279 research outputs found
Deliverable, Low-Cost Student Response Systems
This paper describes three deliverable, low-cost student response systems - software tools for providing Instructors with immediate feedback on students. Each of these tools has been and Is being developed at the United States Military Academy for similar purposes. First, the software can be used as a lesson structuring tool. Instructors can tailor their presentations to classes based on the results of their students\u27 lesson preparation the night before. This results in classes that are specifically targeted at those subjects the students had difficulty with. As a result, the instructors can better utilize their class period and the students will find the classroom Instruction more valuable. Second, we have used the software during class to validate that the students understand a particular learning objective before moving on to the next learning objective or to tabulate the class\u27 opinion on a student submission anonymously. Due to the automatic, real-time grading of results, the student response system allows greater control over class presentations by providing relevant feedback to the instructor and the student in real-time. Finally, the student response system can be incorporated into courses taught using hypermedia. As before, the system provides critical feedback to the student and Instructor alike and allows for the tailoring of study sessions and course material respectively
A Generalized Probabilistic Learning Approach for Multi-Fidelity Uncertainty Propagation in Complex Physical Simulations
Two of the most significant challenges in uncertainty propagation pertain to
the high computational cost for the simulation of complex physical models and
the high dimension of the random inputs. In applications of practical interest
both of these problems are encountered and standard methods for uncertainty
quantification either fail or are not feasible. To overcome the current
limitations, we propose a probabilistic multi-fidelity framework that can
exploit lower-fidelity model versions of the original problem in a small data
regime. The approach circumvents the curse of dimensionality by learning
dependencies between the outputs of high-fidelity models and lower-fidelity
models instead of explicitly accounting for the high-dimensional inputs. We
complement the information provided by a low-fidelity model with a
low-dimensional set of informative features of the stochastic input, which are
discovered by employing a combination of supervised and unsupervised
dimensionality reduction techniques. The goal of our analysis is an efficient
and accurate estimation of the full probabilistic response for a high-fidelity
model. Despite the incomplete and noisy information that low-fidelity
predictors provide, we demonstrate that accurate and certifiable estimates for
the quantities of interest can be obtained in the small data regime, i.e., with
significantly fewer high-fidelity model runs than state-of-the-art methods for
uncertainty propagation. We illustrate our approach by applying it to
challenging numerical examples such as Navier-Stokes flow simulations and
monolithic fluid-structure interaction problems.Comment: 31 pages, 14 figure
Recommended from our members
Purification of supercritical-fluid carotenoid-rich extracts by hydrophobic interaction chromatography
Supercritical fluid extraction (SFE) has been widely used for extracting several valuable phytochemicals, including carotenoids. However, there is a scarcity of works dealing with the purification of SFE extracts. The aim of this work was to assess the feasibility and efficiency of a hydrophobic interaction chromatography (HIC) protocol for purifying carotenoid-rich extracts obtained by SFE. Initial batch experiments were carried out to calculate the resin adsorption capacity and adsorption kinetics. Subsequent runs were performed in a manually-packed chromatographic column, using the Amberlite XAD-1180N resin, where breakthrough curves and adsorption isotherms were obtained and fitted to the Langmuir model. The antioxidant activity and carotenoid degradation rates were monitored throughout the processes. In batch, the resin presented a maximum carotenoid adsorption capacity of 1.89 ÎĽg/mg, while in column, this value increased to 10.4 ÎĽg/mg. The global carotenoid adsorption rate was 93.3% and the elution rate, 94.7%, resulting in a global recovery of 88.4% for total carotenoids and 92.1% for carotenes. The Langmuir model fitted well the experimental data. Analysis of the extracts demonstrated that a 5.5-fold reduction in extract mass was achieved, accompanied by a 4.7-fold and 2.1-fold increase in carotenoid concentration and antioxidant activity, respectively. This work presents a novel process based on preparative HIC for the purification of carotenoid extracts and provides a fundamental understanding on process performance. It is potentially scalable and can be implemented in extraction and purification of carotenoids from natural sources, as an alternative to their production through chemical synthesis
Bioarchaeology aids the cultural understanding of six characters in search of their agency (Tarquinia, ninth–seventh century BC, central Italy)
Etruria contained one of the great early urban civilisations in the Italian peninsula during the first millennium BC, much studied from a cultural, humanities-based, perspective, but relatively little with scientific data, and rarely in combination. We have addressed the unusual location of twenty inhumations found in the sacred heart of the Etruscan city of Tarquinia, focusing on six of these as illustrative, contrasting with the typical contemporary cremations found in cemeteries on the edge of the city. The cultural evidence suggests that the six skeletons were also distinctive in their ritualization and memorialisation. Focusing on the six, as a representative sample, the scientific evidence of osteoarchaeology, isotopic compositions, and ancient DNA has established that these appear to show mobility, diversity and violence through an integrated bioarchaeological approach. The combination of multiple lines of evidence makes major strides towards a deeper understanding of the role of these extraordinary individuals in the life of the early city of Etruria
Polarimetric Multi-View Inverse Rendering
A polarization camera has great potential for 3D reconstruction since the
angle of polarization (AoP) of reflected light is related to an object's
surface normal. In this paper, we propose a novel 3D reconstruction method
called Polarimetric Multi-View Inverse Rendering (Polarimetric MVIR) that
effectively exploits geometric, photometric, and polarimetric cues extracted
from input multi-view color polarization images. We first estimate camera poses
and an initial 3D model by geometric reconstruction with a standard
structure-from-motion and multi-view stereo pipeline. We then refine the
initial model by optimizing photometric and polarimetric rendering errors using
multi-view RGB and AoP images, where we propose a novel polarimetric rendering
cost function that enables us to effectively constrain each estimated surface
vertex's normal while considering four possible ambiguous azimuth angles
revealed from the AoP measurement. Experimental results using both synthetic
and real data demonstrate that our Polarimetric MVIR can reconstruct a detailed
3D shape without assuming a specific polarized reflection depending on the
material.Comment: Paper accepted in ECCV 202
First case of human gongylonemosis in France
Gongylonema spp. are cosmopolitan spirurid nematodes that are common parasites of wild and domesticated mammals and birds. Gongylonema pulchrum Molin, 1857 is most common in ruminants, where it invades mucosa and submucosa of the mouth, tongue, oesophagus and forestomachs. It extremely rarely occurs in man, and fewer than 60 cases have been reported worldwide. We report a case from the Alsace region, which appears to be the first case of human gongylonemosis described in France.
