Evolutionary conservation of transcription factors affecting longevity

Gene expression can be optimised for health and longevity through manipulation of transcription factor (TF) activity. The effects of many such TFs are conserved between animal species indicating evolutionary conservation of underlying mechanisms. Lifespan-determining TFs regulate a plethora of cellular and organismal functions, including stress resistance, metabolism and growth. They interact with each other both within and between cells. Manipulating their activity in a single cell type can often be sufficient to insure longevity. The evolutionary conservation of their effects on ageing is most likely a reflection of the conservation of their function in processes, such as reproduction, growth, and metabolism, that are important earlier in life. Their effects on early and late life can, however, often be uncoupled

The Chandra Dust Scattering Halo of Galactic Center transient Swift J174540.7-290015

We report the detection of a dust scattering halo around a recently discovered X-ray transient, Swift J174540.7-290015, which in early February of 2016 underwent one of the brightest outbursts (F_X ~ 5e-10 erg/cm^2/s) observed from a compact object in the Galactic Center field. We analyze four Chandra images that were taken as follow-up observations to Swift discoveries of new Galactic Center transients. After adjusting our spectral extraction for the effects of detector pileup, we construct a point spread function for each observation and compare it to the GC field before the outburst. We find residual surface brightness around Swift J174540.7-290015, which has a shape and temporal evolution consistent with the behavior expected from X-rays scattered by foreground dust. We examine the spectral properties of the source, which shows evidence that the object transitioned from a soft to hard spectral state as it faded below L_X ~ 1e36 erg/s. This behavior is consistent with the hypothesis that the object is a low mass X-ray binary in the Galactic Center.Comment: Accepted for publication in Ap

Dust in the Circumgalactic Medium of Low-Redshift Galaxies

Using spectroscopically selected galaxies from the Sloan Digital Sky Survey we present a detection of reddening due to dust in the circumgalactic medium of galaxies. We detect the mean change in the colors of "standard crayons" correlated with the presence of foreground galaxies at z ~0.05 as a function of angular separation. Following Peek & Graves (2010), we create standard crayons using passively evolving galaxies corrected for Milky Way reddening and color-redshift trends, leading to a sample with as little as 2% scatter in color. We devise methods to ameliorate possible systematic effects related to the estimation of colors, and we find an excess reddening induced by foreground galaxies at a level ranging from 10 to 0.5 millimagnitudes on scales ranging from 30 kpc to 1 Mpc. We attribute this effect to a large-scale distribution of dust around galaxies similar to the findings of Menard et al. 2010. We find that circumgalactic reddening is a weak function of stellar mass over the range $6 \times 10^9 M_\odot$ -- $6 \times 10^{10} M_\odot$ and note that this behavior appears to be consistent with recent results on the distribution of metals in the gas phase.Comment: Submitted to Ap

Importance of the temperature in the interaction plant-geminivirus

Introduction. Geminivirusare plant viruses that have circular single-stranded DNA (ssDNA) genome encapsidated in twinned quasi-icosahedral (geminate) virionsand are a serious threat to diverse economically important crops such as tomato, pepper and cassava. TYLCV (Tomato yellow leaf curl virus) belongs to the genus begomovirus which is by far, the largest of the seven genera in the family Geminiviridae and it is a pathogen that induces a devastating disease in tomato in the Mediterranean region. Cultured tomatoes are often exposed to a combination of extreme heat and infection with TYLCV and this combination leads to intense disease symptoms and yield losses.The impact of temperature over the interaction tomato- TYLCVhas been characterized (Ghandi et al., 2016) but these results seem to be contradictory to our findings. Objective. The main objective of this work is to improve our understanding of the impact that high temperature has in the interaction plant-geminivirus.Material and methods. Nicotianabenthamiana plants were infected with TYLCV and growth in a chamber at 21 ºC or at 35 ºC. The amount of virus, symptoms, plant height and number of leaves were monitored at 14, 21 and 28 dpi (days post-infection). Three biological replicates were performed, each containing 15 infected plants and 10 non-infected plants (mock). Results. No differences were observed between non-infected and infected plants at both temperatures, in plant height or in the number of leaves, but the amount of virus and the severity of symptoms were significantly reduced in plants at high temperature. Conclusions. We conclude that TYLCV yield decreases in N. benthamiana due to high temperature and ongoing experiments in tomato TYLCV-infected plants will let us determine the importance of this finding in an agronomical important crop and to compare our results with the published data.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

