125 research outputs found
Magnetic domain wall propagation in a submicron spin-valve stripe: influence of the pinned layer
The propagation of a domain wall in a submicron ferromagnetic spin-valve
stripe is investigated using giant magnetoresistance. A notch in the stripe
efficiently traps an injected wall stopping the domain propagation. The authors
show that the magnetic field at which the wall is depinned displays a
stochastic nature. Moreover, the depinning statistics are significantly
different for head to head and tail-to-tail domain walls. This is attributed to
the dipolar field generated in the vicinity of the notch by the pinned layer of
the spin-valve
SAVoR: A Server for Sequencing Annotation and Visualization of RNA Structures
RNA secondary structure is required for the proper regulation of the cellular transcriptome. This is because the functionality, processing, localization and stability of RNAs are all dependent on the folding of these molecules into intricate structures through specific base pairing interactions encoded in their primary nucleotide sequences. Thus, as the number of RNA sequencing (RNA-seq) data sets and the variety of protocols for this technology grow rapidly, it is becoming increasingly pertinent to develop tools that can analyze and visualize this sequence data in the context of RNA secondary structure. Here, we present Sequencing Annotation and Visualization of RNA structures (SAVoR), a web server, which seamlessly links RNA structure predictions with sequencing data and genomic annotations to produce highly informative and annotated models of RNA secondary structure. SAVoR accepts read alignment data from RNA-seq experiments and computes a series of per-base values such as read abundance and sequence variant frequency. These values can then be visualized on a customizable secondary structure model. SAVoR is freely available at http://tesla.pcbi.upenn.edu/savor
Bounding biomass in the Fisher equation
The FKPP equation with a variable growth rate and advection by an
incompressible velocity field is considered as a model for plankton dispersed
by ocean currents. If the average growth rate is negative then the model has a
survival-extinction transition; the location of this transition in the
parameter space is constrained using variational arguments and delimited by
simulations. The statistical steady state reached when the system is in the
survival region of parameter space is characterized by integral constraints and
upper and lower bounds on the biomass and productivity that follow from
variational arguments and direct inequalities. In the limit of
zero-decorrelation time the velocity field is shown to act as Fickian diffusion
with an eddy diffusivity much larger than the molecular diffusivity and this
allows a one-dimensional model to predict the biomass, productivity and
extinction transitions. All results are illustrated with a simple growth and
stirring model.Comment: 32 Pages, 13 Figure
The Very Young Type Ia Supernova 2012cg: Discovery and Early-Time Follow-Up Observations
On 2012 May 17.2 UT, only 1.5 +/- 0.2 d after explosion, we discovered SN
2012cg, a Type Ia supernova (SN Ia) in NGC 4424 (d ~ 15 Mpc). As a result of
the newly modified strategy employed by the Lick Observatory SN Search, a
sequence of filtered images was obtained starting 161 s after discovery.
Utilizing recent models describing the interaction of SN ejecta with a
companion star, we rule out a ~1 M_Sun companion for half of all viewing angles
and a red-giant companion for nearly all orientations. SN 2012cg reached a
B-band maximum of 12.09 +/- 0.02 mag on 2012 June 2.0 and took ~17.3 d from
explosion to reach this, typical for SNe Ia. Our pre-maximum brightness
photometry shows a narrower-than-average B-band light curve for SN 2012cg,
though slightly overluminous at maximum brightness and with normal color
evolution (including some of the earliest SN Ia filtered photometry ever
obtained). Spectral fits to SN 2012cg reveal ions typically found in SNe Ia at
early times, with expansion velocities >14,000 km/s at 2.5 d past explosion.
