting the
data into formats suitable for these application programs has been made public
in order to encourage and facilitate the use of Hipparcos Transit Data.Comment: A&AS, accepted for publication, 17 pages, 9 figures, 1 Table,
Software available via http://www.astro.lu.se/~lennart/TD/index.html, Figures
4, 5, 6 and 7 need to copied separately, A complete postscript file can be
found at http://www.astro.lu.se/~lennart/TD/ds1699.ps.g
Searching for Failed Supernovae With Astrometric Binaries
Stars in the mass range 8 Msun<M<30 Msun are thought to end their lives as
luminous supernovae that leave behind a neutron star. However, if a substantial
fraction of these stars instead ended as black-hole remnants, without producing
a supernova (a `failed' supernova), how would one know? We show that, under
plausible assumptions, the Hipparcos catalog should contain about 30 f_{fail}
astrometric binaries with black-hole companions, where f_{fail} is the fraction
of supernovae that fail. Since no black-hole astrometric binaries are found in
Hipparcos, one might like to conclude that such failed supernovae are very
rare. However, the most important assumption required for this argument, the
initial companion mass function (ICMF) of G stars (the majority of Hipparcos
stars) in the high-mass companion regime, is without any observational basis.
We show how the ICMF of G stars can be measured using the Full-Sky Astrometric
Explorer (FAME), thereby permitting an accurate measurement of the rate of
supernovae that fail.Comment: Submitted to ApJ, 14 pages including 4 figure
Cost-minimisation analysis of a treat-and-extend regimen with anti-VEGFs in patients with neovascular age-related macular degeneration
PURPOSE: Although intraocular anti-vascular endothelial growth factors (anti-VEGFs) are effective as treatment of neovascular age-related macular degeneration (nAMD), the (economic) burden on the healthcare system is considerable. A treat-and-extend (T&E) regimen is associated with a lower number of injections without compromising the effectiveness and can therefore help optimise nAMD treatment. This study investigates the per-patient costs associated with nAMD treatment, when using aflibercept, bevacizumab, or ranibizumab with a T&E regimen. METHODS: In this cost-minimisation model, the per-patient costs in the Netherlands were modelled using a healthcare payers’ perspective over a 3-year time horizon with the assumption that efficacy of treatments is similar. Additionally, the break-even price of the different anti-VEGFs was calculated relative to the cheapest option and injection frequency. RESULTS: The injection frequency varied from 14.2 for aflibercept to 27.4 for bevacizumab in 3 years. Nonetheless, bevacizumab remains the cheapest treatment option (€14,215), followed by aflibercept (€18,202) and ranibizumab (€31,048). The medication covers the majority of the per-patient costs for aflibercept and ranibizumab, while administration covers the majority of the per-patient costs for bevacizumab. The break-even prices of aflibercept and ranibizumab are respectively €507 and €60.58 per injection. Brolucizumab was included in the scenario analysis and was more expensive than aflibercept (€20,446). Brolucizumab should reduce to 13.8 injections over 3 years to be as costly as aflibercept. CONCLUSION: Bevacizumab is the cheapest anti-VEGF treatment. The list prices of all anti-VEGFs should reduce to be as costly as bevacizumab. Aflibercept is the second-choice treatment and so far brolucizumab is not
Antenatal intervention for congenital fetal lower urinary tract obstruction (LUTO): a systematic review and meta-analysis.
To evaluate the effectiveness of antenatal intervention for the treatment of congenital lower urinary tract obstruction (LUTO) in improving perinatal survival and postnatal renal function.
METHODS:
Electronic databases were searched from their inception until May 2018. Selection criteria included randomized controlled trials and controlled nonrandomized observational studies including fetuses with ultrasound evidence of LUTO evaluating antenatal intervention for improving perinatal outcomes. Any type of intervention was analyzed. The primary outcome was perinatal survival. The secondary outcome was postnatal survival with normal renal function. The summary measures were reported as summary odds ratio (OR) with 95% of confidence interval (CI).
RESULTS:
Ten articles with a total of 355 fetuses were included in the meta-analysis. Inclusion criteria of the selected studies were singleton pregnancy with severe LUTO confirmed on detailed fetal ultrasound examination. Nine studies, analyzed the efficacy of vesico-amniotic shunt performed in the second trimester. The overall estimate survival was higher in the vesico-amniotic shunt group compared to the conservative group (OR 2.54, 95% CI 1.14-5.67). 64/112 fetuses (57.1%) survived in the vesico-amniotic shunt group compared to 52/134 (38.8%) in the control group. Five studies reported on postnatal renal function between 6 months and 2 years. Postnatal renal function was higher in the vesico-amniotic shunt group compared to the conservative group (OR 2.09, 95% CI 0.74-5.9). Fetal cystoscopy was performed in only two included studies. Overall, 45 fetuses underwent fetal cystoscopy. The perinatal survival was higher in the cystoscopy group compared to the conservative management group (OR 2.63, 95% CI 1.07-6.47). Normal renal function was noted in 13/34 fetuses in the cystoscopy group versus 12/61 in the conservative management group at 6 months follow-up (OR 1.75, 95% CI 1.05-2.92) Conclusions: Antenatal bladder drainage appears to improve perinatal survival in cases of LUTO. Further randomized trials with long-term follow-up are required to determine the role of antenatal treatment in clinical setting
The Iowa Homemaker vol.3, no.11
Table of Contents
Identity by Ruth Elaine Wilson, page 2
The Responsibility of American Women to Citizenship by Marcia M. Roberts, page 3
Hearth and Home by Amanda Jacobsen, page 4
A Parent “That Needeth Not to be Ashamed” by Thomas F. Vance, page 5
Corn – Greatest Crop of Iowa by Gertrude E. Murray, page 6
American Home Economics Association Meets by Lela Johnson, page 7
The Evolution of Home Economics at Iowa State by Ruth Elaine Wilson, page 7
Hints for the Spring Wardrobe by Grace L. Heidbreder and Helen Brennan, page 8
