6609 research outputs found
Sort by
Incorporating Presence Conditions into Goal Models that Evolve Over Time: Supplemental Video
No full textSupplemental video for the research paper entitled, Incorporating Presence Conditions into Goal Models that Evolve Over Time . This workshop paper investigates the problem of specifying and reasoning about goal models when some stakeholders and their intentions are not present for the entirety of a timeline under consideration. The paper presents a specification and implementation of presence conditions in the Evolving Intentions framework and the BloomingLeaf tool. This supplement contains a video demonstrating the given solution on a large model from the literature
Dead Clade Walking: Archaeocyaths in the Lower Cambrian Mule Spring Limestone, Nevada
No full textArchaeocyath sponges are the first animal reef-builders of the Phanerozoic. Archaeocyaths, divided into two different subgroups—regular and irregular—based on the complexity of morphology, diversified greatly until the Stage 3 to Stage 4 boundary. By the end of the early Cambrian (Series 2 Stage 4), archaeocyaths faced total extinction. The exact timing of this extinction varies regionally. This research presents archaeocyaths that are stratigraphically younger than the extinction from several small patch reef mounds in the lowermost part of the upper unit of the Mule Spring Limestone near Split Mountain, Nevada (upper Stage 4). Thin section analysis revealed the presence of archaeocyaths and microbial fabrics, such as stromatolites, thrombolites, and encrusting microbes, along with other reef-dwelling organisms, including trilobites and echinoderms. Archaeocyathus, an irregular genus, was the only genus present and identified in the Mule Spring Limestone thin sections. Individuals of Archaeocyathus were found in all of the reef mounds. Fossil debris—trilobites and echinoderms—was sparse within the reef mounds but was abundant in beds below and regions between the mounds. Here, Archaeocyathus could represent the last gasp of archaeocyathan reef building in the early Cambrian before their extinction. The Mule Spring Limestone differs from the underlying Harkless Formation, as this was characterized by higher biodiversity and abundance of archaeocyaths and reef-dwellers. Thus, this occurrence of Archaeocyathus is interpreted to be an example of a dead clade walking—the last true archaeocyaths that persisted in this region beyond the archaeocyath extinction during mid-Stage 4. As some of the youngest-known archaeocyaths in Laurentia, the archaeocyaths of the Mule Spring Limestone provide an opportunity to better understand ii the environmental and ecological conditions surrounding animal reefs in the early Cambrian. It is possible that the irregularity and modularity of Archaeocyathus allowed this genus to briefly persist beyond the extinction of archaeocyaths in Laurentia
Using Sensitivity Analyses to Approximate Total COVID-19 Infections: State and County level in the United States, March 2021 - March 2022
No full textAs we have navigated the COVID-19 pandemic, case counts have been a central source of information for understanding transmission dynamics and the effect of public health interventions. However, because the number of cases we observe is limited by the testing effort in a given location, the case counts presented on local or national dashboards are only a fraction of the true infections. Variation in testing rate by time and location impacts the number of cases that go unobserved, which can cloud our understanding of the true COVID-19 incidence at a given time point and can create biases in downstream analyses. Additionally, the number of cases we observe is impacted by the sensitivity and specificity of the diagnostic test. To quantify the number of true infections given incomplete testing and diagnostic test inaccuracy, we implement probabilistic bias analysis at a biweekly time scale from the beginning of March of 2021 to the beginning of March of 2022. In doing so, we estimate a range of possible true infections for every given time interval and location considered. This approach can be applied at the state level across the United States, as well as in some counties where the needed data are available
Desert Genealogies: (De)Colonizing Conceptions of Naqab Bedouin Land and Space Under the Israeli State
No full textUV-optical Emission of AB Aur b Is Consistent with Scattered Stellar Light
Get PDFThe proposed protoplanet AB Aur b is a spatially concentrated emission source imaged in the millimeter-wavelength disk gap of the Herbig Ae/Be star AB Aur. Its near-infrared spectrum and absence of strong polarized light have been interpreted as evidence supporting the protoplanet interpretation. However, the complex scattered-light structures in the AB Aur disk pose challenges in resolving the emission source and interpreting the true nature of AB Aur b. We present new images of the AB Aur system obtained using the Hubble Space Telescope Wide Field Camera 3 in the ultraviolet (UV) and optical bands. AB Aur b and the known disk spirals are recovered in the F336W, F410M, and F645N bands. The spectral energy distribution of AB Aur b shows absorption in the Balmer jump, mimicking that of early-type stars. By comparing the colors of AB Aur b to those of the host star, the disk spirals, and predictions from scattered light and self-luminous models, we find that the emission from AB Aur b is inconsistent with planetary photospheric or accretion shock models. Instead, it is consistent with those measured in the circumstellar disks that trace scattered light. We conclude that the UV and visible emission from AB Aur b does not necessitate the presence of a protoplanet. We synthesize observational constraints on AB Aur b and discuss inconsistent interpretations among different data sets. Considering the significance of the AB Aur b discovery, we advocate for further observational evidence to verify its planetary nature
