17,709 research outputs found
Anopheline fauna of parts of Tirap district, Arunachal Pradesh with reference to malaria transmission
In a survey on the anopheline fauna in highly malaria endemic areas of the Tirap district of Arunachal Pradesh, 7476 anophelines belonging to 17 species were collected, including seven species of anophelines which are recognized malaria vectors in India. Anopheles tessellatus and A. jamesii were recorded for the first time in this area. The parasitological survey revealed that the area was endemic for malaria particularly P. falciparum. the slide positivity rate and slide falciparum rate being 25.63 and 19.21 per cent respectively. On dissection of 10 anopheies species, malarial infection was detected in two viz., A. minimus and A. dirus
Cooperative information sharing to improve distributed learning in multi-agent systems
Effective coordination of agents' actions in partially-observable domains is a major challenge of multi-agent systems research. To address this, many researchers have developed techniques that allow the agents to make decisions based on estimates of the states and actions of other agents that are typically learnt using some form of machine learning algorithm. Nevertheless, many of these approaches fail to provide an actual means by which the necessary information is made available so that the estimates can be learnt. To this end, we argue that cooperative communication of state information between agents is one such mechanism. However, in a dynamically changing environment, the accuracy and timeliness of this communicated information determine the fidelity of the learned estimates and the usefulness of the actions taken based on these. Given this, we propose a novel information-sharing protocol, post-task-completion sharing, for the distribution of state information. We then show, through a formal analysis, the improvement in the quality of estimates produced using our strategy over the widely used protocol of sharing information between nearest neighbours. Moreover, communication heuristics designed around our information-sharing principle are subjected to empirical evaluation along with other benchmark strategies (including Littman's Q-routing and Stone's TPOT-RL) in a simulated call-routing application. These studies, conducted across a range of environmental settings, show that, compared to the different benchmarks used, our strategy generates an improvement of up to 60% in the call connection rate; of more than 1000% in the ability to connect long-distance calls; and incurs as low as 0.25 of the message overhead
Using mobility data in the design of optimal lockdown strategies for the COVID-19 pandemic
A mathematical model for the COVID-19 pandemic spread, which integratesage-structured Susceptible-Exposed-Infected-Recovered-Deceased dynamics with realmobile phone data accounting for the population mobility, is presented. The dynamicalmodel adjustment is performed via Approximate Bayesian Computation. Optimallockdown and exit strategies are determined based on nonlinear model predictivecontrol, constrained to public-health and socio-economic factors. Through an extensivecomputational validation of the methodology, it is shown that it is possible to computerobust exit strategies with realistic reduced mobility values to inform public policymaking, and we exemplify the applicability of the methodology using datasets fromEngland and France
Double Time Window Targeting Technique: Real time DMRG dynamics in the PPP model
We present a generalized adaptive time-dependent density matrix
renormalization group (DMRG) scheme, called the {\it double time window
targeting} (DTWT) technique, which gives accurate results with nominal
computational resources, within reasonable computational time. This procedure
originates from the amalgamation of the features of pace keeping DMRG
algorithm, first proposed by Luo {\it et. al}, [Phys.Rev. Lett. {\bf 91},
049701 (2003)], and the time-step targeting (TST) algorithm by Feiguin and
White [Phys. Rev. B {\bf 72}, 020404 (2005)]. Using the DTWT technique, we
study the phenomena of spin-charge separation in conjugated polymers (materials
for molecular electronics and spintronics), which have long-range
electron-electron interactions and belong to the class of strongly correlated
low-dimensional many-body systems. The issue of real time dynamics within the
Pariser-Parr-Pople (PPP) model which includes long-range electron correlations
has not been addressed in the literature so far. The present study on PPP
chains has revealed that, (i) long-range electron correlations enable both the
charge and spin degree of freedom of the electron, to propagate faster in the
PPP model compared to Hubbard model, (ii) for standard parameters of the PPP
model as applied to conjugated polymers, the charge velocity is almost twice
that of the spin velocity and, (iii) the simplistic interpretation of
long-range correlations by merely renormalizing the {\it U} value of the
Hubbard model fails to explain the dynamics of doped holes/electrons in the PPP
model.Comment: Final (published) version; 39 pages, 13 figures, 1 table; 2 new
references adde
Steps on current-voltage characteristics of a silicon quantum dot covered by natural oxide
Considering a double-barrier structure formed by a silicon quantum dot
covered by natural oxide with two metallic terminals, we derive simple
conditions for a step-like voltage-current curve. Due to standard chemical
properties, doping phosphorus atoms located in a certain domain of the dot form
geometrically parallel current channels. The height of the current step
typically equals to (1.2 pA)N, where N=0,1,2,3... is the number of doping atoms
inside the domain, and only negligibly depends on the actual position of the
dopants. The found conditions are feasible in experimentally available
structures.Comment: 4 pages, 3 figure
Clustered superfluids in the one-dimensional Bose-Hubbard model with extended correlated hopping
Bosonic lattice systems with nontrivial interactions represent an intriguing platform to study exotic phases of matter. Here, we study the effects of extended correlated hopping processes in a system of bosons trapped in a lattice geometry. The interplay between single particle tunneling terms, correlated hopping processes, and onsite repulsion is studied by means of a combination of exact diagonalization, strong coupling expansion, and cluster mean field theory. We identify a rich ground state phase diagram where, apart from the usual Mott and superfluid states, superfluid phases with interesting clustering properties occur
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