97 research outputs found
Analytic Determination of the Critical Coupling for Oscillators in a Ring
We study a model of coupled oscillators with bidirectional first nearest
neighbours coupling with periodic boundary conditions. We show that a stable
phase-locked solution is decided by the oscillators at the borders between the
major clusters, which merge to form a larger one of all oscillators at the
stage of complete synchronization. We are able to locate these four oscillators
as well as the size of major clusters in the vicinity of the stage of full
synchronization which we show to depend only on the set of initial frequencies.
Using the method presented here, we are able to obtain an analytic form of the
critical coupling, at which the complete synchronization state occurs.Comment: 5 pages and 3 figure
Transition to complete synchronization in phase coupled oscillators with nearest neighbours coupling
We investigate synchronization in a Kuramoto-like model with nearest
neighbour coupling. Upon analyzing the behaviour of individual oscillators at
the onset of complete synchronization, we show that the time interval between
bursts in the time dependence of the frequencies of the oscillators exhibits
universal scaling and blows up at the critical coupling strength. We also bring
out a key mechanism that leads to phase locking. Finally, we deduce forms for
the phases and frequencies at the onset of complete synchronization.Comment: 6 pages, 4 figures, to appear in CHAO
Range expansion with mutation and selection: dynamical phase transition in a two-species Eden model
The colonization of unoccupied territory by invading species, known as range expansion, is a spatially heterogeneous non-equilibrium growth process. We introduce a two-species Eden growth model to analyze the interplay between uni-directional (irreversible) mutations and selection at the expanding front. While the evolutionary dynamics leads to coalescence of both wild-type and mutant clusters, the non-homogeneous advance of the colony results in a rough front. We show that roughening and domain dynamics are strongly coupled, resulting in qualitatively altered bulk and front properties. For beneficial mutations the front is quickly taken over by mutants and growth proceeds Eden-like. In contrast, if mutants grow slower than wild-types, there is an antagonism between selection pressure against mutants and growth by the merging of mutant domains with an ensuing absorbing state phase transition to an all-mutant front. We find that surface roughening has a marked effect on the critical properties of the absorbing state phase transition. While reference models, which keep the expanding front flat, exhibit directed percolation critical behavior, the exponents of the two-species Eden model strongly deviate from it. In turn, the mutation-selection process induces an increased surface roughness with exponents distinct from that of the classical Eden model
Quantum properties of a cyclic structure based on tripolar fields
The properties of cyclic structures (toroidal oscillators) based on classical
tripolar (colour) fields are discussed, in particular, of a cyclic structure
formed of three colour-singlets spinning around a ring-closed axis. It is shown
that the helicity and handedness of this structure can be related to the
quantum properties of the electron. The symmetry of this structure corresponds
to the complete cycle of -rotations of its constituents, which leads
to the exact overlapping of the paths of its three complementary coloured
constituents, making the system dynamically colourless. The gyromagnetic ratio
of this system is estimated to be g, which agrees with the Land\'e
g-factor for the electron.Comment: 11 pages, 4 figures, journal versio
Crossover effects in a discrete deposition model with Kardar-Parisi-Zhang scaling
We simulated a growth model in 1+1 dimensions in which particles are
aggregated according to the rules of ballistic deposition with probability p or
according to the rules of random deposition with surface relaxation (Family
model) with probability 1-p. For any p>0, this system is in the
Kardar-Parisi-Zhang (KPZ) universality class, but it presents a slow crossover
from the Edwards-Wilkinson class (EW) for small p. From the scaling of the
growth velocity, the parameter p is connected to the coefficient of the
nonlinear term of the KPZ equation, lambda, giving lambda ~ p^gamma, with gamma
= 2.1 +- 0.2. Our numerical results confirm the interface width scaling in the
growth regime as W ~ lambda^beta t^beta, and the scaling of the saturation time
as tau ~ lambda^(-1) L^z, with the expected exponents beta =1/3 and z=3/2 and
strong corrections to scaling for small lambda. This picture is consistent with
a crossover time from EW to KPZ growth in the form t_c ~ lambda^(-4) ~ p^(-8),
in agreement with scaling theories and renormalization group analysis. Some
consequences of the slow crossover in this problem are discussed and may help
investigations of more complex models.Comment: 16 pages, 7 figures; to appear in Phys. Rev.
