6,974 research outputs found
Improving Image Classification with Location Context
With the widespread availability of cellphones and cameras that have GPS
capabilities, it is common for images being uploaded to the Internet today to
have GPS coordinates associated with them. In addition to research that tries
to predict GPS coordinates from visual features, this also opens up the door to
problems that are conditioned on the availability of GPS coordinates. In this
work, we tackle the problem of performing image classification with location
context, in which we are given the GPS coordinates for images in both the train
and test phases. We explore different ways of encoding and extracting features
from the GPS coordinates, and show how to naturally incorporate these features
into a Convolutional Neural Network (CNN), the current state-of-the-art for
most image classification and recognition problems. We also show how it is
possible to simultaneously learn the optimal pooling radii for a subset of our
features within the CNN framework. To evaluate our model and to help promote
research in this area, we identify a set of location-sensitive concepts and
annotate a subset of the Yahoo Flickr Creative Commons 100M dataset that has
GPS coordinates with these concepts, which we make publicly available. By
leveraging location context, we are able to achieve almost a 7% gain in mean
average precision
A Universal Constraint on the Infrared Behavior of the Ghost Propagator in QCD
With proposing a unified description of the fields variation at the level of
generating functional, we obtain a new identity for the quark-gluon interaction
vertex based on gauge symmetry, which is similar to the Slavnov-Taylor
Identities(STIs) based on the Becchi-Rouet-Stora-Tyutin transformation. With
these identities, we find that in Landau gauge, the dressing function of the
ghost propagator approaches to a constant as its momentum goes to zero, which
provides a strong constraint on the infrared behaviour of ghost propagator.Comment: 4 pages, no figur
A three-loop radiative neutrino mass model with dark matter
We present a model that generates small neutrino masses at three-loop level
due to the existence of Majorana fermionic dark matter, which is stabilized by
a Z2 symmetry. The model predicts that the lightest neutrino is massless. We
show a prototypical parameter choice allowed by relevant experimental data,
which favors the case of normal neutrino mass spectrum and the dark matter with
m \sim 50-135 GeV and a sizable Yukawa coupling. It means that new particles
can be searched for in future e+e- collisions.Comment: 7 pages, 3 figure
Neutron scattering study on R2PdSi3 (R = Ho, Er, Tm) compounds
Previous studies on the family of inter-metallic rare-earth compounds R2PdSi3 revealed multifaceted magnetic properties, for instance, spin-glass like behavior. Experimental observations include: Signs of a crystallographic superstructure, complicated magnetic structures both in zero field and in applied magnetic fields as well as a generic phase in applied fields for compounds in the series with the heavy rare-earths R = Gd, Tb, Dy, Ho, Er and Tm.
This thesis expands the studies on the magnetic properties of R2PdSi3 employing mainly neutron scattering on single crystals with the focus on the compounds with R = Ho, Er and Tm. A detailed analysis of the crystallographic superstructure using modulation wave approach and group theory is presented. The resulting structure implies the existence of two different rare-earth sites with reduced symmetry and an arrangement of the different sites according to sequences as determined by the superstructure. It will be shown that the reduced symmetry of the rare-earth sites is explicitly observed in the energy spectra of inelastic neutron scattering. The results on the magnetic structures and excitations are shown and discussed in the framework of the superstructure model. Specifically the generic phase in applied fields is interpreted as a direct consequence of the crystallographic superstructure. It is rather unusual that a crystallographic superstructure is playing such a decisive, and through the field dependence also tunable role in determining the magnetic properties as observed in R2PdSi3. The mediating interactions between the crystallographic part and the magnetic part of the system will be discussed.Frühere Untersuchungen der Familie der intermetallischen Selten-Erd Verbindungen R2PdSi3 zeigten vielfältige magnetische Eigenschaften, zum Beispiel ein Spin-glas ähnliches Verhalten. Die experimentellen Beobachtungen beinhalten: Zeichen für eine kristallographische Überstruktur, komplizierte magnetische Strukturen, sowohl im Nullfeld als auch in angelegten Magnetfeldern und darüberhinaus eine generische Phase in Magnetfeldern in den untersuchten Verbindungen mit den schweren Selten-Erden R = Gd, Tb, Dy, Ho, Er und Tm.
Diese Dissertation erweitert die Untersuchungen der magnetischen Eigenschaften von R2PdSi3, hauptsächlich durch Verwendung von Neutronenstreuung an Einkristallen, mit dem Schwerpunkt auf den Verbindungen mit R = Ho, Er und Tm. Eine genaue Analyse der kristallographischen Überstruktur mittels Modulationswellenansatz und Gruppentheorie wird präsentiert. Das resultierende Strukturmodell impliziert die Existenz zweier unterschiedlicher Selten-Erd Lagen mit reduzierter Symmetrie in einer Anordnung entsprechend der durch die Überstruktur festgelegten Sequenzen. Es wird gezeigt, dass die reduzierte Symmetrie der Selten-Erd Lagen durch Beobachtungen der inelastischen Neutronenstreuung explizit bestätigt wird. Die Ergebnisse der magnetischen Strukturen und Anregungen werden im Rahmen des Überstrukturmodels diskutiert. Speziell die generische Phase folgt als direkte Konsequenz aus der Überstruktur. Es ist eher ungewöhnlich, dass eine kristallographische Überstruktur eine solch bestimmende und bei Magnetfeldvariation auch “tunebare” Rolle spielt, wie dies in den R2 PdSi3 Verbindungen beobachtet wird. Die vermittelnden Wechselwirkungen zwischen Struktur und Magnetismus werden diskutiert
Integrating Diverse Methodologies and Strategies for the Total Synthesis of Certain Alkaloids and Terpenoids
The body of this thesis is comprised of five scientific articles and is preceded by an overview that contextualizes all of this published/submitted/to be submitted work.
