Constraints on field flows of quintessence dark energy

The quest for understanding the late-time acceleration is haunted by an immense freedom in the analysis of dynamical models for dark energy in extended parameter spaces. Oftentimes having no prior knowledge at our disposal, arbitrary choices are implemented to reduce the degeneracies between parameters. We also encounter this issue in the case of quintessence fields, where a scalar degree of freedom drives the late-time acceleration. In this study, we implement a more physical prescription, the flow condition, to fine-tune the quintessence evolution for several field potentials. We find that this prescription agrees well with the most recent catalogue of data, namely supernovae type Ia, baryon acoustic oscillations, cosmic clocks, and distance to the last scattering surface, and it enables us to infer the initial conditions for the field, both potential and cosmological parameters. At 2σ we find stricter bounds on the potential parameters f/mpl>0.26 and n<0.15 for the PNGB and IPL potentials, respectively, while constraints on cosmological parameters remain extremely consistent across all assumed potentials. By implementing information criteria to assess their ability to fit the data, we do not find any evidence against thawing models, which in fact are statistically equivalent to ΛCDM, and the freezing ones are moderately disfavored. Through our analysis we place upper bounds on the slope of quintessence potentials, consequently revealing a strong tension with the recently proposed swampland criterion, finding the 2σ upper bound of λ∼0.31 for the exponential potential. © 2019 American Physical Society

Modelo celular de retinitis pigmentaria basado en células de pluripotencia inducida

Motivación: La retinitis pigmentaria (RP) se caracteriza por una degeneración de los fotorreceptores y de las células del epitelo pigmentario (RPE) que se manifiesta con ceguera nocturna seguida por constricción del campo visual y posterior pérdida global de la visión. El mecanismo molecular de esta y otras distrofias retinianas hereditarias es desconocido por la escasez de material humano y la poca fiabilidad de los modelos animales debido a las diferencias fisiológicas y estructurales entre la retina humana y la de los roedores.El desarrollo de células de pluripotencia inducida (iPSC) nos ofrece una oportunidad sin precedentes para obtener células de pacientes con la enfermedad específica debido a su alta capacidad de expansión y diferenciación a cualquier tipo celular humano. Esta tecnología se ha usado para crear el modelo de RP in vitro que reproduce el fenotipo clínico. Las células iPS derivadas de fibroblastos de paciente de RP e individuo sano se han caracterizado y diferenciado a RPE. El paciente es portador de la mutación en el gen MERTK(Ser331fs), responsable de la trasmision de la señal en la fagocitosis de los segmentos exteriores de los fotorreceptores, una actividad que realizan las células RPE diariamente, por lo que esperamos que las células RPE de paciente resulten defectuosas en el ensayo de fagocitosis.Métodos: La células iPS de paciente e individuo sano se caracterizaron por Inmunocitoquímica para marcadores de pluripotencia y su capacidad de diferenciación en las tres capas germinales mediante el ensayo de teratoma en ratones inmunodeprimidos. Las iPSC se han diferenciado hacia células RPE mediante protocolo de diferenciación espontánea observándose la morfologia típica de células RPE. La expresión de genes y proteínas específicos de RPE se detectó mediante RT-PCR y Western blott.Resultados: Las iPSC de ambos pacientes fueron teñidas con marcadores de pluripotencia y han sido capaces de desarrollar las tres capas germinales (ectodermo, mesodermo y endodermo) en el ensayo de teratoma, no encontrando diferencias entre ambas. Una vez diferenciadas en RPE (iPS-RPE) se observó la diferencia en la expresion de la proteína MERTK, mientras las demás proteinas están expresadas igualmente en ambos.Conclusiones: Hemos conseguido obtener células RPE especificas de paciente que carecen de la expresión de la proteína MERTK. En los siguientes ensayos, esperamos ver defectos en fagocitosis con las iPS-RPE de paciente

Volume Characteristics of Landslides Triggered by the MW 7.8 2016 Kaikōura Earthquake, New Zealand, Derived From Digital Surface Difference Modeling

We use a mapped landslide inventory coupled with a 2‐m resolution vertical difference model covering an area of 6,875 km2 to accurately constrain landslide volume‐area relationships. We use the difference model to calculate the source volumes for landslides triggered by the MW 7.8 Kaikōura, New Zealand, earthquake of 14 November 2016. Of the 29,519 mapped landslides in the inventory, 28,394 are within the analysis area, and of these, we have calculated the volume of 17,256 source areas that are ≥90% free of debris. Of the 28,394 landslides, about 80% are classified as soil or rock avalanches and the remainder as mainly translational slides. Our results show that both the soil avalanches and the rock avalanches, ignoring their source geology, have area to volume power‐law scaling exponents (γ) of 0.921 to 1.060 and 1.040 to 1.138, respectively. These are lower than the γ values of 1.1–1.3 (for soil) and 1.3–1.6 (for rock) reported in the literature for undifferentiated landslide types. They are, however, similar to those γ values estimated from other coseismic landslide inventories. In contrast, for 50 selected rotational, translational (planar slide surfaces), or compound slides, where much of the debris remains in the source area, we found γ values range between 1.46 and 1.47, indicating that their slide surfaces were considerably deeper than those landslides classified as avalanches. This study, like previous studies on coseismic landslides, shows that soil and rock avalanches (disrupted landslides) are the dominant landslide type triggered by earthquakes and that they tend to be shallow.Key PointsWe use a 2‐m resolution vertical difference model to estimate source volumes for 17,256 landslides with sources ≥90% free of debris triggered by the MW7.8 2016 Kaikōura EarthquakeThe model was derived by subtracting a tectonically adjusted pre‐EQ surface model from a post‐EQ model, covering an area of 6,875 km2Landslide trigger mechanism, type/failure mode, and source material are critical for accurate estimation of landslide volumes from source‐area geometriesPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156166/2/jgrf21176.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156166/1/jgrf21176_am.pd

