51 research outputs found
Rethinking Equitable Estoppel in Patent Law
In almost every context, the Federal Circuit has used estoppel doctrines to provide protection to parties from some sort of injustice. Yet recently, with equitable estoppel, the Federal Circuit has decided to infuse concepts of Article III justiciability to justify limiting the doctrine as only applicable to issued patents. In doing so, the Federal Circuit has ignored the long history behind equitable estoppel in favor of a rule that is improperly rationalized by the Constitution. This note argues that Federal Circuit\u27s recent equitable estoppel jurisprudence is inconsistent with equity\u27s goal of fairness and presents a new theory of equitable estoppel — inchoate estoppel — which would create fairer outcomes for patentees and defendants alike
Impact of Pneumococcal Conjugate Vaccines on Pneumonia Hospitalizations in High- and Low-Income Subpopulations in Brazil.
BackgroundPneumococcal conjugate vaccines (PCVs) are being used worldwide. A key question is whether the impact of PCVs on pneumonia is similar in low- and high-income populations. However, most low-income countries, where the burden of disease is greatest, lack reliable data that can be used to evaluate the impact. Data from middle-income countries that have both low- and high-income subpopulations can provide a proxy measure for the impact of the vaccine in low-income countries.MethodsWe evaluated the impact of PCV10 on hospitalizations for all-cause pneumonia in Brazil, a middle-income country with localities that span a broad range of human development index (HDI) levels. We used complementary time series and spatiotemporal methods (synthetic controls and hierarchical Bayesian spatial regression) to test whether the decline in pneumonia hospitalizations associated with vaccine introduction varied across the socioeconomic spectrum.ResultsWe found that the declines in all-cause pneumonia hospitalizations in children and young and middle-aged adults did not vary substantially across low and high HDI subpopulations. Moreover, the estimated declines seen in infants and young adults were associated with higher levels of uptake of the vaccine at a local level.ConclusionsThese results suggest that PCVs have an important impact on hospitalizations for all-cause pneumonia in both low- and high-income populations
The Need for Laboratory Measurements and Ab Initio Studies to Aid Understanding of Exoplanetary Atmospheres
We are now on a clear trajectory for improvements in exoplanet observations
that will revolutionize our ability to characterize their atmospheric
structure, composition, and circulation, from gas giants to rocky planets.
However, exoplanet atmospheric models capable of interpreting the upcoming
observations are often limited by insufficiencies in the laboratory and
theoretical data that serve as critical inputs to atmospheric physical and
chemical tools. Here we provide an up-to-date and condensed description of
areas where laboratory and/or ab initio investigations could fill critical gaps
in our ability to model exoplanet atmospheric opacities, clouds, and chemistry,
building off a larger 2016 white paper, and endorsed by the NAS Exoplanet
Science Strategy report. Now is the ideal time for progress in these areas, but
this progress requires better access to, understanding of, and training in the
production of spectroscopic data as well as a better insight into chemical
reaction kinetics both thermal and radiation-induced at a broad range of
temperatures. Given that most published efforts have emphasized relatively
Earth-like conditions, we can expect significant and enlightening discoveries
as emphasis moves to the exotic atmospheres of exoplanets.Comment: Submitted as an Astro2020 Science White Pape
JWST/NIRCam Transmission Spectroscopy of the Nearby Sub-Earth GJ 341b
We present a JWST/NIRCam transmission spectrum from m of the
recently-validated sub-Earth GJ 341b (
, K) orbiting a nearby bright M1
star ( pc, ). We use three independent
pipelines to reduce the data from the three JWST visits and perform several
tests to check for the significance of an atmosphere. Overall, our analysis
does not uncover evidence of an atmosphere. Our null hypothesis tests find that
none of our pipelines' transmission spectra can rule out a flat line, although
there is weak evidence for a Gaussian feature in two spectra from different
pipelines (at 2.3 and ). However, the candidate features are seen at