The first major part of this thesis is comprised of publication 1. This is a review concerned with the application of Raney-cobalt in organic synthesis. The author's work described in publications 2 and 3 featured Raney-cobalt mediated reductive cyclization reactions as key steps in the construction of the framework of various uleine alkaloids and certain of these are highlighted in this review.
Publication 2 comprises the second major part of this thesis. This article details the total syntheses of some key members of uleine alkaloid family (specifically uleine, noruleine, dasycarpidone, nordasycarpidone) by using, as key steps, a palladium-catalysed Ullmann cross-coupling reaction to generate key coupling product and the immediate reductive cyclization of this so as to assemble the uleine alkaloid framework.
The third major part of this thesis is comprised of publication 3. This article describes the total synthesis of uleine alkaloid gilbertine. The key intermediate embodying the framework of uleine-type alkaloids was assembled by the Raney-cobalt mediated reductive cyclization of an nitrile compound which was itself constructed via a reaction sequence including a palladium-catalysed Ullmann cross-coupling process. The end-game associated with the synthesis involved a cationic (and possibly biomimetic) cyclisation reaction that established the final, tetrahydropyran ring of gilbertine.
The fourth major part of this thesis is comprised of publication 4. This details the total synthesis of a marine-derived sesquiterpene (+)-viridianol. The target molecule was derived from a key intermediate cyclobutone through various functional group manipulations. This cyclobutone was prepared through a photochemically-promoted 1,3-acyl migration reaction involving the cyclopentannulated bicyclo[2.2.2]-octenone, itself constructed from the homochiral compound cis-1,2-dihydrocatechol using Negishi cross-coupling and intramolecular Diels-Alder (IMDA) cycloaddition reactions as key steps. The starting material, a cis-1,2-dihydrocatechol, was obtained through the whole-cell biotransformation of p-iodotoluene using a genetically engineered micro-organism over-expressing the enzyme toluene dioxygenase.
The fifth major part of this thesis is comprised of publication 5. This article details a model study relevant to the total synthesis of the marine-derived sesquiterpene (+)-viridianol. Specifically, two structurally related ring-fused cyclopropanes were subjected to the same hydrogenolytic conditions. However, they showed dramatically divergent behavior
POPULATION PHARMACOKINETIC MODELING AND GENETIC ASSOCIATION ANALYSIS IN INFANTS WITH NEONATAL ABSTINENCE SYNDROME RECEIVING MORPHINE OR CLONIDINE
Neonatal abstinence syndrome, or NAS, is a postnatal opioid withdrawal syndrome occurring in 55% to 94% of neonates as a result of in utero exposure to opioids. It has emerged as a significant public health issue, as its incidence more than quadrupled in the past decade. There is significant variability in disease severity and treatment outcomes in neonates with NAS due to patient-specific factors and treatment- or site-specific factors. To understand what contributes to variability in length of hospital stay and other outcomes in neonates with NAS, we assessed population pharmacokinetics (PK) of clonidine and morphine, and we investigated potential associations between pre-specified single nucleotide polymorphisms (SNPs) and PK or disease severity/outcome measures.
Samples collected from neonates enrolled in the No-POPPY trial (NCT03396588) up to early 2020 were used for analysis. PK samples from treated subjects on oral morphine or oral clonidine were analyzed for morphine, morphine-3-glucuronide, morphine-6-glucuronide and clonidine concentrations by LC-MS/MS. DNA was isolated from lysed whole blood or buccal swabs from treated and non-treated subjects and analyzed by TaqMan SNP genotyping assays using real-time PCR. Genetic association analysis was performed on COMT 472G\u3eA and OPRM1 118A\u3eG in all trial subjects, and on GNB3 825C\u3eT and ADRA2A -1291G\u3eC in clonidine-treated subjects. NONMEM (ver 7.3) was used to build population PK models and identify covariates associated with PK variability, including SNPs potentially associated with PK of morphine/clonidine (OCT1*2-*5, ABCC3 -211C\u3eT, and CYP2D6 metabolizer class).
In the genetic association analysis, in contrast to a previous report, the relationship between COMT 472G\u3eA or OPRM1 118A\u3eG and hospital length of stay or other outcome measures was inconclusive. Clonidine-treated patients with TT genotype in GNB3 825C\u3eT had an average length of stay that was 3.7 days shorter than those with CC/CT genotypes (p=0.045), which did not meet experiment-wise significance. Significant associations between several clinical factors and one or more measures of NAS severity were identified, including breastfeeding and maternal use of benzodiazepines and gabapentin during pregnancy. In the population PK analysis, one-compartment models, with allometric scaling incorporated a priori, were used for clonidine and morphine. Age was a significant covariate in both models, and a sigmoidal maturation model incorporating postnatal age on clearance provided a good fit to clonidine concentration data. The clonidine PK model was successfully used to simulate alternative initial dosing regimens that were more likely to achieve earlier symptom stabilization. Genetic factors evaluated in the population PK analysis did not significantly affect the disposition of clonidine or morphine. Within the scope of this project, clinical factors appeared to be more important factors affecting disposition of treatment agents and NAS severity/treatment outcomes than the genetic factors evaluated. As the next step, efforts will be made to extend current analysis as the clinical trial continues to enroll subjects
Research on Liability for Oil Pollution Between China and US
This article discusses question about compensation for oil pollution in China and United states. Both China and US have law and regulations on liability for pollution resulted by oil spill, but the method of remedies of two countries is different, the difference lies in regulations, litigation procedure, trial court which to handle the cases of oil spill. The article will analyze the differences
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