Context.
The nearby ultra-compact multiplanetary system YZ Ceti consists of at least three planets, and a fourth tentative signal. The orbital period of each planet is the subject of discussion in ...the literature due to strong aliasing in the radial velocity data. The stellar activity of this M dwarf also hampers significantly the derivation of the planetary parameters.
Aims.
With an additional 229 radial velocity measurements obtained since the discovery publication, we reanalyze the YZ Ceti system and resolve the alias issues.
Methods.
We use model comparison in the framework of Bayesian statistics and periodogram simulations based on a method by Dawson and Fabrycky to resolve the aliases. We discuss additional signals in the RV data, and derive the planetary parameters by simultaneously modeling the stellar activity with a Gaussian process regression model. To constrain the planetary parameters further we apply a stability analysis on our ensemble of Keplerian fits.
Results.
We find no evidence for a fourth possible companion. We resolve the aliases: the three planets orbit the star with periods of 2.02 d, 3.06 d, and 4.66 d. We also investigate an effect of the stellar rotational signal on the derivation of the planetary parameters, in particular the eccentricity of the innermost planet. Using photometry we determine the stellar rotational period to be close to 68 d and we also detect this signal in the residuals of a three-planet fit to the RV data and the spectral activity indicators. From our stability analysis we derive a lower limit on the inclination of the system with the assumption of coplanar orbits which is
i
min
= 0.9 deg. From the absence of a transit event with TESS, we derive an upper limit of the inclination of
i
max
= 87.43 deg.
Conclusions.
YZ Ceti is a prime example of a system where strong aliasing hindered the determination of the orbital periods of exoplanets. Additionally, stellar activity influences the derivation of planetary parameters and modeling them correctly is important for the reliable estimation of the orbital parameters in this specific compact system. Stability considerations then allow additional constraints to be placed on the planetary parameters.
To evaluate the ability of the papillomacular bundle (PMB) retinal nerve fiber layer and macular inner retinal layer thickness measurements with Spectralis optical coherence tomography (OCT) to ...differentiate eyes with nonarteritic anterior ischemic optic neuropathy (NAION) from uninvolved eyes and to evaluate whether their thicknesses correlate with visual acuity.
An observational, cross-sectional study was performed, including 29 eyes with NAION and 29 uninvolved eyes from 29 patients. Eyes underwent scanning with Cirrus OCT (peripapillary and macular scanning) and Spectralis OCT (N-site axonal peripapillary scan and a new automated segmentation macular scan to measure individual retinal layers) in both eyes.
The NAION eyes showed significant thinning versus uninvolved eyes in the macular retinal nerve fiber (P < 0.05), ganglion cell layer (GCL; P < 0.001), and inner plexiform layer (IPL; P < 0.01) by Spectralis and in the GCL-IPL by Cirrus (P < 0.02). Average and sectors of peripapillary retinal nerve fiber layer (pRNFL) and total macular thickness (TMT) were significantly reduced in NAION eyes, with both Spectralis and Cirrus OCT (P < 0.05). Spectralis temporal (ρSpearman = -0.768; P < 0.001) and PMB pRNFL thicknesses (ρSpearman = -0.675; P < 0.001), as well as central macular IPL thickness (ρSpearman = -0.735; P < 0.001), correlated strongly with best corrected visual acuity (BCVA). Quadratic regression using outer nasal TMT by Cirrus OCT and temporal pRNFL thickness by Spectralis were the best models to predict BCVA.
Macular segmentation by Spectralis and Cirrus OCT revealed inner retinal layer atrophy in NAION eyes. The temporal and PMB pRNFL thicknesses and central macular IPL thickness by Spectralis-OCT and outer nasal TMT by Cirrus were strongly correlated with BCVA in NAION eyes.
The EBT3 radiochromic film was introduced as the next generation of EBT and EBT2 films, maintaining the composition of the active layer. X-ray radiation produces a change in its visible light ...absorption spectrum and optical properties being granted make the films suitable for dosimetric applications. The goal of this study is to present results of absorption spectra measurements for the EBT3 radiochromic film exposed to 6 MV X-ray radiation in the dose range from 0 to 50 Gy. Results showed that the spectrum of the EBT3 radiochromic has an intense band centered at around 636 nm and a less intense centered at around 585 nm. Spectral analysis show that in addition to the two main absorption bands, the absorption spectrum in the spectral range from 400 to 700 nm contains nine more absorption bands. Because to the symmetrical structure of the EBT3 radiochromic film, we assume that the additional absorption bands in the spectral range 400–540 nm are due to an interference pattern that is characteristic of a Fabry-Perot cavity.
•The EBT3 film exhibit two absorption bands centered at around 636 and 585 nm.•Absorption spectra of the EBT3 films was decomposed into Lorentzian functions.•The symmetrical structure of the EBT3 film behaves like a Fabry-Perot cavity.
Photocatalytic degradation of phenol using titanium dioxide (TiO
2
), either alone or in combination with other materials, has been tested. Mg/Al hydrotalcites prepared by two methods using inorganic ...(HC) or organic (HS) chemical reagents, along with mixed oxides produced by calcination of these products (HCC and HSC), were mixed with titanium isopropoxide to obtain hydroxide–TiO
2
compounds (HCC–TiO
2
and HSC–TiO
2
) and their photocatalytic activity tested in solutions of 10 mg/L phenol at 120 min under illumination at
λ
UV
= 254 nm with power of 4 W or 8 W. The obtained materials were characterized by various techniques, revealing that TiO
2
was incorporated into the mixed oxides of the calcined hydrotalcite to form the above-mentioned compounds. The photocatalytic test results indicate that the activity of HCC–TiO
2
can be attributed to increased phenol adsorption by hydrotalcite for transfer to the active photocatalytic phase of the impregnated TiO
2
particles, while the better results obtained for HSC–TiO
2
are due to greater catalyst impregnation on the surface of the calcined hydrotalcite, reducing the screening phenomenon and achieving HSC–TiO
2
degradation of up to 21.0% at 8 W. Reuse of both compounds indicated tight combination of HCC or HSC with TiO
2
, since in four successive separation cycles there was little reduction of activity, being associated primarily with material loss during recovery.
