86 research outputs found
Simple Combined Model for Nonlinear Excitations in DNA
We propose a new simple model for DNA denaturation bases on the pendulum
model of Englander\cite{A1} and the microscopic model of Peyrard {\it et
al.},\cite{A3} so called "combined model". The main parameters of our model
are: the coupling constant along each strand, the mean stretching
of the hydrogen bonds, the ratio of the damping constant and driven force
. We show that both the length of unpaired bases and the velocity
of kinks depend on not only the coupling constant but also the
temperature . Our results are in good agreement with previous works.Comment: 6 pages, 10 figures, submitted to Phys. Rev.
User Selection Approaches to Mitigate the Straggler Effect for Federated Learning on Cell-Free Massive MIMO Networks
This work proposes UE selection approaches to mitigate the straggler effect
for federated learning (FL) on cell-free massive multiple-input multiple-output
networks. To show how these approaches work, we consider a general FL framework
with UE sampling, and aim to minimize the FL training time in this framework.
Here, training updates are (S1) broadcast to all the selected UEs from a
central server, (S2) computed at the UEs sampled from the selected UE set, and
(S3) sent back to the central server. The first approach mitigates the
straggler effect in both Steps (S1) and (S3), while the second approach only
Step (S3). Two optimization problems are then formulated to jointly optimize UE
selection, transmit power and data rate. These mixed-integer mixed-timescale
stochastic nonconvex problems capture the complex interactions among the
training time, the straggler effect, and UE selection. By employing the online
successive convex approximation approach, we develop a novel algorithm to solve
the formulated problems with proven convergence to the neighbourhood of their
stationary points. Numerical results confirm that our UE selection designs
significantly reduce the training time over baseline approaches, especially in
the networks that experience serious straggler effects due to the moderately
low density of access points.Comment: submitted for peer review
Emergency extra-intracranial bypass surgery in a patient with neurologic deficit after an accident in carotid occlusive test: A case report.
OBJECTIVE: BTO is the procedure performed to assess the collateral circulation within the Willis circle in a giant ICA aneurysm. An ICA occlusion after BTO is very rare. We present a case of an internal carotid artery occlusion as a complication of BTO that required urgent revascularization surgery.
CASE PRESENTATION: A 56-year-old female with a history of transient ischemic attacks for one year was diagnosed with multiple aneurysms: a giant aneurysm of the left supra-clinoid ICA, two small ones on left MCA and right ophthalmic. A BTO was performed to assess collateral supply and determine whether bypass surgery should be necessary. During the procedure, the balloon was detached while insufflating, and the patient had a subsequent neurological decline consistent with an MCA syndrome. EC-IC bypass surgery was performed with an end-to-side anastomosis of STA-MCA by trapping the giant aneurysm and clipping the ipsilateral MCA aneurysm. The patient had a reversal of neurological symptoms and made an uneventful recovery.
DISCUSSION: We discuss the epidemiology of giant ICA aneurysms, the indications for BTO, and its complication. Emergency intracranial and extracranial bypass surgery in case of acute ICA injury is also discussed. We also highlighted the attributable factors to treatment strategies under restrictive conditions in Vietnam.
CONCLUSIONS: ICA occlusion due to insufflated balloon detachment is an unreported complication in literature. Emergency bypass surgery is a potential treatment choice for this unusual iatrogenic complication
VLSP Shared Task: Named Entity Recognition
Named entities (NE) are phrases that contain the names of persons, organizations, locations, times and quantities, monetary values, percentages, etc. Named Entity Recognition (NER) is the task of recognizing named entities in documents. NER is an important subtask of Information Extraction, which has attracted researchers all over the world since 1990s. For Vietnamese language, although there exists some research projects and publications on NER task before 2016, no systematic comparison of the performance of NER systems has been done. In 2016, the organizing committee of the VLSP workshop decided to launch the first NER shared task, in order to get an objective evaluation of Vietnamese NER systems and to promote the development of high quality systems. As a result, the first dataset with morpho-syntactic and NE annotations has been released for benchmarking NER systems. At VLSP 2018, the NER shared task has been organized for the second time, providing a bigger dataset containing texts from various domains, but without morpho-syntactic annotation. These resources are available for research purpose via the VLSP website vlsp.org.vn/resources. In this paper, we describe the datasets as well as the evaluation results obtained from these two campaigns
The assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on pollinators, pollination and food production
The thematic assessment of pollinators, pollination and food production carried out under the auspices of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services aims to assess animal pollination as a regulating ecosystem service underpinning food production in the context of its contribution to nature’s gifts to people and supporting a good quality of life. To achieve this, it focuses on the role of native and managed pollinators, the status and trends of pollinators and pollinator-plant networks
