A highly oriented cubic phase formed by lipids under shear

We demonstrate the formation of a macroscopically oriented inverse bicontinuous cubic (QII) lipid phase from a sponge (L3) phase by controlled hydration during shear flow. The L3 phase was the monoolein/ butanediol/water system; the addition of water reduces the butanediol concentration, inducing the formation of a diamond (QIID) cubic phase, which is oriented by the shear flow. The phenomenon was reproduced in both capillary and Couette geometries, indicating that this represents a robust general route for the production of highly aligned bulkQII samples, with applications in nanomaterial templating and protein research

Asymmetric trehalose analogues to probe disaccharide processing pathways in mycobacteria

The uptake and metabolism of the disaccharide trehalose by Mycobacterium tuberculosis is essential for the virulence of this pathogen. Here we describe the chemoenzymatic synthesis of new azido-functionalised asymmetric trehalose probes that resist degradation by mycobacterial enzymes and are used to probe trehalose processing pathways in mycobacteria

The 2+1 charged black hole in topologically massive Electrodynamics

The 2+1 black hole coupled to a Maxwell field can be charged in two different ways. On the one hand, it can support a Coulomb field whose potential grows logarithmically in the radial coordinate. On the other, due to the existence of a non-contractible cycle, it also supports a topological charge whose value is given by the corresponding Abelian holonomy. Only the Coulomb charge, however, is given by a constant flux integral with an associated continuity equation. The topological charge does not gravitate and is somehow decoupled from the black hole. This situation changes abruptly if one turns on the Chern-Simons term for the Maxwell field. First, the flux integral at infinity becomes equal to the topological charge. Second, demanding regularity of the black hole horizon, it is found that the Coulomb charge (whose associated potential now decays by a power law) must vanish identically. Hence, in 2+1 topologically massive electrodynamics coupled to gravity, the black hole can only support holonomies for the Maxwell field. This means that the charged black hole, as the uncharged one, is constructed from the vacuum by means of spacetime identifications.Comment: 4 pages, no figures, LaTex, added reference

X-ray spectra reveal the reawakening of the repeat changing-look AGN NGC 1566

We present simultaneous XMM-Newton and NuSTAR observations of the repeat changing-look AGN NGC 1566, which dramatically increased in brightness in the IR to X-ray bands in 2018. The broad-band X-ray spectrum was taken at the peak of the outburst and is typical of Seyfert 1 AGN. The spectrum shows a soft excess, Compton hump, warm absorption and reflection, ruling out tidal disruption as the cause of the outburst and demonstrating that a 'standard' accretion disk can develop very rapidly. The high resolution grating spectrum reveals that the outburst has launched a ~ 500 km/s outflow, and shows photoionised emission lines from rest-frame gas. We discuss possible mechanisms for the outburst, and conclude that it is most likely caused by a disk instability.Comment: 5 pages, 2 figures, accepted to MNRAS letter

Characterizations of inner product structures involving the radius of the inscribed or circumscribed circumference

summary:We define the radius of the inscribed and circumscribed circumferences in a triangle located in a real normed space and we obtain new characterizations of inner product spaces

Social support, self-efficacy and academic satisfaction of university students during the COVID-19 lockdown

This work aimed to analyze the relationships between the students perceived institutional support, teachers’ support, peers’ support, and their academic satisfaction, mediated by their self-efficacy in information and comunication technologies (ICT). Participants were 157 students who were studying from first to fourth year in different disciplines of the Valencia University. Structural equation models with latent factors were tested. A final model had satisfactory fit indices to the observed data. It is worth highlighting the strong direct effect of the teaching staff support on student’ academic satisfaction, with less weight, although significant, being the effect of institutional support. In conclusion, teacher’s figure is of paramount importance for student’s academic satisfaction.Este trabajo tuvo como objetivo analizar las relaciones entre el apoyo institucional percibido por los estudiantes, el apoyo de los profesores, el apoyo de los compañeros y su satisfacción académica, mediada por su autoeficacia en las tecnologías de la información y la comunicación (TIC). Participaron 157 estudiantes que cursaban de primero a cuarto año en diferentes disciplinas de la Universidad de Valencia. Se probaron modelos de ecuaciones estructurales con factores latentes. El modelo final aportó índices de ajuste satisfactorios a los datos observados. Cabe destacar el fuerte efecto directo del apoyo del profesorado sobre la satisfacción académica de los estudiantes, mientras que tuvo menor peso, aunque también significativo, el efecto del apoyo institucional. En conclusión, la figura del docente es de suma importancia para la satisfacción académica de los estudiantes

Measuring School Engagement: Validation and Measurement Equivalence of the Student Engagement Scale on Angolan Male and Female Adolescents

School engagement is defined primarily in relation to the participation of the student in academic achievement, and it is viewed as a multidimensional and integrative construct, or macroconstruct made up of several dimensions. The most repeated typology recognizes three specific dimensions: Cognitive, behavioral, and emotional (affective). Recently, a fourth new dimension, personal agency, has been proposed, which reflects students’ constructive engagement with the academic instructions. F. Veiga has been the first to present a self-report instrument, in Portuguese, to measure these four components, the Student Engagement Scale-4 dimensions (SES-4DS). This research has studied the validity and reliability of this scale and its gender invariance in a sample of 2034 Angolan students. Results have shown a clear scalar invariant factor structure, some reliability problems, and adequate convergent and nomological validity. Latent differences were found between males and females for cognitive and affective engagement. Results are discussed in light of the existing literature

A study of temperature-related non-linearity at the metal-silicon interface

In this paper, we investigate the temperature dependencies of metal-semiconductor interfaces in an effort to better reproduce the current-voltage-temperature (IVT) characteristics of any Schottky diode, regardless of homogeneity. Four silicon Schottky diodes were fabricated for this work, each displaying different degrees of inhomogeneity; a relatively homogeneous NiV/Si diode, a Ti/Si and Cr/Si diode with double bumps at only the lowest temperatures, and a Nb/Si diode displaying extensive non-linearity. The 77–300 K IVT responses are modelled using a semi-automated implementation of Tung's electron transport model, and each of the diodes are well reproduced. However, in achieving this, it is revealed that each of the three key fitting parameters within the model display a significant temperature dependency. In analysing these dependencies, we reveal how a rise in thermal energy “activates” exponentially more interfacial patches, the activation rate being dependent on the carrier concentration at the patch saddle point (the patch's maximum barrier height), which in turn is linked to the relative homogeneity of each diode. Finally, in a review of Tung's model, problems in the divergence of the current paths at low temperature are explained to be inherent due to the simplification of an interface that will contain competing defects and inhomogeneities

Luminosity Tuning at the Interaction Point

Minimisation of the emittance in a linear collider is not enough to achieve optimal performance. For optimisation of the luminosity, tuning of collision parameters such as angle, offset, waist, etc. is needed, and a fast and reliable tuning signal is required. In this paper tuning knobs are presented, and their optimisation using beamstrahlung as a tuning signal is studied