Dynamic charge correlations near the Peierls transition

The quantum phase transition between a repulsive Luttinger liquid and an insulating Peierls state is studied in the framework of the one-dimensional spinless Holstein model. We focus on the adiabatic regime but include the full quantum dynamics of the phonons. Using continuous-time quantum Monte Carlo simulations, we track in particular the dynamic charge structure factor and the single-particle spectrum across the transition. With increasing electron-phonon coupling, the dynamic charge structure factor reveals the emergence of a charge gap, and a clear signature of phonon softening at the zone boundary. The single-particle spectral function evolves continuously across the transition. Hybridization of the charge and phonon modes of the Luttinger liquid description leads to two modes, one of which corresponds to the coherent polaron band. This band acquires a gap upon entering the Peierls phase, whereas the other mode constitutes the incoherent, high-energy spectrum with backfolded shadow bands. Coherent polaronic motion is a direct consequence of quantum lattice fluctuations. In the strong-coupling regime, the spectrum is described by the static, mean-field limit. Importantly, whereas finite electron density in general leads to screening of polaron effects, the latter reappear at half filling due to charge ordering and lattice dimerization.Comment: 8 pages, 7 figures, final versio

Laser Improves Biogas Production by Anaerobic Digestion of Cow Dung

This study investigates the digestion of cow dung (CD) for biogas production at laboratory scales. The study was carried out through anaerobic fermentation using cow dung as substrate. The digester was operated at ambient temperatures of 39.5 °C for a period of 10 days. The effect of iron powder in controlling the production of hydrogen sulfide (H2S) has been tested. The optimum concentration of iron powder was 4g/L with the highest biogas production. A Q – swatch Nd:YAG laser has been used to mix and homogenize the components of one of the six digesters and accelerate digestion. At the end of digestion, all digestions effluent was subjected to 5 laser pulses with 250mJ/pules to dispose waste biomass

Effect of Electron-Phonon Interaction Range for a Half-Filled Band in One Dimension

We demonstrate that fermion-boson models with nonlocal interactions can be simulated at finite band filling with the continuous-time quantum Monte Carlo method. We apply this method to explore the influence of the electron-phonon interaction range for a half-filled band in one dimension, covering the full range from the Holstein to the Fr\"ohlich regime. The phase diagram contains metallic, Peierls, and phase-separated regions, which we characterize in terms of static and dynamical correlation functions. In particular, our results reveal a suppression of $2k_F$ charge correlations with increasing interaction range, allowing for a power-law decay comparable to the pairing correlations.Comment: 5 pages, 5 figure

Electrical Properties of Blend Polymers of Polyvinyl Alcohol/Poly (O-Toluidine)

The chemical polymerization method was used to prepare a poly (o-toluidine) which was characterized by different techniques including (FTIR, XRD, SEM) while, blend polymer of poly (o-toluidine)/polyvinyl alcohol (PVA) was made by mixing different volume ratios of PVA and POT (1:1, 1:2, 2:1)respectively. Thin films of the blend polymers were prepared by spin coating method on interdigitated fingers electrodes

(U-Th)/He dating of supergene iron (oxyhydr-)oxides of the Nefza-Sejnane district (Tunisia):new insights into mineralization and mammalian biostratigraphy

The mining district of Nefza-Sejnane (Tunisia) encloses numerous ores and raw material deposits, all formed in relation with successive Fe-rich fluids of meteoric and/or hydrothermal origins. Here, for the first time in Tunisia, (U-Th)/He ages were obtained on supergene goethite from various localities/deposits of the district highlight direct dating of significant weathering episodes during late Tortonian and late Pleistocene. These weathering events are most likely associated with favorable conditions that combine (i) wet climate displaying sufficient meteoric water/fluid; and (ii) regional exhumation, due to large-scale vertical lithospheric movements enhancing the percolation of fluids. Matched with previous works, these results refine the stratigraphic frame for the polymetallic mineralization and clay deposits in the district, confirming the influence of meteoric fluids circulation during the late Cenozoic. As a consequence of the new (U-Th)/He data, we moreover propose a taxonomic and stratigraphic revision of the well-known mammalian fauna from the Fe-rich Douahria locality, suggesting an early Tortonian age for the fossils, i.e., prior to the first episode of meteoric event in the area

Single hole dynamics in the t-J model on a square lattice

We present quantum Monte Carlo (QMC) simulations for a single hole in a t-J model from J=0.4t to J=4t on square lattices with up to 24 x 24 sites. The lower edge of the spectrum is directly extracted from the imaginary time Green's function. In agreement with earlier calculations, we find flat bands around $(0,\pm\pi)$, $(\pm\pi,0)$ and the minimum of the dispersion at $(\pm\pi/2,\pm\pi/2)$. For small J both self-consistent Born approximation and series expansions give a bandwidth for the lower edge of the spectrum in agreement with the simulations, whereas for J/t > 1, only series expansions agree quantitatively with our QMC results. This band corresponds to a coherent quasiparticle. This is shown by a finite size scaling of the quasiparticle weight $Z(\vec k)$ that leads to a finite result in the thermodynamic limit for the considered values of $J/t$. The spectral function $A(\vec k, \omega)$ is obtained from the imaginary time Green's function via the maximum entropy method. Resonances above the lowest edge of the spectrum are identified, whose J-dependence is quantitatively described by string excitations up to J/t=2

