Broad-band spectrophotometry of the hot Jupiter HAT-P-12b from the near-UV to the near-IR

The detection of trends or gradients in the transmission spectrum of extrasolar planets is possible with observations at very low spectral resolution. Transit measurements of sufficient accuracy using selected broad-band filters allow for an initial characterization of the atmosphere of the planet. We obtained time series photometry of 20 transit events and analyzed them homogeneously, along with eight light curves obtained from the literature. In total, the light curves span a range from 0.35 to 1.25 microns. During two observing seasons over four months each, we monitored the host star to constrain the potential influence of starspots on the derived transit parameters. We rule out the presence of a Rayleigh slope extending over the entire optical wavelength range, a flat spectrum is favored for HAT-P-12b with respect to a cloud-free atmosphere model spectrum. A potential cause of such gray absorption is the presence of a cloud layer at the probed latitudes. Furthermore, in this work we refine the transit parameters, the ephemeris and perform a TTV analysis in which we found no indication for an unseen companion. The host star showed a mild non-periodic variability of up to 1%. However, no stellar rotation period could be detected to high confidence.Comment: 13 pages, 6 figures, Accepted for publication in A&

One-loop self-energy correction to the 1s and 2s hyperfine splitting in H-like systems

The one-loop self-energy correction to the hyperfine splitting of the 1s and 2s levels in H-like low-Z atoms is evaluated to all orders in Z\alpha. The results are compared to perturbative calculations. The residual higher-order contribution is evaluated. Implications to the specific difference of the hyperfine structure intervals 8\Delta \nu_2 - \Delta \nu_1 in He^+ are investigated.Comment: 17 pages, RevTeX, 3 figure

Leading Chiral Logarithms to the Hyperfine Splitting of the Hydrogen and Muonic Hydrogen

We study the hydrogen and muonic hydrogen within an effective field theory framework. We perform the matching between heavy baryon effective theory coupled to photons and leptons and the relevant effective field theory at atomic scales. This matching can be performed in a perturbative expansion in alpha, 1/m_p and the chiral counting. We then compute the O(m_{l_i}^3 alpha^5/m_p^2 x logarithms) contribution (including the leading chiral logarithms) to the Hyperfine splitting and compare with experiment. They can explain about 2/3 of the difference between experiment and the pure QED prediction when setting the renormalization scale at the rho mass. We give an estimate of the matching coefficient of the spin-dependent proton-lepton operator in heavy baryon effective theory.Comment: 17 pages, LaTeX, minor changes, one reference adde

Long-Term Optical Monitoring of Eta Carinae. Multiband light curves for a complete orbital period

The periodicity of 5.5 years for some observational events occurring in Eta Carinae manifests itself across a large wavelength range and has been associated with its binary nature. These events are supposed to occur when the binary components are close to periastron. To detect the previous periastron passage of Eta Car in 2003, we started an intensive, ground-based, optical, photometric observing campaign. We continued observing the object to monitor its photometric behavior and variability across the entire orbital cycle. Our observation program consisted of daily differential photometry from CCD images, which were acquired using a 0.8 m telescope and a standard BVRI filter set at La Plata Observatory. The photometry includes the central object and the surrounding Homunculus nebula. We present up-to-date results of our observing program, including homogeneous photometric data collected between 2003 and 2008. Our observations demonstrated that Eta Car has continued increasing in brightness at a constant rate since 1998. In 2006, it reached its brightest magnitude (V ~ 4.7) since about 1860s. The object then suddenly reverted its brightening trend, fading to V = 5.0 at the beginning of 2007, and has maintained a quite steady state since then. We continue the photometric monitoring of Eta Car in anticipation of the next "periastron passage", predicted to occur at the beginning of 2009.Comment: Accepted by A&A. The paper contains 3 figures and 2 table

Probing the atmosphere of HD189733b with the Na I and K I lines

High spectral resolution transmission spectroscopy is a powerful tool to characterize exoplanet atmospheres. Especially for hot Jupiters, this technique is highly relevant, due to their high altitude absorption e.g. from resonant sodium (Na I) and potassium (K I) lines. We resolve the atmospheric K I-absorption on HD189733b with the aim to compare the resolved K I -line and previously obtained high resolution Na I-D-line observations with synthetic transmission spectra. The line profiles suggest atmospheric processes leading to a line broadening of the order of 10 km/s for the Na I-D-lines, and only a few km/s for the K I-line. The investigation hints that either the atmosphere of HD189733b lacks a significant amount of K I or the alkali lines probe different atmospheric regions with different temperature, which could explain the differences we see in the resolved absorption lines

