3,061 research outputs found
Space station attitude disturbance arising from internal motions
A source of space station attitude disturbances is identified. The attitude disturbance is driven by internal space station motions and is a direct result of conservation of angular momentum. Three examples are used to illustrate the effect: a planar three link system, a rigid carrier body with two moveable masses, and a nonplanar five link system. Simulation results are given to show the magnitude of the attitude change in each example. Factors which accentuate or attenuate this disturbance effect are discussed
Melioidosis: refining management of a tropical time bomb
10.1016/S0140-6736(13)62143-1The Lancet3839919762-764LANC
Theory of Quasi-Particles in the Underdoped High Tc Superconducting State
The microscopic theory of superconducting (SC) state in the SU(2) slave-boson
model is developed. We show how the pseudogap and Fermi surface (FS) segments
in the normal state develop into a d-wave gap in the superconducting state.
Even though the superfluid density is of order x (the doping concentration),
the physical properties of the low lying quasiparticles are found to resemble
those in BCS theory. Thus the microscopic theory lay the foundation for our
earlier phenomenological discussion of the unusual SC properties in the
underdoped cuprates.Comment: 4 pages in RevTeX, 1 figure in eps, revised versio
The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 Parsec White Dwarf Sample
We present 114 trigonometric parallaxes for 107 nearby white dwarf (WD)
systems from both the Cerro Tololo Inter-American Observatory Parallax
Investigation (CTIOPI) and the U. S. Naval Observatory Flagstaff Station (NOFS)
parallax programs. Of these, 76 parallaxes for 69 systems were measured by the
CTIOPI program and 38 parallaxes for as many systems were measured by the NOFS
program. A total of 50 systems are confirmed to be within the 25 pc horizon of
interest. Coupled with a spectroscopic confirmation of a common proper motion
companion to a Hipparcos star within 25 pc as well as confirmation parallax
determinations for two WD systems included in the recently released Tycho Gaia
Astrometric Solution (TGAS) catalog, we add 53 new systems to the 25 pc WD
sample a 42% increase. Our sample presented here includes four strong
candidate halo systems, a new metal-rich DAZ WD, a confirmation of a recently
discovered nearby short-period (P = 2.85 hr) double degenerate, a WD with a new
astrometric pertubation (long period, unconstrained with our data), and a new
triple system where the WD companion main-sequence star has an astrometric
perturbation (P 1.6 yr).Comment: 32 pages, 12 figures. Figure 4 in the manuscript is a representative
set of plots - plots for all WDs presented here are available
(allfits_photo.pdf, allfits_photo_DQ.pdf, and allfits_photo_DZ.pdf). Accepted
for publication in The Astronomical Journa
Ab initio calculation of the 66 low lying electronic states of HeH: adiabatic and diabatic representations
We present an ab initio study of the HeH molecule. Using the quantum
chemistry package MOLPRO and a large adapted basis set, we have calculated the
adiabatic potential energy curves of the first 20 , 19
, 12 , 9 , 4 and 2 electronic
states of the ion in CASSCF and CI approaches. The results are compared with
previous works. The radial and rotational non-adiabatic coupling matrix
elements as well as the dipole moments are also calculated. The asymptotic
behaviour of the potential energy curves and of the various couplings between
the states is also studied. Using the radial couplings, the diabatic
representation is defined and we present an example of our diabatization
procedure on the states.Comment: v2. Minor text changes. 28 pages, 18 figures. accepted in J. Phys.
In vitro, in vivo and clinical studies comparing the efficacy of ceftazidime-avibactam monotherapy with ceftazidime-avibactam-containing combination regimens against carbapenem-resistant Enterobacterales and multidrug-resistant Pseudomonas aeruginosa isolates or infections: a scoping review
IntroductionCarbapenem-resistant Enterobacterales (CRE) and multidrug-resistant Pseudomonas aeruginosa (MDR-PA) infections are associated with a high risk of morbidity, mortality, and treatment costs. We aimed to evaluate in vitro, in vivo and clinical studies comparing the efficacy of ceftazidime-avibactam (CZA) combination regimens with CZA alone against CRE and/or MDR-PA isolates or infections.MethodsWe systematically reviewed the relevant literature in CINAHL/MEDLINE, Pubmed, Cochrane, Web of Science, Embase, and Scopus until December 1, 2022. Review articles, grey literature, abstracts, comments, editorials, non-peer reviewed articles, non-English articles, and in vitro synergy studies conducted on single isolates were excluded.Results22 in vitro, 7 in vivo and 20 clinical studies were evaluated. In vitro studies showed reliable synergy between CZA and aztreonam against metallo-β-lactamase (MBL)-producing isolates. Some studies indicated good in vitro synergy between CZA and amikacin, meropenem, fosfomycin and polymyxins against CRE isolates. For MDR-PA isolates, there are comparatively fewer in vitro or in vivo studies. In observational clinical studies, mortality, clinical cure, adverse events, and development of CZA resistance after exposure were generally similar in monotherapy and combination therapy groups. However, antibiotic-related nephrotoxicity and infection relapses were higher in patients receiving CZA combination therapies.DiscussionThe benefit, if any, of CZA combination regimens in MDR-PA infections is elusive, as very few clinical studies have included these infections. There is no currently documented clinical benefit for the use of CZA combination regimens rather than CZA monotherapy. CZA combined with aztreonam for serious infections due to MBL producers should be evaluated by randomized controlled trials.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=278552, CRD42021278552
