1,676 research outputs found
Wild Trypanosoma cruzi I genetic diversity in Brazil suggests admixture and disturbance in parasite populations from the Atlantic Forest region
Background
Trypanosoma cruzi (Kinetoplastida, Trypanosomatidae) infection is an ancient and widespread zoonosis distributed throughout the Americas. Ecologically, Brazil comprises several distinct biomes: Amazonia, Cerrado, Caatinga, Pantanal and the Atlantic Forest. Sylvatic T. cruzi transmission is known to occur throughout these biomes, with multiple hosts and vectors involved. Parasite species-level genetic diversity can be a useful marker for ecosystem health. Our aims were to: investigate sylvatic T. cruzi genetic diversity across different biomes, detect instances of genetic exchange, and explore the possible impact of ecological disturbance on parasite diversity at an intra-species level.
Methods
We characterised 107 isolates of T. cruzi I (TcI; discrete typing unit, DTU I) from different major Brazilian biomes with twenty-seven nuclear microsatellite loci. A representative subset of biologically cloned isolates was further characterised using ten mitochondrial gene loci. We compared these data generated from Brazilian TcI isolates from around America.
Results
Genetic diversity was remarkably high, including one divergent cluster that branched outside the known genetic diversity of TcI in the Americas. We detected evidence for mitochondrial introgression and genetic exchange between the eastern Amazon and Caatinga. Finally, we found strong signatures of admixture among isolates from the Atlantic Forest region by comparison to parasites from other study sites.
Conclusions
Atlantic Forest sylvatic TcI populations are highly fragmented and admixed by comparison to others around Brazil. We speculate on: the possible causes of Atlantic Forest admixture; the role of T. cruzi as a sentinel for ecosystem health, and the impact disrupted sylvatic transmission cycles might have on accurate source attribution in oral outbreaks
Editorial: The underlying relationship between sleep and neurodegenerative diseases
Editorial on the Research Topic: The underlying relationship between sleep and neurodegenerative diseasesS-BL was supported in part by Sleep Research Society Foundation Career Development Award (030-JP-21) and Fudan University (JIF2641029Y and JIH2642002/155). ML was recipient of CNPq fellowship (CNPq-306432/2022-6)
An Euler-type formula for and closed-form expressions for a class of zeta series
In a recent work, Dancs and He found an Euler-type formula for
, being a positive integer, which contains a series
they could not reduce to a finite closed-form. This open problem reveals a
greater complexity in comparison to , which is a rational multiple
of . For the Dirichlet beta function, the things are `inverse':
is a rational multiple of and no closed-form
expression is known for . Here in this work, I modify the Dancs-He
approach in order to derive an Euler-type formula for ,
including , the Catalan's constant. I also convert the
resulting series into zeta series, which yields new exact closed-form
expressions for a class of zeta series involving and a finite
number of odd zeta values. A closed-form expression for a certain zeta series
is also conjectured.Comment: 11 pages, no figures. A few small corrections. ACCEPTED for
publication in: Integral Transf. Special Functions (09/11/2011
Bayesian Analysis and Constraints on Kinematic Models from Union SNIa
The kinematic expansion history of the universe is investigated by using the
307 supernovae type Ia from the Union Compilation set. Three simple model
parameterizations for the deceleration parameter (constant, linear and abrupt
transition) and two different models that are explicitly parametrized by the
cosmic jerk parameter (constant and variable) are considered. Likelihood and
Bayesian analyses are employed to find best fit parameters and compare models
among themselves and with the flat CDM model. Analytical expressions
and estimates for the deceleration and cosmic jerk parameters today ( and
) and for the transition redshift () between a past phase of cosmic
deceleration to a current phase of acceleration are given. All models
characterize an accelerated expansion for the universe today and largely
indicate that it was decelerating in the past, having a transition redshift
around 0.5. The cosmic jerk is not strongly constrained by the present
supernovae data. For the most realistic kinematic models the
confidence limits imply the following ranges of values: ,
and , which are compatible with the
CDM predictions, , and .
We find that even very simple kinematic models are equally good to describe the
data compared to the concordance CDM model, and that the current
observations are not powerful enough to discriminate among all of them.Comment: 13 pages. Matches published versio
Cosmological models with linearly varying deceleration parameter
We propose a new law for the deceleration parameter that varies linearly with
time and covers Berman's law where it is constant. Our law not only allows one
to generalize many exact solutions that were obtained assuming constant
deceleration parameter, but also gives a better fit with data (from SNIa, BAO
and CMB), particularly concerning the late time behavior of the universe.