different wavelengths (4.3 m vs 4.7 m), and our retrieval analysis
finds that different gas species can explain these features in the two
reductions (CO at compared to O at ), suggesting
that they are not real astrophysical signals. Our forward model analysis rules
out a low mean molecular weight atmosphere ( solar metallicity) to
at least , and disfavors CH-dominated atmospheres at ,
depending on the reduction. Instead, the forward models find our transmission
spectra are consistent with no atmosphere, a hazy atmosphere, or an atmosphere
containing a species that does not have prominent molecular bands across the
NIRCam/F444W bandpass, such as a water-dominated atmosphere. Our results
demonstrate the unequivocal need for two or more transit observations analyzed
with multiple reduction pipelines, alongside rigorous statistical tests, to
determine the robustness of molecular detections for small exoplanet
atmospheres.Comment: 25 pages, 18 figures, 6 tables. Accepted for publication in A
Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H
The search for rocky planet atmospheres with JWST has focused on planets
transiting M dwarfs. Such planets have favorable planet-to-star size ratios,
enhancing the amplitude of atmospheric features. Since the expected signal
strength of atmospheric features is similar to the single-transit performance
of JWST, multiple observations are required to confirm any detection. Here, we
present two transit observations of the rocky planet GJ 1132 b with JWST
NIRSpec G395H, covering 2.8-5.2 m. Previous HST WFC3 observations of GJ
1132 b were inconclusive, with evidence reported for either an atmosphere or a
featureless spectrum based on analyses of the same dataset. Our JWST data
exhibit substantial differences between the two visits. One transit is
consistent with either a HO-dominated atmosphere containing ~1% CH and
trace NO ( = 1.13) or stellar contamination from unocculted
starspots ( = 1.36). However, the second transit is consistent
with a featureless spectrum. Neither visit is consistent with a previous report
of HCN. Atmospheric variability is unlikely to explain the scale of the
observed differences between the visits. Similarly, our out-of-transit stellar
spectra show no evidence of changing stellar inhomogeneity between the two
visits - observed 8 days apart, only 6.5% of the stellar rotation rate. We
further find no evidence of differing instrumental systematic effects between
visits. The most plausible explanation is an unlucky random noise draw leading
to two significantly discrepant transmission spectra. Our results highlight the
importance of multi-visit repeatability with JWST prior to claiming atmospheric
detections for these small, enigmatic planets.Comment: 22 pages, 10 figures, 2 tables. Accepted for publication in ApJ
Letters. Co-First Authors. Bonus materials and spectral data:
https://doi.org/10.5281/zenodo.1000208
Superhelical Duplex Destabilization and the Recombination Position Effect
The susceptibility to recombination of a plasmid inserted into a chromosome
varies with its genomic position. This recombination position effect is known to
correlate with the average G+C content of the flanking sequences. Here we
propose that this effect could be mediated by changes in the susceptibility to
superhelical duplex destabilization that would occur. We use standard
nonparametric statistical tests, regression analysis and principal component
analysis to identify statistically significant differences in the
destabilization profiles calculated for the plasmid in different contexts, and
correlate the results with their measured recombination rates. We show that the
flanking sequences significantly affect the free energy of denaturation at
specific sites interior to the plasmid. These changes correlate well with
experimentally measured variations of the recombination rates within the
plasmid. This correlation of recombination rate with superhelical
destabilization properties of the inserted plasmid DNA is stronger than that
with average G+C content of the flanking sequences. This model suggests a
possible mechanism by which flanking sequence base composition, which is not
itself a context-dependent attribute, can affect recombination rates at
positions within the plasmid
A roadmap to the efficient and robust characterization of temperate terrestrial planet atmospheres with JWST
Ultra-cool dwarf stars are abundant, long-lived, and uniquely suited to
enable the atmospheric study of transiting terrestrial companions with JWST.