Single hole dynamics in the t-J model on two- and three-leg ladders

The dynamics of a single hole in the t-J model on two- (2LL) and three- (3LL) leg ladders is studied using a recently developed quantum Monte Carlo algorithm. For the 2LL it is shown that in addition to the most pronounced features of the spectral function, well described by the limit of strong coupling along the rungs, a clear shadow band appears in the antibonding channel. Moreover, both the bonding band and its shadow have a finite quasiparticle (QP) weight in the thermodynamic limit. For strong coupling along the rungs of the 3LL, the low-energy spectrum in the antisymmetric channel is similar to a one-dimensional chain, whereas in the two symmetric channels it resembles the 2LL. The QP weight vanishes in the antisymmetric channel, but is finite in the symmetric one

The Genome Sequence of Leishmania (Leishmania) amazonensis: Functional Annotation and Extended Analysis of Gene Models

We present the sequencing and annotation of the Leishmania (Leishmania) amazonensis genome, an etiological agent of human cutaneous leishmaniasis in the Amazon region of Brazil. L. (L.) amazonensis shares features with Leishmania (L.) mexicana but also exhibits unique characteristics regarding geographical distribution and clinical manifestations of cutaneous lesions (e.g. borderline disseminated cutaneous leishmaniasis). Predicted genes were scored for orthologous gene families and conserved domains in comparison with other human pathogenic Leishmania spp. Carboxypeptidase, aminotransferase, and 3'-nucleotidase genes and ATPase, thioredoxin, and chaperone-related domains were represented more abundantly in L. (L.) amazonensis and L. (L.) mexicana species. Phylogenetic analysis revealed that these two species share groups of amastin surface proteins unique to the genus that could be related to specific features of disease outcomes and host cell interactions. Additionally, we describe a hypothetical hybrid interactome of potentially secreted L. (L.) amazonensis proteins and host proteins under the assumption that parasite factors mimic their mammalian counterparts. the model predicts an interaction between an L. (L.) amazonensis heat-shock protein and mammalian Toll-like receptor 9, which is implicated in important immune responses such as cytokine and nitric oxide production. the analysis presented here represents valuable information for future studies of leishmaniasis pathogenicity and treatment.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, EPM UNIFESP, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilLNBio CNPEM, Lab Nacl Biociencias, Campinas, SP, BrazilLGE UNICAMP, Lab Genom & Expressao, Campinas, SP, BrazilInst Agron Campinas, Ctr Pesquisa & Desenvolvimento Recursos Geneti Ve, Campinas, SP, BrazilUniv Calif San Diego, Sch Med, Dept Pediat, San Diego, CA 92103 USAUniversidade Federal de São Paulo, UNIFESP, Dept Ciencia & Tecnol, Sao Jose Dos Campos, BrazilUniv N Carolina, Sch Med, Dept Genet, Chapel Hill, NC USAUniv Fed Minas Gerais, ICB UFMG, Inst Ciencias Biol, Dept Biol Geral, Belo Horizonte, MG, BrazilUniversidade Federal de São Paulo, EPM UNIFESP, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Ciencia & Tecnol, Sao Jose Dos Campos, BrazilFAPESP: 07/50551-2FAPESP: 10/19335-4Web of Scienc

The global burden of falls: Global, regional and national estimates of morbidity and mortality from the Global Burden of Disease Study 2017

Background: Falls can lead to severe health loss including death. Past research has shown that falls are an important cause of death and disability worldwide. The Global Burden of Disease Study 2017 (GBD 2017) provides a comprehensive assessment of morbidity and mortality from falls. Methods: Estimates for mortality, years of life lost (YLLs), incidence, prevalence, years lived with disability (YLDs) and disability-adjusted life years (DALYs) were produced for 195 countries and territories from 1990 to 2017 for all ages using the GBD 2017 framework. Distributions of the bodily injury (eg, hip fracture) were estimated using hospital records. Results: Globally, the age-standardised incidence of falls was 2238 (1990-2532) per 100 000 in 2017, representing a decline of 3.7% (7.4 to 0.3) from 1990 to 2017. Age-standardised prevalence w

Critical Role of IRF-5 in the Development of T helper 1 responses to Leishmania donovani infection

The transcription factor Interferon Regulatory Factor 5 (IRF-5) has been shown to be involved in the induction of proinflammatory cytokines in response to viral infections and TLR activation and to play an essential role in the innate inflammatory response. In this study, we used the experimental model of visceral leishmaniasis to investigate the role of IRF-5 in the generation of Th1 responses and in the formation of Th1-type liver granulomas in Leishmania donovani infected mice. We show that TLR7-mediated activation of IRF-5 is essential for the development of Th1 responses to L. donovani in the spleen during chronic infection. We also demonstrate that IRF-5 deficiency leads to the incapacity to control L. donovani infection in the liver and to the formation of smaller granulomas. Granulomas in Irf5-/- mice are characterized by an increased IL-4 and IL-10 response and concomitant low iNOS expression. Collectively, these results identify IRF-5 as a critical molecular switch for the development of Th1 immune responses following L. donovani infections and reveal an indirect role of IRF-5 in the regulation of iNOS expression