and pollination, drivers of change, impacts on human well-being, food production in response to pollination declines and deficits and the effectiveness of responses
INCLUDING INDIGENOUS AND LOCAL KNOWLEDGE IN THE WORK OF THE INTERGOVERNMENTAL SCIENCE-POLICY PLATFORM ON BIODIVERSITY AND ECOSYSTEM SERVICES (IPBES) GLOBAL ASSESSMENT : Outcomes and lessons for the future
This chapter makes a strong case for greater inclusion of Indigenous and Local Knowledge (ILK) in global environmental policy fora and in science-policy interfaces. The chapter specifically looks at the IPBES Global Assessment which has developed one of the first global-scale mechanisms for operationalizing ILK in sustainability decision-making. The types of knowledges that have been successfully integrated into this assessment include ways in which ILK can help (1) to assess ecosystem change and associated human vulnerability; (2) to inform the achievement of global goals like the Sustainable Development Goals and Aichi Targets; and (3) to inform policy-relevant options for decision-makers. It is argued that other global initiatives seeking to engage ILK in their endeavours can learn from the ILK approach of the IPBES Global Assessment.Peer reviewe
Summary for policymakers of the thematic assessment on pollinators, pollination and food production
The thematic assessment of pollinators, pollination
and food production carried out under the auspices
of the Intergovernmental Science-Policy Platform on
Biodiversity and Ecosystem Services aims to assess
animal pollination as a regulating ecosystem service
underpinning food production in the context of its
contribution to nature’s gifts to people and supporting
a good quality of life. To achieve this, it focuses
on the role of native and managed pollinators, the
status and trends of pollinators and pollinator-plant
networks and pollination, drivers of change, impacts
on human well-being, food production in response to
pollination declines and deficits and the effectiveness
of responses.
The chapters and their executive summaries of this
assessment are available as document IPBES/4/INF/1/Rev.2 (www.ipbes.net). The present document
is a summary for policymakers of the information
presented in these chapters
The antimicrobial resistance patterns and associated determinants in Streptococcus suis isolated from humans in southern Vietnam, 1997-2008
<p>Abstract</p> <p>Background</p> <p><it>Streptococcus suis </it>is an emerging zoonotic pathogen and is the leading cause of bacterial meningitis in adults in Vietnam. Systematic data on the antimicrobial susceptibility profiles of <it>S. suis </it>strains isolated from human cases are lacking. We studied antimicrobial resistance and associated resistance determinants in <it>S. suis </it>isolated from patients with meningitis in southern Vietnam.</p> <p>Methods</p> <p><it>S. suis </it>strains isolated between 1997 and 2008 were investigated for their susceptibility to six antimicrobial agents. Strains were screened for the presence and expression of tetracycline and erythromycin resistance determinants and the association of <it>tet</it>(M) genes with <it>Tn</it>916- like transposons. The localization of tetracycline resistance gene <it>tet</it>(L) was determined by pulse field gel electrophoresis and Southern blotting.</p> <p>Results</p> <p>We observed a significant increase in resistance to tetracycline and chloramphenicol, which was concurrent with an increase in multi-drug resistance. In tetracycline resistance strains, we identified <it>tet</it>(M), <it>tet</it>(O), <it>tet</it>(W) and <it>tet</it>(L) and confirmed their expression. All <it>tet</it>(M) genes were associated with a <it>Tn</it>916-like transposon. The co-expression of <it>tet</it>(L) and other tetracycline resistance gene(s) encoding for ribosomal protection protein(s) was only detected in strains with a minimum inhibitory concentration (MIC) of tetracycline of ≥ 64 mg/L</p> <p>Conclusions</p> <p>We demonstrated that multi-drug resistance in <it>S. suis </it>causing disease in humans in southern Vietnam has increased over the 11-year period studied. We report the presence and expression of <it>tet</it>(L) in <it>S. suis </it>strains and our data suggest that co-expression of multiple genes encoding distinct mechanism is required for an MIC ≥ 64 mg/L to tetracycline.</p
Environmental Radionuclides in Surface Soils of Vietnam
A database on 238U, 232Th, 40K, and 137Cs in surface soils was established to provide inputs for the assessment of the collective dose to the population of Vietnam and to support soil erosion studies using 137Cs as a tracer. A total of 292 soil samples was taken from undisturbed sites across the territory and the concentrations of radionuclides were determined by gamma spectrometry method. The multiple regression of 137Cs inventories against characteristics of sampling locations allowed us to establish the distribution of 137Cs deposition density and its relationship with latitude and annual rainfall. The 137Cs deposition density increases northward and varies from 178 Bq m–2 to 1,920 Bq m–2. High rainfall areas in the northern and central parts of the country have received considerable 137Cs inputs exceeding 600 Bq m–2, which is the maximum value that can be expected for Vietnam from the UNSCEAR global pattern. The mean activity concentrations of naturally occurring radionuclides 238U, 232Th, and 40K are 45, 59, and 401 Bq kg–1, respectively, which entail an average absorbed dose rate in air of 62 nGy h–1, which is about 7% higher than the world average
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