Amongst them, the most prominent is the M8.5V star TRAPPIST-1 and its seven
planets, which have been the favored targets of eight JWST Cycle 1 programs.
While Cycle 1 observations have started to yield preliminary insights into the
planets, they have also revealed that their atmospheric exploration requires a
better understanding of their host star. Here, we propose a roadmap to
characterize the TRAPPIST-1 system -- and others like it -- in an efficient and
robust manner. We notably recommend that -- although more challenging to
schedule -- multi-transit windows be prioritized to constrain stellar
heterogeneities and gather up to 2 more transits per JWST hour spent.
We conclude that in such systems planets cannot be studied in isolation by
small programs, thus large-scale community-supported programs should be
supported to enable the efficient and robust exploration of terrestrial
exoplanets in the JWST era
Ontogeny-Driven rDNA Rearrangement, Methylation, and Transcription, and Paternal Influence
Gene rearrangement occurs during development in some cell types and this genome dynamics is modulated by intrinsic and extrinsic factors, including growth stimulants and nutrients. This raises a possibility that such structural change in the genome and its subsequent epigenetic modifications may also take place during mammalian ontogeny, a process undergoing finely orchestrated cell division and differentiation. We tested this hypothesis by comparing single nucleotide polymorphism-defined haplotype frequencies and DNA methylation of the rDNA multicopy gene between two mouse ontogenic stages and among three adult tissues of individual mice. Possible influences to the genetic and epigenetic dynamics by paternal exposures were also examined for Cr(III) and acid saline extrinsic factors. Variables derived from litters, individuals, and duplicate assays in large mouse populations were examined using linear mixed-effects model. We report here that active rDNA rearrangement, represented by changes of haplotype frequencies, arises during ontogenic progression from day 8 embryos to 6-week adult mice as well as in different tissue lineages and is modifiable by paternal exposures. The rDNA methylation levels were also altered in concordance with this ontogenic progression and were associated with rDNA haplotypes. Sperm showed highest level of methylation, followed by lungs and livers, and preferentially selected haplotypes that are positively associated with methylation. Livers, maintaining lower levels of rDNA methylation compared with lungs, expressed more rRNA transcript. In vitro transcription demonstrated haplotype-dependent rRNA expression. Thus, the genome is also dynamic during mammalian ontogeny and its rearrangement may trigger epigenetic changes and subsequent transcriptional controls, that are further influenced by paternal exposures
Early Release Science of the exoplanet WASP-39b with JWST NIRCam
Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet
atmospheres is a fundamental step towards constraining the dominant chemical
processes at work and, if in equilibrium, revealing planet formation histories.
Transmission spectroscopy provides the necessary means by constraining the
abundances of oxygen- and carbon-bearing species; however, this requires broad
wavelength coverage, moderate spectral resolution, and high precision that,
together, are not achievable with previous observatories. Now that JWST has
commenced science operations, we are able to observe exoplanets at previously
uncharted wavelengths and spectral resolutions. Here we report time-series
observations of the transiting exoplanet WASP-39b using JWST's Near InfraRed
Camera (NIRCam). The long-wavelength spectroscopic and short-wavelength
photometric light curves span 2.0 - 4.0 m, exhibit minimal systematics,
and reveal well-defined molecular absorption features in the planet's spectrum.
Specifically, we detect gaseous HO in the atmosphere and place an upper
limit on the abundance of CH. The otherwise prominent CO feature at 2.8
m is largely masked by HO. The best-fit chemical equilibrium models
favour an atmospheric metallicity of 1-100 solar (i.e., an enrichment
of elements heavier than helium relative to the Sun) and a sub-stellar
carbon-to-oxygen (C/O) ratio. The inferred high metallicity and low C/O ratio
may indicate significant accretion of solid materials during planet formation
or disequilibrium processes in the upper atmosphere.Comment: 35 pages, 13 figures, 3 tables, Nature, accepte
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