El método de laboratorio utilizando computación simbólica : una alternativa de aprendizaje en el curso de cálculo de primer año de la Licenciatura en matemática.

El estudio que se presenta determinó las ventajas y limitaciones de implementar el método de laboratorios, utilizando computación simbólica, en el curso de Cálculo 1 de la Licenciatura en Matemática. Los fundamentos teóncos que apoyan la ejecución de los laboratorios a través de la computación simbólica, particularmente en el área de Cálculo, en matemáticas, fueron sustentados en el marco teórico de la investigación En cuanto a la metodología empleada se desarrolló un estudio de corte experimental solo con postprueba, en el grupo de estudiantes de primer año de la Licenciatura en Matemática. El grupo fue subdividido en dos-uno denominado grupo expenrnental quienes complementaron sus jornadas de clases con laboratorios de computación simbólica El otro, grupo control, utilizó el método expositivo y solución de prácticas para complementar la teoría Se comprobó, por medio de la aplicación de la prueba t de Student para diferencia de medias, la hipótesis planteada de que el rendimiento académico de los estudiantes que utilizan el método de laboratorios es supenor al que desarrolla sus ciases por medio de la metodología tradicional expositiva. Los hallazgos encontrados en esta investigación nos permiten presentar una propuesta para el desarrollo de un seminario taller en el cual se promueva la implementación del método de laboratorios, utilizando computación simbólica, en el curso de Cálculo 1 que se ofrecen en la Licenciatura en Matemática De igual forma, se recomienda la implementación de la computación simbólica en los diferentes cursos de cálculo que se imparten en la Universidad de Panamá y en los distintos Centros Regionale

A femtosecond velocity map imaging study on B-band predissociation in CH 3I. II. the 2 0 1 and 3 0 1 vibronic levels

Femtosecond time-resolved velocity map imaging experiments are reported on several vibronic levels of the second absorption band (B-band) of CH 3I, including vibrational excitation in the 2 and 3 modes of the bound 3R 1(E) Rydberg state. Specific predissociation lifetimes have been determined for the 201 and 301 vibronic levels from measurements of time-resolved I*( 2P 12) and CH 3 fragment images, parent decay, and photoelectron images obtained through both resonant and non-resonant multiphoton ionization. The results are compared with our previously reported predissociation lifetime measurements for the band origin 000 [Gitzinger, J. Chem. Phys. 132, 234313 (2010)10.1063/1.3455207]. The result, previously reported in the literature, where vibrational excitation to the C-I stretching mode ( 3) of the CH 3I 3R 1(E) Rydberg state yields a predissociation lifetime about four times slower than that corresponding to the vibrationless state, whereas predissociation is twice faster if the vibrational excitation is to the umbrella mode ( 2), is confirmed in the present experiments. In addition to the specific vibrational state lifetimes, which were found to be 0.85 0.04 ps and 4.34 0.13 ps for the 201 and 301 vibronic levels, respectively, the time evolution of the fragment anisotropy and the vibrational activity of the CH 3 fragment are presented. Additional striking results found in the present work are the evidence of ground state I( 2P 32) fragment production when excitation is produced specifically to the 301 vibronic level, which is attributed to predissociation via the A-band 1Q 1 potential energy surface, and the indication of a fast adiabatic photodissociation process through the repulsive A-band 3A 1(4E) state, after direct absorption to this state, competing with absorption to the 301 vibronic level of the 3R 1(E) Rydberg state of the B-band.Peer Reviewe