Unraveling the developmental roadmap toward human brown adipose tissue

Increasing brown adipose tissue (BAT) mass and activation is a therapeutic strategy to treat obesity and complications. Obese and diabetic patients possess low amounts of BAT, so an efficient way to expand their mass is necessary. There is limited knowledge about how human BAT develops, differentiates, and is optimally activated. Accessing human BAT is challenging, given its low volume and anatomical dispersion. These constraints make detailed BAT-related developmental and functional mechanistic studies in humans virtually impossible. We have developed and characterized functionally and molecularly a new chemically defined protocol for the differentiation of human pluripotent stem cells (hPSCs) into brown adipocytes (BAs) that overcomes current limitations. This protocol recapitulates step by step the physiological developmental path of human BAT. The BAs obtained express BA and thermogenic markers, are insulin sensitive, and responsive to β-adrenergic stimuli. This new protocol is scalable, enabling the study of human BAs at early stages of development

Landslides Triggered by the MW 7.8 14 November 2016 Kaikoura Earthquake, New Zealand

The MW 7.8 14 November 2016 Kaikoura earthquake generated more than 10000 landslides over a total area of about 10000 km2, with the majority concentrated in a smaller area of about 3600 km2. The largest landslide triggered by the earthquake had an approximate volume of 20 (±2) M m3, with a runout distance of about 2.7 km, forming a dam on the Hapuku River. In this paper, we present version 1.0 of the landslide inventory we have created for this event. We use the inventory presented in this paper to identify and discuss some of the controls on the spatial distribution of landslides triggered by the Kaikoura earthquake. Our main findings are (1) the number of medium to large landslides (source area ≥10000 m2) triggered by the Kaikoura earthquake is smaller than for similar sized landslides triggered by similar magnitude earthquakes in New Zealand; (2) seven of the largest eight landslides (from 5 to 20 x 106 m3) occurred on faults that ruptured to the surface during the earthquake; (3) the average landslide density within 200 m of a mapped surface fault rupture is three times that at a distance of 2500 m or more from a mapped surface fault rupture ; (4) the “distance to fault” predictor variable, when used as a proxy for ground-motion intensity, and when combined with slope angle, geology and elevation variables, has more power in predicting landslide probability than the modelled peak ground acceleration or peak ground velocity; and (5) for the same slope angles, the coastal slopes have landslide point densities that are an order of magnitude greater than those in similar materials on the inland slopes, but their source areas are significantly smaller

Surface rupture of multiple crustal faults in the 2016 Mw 7.8 Kaikōura, New Zealand, earthquake

Multiple (>20 >20 ) crustal faults ruptured to the ground surface and seafloor in the 14 November 2016 M w Mw 7.8 Kaikōura earthquake, and many have been documented in detail, providing an opportunity to understand the factors controlling multifault ruptures, including the role of the subduction interface. We present a summary of the surface ruptures, as well as previous knowledge including paleoseismic data, and use these data and a 3D geological model to calculate cumulative geological moment magnitudes (M G w MwG ) and seismic moments for comparison with those from geophysical datasets. The earthquake ruptured faults with a wide range of orientations, sense of movement, slip rates, and recurrence intervals, and crossed a tectonic domain boundary, the Hope fault. The maximum net surface displacement was ∼12  m ∼12  m on the Kekerengu and the Papatea faults, and average displacements for the major faults were 0.7–1.5 m south of the Hope fault, and 5.5–6.4 m to the north. M G w MwG using two different methods are M G w MwG 7.7 +0.3 −0.2 7.7−0.2+0.3 and the seismic moment is 33%–67% of geophysical datasets. However, these are minimum values and a best estimate M G w MwG incorporating probable larger slip at depth, a 20 km seismogenic depth, and likely listric geometry is M G w MwG 7.8±0.2 7.8±0.2 , suggests ≤32% ≤32% of the moment may be attributed to slip on the subduction interface and/or a midcrustal detachment. Likely factors contributing to multifault rupture in the Kaikōura earthquake include (1) the presence of the subduction interface, (2) physical linkages between faults, (3) rupture of geologically immature faults in the south, and (4) inherited geological structure. The estimated recurrence interval for the Kaikōura earthquake is ≥5,000–10,000  yrs ≥5,000–10,000  yrs , and so it is a relatively rare event. Nevertheless, these findings support the need for continued advances in seismic hazard modeling to ensure that they incorporate multifault ruptures that cross tectonic domain boundaries

Simulations and performance of the QUBIC optical beam combiner

QUBIC, the Q & U Bolometric Interferometer for Cosmology, is a novel ground-based instrument that aims to measure the extremely faint B-mode polarisation anisotropy of the cosmic microwave background at intermediate angular scales (multipoles o

Carbonation of cement paste: Understanding, challenges, and opportunities

Cement paste is known to react with atmospheric carbon dioxide. Carbonation of cement paste has long been recognized as one of the causes of reinforcement corrosion. On the other hand, carbonation causes numerous chemomechanical changes in the cement paste, most notably changes in strength, porosity, pore size distribution, and chemistry. Furthermore, it can cause shrinkage and cracking of the cementitious matrix. The present review summarises the state of the art regarding the understanding and consequences of carbonation of cement paste. Apart from the passive process of reaction of atmospheric CO2 with cement paste, carbonation is sometimes used on purpose in order to improve certain properties of cementitious materials. This review further summarises recent efforts regarding active use of carbonation as a tool for manipulating certain properties of cement based materials. Possible fields of application include accelerated curing, improvement of fibre reinforced cementitious composites, concrete recycling, and waste immobilization.Materials and EnvironmentSteel & Composite Structure