Etiquette for College Girl by Marcella Dewell, page 9
Who’s There and Where by Dryden Quist, page 1
Multidimensional Atomic Force Microscopy: A Versatile Novel Technology for Nanopharmacology Research
Nanotechnology is giving us a glimpse into a nascent field of nanopharmacology that deals with pharmacological phenomena at molecular scale. This review presents our perspective on the use of scanning probe microscopy techniques with special emphasis to multidimensional atomic force microscopy (m-AFM) to explore this new field with a particular emphasis to define targets, design therapeutics, and track outcomes of molecular-scale pharmacological interactions. The approach will be to first discuss operating principles of m-AFM and provide representative examples of studies to understand human health and disease at the molecular level and then to address different strategies in defining target macromolecules, screening potential drug candidates, developing and characterizing of drug delivery systems, and monitoring target–drug interactions. Finally, we will discuss some future directions including AFM tip-based parallel sensors integrated with other high-throughput technologies which could be a powerful platform for drug discovery
The Primordial Binary Population - I: A near-infrared adaptive optics search for close visual companions to A star members of Scorpius OB2
We present the results of a near-infrared adaptive optics survey with the aim
to detect close companions to Hipparcos members in the three subgroups of the
nearby OB association Sco OB2: Upper Scorpius (US), Upper Centaurus Lupus (UCL)
and Lower Centaurus Crux (LCC). We have targeted 199 A-type and late B-type
stars in the Ks band, and a subset also in the J and H band. We find 151
stellar components other than the target stars. A brightness criterion is used
to separate these components into 77 background stars and 74 candidate physical
companion stars. Out of these 74 candidate companions, 41 have not been
reported before (14 in US; 13 in UCL; 14 in LCC). Companion star masses range
from 0.1 to 3 Msun. The mass ratio distribution follows f(q) = q^-0.33, which
excludes random pairing. No close (rho < 3.75'') companion stars or background
stars are found in the magnitude range 12 < Ks < 14. The lack of stars with
these properties cannot be explained by low-number statistics, and may imply a
lower limit on the companion mass of ~ 0.1 Msun. Close stellar components with
Ks > 14 are observed. If these components are very low-mass companion stars, a
gap in the companion mass distribution might be present. The small number of
close low-mass companion stars could support the embryo-ejection formation
scenario for brown dwarfs. Our findings are compared with and complementary to
visual, spectroscopic, and astrometric data on binarity in Sco OB2. We find an
overall companion star fraction of 0.52 in this association. This paper is the
first step toward our goal to derive the primordial binary population in Sco
OB2.Comment: 27 pages, to accepted by A&
Assessment of Potential Augmentation and Management Strategies for Razorback Sucker \u3cem\u3eXyrauchen texanus\u3c/em\u3e in Lake Mead and Grand Canyon: A 2021 Science Panel Summary
Razorback Sucker Xyrauchen texanus is a large-bodied, long-lived species endemic to the Colorado River Basin. This species historically ranged throughout the basin from the Colorado River delta in Mexico to Wyoming and Colorado. Currently, the species persists ,in a small portion of its historical range with the help of intensive management efforts including augmentation. Recruitment to adult life stages is extremely limited in the wild, but is documented consistently in Lake Mead. Research and monitoring efforts in Lake Mead are ongoing since 1996 and have recently expanded to include the Colorado River inflow area and portions of lower Grand Canyon. Despite evidence of recruitment, the current population size in Lake Mead and Grand Canyon is believed to be small (data) and susceptible to stochastic effects. This raised interest in the potential to augment the population to prevent loss of genetic diversity and increase abundance and distribution in general, as well as explore recruitment bottlenecks. To address critical uncertainties surrounding this management option and to brainstorm other potential options, a Planning Committee and Steering Committee made up of representatives of state (Arizona, Nevada), tribal (Hualapai Tribe, Navajo Nation), and federal (Bureau of Reclamation, National Park Service, and U.S. Fish and Wildlife Service) management agencies convened an Expert Science Panel (ESP; 2021), to consider augmentation and management strategies for Razorback Sucker in Lake Mead and Grand Canyon. The purpose of this report is to summarize those findings
Crater formation by fast ions: comparison of experiment with Molecular Dynamics simulations
An incident fast ion in the electronic stopping regime produces a track of
excitations which can lead to particle ejection and cratering. Molecular
Dynamics simulations of the evolution of the deposited energy were used to
study the resulting crater morphology as a function of the excitation density
in a cylindrical track for large angle of incidence with respect to the surface
normal. Surprisingly, the overall behavior is shown to be similar to that seen
in the experimental data for crater formation in polymers. However, the
simulations give greater insight into the cratering process. The threshold for
crater formation occurs when the excitation density approaches the cohesive
energy density, and a crater rim is formed at about six times that energy
density. The crater length scales roughly as the square root of the electronic
stopping power, and the crater width and depth seem to saturate for the largest
energy densities considered here. The number of ejected particles, the
sputtering yield, is shown to be much smaller than simple estimates based on
crater size unless the full crater morphology is considered. Therefore, crater
size can not easily be used to estimate the sputtering yield.Comment: LaTeX, 7 pages, 5 EPS figures. For related figures/movies, see:
http://dirac.ms.virginia.edu/~emb3t/craters/craters.html New version uploaded
5/16/01, with minor text changes + new figure
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