Dynamics and stability of Bose-Einstein solitons in tilted optical lattices

Bloch oscillations of Bose-Einstein condensates realize sensitive matter-wave interferometers. We investigate the dynamics and stability of bright-soliton wave packets in one-dimensional tilted optical lattices with a modulated mean-field interaction $g(t)$. By means of a time-reversal argument, we prove the stability of Bloch oscillations of breathing solitons that would be quasistatically unstable. Floquet theory shows that these breathing solitons can be more stable against certain experimental perturbations than rigid solitons or even non-interacting wave packets.Comment: final, published versio

Development and validation of an in-house library for filamentous fungi identification by MALDI-TOF MS in a clinical laboratory in Medellin (Colombia)

Identification of filamentous fungi by conventional phenotypic methods are time-consuming, and a correct identification at the species level is prone to errors. Therefore, a more accurate and faster time-to-results, and cost-effective technique, is required, such as the Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). In this study, we describe the development of an in-house spectra library for the identification of filamentous fungi frequently isolated from patients with infections. An in-house spectra library was constructed using 14 reference strains grown in solid medium. Clinical isolates were identified either by the in-house spectra library or the Biotyper commercial library from Bruker Daltonics. Fungal identification was carried following the Biotyper’s established scores: ≤1.699: not reliably identified (NRI); 1.700–1.999: genus-level; ≥2.000: species-level. Clinical isolates were identified, with the in-house library, at species- and genus-level at 88.70% (55) and 3.22% (2), respectively. While 4.80% (3) was NRI and 3.22% (2) was discrepant concerning sequencing. On the contrary, identification up to species and genus-level with the commercial library was 44.44% (16) and 22.22% (8), respectively. NRI and the discrepancy was 30.55% (11) and 2.77% (1), respectively. For the reaming 26 isolates, 16 from Neoscytalidium dimidiatum and 10 from Sporothrix spp., respectively, the absence of spectrum and the specific spectra within the Sporothrix complex in the commercial library resulted in the inability to obtain an identification. In conclusion, the current results advocate the importance that each clinical microbiological laboratory needs to develop an ad hoc library associated with the MALDI-TOF MS fungal identification to overcome the limitations of the available commercial libraries.Comité para el Desarrollo de la Investigación, Universidad de Antioquia, Medellín, Colombia. Grant No 2604 and by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020-Programa Operacional Regional do Norteinfo:eu-repo/semantics/publishedVersio

Long Range Electron Transfer Quenching in Polyamine Chains Bearing a Terminal Naphthalene Unit

The fluorescence emission of a naphthalene unit attached to a polyamine chain is quenched by intramolecular electron transfer from the deprotonated amines to the excited fluorophore. Measurements of the respective quenching rate constants as a function of the distance, reveal an exponential dependence with β = 0.45 Å-1. Identical measurements carried out in deuterated water have shown a similar dependence with the distance β = 0.49 Å-1 but an average reduction of the absolute values of the rate constants of ca. 1.2. The polyamine chains seem to constitute a bridge through which the electron can find a route to its movement, more efficiently than through space

Unified dark energy thermodynamics: varying w and the -1-crossing

We investigate, in a unified and general way, the thermodynamic properties of dark energy with an arbitrary, varying equation-of-state parameter w(a). We find that all quantities are well defined and regular for every w(a), including at the -1-crossing, with the temperature being negative in the phantom regime (w(a)-1). The density and entropy are always positive while the chemical potential can be arbitrary. At the -1-crossing, both temperature and chemical potential are zero. The temperature negativity can only be interpreted in the quantum framework. The regular behavior of all quantities at the -1-crossing, leads to the conclusion that such a crossing does not correspond to a phase transition, but rather to a smooth cross-over.Comment: 5 pages, version published in Class. Quant. Gra

Polyphasic identification and typing Trichophytum rubrum strains of clinical origin

The dermatophyte Trychophytum rubrum is the most frequent aetiological agent of dermatophytosis in humans around the world representing a major public health problem, not just for European countries but also for tropical countries where climate conditions allow major propagation for this ascomycete. For instance, in Portugal, T. rubrum was the dermatophyte most frequently isolated (83.3%) in a toenail onychomycosis geriatric population survey [1]. The identification, pathogenicity, biology, and epidemiology of T. rubrum, is of interest for both dermatologists and medical mycologists [1,2]. Currently, in many countries and clinical laboratories, the T. rubrum strains isolated from lesions are primarily identified by conventional culture-based methods, including colony morphology and slide culture only. This approach does not provide evidence of intraspecific variations with a lack of information to track infections, determine common sources of infections and recurrence or reinfection after treatment, and analyse their virulence and drug resistance [3]. The aim of this work is to use a polyphasic approach to study T. rubrum from different geographic origins in order to identify intraspecific characteristics with clinical interest. Materials and Methods About 40 European and South American T. rubrum and reference strains were used. Macro and micro morphological techniques, urease assay, dermatophyte milk agar test and hair perforation test (HPT) where combined with molecular biology techniques, such as the analysis of internal transcribed spacer (ITS) region, Trubrum specific primers for species differentiation among close related species, mating type MAT1-1 -box characterisation and DNA fingerprinting (e.g., (GACA)4). Results and conclusions Culturally T. rubrum strains showed on the plates white and cottony colonies on the obverse and blood-red pigment on the reverse. T. rubrum strains were urease negative and inhibited in dermatophyte milk agar. In the HPT, which is useful to differentiate T. rubrum from T. interdigitale, any strain was able to perforate the hair despite normal growth being observed. The analysis of ITS region confirmed all the strains as a T. rubrum species as well as the Trubrum primers generate a typical amplicon of 200 bp. The DNA fingerprinting is now explored in order to find the best approach to differentiate intraspecific variations and/or geographic differences. In conclusion, there are several techniques that can be applied to identify and characterise T. rubrum from different origins depending of the technologies available in each clinical laboratory or country.info:eu-repo/semantics/publishedVersio