Whole exome sequencing and molecular modeling of a missense variant in TNFAIP3 that segregates with disease in a family with chronic urticaria and angioedema
Chronic urticaria is a common condition characterized by recurrent hives lasting several weeks or months and is usually idiopathic. Approximately half of the individuals with chronic urticaria will present with episodes of angioedema that can be severe and debilitating. In this report, we describe a 47-year-old Hispanic male who presented initially for an evaluation of chronic hives following hospitalization due to hive-induced anaphylaxis. The individual had a history significant for urticaria and angioedema beginning in his early 30s. Interestingly, both the individual’s 41-year-old sister and 12-year-old daughter were also affected with chronic urticaria and severe angioedema. Whole exome sequencing of the proband and several family members revealed a heterozygous variant of uncertain significance in exon 2 of TNFAIP3, denoted as c.65G>A (p.R22Q), in all affected members. Variants in TNFAIP3 have been associated with multiple autoimmune diseases, susceptibility to allergy and asthma, and periodic fever syndromes, suggesting that this variant could potentially play a role in disease
Whole Exome Sequencing and Molecular Modeling of a Missense Variant in TNFAIP3
Chronic urticaria is a common condition characterized by recurrent hives lasting several weeks or months and is usually idiopathic. Approximately half of the individuals with chronic urticaria will present with episodes of angioedema that can be severe and debilitating. In this report, we describe a 47-year-old Hispanic male who presented initially for an evaluation of chronic hives following hospitalization due to hive-induced anaphylaxis. The individual had a history significant for urticaria and angioedema beginning in his early 30s. Interestingly, both the individual’s 41-year-old sister and 12-year-old daughter were also affected with chronic urticaria and severe angioedema. Whole exome sequencing of the proband and several family members revealed a heterozygous variant of uncertain significance in exon 2 of TNFAIP3, denoted as c.65G>A (p.R22Q), in all affected members. Variants in TNFAIP3 have been associated with multiple autoimmune diseases, susceptibility to allergy and asthma, and periodic fever syndromes, suggesting that this variant could potentially play a role in disease
The Hubble Constant from Observations of the Brightest Red Giant Stars in a Virgo-Cluster Galaxy
The Virgo and Fornax clusters of galaxies play central roles in determining
the Hubble constant H_0. A powerful and direct way of establishing distances
for elliptical galaxies is to use the luminosities of the brightest red-giant
stars (the TRGB luminosity, at M_I = -4.2). Here we report the direct
observation of the TRGB stars in a dwarf elliptical galaxy in the Virgo
cluster. We find its distance to be 15.7 +- 1.5 Megaparsecs, from which we
estimate a Hubble constant of H_0 = 77 +- 8 km/s/Mpc. Under the assumption of a
low-density Universe with the simplest cosmology, the age of the Universe is no
more than 12-13 billion years.Comment: 12 pages, LaTeX, with 2 postscript figures; in press for Nature, July
199
The Optical-Near-IR Spectrum of the M87 Jet From HST Observations
We present 1998 HST observations of M87 which yield the first single-epoch
optical and radio-optical spectral index images of the jet at
resolution. We find , comparable to previous
measurements, and (),
slightly flatter than previous workers. Reasons for this discrepancy are
discussed. These observations reveal a large variety of spectral slopes. Bright
knots exhibit flatter spectra than interknot regions. The flattest spectra
(; comparable to or flatter than ) are
found in two inner jet knots (D-East and HST-1) which contain the fastest
superluminal components. In knots A, B and C, and are
essentially anti-correlated. Near the flux maxima of knots HST-1 and F, changes
in lag changes in , but in knots D and E, the opposite
relationship is observed. This is further evidence that radio and optical
emissions in the M87 jet come from substantially different physical regions.
The delays observed in the inner jet are consistent with localized particle
acceleration, with for optically emitting electrons in
knots HST-1 and F, and for optically emitting electrons
in knots D and E. Synchrotron models yield \nu_B \gsim 10^{16} Hz for knots
D, A and B, and somewhat lower values, Hz, in
other regions. If X-ray emissions from knots A, B and D are co-spatial with
optical and radio emission, we can strongly rule out the ``continuous
injection'' model. Because of the short lifetimes of X-ray synchrotron emitting
particles, the X-ray emission likely fills volumes much smaller than the
optical emission regions.Comment: Text 17 pages, 3 Tables, 11 figures, accepted by Ap
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