According to our law only the spatially closed and flat universes are allowed;
in both cases the cosmological fluid we obtain exhibits quintom like behavior
and the universe ends with a big-rip. This is a result consistent with recent
cosmological observations.Comment: 12 pages, 7 figures; some typo corrections; to appear in
International Journal of Theoretical Physic
Configuration and role of appraisal system on reportage genre
In this article, we aim to analyze the configuration and rule of the appraisal system on reportage genre. We seek, first, explain the appraisal system theory, as proposed by Martin and White (2005). Then, we proceed to the analysis of a specimen of the reportage genre, in order to identify how the discursive subject (a) express affective, ethical and aesthetic evaluations (attitude subsystem), (b) engage in discourse (engagement subsystem) and (c) mitigate or intensify their evaluations (graduation subsystem). The results of the analysis of reportage “Ready for the nineteenth century” by Monica Weinberg and Camila Pereira, published in Veja (Weinberg and Pereira, 2008), indicate that judgment (attitude subsystem) and entertainment and the attribution (dialogical expansion meanings, one of the engagement subsystems) are rhetorical structuring elements of the studied genre.Key words: text genre, appraisal system, reportage.</p
Configuração e papel do sistema de avaliatividade no gênero reportagem
In this article, we aim to analyze the configuration and rule of the appraisal system on reportage genre. We seek, first, explain the appraisal system theory, as proposed by Martin and White (2005). Then, we proceed to the analysis of a specimen of the reportage genre, in order to identify how the discursive subject (a) express affective, ethical and aesthetic evaluations (attitude subsystem), (b) engage in discourse (engagement subsystem) and (c) mitigate or intensify their evaluations (graduation subsystem). The results of the analysis of reportage “Ready for the nineteenth century” by Monica Weinberg and Camila Pereira, published in Veja (Weinberg and Pereira, 2008), indicate that judgment (attitude subsystem) and entertainment and the attribution (dialogical expansion meanings, one of the engagement subsystems) are rhetorical structuring elements of the studied genre.Key words: text genre, appraisal system, reportage.Neste artigo, temos como objetivo analisar a configuração e o papel do sistema de avaliatividade no gênero reportagem. Buscamos, num primeiro momento, fazer uma explicitação da teoria do sistema de avaliatividade, conforme proposta por Martin e White (2005). Em seguida, procedemos à análise de um exemplar do gênero reportagem, a fim de identificar o modo como os sujeitos discursivos: (a) expressam avaliações afetivas, éticas e estéticas (subsistema atitude), (b) engajam-se no discurso (subsistema engajamento) e (c) mitigam ou intensificam suas avaliações (subsistema gradação). Os resultados encontrados na análise da reportagem Prontos para o século XIX, de Monica Weinberg e Camila Pereira, publicada na Revista Veja (Weinberg e Pereira, 2008), dão sinais de que o julgamento, subsistema da atitude, e o entretenimento e a atribuição, sentidos de expansão dialógica, um dos subsistemas do engajamento, constituem elementos retóricos estruturadores do gênero estudado.Palavras-chave: gênero textual, sistema de avaliatividade, reportagem
REM sleep deprivation promotes a dopaminergic influence in the striatal MT2 anxiolytic-like effects
AbstractThe aim of this study was to investigate the possible anxiolytic-like effects of striatal MT2 activation, and its counteraction induced by the selective blockade of this receptor. Furthermore, we analyzed this condition under the paradigm of rapid eye movement (REM) sleep deprivation (REMSD) and the animal model of Parkinson’s disease (PD) induced by rotenone. Male Wistar rats were infused with intranigral rotenone (12μg/μL), and 7 days later were subjected to 24h of REMSD. Afterwards the rats underwent striatal micro-infusions of selective melatonin MT2 receptor agonist, 8-M-PDOT (10μg/μL) or selective melatonin MT2 receptor antagonist, 4-P-PDOT (5μg/μL) or vehicle. Subsequently, the animals were tested in the open-field (OP) and elevated plus maze (EPM) tests. Results indicated that the activation of MT2 receptors produced anxiolytic-like effects. In opposite, the MT2 blockade did not show an anxiogenic-like effect. Besides, REMSD induced anxiolytic-like effects similar to 8-M-PDOT. MT2 activation generated a prevalent locomotor increase compared to MT2 blockade in the context of REMSD. Together, these results suggest a striatal MT2 modulation associated to the REMSD-induced dopaminergic supersensitivity causing a possible dopaminergic influence in the MT2 anxiolytic-like effects in the intranigral rotenone model of PD
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