MOBFLOW: Movilidad para los procesos de negocio de la organización

Este artículo presenta la plataforma MobFlow (Mobile Flow); un sistema que permite particionar, distribuir, y ejecutar en entornos móviles, procesos de negocio descritos a través del estándar BPEL. También, MobFlow realiza el monitoreo de la ejecución de los procesos de negocio de la organización, los cuales son consumidos en tiempo real en los dispositivos móviles de los empleados. Además de exponer los módulos que componen la plataforma, el artículo presenta la implementación de un prototipo que valida la arquitectura propuesta, y un caso de estudio práctico de un proceso de ventas, que expone el funcionamiento de la plataforma

FtsZ of filamentous, heterocyst-forming cyanobacteria has a conserved N-Terminal peptide required for normal FtsZ polymerization and cell division

Filamentous cyanobacteria grow by intercalary cell division, which should involve distinct steps compared to those producing separate daughter cells. The N-terminal region of FtsZ is highly conserved in the clade of filamentous cyanobacteria capable of cell differentiation. A derivative of the model strain Anabaena sp. PCC 7120 expressing only an FtsZ lacking the amino acids 2-51 of the N-terminal peptide (1N-FtsZ) could not be segregated. Strain CSL110 expresses both 1N-FtsZ, from the endogenous ftsZ gene promoter, and the native FtsZ from a synthetic regulated promoter. Under conditions of 1N-FtsZ predominance, cells of strain CSL110 progressively enlarge, reflecting reduced cell division, and show instances of asymmetric cell division and aberrant Z-structures notably differing from the Z-ring formed by FtsZ in the wild type. In bacterial 2-hybrid assays FtsZ interacted with 1N-FtsZ. However, 1N-FtsZ-GFP appeared impaired for incorporation into Z-rings when expressed together with FtsZ. FtsZ, but not 1N-FtsZ, interacted with the essential protein SepF. Both FtsZ and 1N-FtsZ polymerize in vitro exhibiting comparable GTPase activities. However, filaments of FtsZ show a distinct curling forming toroids, whereas 1N-FtsZ form thick bundles of straight filaments. Thus, the N-terminal FtsZ sequence appears to contribute to a distinct FtsZ polymerization mode that is essential for cell division and division plane location in Anabaena.Agencia Estatal de Investigación BFU2013-44686-P BFU2016-77097-

Morphological Study of Granular-Granular Impact Craters through Time-of-Flight Cameras: from Concept to Automation in Python

Laboratory made granular-granular impact craters have been used as model analogues of planetary impact craters. These kind of craters have been observed and studied using profilometry techniques that allow to retrieve important morphologic features from the impacted surface. In this work, we propose to use a Time-of-Flight camera (Microsoft Kinect One) for the acquisition of depth data. We show comparisons between the typically used technique and the analysis derived from the Time-of-Flight data. We also release craterslab, a Python library developed to automate most of the tasks from the process of studying impact craters produced by granular projectiles hitting on the surface of granular targets. The library is able to acquire, identify, and measure morphological features of impacted surfaces through the reconstruction of 3D topographic maps. Our results show that using a Time-of-Flight camera and automating the data processing with a software library for the systematic study of impact craters can produce very accurate results while reducing the time spent on different stages of the process

Microscopic theory of network glasses

A molecular theory of the glass transition of network forming liquids is developed using a combination of self-consistent phonon and liquid state approaches. Both the dynamical transition and the entropy crisis characteristic of random first order transitions are mapped out as a function of the degree of bonding and the density. Using a scaling relation for a soft-core model to crudely translate the densities into temperatures, the theory predicts that the ratio of the dynamical transition temperature to the laboratory transition temperature rises as the degree of bonding increases, while the Kauzmann temperature falls relative to the laboratory transition. These results indicate why highly coordinated liquids should be "strong" while van der Waals liquids without coordination are "fragile".Comment: slightly revised version that has been accepted for publication in Phys. Rev. Let