Metabolomic profile, anti-trypanosomal potential and molecular docking studies of <i>Thunbergia grandifolia</i>
Trypanosomiasis is a protozoan disease transmitted via Trypanosoma brucei. This study aimed to examine the metabolic profile and anti-trypanosomal effect of methanol extract of Thunbergia grandifolia leaves. The liquid chromatography-high resolution electrospray ionisation mass spectrometry (LC-HRESIMS) revealed the identification of fifteen compounds of iridoid, flavonoid, lignan, phenolic acid, and alkaloid classes. The extract displayed a promising inhibitory activity against T. brucei TC 221 with MIC value of 1.90 μg/mL within 72 h. A subsequent in silico analysis of the dereplicated compounds (i.e. inverse docking, molecular dynamic simulation, and absolute binding free energy) suggested both rhodesain and farnesyl diphosphate synthase as probable targets for two compounds among those dereplicated ones in the plant extract (i.e. diphyllin and avacennone B). The absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiling of diphyllin and avacennone were calculated accordingly, where both compounds showed acceptable drug-like properties. This study highlighted the antiparasitic potential of T. grandifolia leaves
Uric Acid Is a Mediator of the Plasmodium falciparum-Induced Inflammatory Response
Malaria triggers a high inflammatory response in the host that mediates most of the associated pathologies and contributes to death. The identification of pro-inflammatory molecules derived from Plasmodium is essential to understand the mechanisms of pathogenesis and to develop targeted interventions. Uric acid derived from hypoxanthine accumulated in infected erythrocytes has been recently proposed as a mediator of inflammation in rodent malaria.We found that human erythrocytes infected with Plasmodium falciparum gradually accumulate hypoxanthine in their late stages of development. To analyze the role of hypoxanthine-derived uric acid induced by P. falciparum on the inflammatory cytokine response from human blood mononuclear cells, cultures were treated with allopurinol, to inhibit uric acid formation from hypoxanthine, or with uricase, to degrade uric acid. Both treatments significantly reduce the secretion of TNF, IL-6, IL-1beta and IL-10 from human cells.Uric acid is a major contributor of the inflammatory response triggered by P. falciparum in human peripheral blood mononuclear cells. Since the inflammatory reaction induced by P. falciparum is considered a major cause of malaria pathogenesis, identifying the mechanisms used by the parasite to induce the host inflammatory response is essential to develop urgently needed therapies against this disease
PERAN PEREMPUAN DALAM MENINGKATKAN PENDAPATAN KELUARGA (STUDI KASUS USAHA KERAJINAN BAMBU DI DESA BARAE KECAMATAN MARIORIWAWO KABUPATEN SOPPENG)
women as one of the human resources in the labor market, especially in Indonesia, have a large contribution,in the sense that the number of women who offer themselves to work is quite large. Women in Barae Villageparticipate especially in fulfilling the economic functions of their families and households. The participationof women workers is closely related to family background, given that the function of the family in decisionmaking is very decisive. It’s just that the value of female labor is sometimes still low, while women also havehousehold obligations that cannot be ignored. This study aims to determine the role of women in bamboomanagement and the contribution of women to family income in Barae Village, Marioriwawo district,soppeng Regency. The study was conducted in Barae Village, Marioriwawo district, soppeng Regencyfrom March to april 2022. The population in the study were women who worked in the bamboo managementindustry and a sample of 36 people. data collection methods are observation and interviews. The dataanalysis used is descriptive and contribution analysis. The results showed that the role of women in bamboo management, from the production process to the marketing of the produce, was carried out by women. Theproducts produced are winnows, rice baskets, and parcel baskets. The contribution of women’s income tofamily income is 24.52%. The total average income obtained based on the results of the analysis is Rp.2,083,889,- per month. for respondents’ income from the sale of woven bamboo products - an average of495,000, - per month
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