Les nématodes du genre Gongylonema sont des spiruridés cosmopolites parasites fréquents dans de nombreux mammifères et oiseaux sauvages ou domestiques. Gongylonema pulchrum Molin, 1857 est l’espèce la plus souvent rapportée chez les ruminants, dans la muqueuse et la sous-muqueuse de leur bouche, langue, œsophage et rumen. Il n’est que très exceptionnellement retrouvé chez l’homme. Moins de 60 cas ont été décrits à travers le monde. Nous rapportons dans cet article le premier cas français, découvert en Alsace
Chemical composition, antioxidant activity and bioaccessibility studies in phenolic extracts of two Hericium wild edible species
Mushrooms are rich sources of bioactive compounds such as phenolic acids. When ingested, these molecules have to be released from the matrix to be transformed/absorbed by the organism, so that they can exert their bioactivity. Several
in vitro methodologies have been developed in order to evaluate the bioavailability of
bioactive compounds. Herein, two Hericium species were analyzed for their chemical
composition and antioxidant activity. Furthermore, an in vitro digestion of the
mushrooms and mushroom phenolic extracts was performed, and the digested samples
were also submitted to antioxidant activity evaluation in order to evaluate the
bioaccessibility of the phenolic acids identified in the samples. Hericium species
showed similar chemical profiles (except for tocopherols), varying only in the
concentration of the compounds. The phenolic extracts revealed higher antioxidant
activity than the in vitro digested samples, meaning that this process decrease the
antioxidant properties of the extract/mushroom. Nevertheless, phenolic acids were
found in the digested samples, meaning that those molecules are bioaccessible.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for
financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011), S.A. Heleno
grant (BD/70304/2010) and L. Barros contract under “Programa Compromisso com a
Ciência-2008”
The Jurassic–Cretaceous depositional and tectonic evolution of the southernwestern margin of the Neotethys Ocean, Northern Oman and United Arab Emirates
The concept that the autochthonous, parautochthonous and allochthonous Permian–Cretaceous sequences in the United Arab Emirates (UAE) and Oman record the transition from platform, slope to basin sedimentation within the southern part of Neotethys has been fundamental to the interpretation of the geological history of the region. The results of a major geological mapping programme of the UAE, carried out by the British Geological Survey for the Federal Government of the UAE, coupled with the detailed examination of key sections within northern Oman has led to a re-evaluation of the geological evolution of this region. This detailed study has led to a greater appreciation of the sedimentology and depositional setting of the sediments laid down along the northeastern Arabian continental margin during the Jurassic to Cretaceous, allowing a more refined model of Neotethys Ocean basin evolution to be established. The model charts the progressive breakup of the Arabian continental margin and closure of Neotethys during the mid to late Cretaceous and is divided into three main stages: Stage 1—Initial rifting and formation of the Neotethys Ocean, followed by a prolonged period of stable, passive margin sedimentation which extended from the Permian to Late Jurassic times; Stage 2—Uplift and erosion of the shelf margin during the Late Jurassic to Early Cretaceous, coincident with increased carbonate-clastic sedimentation in the outer ramp, distal slope and basinal areas; Stage 3—Increased instability during the Late Cretaceous leading to the breakup of the platform margin and foreland basin sedimentation accompanying the obduction of the Oman-UAE ophiolite. Data obtained for the upper part of the platform and platform margin to slope successions has revealed that the topography of the “shelf”-slope-basinal margin was more subdued than previously thought, with this more gentle ramp margin morphology persisting until early to mid-Cretaceous times when the platform margin started to become unstable during ophiolite obduction. The thrust-repeated allochthonous sedimentary rocks of the Hamrat Duru Group were deposited on the outer platform margin/lower slope rise to basinal plain of this basin margin and includes the dismembered remains of two turbidite fan systems which fed carbonate-rich detritus into deeper parts of the ocean. A re-evaluation of the chert-rich sequences, previously equated with deposition on the abyssal plain of Neotethys, has led to the conclusion that they may record sedimentation at a much shallower level within a starved ocean basin, possibly in a mid-ramp (above storm wave base) to outer ramp setting. A marked change in basin dynamics occurred during the mid-Cretaceous leading to the development of a shallow ramp basin margin in Oman with terrestrial to shallow marine sedimentary rocks interdigitating with red siliceous mudstones. By contrast, the contemporaneous succession in the Dibba Zone of the UAE indicates considerable instability on a steep shelf break. This instability is recorded by the presence of several major olistostrome deposits within the Aruma Group of the UAE which are thought to have been generated in advance of the rapidly obducting Oman-UAE ophiolite
- …