224 research outputs found
Nondivergence form degenerate linear parabolic equations on the upper half space
We study a class of nondivergence form second-order degenerate linear
parabolic equations in with the
homogeneous Dirichlet boundary condition on , where and is given. The
coefficient matrices of the equations are the product of and bounded
positive definite matrices, where behaves like for some
given , which are degenerate on the boundary of
the domain. The divergence form equations in this setting were studied in [14].
Under a partially weighted VMO assumption on the coefficients, we obtain the
wellposedness and regularity of solutions in weighted Sobolev spaces. Our
research program is motivated by the regularity theory of solutions to
degenerate viscous Hamilton-Jacobi equations.Comment: 40 pages, minor revision. Added a weighted parabolic embedding result
and a local boundary estimat
Generating Rules to Filter Candidate Triples for their Correctness Checking by Knowledge Graph Completion Techniques
Knowledge Graphs (KGs) contain large amounts of structured information.
Due to their inherent incompleteness, a process known
as KG completion is often carried out to find the missing triples in a
KG, usually by training a fact checking model that is able to discern
between correct and incorrect knowledge. After the fact checking
model has been trained and evaluated, it has to be applied to a set
of candidate triples, and those that are considered correct are added
to the KG as new knowledge. However, this process needs a set
of candidate triples of a reasonable size that represents possible
new knowledge, in order to be evaluated by the fact checking task
and, if considered to be correct, added to the KG, enriching it. Current
approaches for selecting candidate triples for their correctness
checking either use the full set possible missing candidate triples
(and thus provide no filtering) or apply very basic rules to filter
out unlikely candidates, which may have a negative effect on the
completion performance as very few candidate triples are filtered
out. In this paper we present CHAI, a method for producing more
complex rules that are able to filter candidate triples by combining
a set of criteria to optimize a fitness function. Our experiments
show that CHAI is able to generate rules that, when applied, yield
smaller candidate sets than similar proposals while still including
promising candidate triples.Ministerio de EconomÃa y Competitividad TIN2016-75394-
STUDY ON TREATMENT OF THE LEACHATE FROM LANDFILL SITE AT NAMSON, SOCSON, HANOI
Joint Research on Environmental Science and Technology for the Eart
Shigella sonnei genome sequencing and phylogenetic analysis indicate recent global dissemination from Europe
Shigella are human-adapted Escherichia coli that have gained the ability to invade the human gut mucosa and cause dysentery1,2, spreading efficiently via low-dose fecal-oral transmission3,4. Historically, S. sonnei has been predominantly responsible for dysentery in developed countries, but is now emerging as a problem in the developing world, apparently replacing the more diverse S. flexneri in areas undergoing economic development and improvements in water quality4-6. Classical approaches have shown S. sonnei is genetically conserved and clonal7. We report here whole-genome sequencing of 132 globally-distributed isolates. Our phylogenetic analysis shows that the current S. sonnei population descends from a common ancestor that existed less than 500 years ago and has diversified into several distinct lineages with unique characteristics. Our analysis suggests the majority of this diversification occurred in Europe, followed by more recent establishment of local pathogen populations in other continents predominantly due to the pandemic spread of a single, rapidly-evolving, multidrug resistant lineage
Genetic variants of MICB and PLCE1 and associations with the laboratory features of dengue
Background: A previous genome-wide association study identified 2 susceptibility loci for severe dengue at MICB rs3132468 and PLCE1 rs3740360 and further work showed these mutations to be also associated with less severe clinical presentations. The aim of this study was to determine if these specific loci were associated with laboratory features of dengue that correlate with clinical severity with the aim of elucidating the functional basis of these genetic variants. Methods: This was a case-only analysis of laboratory-confirmed dengue patients obtained from 2 prospective cohort studies and 1 randomised clinical trial in Vietnam (Trial registration: ISRCTN ISRCTN03147572. Registered 24th July 2012). 2742 dengue cases were successfully genotyped at MICB rs3132468 and PLCE1 rs3740360. Laboratory variables were compared between genotypes and stratified by DENV serotype. Results: The analysis showed no association between MICB and PLCE1 genotype and early viraemia level, platelet nadir, white cell count nadir, or maximum haematocrit in both overall analysis and in analysis stratified by serotype. Discussion: The lack of an association between genotype and viremia level may reflect the sampling procedures within the included studies. The study findings mean that the functional basis of these mutations remains unclear. Trial registration: ISRCTN ISRCTN03147572. Registered 24th July 2012
Physicians, Primary Caregivers and Topical Repellent: All Under-Utilised Resources in Stopping Dengue Virus Transmission in Affected Households
BACKGROUND: Primary health care facilities frequently manage dengue cases on an ambulatory basis for the duration of the patient’s illness. There is a great opportunity for specific messaging, aimed to reduce dengue virus (DENV) transmission in and around the home, to be directly targeted toward this high-risk ambulatory patient group, as part of an integrated approach to dengue management. The extent however, to which physicians understand, and can themselves effectively communicate strategies to stop focal DENV transmission around an ambulatory dengue case is unknown; the matter of patient comprehension and recollection then ensues. In addition, the effectiveness of N,N-diethyl-3-methylbenzamide (DEET)-based insect repellent in protecting dengue patients from Aedes aegypti mosquitoes’ bites has not been investigated.
METHODOLOGY: A knowledge, attitude and practice (KAP) survey, focusing on the mechanisms of DENV transmission and prevention, was performed using semi-structured questionnaires. This survey was targeted towards the patients and family members providing supportive care, and physicians routinely involved in dengue patient management in Southern Vietnam. An additional clinical observational study was conducted to measure the efficacy of a widely-used 13% DEET-based insect repellent to repel Ae. aegypti mosquitoes from the forearms of dengue cases and matched healthy controls.
PRINCIPAL FINDINGS: Among both the physician (n = 50) and patient (n = 49) groups there were several respondents lacking a coherent understanding of DENV transmission, leading to some inappropriate attitudes and inadequate acute preventive practices in the household. The application of insect repellent to protect patients and their relatives from mosquito bites was frequently recommended by majority of physicians (78%) participating in the survey. Nevertheless, our tested topical application of 13% DEET conferred only ~1hr median protection time from Ae. aegypti landing. This is notably shorter than that advertised on the manufacturer’s label. No differences in landing time between febrile dengue cases or matched healthy controls (n = 19 experiments) were observed.
CONCLUSIONS/SIGNIFICANCE: Our study identifies missed opportunities for primary care physicians to improve public health through communication of strategies that could prevent focal dengue transmission in and around a case household. We advocate better access to more efficient communication methods for physicians and auxilliary health workers, supporting to educate those at high risk of DENV transmission. Our empirical testing of a widely-available 13% DEET-based repellent was limited in its protective efficacy against Ae. aegypti mosquito bites, and therefore DENV transmission, suggesting more frequent application is necessary to be beneficial
- …