Characterization of Amyloid Precursor Protein Regulation by Orphan G Protein-Coupled Receptors 3, 6 and 12
No full textAlzheimer’s disease (AD) is a progressive neurodegenerative disease that remains incurable. It is hypothesized that one of the main causes of AD is the oligomerization of Amyloid Beta (Aβ) peptides and their disposition into senile plaques, leading to synaptic dysfunction and neuronal degeneration. Aβ results from the cleavage of Amyloid precursor protein (APP) cleavage by β-secretase and γ-secretase. Treatment options through the elimination of APP or Aβ in the past did not yield long-term positive results, thus it is necessary to find molecular elements that can regulate this processing pathway. For example, G protein coupled receptor 3 (GPR3) was shown to be a positive regulator of APP processing leading to high levels of Aβ in both in vitro and in vivo models of AD. Therefore, in this study we aim to characterize the roles of GPR6 and GPR12 due to their high homology with GPR3. These three receptors were co-expressed in HEK293T cells with two APP isoforms, wild-type and mutant APP, which allows us to study these effects in sporadic and familial types of AD. APP levels were analyzed in the presence of each receptor using western blot analysis, with an emphasis on C-terminal fragments (CTFs) of app, primarily C-99 fragment, a direct precursor to Aβ. We also sought to understand the mechanisms through which these receptors elicit any observed effects, focusing mainly on G-protein signaling pathways. Overall, we were able to identify GPR6 as a possible downregulator of APP cleavage into C99, and thus could play a neuroprotective role against amyloidogenesis in both sporadic and familial forms of AD. On the other hand, GPR3 was a positive regulator of APP amyloidogenic processing leading to increased accumulation of C99, which is in line with previous research. However, GPR12 effects remain ambiguous and in between the two other receptors. Subsequently, we also observed a bidirectional effect between APP and G-protein signaling, suggesting a potential interaction between the receptors and APP. All together, this study set the stage for a new research direction focusing on GPR6 as a potential drug target in AD
CD-27°11535: Evidence for a Triple System in the β Pictoris Moving Group
No full textWe present new spatially resolved astrometry and photometry of the CD -27°11535 system, a member of the β Pictoris moving group consisting of two resolved K-type stars on a ∼20 yr orbit. We fit an orbit to relative astrometry measured from NIRC2, GPI, and archival NaCo images, in addition to literature measurements. However, the total mass inferred from this orbit is significantly discrepant from that inferred from stellar evolutionary models using the luminosity of the two stars. We explore two hypotheses that could explain this discrepant mass sum: a discrepant parallax measurement from Gaia due to variability, and the presence of an additional unresolved companion to one of the two components. We find that the ∼20 yr orbit could not bias the parallax measurement, but that variability of the components could produce a large-amplitude astrometric motion, an effect that cannot be quantified exactly without the individual Gaia measurements. The discrepancy could also be explained by an additional star in the system. We jointly fit the astrometric and photometric measurements of the system to test different binary and triple architectures for the system. Depending on the set of evolutionary models used, we find an improved goodness of fit for a triple system architecture that includes a low-mass (M = 0.177 ± 0.055 M ⊙) companion to the primary star. Further studies of this system will be required in order to resolve this discrepancy, either by refining the parallax measurement with a more complex treatment of variability-induced astrometric motion or by detecting a third companion
Neoichnological Framework of Coastal Habitat Shifts Represented by Bahamian Decapod Burrows
Get PDFIn coastal settings, the cumulative spatial and temporal impacts of burrowing, ichnofabric formation, and biodeposition by large crustaceans have been largely neglected at zoogeomorphic scales. These traces also serve as important (paleo-)environmental and (paleo)hydrologic indicators, both vertical (tidal or groundwater level) and lateral (areal wetland or basin extent). To date, 354 only few studies have addressed the comparative value of decapod ichnites generated by land crabs in carbonate settings. The aim of this paper is to introduce a general conceptual framework for burrows created by three crab species in the Bahama Archipelago, using examples from San Salvador Island