Duchenne muscular dystrophy (DMD) is caused by an X-linked mutation that leads to the absence of dystrophin, resulting in life-threatening arrhythmogenesis and associated heart failure. We targeted ...the gap junction protein connexin43 (Cx43) responsible for maintaining cardiac conduction. In mild mdx and severe mdx:utr mouse models of DMD, and human DMD tissues, Cx43 was found to be pathologically mislocalized to lateral sides of cardiomyocytes. In addition, overall Cx43 protein levels were markedly increased in mouse and human DMD heart tissues examined. Electrocardiography on isoproterenol challenged mice showed that both models developed arrhythmias and died within 24 hours, while wild-type mice were free of pathology. Administering peptide mimetics to inhibit lateralized Cx43 function prior to challenge protected mdx mice from arrhythmogenesis and death, while mdx:utr mice displayed markedly improved ECG scores. These findings suggest that Cx43 lateralization contributes significantly to DMD arrhythmogenesis and that selective inhibition may provide substantial benefit.
The mechanisms of Pb(II) toxicity have been studied in human red blood cells using confocal microscopy, immunolabeling, fluorescence-activated cell sorting and atomic force microscopy. The process ...follows a sequence of events, starting with calcium entry, followed by potassium release, morphological change, generation of ceramide, lipid flip-flop and finally cell lysis. Clotrimazole blocks potassium channels and the whole process is inhibited. Immunolabeling reveals the generation of ceramide-enriched domains linked to a cell morphological change, while the use of a neutral sphingomyelinase inhibitor greatly delays the process after the morphological change, and lipid flip-flop is significantly reduced. These facts point to three major checkpoints in the process: first the upstream exchange of calcium and potassium, then ceramide domain formation, and finally the downstream scramblase activation necessary for cell lysis. In addition, partial non-cytotoxic cholesterol depletion of red blood cells accelerates the process as the morphological change occurs faster. Cholesterol could have a role in modulating the properties of the ceramide-enriched domains. This work is relevant in the context of cell death, heavy metal toxicity and sphingolipid signaling.
El dióxido de carbono (CO2) es el gas de efecto invernadero más importante producido por las actividades humanas. Actualmente, cerca de un 20% de las emisiones de CO2 resultan de la eliminación y ...degradación de los ecosistemas forestales. Por medio de datos estadísticos se determinará que especies de la zona estudiada, son más eficientes en el secuestro de CO2 y en su generación de O2, esta investigación se realizó en el parque recreativo "Casa de la Naturaleza" Tampico, Tamaulipas, en un periodo de junio a diciembre del 2018. Se realizo un análisis de varianza a nivel de significancia de a= 0.05; y para determinar la significancia de los promedios entre clase diamétrica; se aplicó la prueba estadística de Tukey. Como resultado se obtuvo que las clases diamétricas más productivas para la absorción de CO2 y generación de O2, fueron las clases (>50 – 75) y (>75 >100) con un promedio de 155.66 toneladas de secuestro de CO2. Mientras que las clases diamétricas con más generación de O2, fueron (>50 – 75) y (>75->100), con un promedio de 253.95 toneladas de oxígeno. Por lo tanto, los arboles con una mayor biomasa y clase diamétrica tienen un elevado índice de absorción de CO2 y una gran generación de O2. Entre los árboles que destacaron ser más eficientes fueron; Orejón (Enterolobium cyclocarpum) y Ceiba (Ceiba pentandra), las cuales son nativas de la región y se encuentran dentro de la "Casa de la Naturaleza".
In this work, CdS nanowires (NWs) were prepared by the catalytic method using Au nanoparticles onto GaAs and CdS substrates. Scanning and transmission electron microscopy techniques (SEM, TEM) ...allowed observing different morphologies in the obtained products: variable diameter, pointed and ultra-long several microns length NWs. Also, a nanotube like hollow structure was identified when CdS/ITO/glass substrates were used, and its possible mechanism of formation is presented. The origins of the obtained morphologies was explained as depending on the type of vapor specie, the growth temperature and the used substrate. The photoluminescence (PL) of the NWs can be observed with the naked eye even at RT. PL spectra as a function of temperature were analysed and related with the morphology features.
The affinity and the binding mode of two benzo g phthalazine compounds, functionalized with one or two 2-(imidazole-4-yl)-ethylamine groups, to DNA and RNA models have been evaluated by means of ...UV-Vis, fluorescence and circular dichroism (CD) spectroscopies in combination with viscometry and molecular dynamics. Both organic molecules bind strongly to all nucleic acid models via the intercalation mode in the duplex structure, especially compound 1 . Intriguingly, 1 exhibits different emission responses depending on the base composition of duplex DNA/RNAs, which points out the possibility of using it as a base selective nucleic acid probe. Moreover, the acid–base behaviour of both compounds has been studied by pH-metric titrations and UV-Vis and emission fluorescence techniques to investigate the unexplored basicity of this type of compound. 1 behaves as a triprotic base whilst 2 is a diprotic base with the protonation of the benzo g phthalazine moiety occurring in the physiological pH range.
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