Identificación de aislamientos clínicos del complejo Sporothrix schenckii por espectrometría de masas MALDI-TOF

[Extracto] Introducción: Sporothrix schenckii es un hongo dimórfico, que por mucho tiempo fue considerado la única especie responsable de la esporotricosis. Sin embargo, con el advenimiento de las técnicas de biología molecular, aplicadas a la investigación taxonómica de hongos, se demostró que S. schenckii es un complejo de especies crípticas conformado por S. brasiliensis, S. schenckii sensu stricto, S. globosa, S. mexicana y S. luriei. Estas especies difieren en sensibilidad antifúngica, distribución geográfica y virulencia. Tradicionalmente la identificación de Sporothrix spp., se ha llevado a cabo con métodos fenotípicos clásicos, sin embargo, estos no son suficientes para la clasificación correcta de las diferentes especies, por la similitud morfológica entre ellas. La espectrometría de masas (EM) MALDI-TOF es una técnica ampliamente utilizada para la identificación rápida de diferentes microorganismos. El objetivo del presente trabajo fue la creación y validación de una base de espectros de diferentes especies del complejo S. schenckii a partir de la forma micelial del hongo para identificar aislamientos clínicos por EM- MALDI-TOF. [...]info:eu-repo/semantics/publishedVersio

An accurate cluster selection function for the J-PAS narrow-band wide-field survey

The impending Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS) will be the first wide-field survey of ≳ 8500 deg^2 to reach the ‘stage IV’ category. Because of the redshift resolution afforded by 54 narrow-band filters, J-PAS is particularly suitable for cluster detection in the range z80 per cent completeness and purity is M_h ∼ 5 × 10^(13) M_⊙ up to z ∼ 0.7. We also model the optical observable, M^∗_(CL)–halo mass relation, finding a non-evolution with redshift and main scatter of σM^∗_(CL)|M_h∼0.14dex down to a factor 2 lower in mass than other planned broad-band stage IV surveys, at least. For the M_h ∼ 1 × 10^(14) M_⊙ Planck mass limit, J-PAS will arrive up to z ∼ 0.85 with a σM^∗_(CL)|M_h∼0.12dex. Therefore, J-PAS will provide the largest sample of clusters and groups up to z ∼ 0.8 with a mass calibration accuracy comparable to X-ray data

Non-Hermitian SUSY Hydrogen-like Hamiltonians with real spectra

It is shown that the radial part of the Hydrogen Hamiltonian factorizes as the product of two not mutually adjoint first order differential operators plus a complex constant epsilon. The 1-susy approach is used to construct non-hermitian Hamiltonians with hydrogen spectra. Other non-hermitian Hamiltonians are shown to admit an extra `complex energy' at epsilon. New self-adjoint hydrogen-like Hamiltonians are also derived by using a 2-susy transformation with complex conjugate pairs epsilon, (c.c) epsilon.Comment: LaTeX2e file, 13 pages, 6 EPS figures. New references added. The present is a reorganized and simplified versio

Opinion dynamics: models, extensions and external effects

Recently, social phenomena have received a lot of attention not only from social scientists, but also from physicists, mathematicians and computer scientists, in the emerging interdisciplinary field of complex system science. Opinion dynamics is one of the processes studied, since opinions are the drivers of human behaviour, and play a crucial role in many global challenges that our complex world and societies are facing: global financial crises, global pandemics, growth of cities, urbanisation and migration patterns, and last but not least important, climate change and environmental sustainability and protection. Opinion formation is a complex process affected by the interplay of different elements, including the individual predisposition, the influence of positive and negative peer interaction (social networks playing a crucial role in this respect), the information each individual is exposed to, and many others. Several models inspired from those in use in physics have been developed to encompass many of these elements, and to allow for the identification of the mechanisms involved in the opinion formation process and the understanding of their role, with the practical aim of simulating opinion formation and spreading under various conditions. These modelling schemes range from binary simple models such as the voter model, to multi-dimensional continuous approaches. Here, we provide a review of recent methods, focusing on models employing both peer interaction and external information, and emphasising the role that less studied mechanisms, such as disagreement, has in driving the opinion dynamics. [...]Comment: 42 pages, 6 figure