Absorption from C II is detected early, as well as high-velocity components of
both Si II 6355 Ang. and Ca II. Our last spectrum (13.5 d past explosion)
resembles that of the somewhat peculiar SN Ia 1999aa. This suggests that SN
2012cg will have a slower-than-average declining light curve, which may be
surprising given the faster-than-average rising light curve.Comment: re-submitted to ApJL, 4 figures, 1 tabl
The ANU WiFeS SuperNovA Program (AWSNAP)
This paper presents the first major data release and survey description for
the ANU WiFeS SuperNovA Program (AWSNAP). AWSNAP is an ongoing supernova
spectroscopy campaign utilising the Wide Field Spectrograph (WiFeS) on the
Australian National University (ANU) 2.3m telescope. The first and primary data
release of this program (AWSNAP-DR1) releases 357 spectra of 175 unique objects
collected over 82 equivalent full nights of observing from July 2012 to August
2015. These spectra have been made publicly available via the WISeREP supernova
spectroscopy repository. We analyse the AWSNAP sample of Type Ia supernova
spectra, including measurements of narrow sodium absorption features afforded
by the high spectral resolution of the WiFeS instrument. In some cases we were
able to use the integral-field nature of the WiFeS instrument to measure the
rotation velocity of the SN host galaxy near the SN location in order to obtain
precision sodium absorption velocities. We also present an extensive time
series of SN 2012dn, including a near-nebular spectrum which both confirms its
"super-Chandrasekhar" status and enables measurement of the sub-solar host
metallicity at the SN site.Comment: Submitted to Publications of the Astronomical Society of Australia
(PASA). Spectra publicly released via WISeREP at
http://wiserep.weizmann.ac.il
A Baker’s Dozen of Top Antimicrobial Stewardship Intervention Publications in 2019
Staying current on literature related to antimicrobial stewardship can be challenging given the ever-increasing number of published articles. The Southeastern Research Group Endeavor (SERGE-45) identified antimicrobial stewardship–related peer-reviewed literature that detailed an actionable intervention for 2019. The top 13 publications were selected using a modified Delphi technique. These manuscripts were reviewed to highlight the actionable intervention used by antimicrobial stewardship programs to provide key stewardship literature for teaching and training and to identify potential intervention opportunities within one’s institution
A Baker’s dozen of top antimicrobial stewardship intervention publications in 2019
© The Author(s) 2020. Staying current on literature related to antimicrobial stewardship can be challenging given the ever-increasing number of published articles. The Southeastern Research Group Endeavor (SERGE-45) identified antimicrobial stewardship–related peer-reviewed literature that detailed an actionable intervention for 2019. The top 13 publications were selected using a modified Delphi technique. These manuscripts were reviewed to highlight the actionable intervention used by antimicrobial stewardship programs to provide key stewardship literature for teaching and training and to identify potential intervention opportunities within one’s institution
A Baker\u27s Dozen of Top Antimicrobial Stewardship Intervention Publications in 2019
Staying current on literature related to antimicrobial stewardship can be challenging given the ever-increasing number of published articles. The Southeastern Research Group Endeavor (SERGE-45) identified antimicrobial stewardship-related peer-reviewed literature that detailed an actionable intervention for 2019. The top 13 publications were selected using a modified Delphi technique. These manuscripts were reviewed to highlight the actionable intervention used by antimicrobial stewardship programs to provide key stewardship literature for teaching and training and to identify potential intervention opportunities within one\u27s institution
Use of Binary Cumulative Sums and Moving Averages in Nosocomial Infection Cluster Detection1
Clusters of nosocomial infection often occur undetected, at substantial cost to the medical system and individual patients. We evaluated binary cumulative sum (CUSUM) and moving average (MA) control charts for automated detection of nosocomial clusters. We selected two outbreaks with genotyped strains and used resistance as inputs to the control charts. We identified design parameters for the CUSUM and MA (window size, k, α, β, p0, p1) that detected both outbreaks, then calculated an associated positive predictive value (PPV) and time until detection (TUD) for sensitive charts. For CUSUM, optimal performance (high PPV, low TUD, fully sensitive) was for 0.1 <α ≤0.25 and 0.2 <β <0.25, with p0 = 0.05, with a mean TUD of 20 (range 8–43) isolates. Mean PPV was 96.5% (relaxed criteria) to 82.6% (strict criteria). MAs had a mean PPV of 88.5% (relaxed criteria) to 46.1% (strict criteria). CUSUM and MA may be useful techniques for automated surveillance of resistant infections
- …