Infrared Ellipsometry Analysis of Heritage Photographic Prints

[EN] Focusing on the photographic archive of Julian Carrillo (Mexico), we study and characterize the photographic processes of a set of 13 photographs dated between 1884 and 1925. By using infrared spectroscopic ellipsometry, we classified a selected set of photographs according to its kind of binder. Thus, we recognized for each photograph, the presence of proteins, and therefore, the particular photographic process. Furthermore, we have identified the presence of baryta layer, the use of plasticizer, and the eventual coating utilized to protect the photograph, whose composition was based in natural organic components, mainly shellac, beeswax, or camphorNieto-Villena, A.; Martinez, JR.; Flores-Camacho, JM.; Lastras-Martinez, A.; De La Cruz-Mendoza, JA.; Ortega-Zarzosa, G.; Valcarcel Andrés, JC.... (2018). Infrared Ellipsometry Analysis of Heritage Photographic Prints. Studies in Conservation. 63(8):466-476. https://doi.org/10.1080/00393630.2018.1476962S466476638Brambilla, L., Riedo, C., Baraldi, C., Nevin, A., Gamberini, M. C., D’Andrea, C., … Toniolo, L. (2011). Characterization of fresh and aged natural ingredients used in historical ointments by molecular spectroscopic techniques: IR, Raman and fluorescence. Analytical and Bioanalytical Chemistry, 401(6), 1827-1837. doi:10.1007/s00216-011-5168-zCasoli, A., & Fornaciari, S. (2014). An analytical study on an early twentieth-century Italian photographs collection by means of microscopic and spectroscopic techniques. Microchemical Journal, 116, 24-30. doi:10.1016/j.microc.2014.04.003Cattaneo, B., Chelazzi, D., Giorgi, R., Serena, T., Merlo, C., & Baglioni, P. (2008). Physico-chemical characterization and conservation issues of photographs dated between 1890 and 1910. Journal of Cultural Heritage, 9(3), 277-284. doi:10.1016/j.culher.2008.01.004Daher, C., Paris, C., Le Hô, A.-S., Bellot-Gurlet, L., & Échard, J.-P. (2010). A joint use of Raman and infrared spectroscopies for the identification of natural organic media used in ancient varnishes. Journal of Raman Spectroscopy, 41(11), 1494-1499. doi:10.1002/jrs.2693Edwards, H. G. M., Farwell, D. W., & Daffner, L. (1996). Fourier-transform Raman spectroscopic study of natural waxes and resins. I. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 52(12), 1639-1648. doi:10.1016/0584-8539(96)01730-8Fujiwara, H. (2007). Spectroscopic Ellipsometry. doi:10.1002/9780470060193Hendriks, K., & Ross, L. (1988). Chemical Treatments of Discoloured Photographic Prints: Image Manipulation or Legitimate Restoration? The Journal of Photographic Science, 36(3), 132-132. doi:10.1080/00223638.1988.11736990Mallégol, J., Gardette, J.-L., & Lemaire, J. (2000). Long-term behavior of oil-based varnishes and paints. Photo- and thermooxidation of cured linseed oil. Journal of the American Oil Chemists’ Society, 77(3), 257-263. doi:10.1007/s11746-000-0042-4Nieto-Villena, A., Martínez, J. R., de la Cruz-Mendoza, J. A., Valcárcel-Andrés, J. C., Ortega-Zarzosa, G., Solbes-García, Á., & Vázquez-Martínez, E. (2018). Atomic force microscopy as a tool for binder identification in ancient photographic processes. Surface and Interface Analysis, 50(4), 496-505. doi:10.1002/sia.6408Ostroff, Eugene. 1966. “Restoration of Photographs by Neutron Activation.” Science 154 (3745): 119–123. http://science.sciencemag.org/content/154/3745/119.Othmer, Kirk, ed. 2005. Encyclopedia of Chemical Technology. Vol. 17, 5th ed. New York: Wiley.Ricci, C., Bloxham, S., & Kazarian, S. G. (2007). ATR-FTIR imaging of albumen photographic prints. Journal of Cultural Heritage, 8(4), 387-395. doi:10.1016/j.culher.2007.07.002Sifontes, Á. B., Cañizales, E., Toro-Mendoza, J., Ávila, E., Hernández, P., Delgado, B. A., … Cruz-Barrios, E. (2015). Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers. Journal of Nanomaterials, 2015, 1-8. doi:10.1155/2015/510376Stulik, Dusan, Herant Khanjian, Alberto de Tagle, and Alexandra M. Botelho. 2002. “Investigation of Jean-Louis-Marie-Eugene Durieu’s Toning and Varnishing Experiments: A Non-Destructive Approach.” ICOM Committee for Conservation 13th Triennial Meeting, Río de Janeiro, 658–663.Price, Beth A., and Boris Pretzel, eds. 2009. Infrared and Raman Users Group Spectral Database. 2007 ed. Vol. 1 & 2. Philadelphia: IRUG. Accessed June 20, 2014. http://www.irug.org/.Vila, A., & Centeno, S. A. (2013). FTIR, Raman and XRF identification of the image materials in turn of the 20th century pigment-based photographs. Microchemical Journal, 106, 255-262. doi:10.1016/j.microc.2012.07.01

A proposal for a coordinated effort for the determination of brainwide neuroanatomical connectivity in model organisms at a mesoscopic scale

In this era of complete genomes, our knowledge of neuroanatomical circuitry remains surprisingly sparse. Such knowledge is however critical both for basic and clinical research into brain function. Here we advocate for a concerted effort to fill this gap, through systematic, experimental mapping of neural circuits at a mesoscopic scale of resolution suitable for comprehensive, brain-wide coverage, using injections of tracers or viral vectors. We detail the scientific and medical rationale and briefly review existing knowledge and experimental techniques. We define a set of desiderata, including brain-wide coverage; validated and extensible experimental techniques suitable for standardization and automation; centralized, open access data repository; compatibility with existing resources, and tractability with current informatics technology. We discuss a hypothetical but tractable plan for mouse, additional efforts for the macaque, and technique development for human. We estimate that the mouse connectivity project could be completed within five years with a comparatively modest budget.Comment: 41 page

Comparative micro-epidemiology of pathogenic avian influenza virus outbreaks in a wild bird population

Understanding the epidemiological dynamics of highly pathogenic avian influenza virus (HPAIV) in wild birds is crucial for guiding effective surveillance and control measures. The spread of H5 HPAIV has been well characterized over large geographical and temporal scales. However, information about the detailed dynamics and demographics of individual outbreaks in wild birds is rare and important epidemiological parameters remain unknown. We present data from a wild population of long-lived birds (mute swans; Cygnus olor) that has experienced three outbreaks of related H5 HPAIVs in the past decade, specifically, H5N1 (2007), H5N8 (2016) and H5N6 (2017). Detailed demographic data were available and intense sampling was conducted before and after the outbreaks; hence the population is unusually suitable for exploring the natural epidemiology, evolution and ecology of HPAIV in wild birds. We show that key epidemiological features remain remarkably consistent across multiple outbreaks, including the timing of virus incursion and outbreak duration, and the presence of a strong age-structure in morbidity that likely arises from an equivalent age-structure in immunological responses. The predictability of these features across a series of outbreaks in a complex natural population is striking and contributes to our understanding of HPAIV in wild birds

Brains studying brains: look before you think in vision

Using our own brains to study our brains is extraordinary. For example, in vision this makes us naturally blind to our own blindness, since our impression of seeing our world clearly is consistent with our ignorance of what we do not see. Our brain employs its 'conscious' part to reason and make logical deductions using familiar rules and past experience. However, human vision employs many 'subconscious' brain parts that follow rules alien to our intuition. Our blindness to our unknown unknowns and our presumptive intuitions easily lead us astray in asking and formulating theoretical questions, as witnessed in many unexpected and counter-intuitive difficulties and failures encountered by generations of scientists. We should therefore pay a more than usual amount of attention and respect to experimental data when studying our brain. I show that this can be productive by reviewing two vision theories that have provided testable predictions and surprising insights

Large-scale changes of the cloud coverage in the ε Indi Ba,Bb system

We present the results of 14 nights of I-band photometric monitoring of the nearby brown dwarf binary, ε Indi Ba,Bb. Observations were acquired over 2 months, and total close to 42 hours of coverage at a typically high cadence of 1.4 minutes. At a separation of just 0.7″, we do not resolve the individual components, and so effectively treat the binary as if it were a single object. However, ε Indi Ba (spectral type T1) is the brightest known T-type brown dwarf, and is expected to dominate the photometric signal. We typically find no strong variability associated with the target during each individual night of observing, but see significant changes in mean brightness - by as much as 0.10 magnitudes - over the 2 months of the campaign. This strong variation is apparent on a timescale of at least 2 days. We detect no clear periodic signature, which suggests we may be observing the T1 brown dwarf almost pole-on, and the days-long variability in mean brightness is caused by changes in the large-scale structure of the cloud coverage. Dynamic clouds will very likely produce lightning, and complementary high cadence V-band and Hα images were acquired to search for the emission signatures associated with stochastic ‘strikes’. We report no positive detections for the target in either of these passbands