Volatile Composition and Outgassing in C/2018 Y1 (IWAMOTO): Extending Detection Limits for High-Resolution IR Cometary Spectroscopy at the NASA-IRTF

We used iSHELL, the powerful high-resolution ( /~ 40,000) cross-dispersed IR spectrograph at the NASA-IRTF to measure the native ice composition and outgassing of moderately bright, long-period comet C/2018 Y1 (Iwamoto) (hereafter Y1) within weeks of its discovery. We measured production rates for H2O, and production rates and abundance ratios relative to H2O for eight trace molecules, including the most complete measure of cometary CH4 achieved to date. Compared with mean abundances measured among comets, our study revealed enriched CH3OH and C2H6 yet depleted CO and C2H2, perhaps indicating highly efficient H- atom addition on interstellar grains prior to their incorporation into the nucleus. The combined high spectral resolving power and broad spectral coverage of iSHELL allowed characterizing cometary composition using only three instrument settings, and its long-slit coverage allowed comparing the spatial distributions of molecular emissions and dust continuum

Larger Stimuli Require Longer Processing Time for Perception

The time it takes for a stimulus to reach awareness is often assessed by measuring reaction times (RTs) or by a temporal order judgement (TOJ) task in which perceived timing is compared against a reference stimulus. Dissociations of RT and TOJ have been reported earlier in which increases in stimulus intensity such as luminance intensity results in a decrease of RT, whereas perceived perceptual latency in a TOJ task is affected to a lesser degree. Here, we report that a simple manipulation of stimulus size has stronger effects on perceptual latency measured by TOJ than on motor latency measured by RT tasks. When participants were asked to respond to the appearance of a simple stimulus such as a luminance blob, the perceptual latency measured against a standard reference stimulus was up to 40 ms longer for a larger stimulus. In other words, the smaller stimulus was perceived to occur earlier than the larger one. RT on the other hand was hardly affected by size. The TOJ results were further replicated in a simultaneity judgement task, suggesting that the effects of size are not due to TOJ-specific response biases but more likely reflect an effect on perceived timing

Detection of Diatomic Molecules in the Dust Forming Nova V2676 Oph

Novae are generally considered to be hot astronomical objects and show effective temperatures up to 10,000 K or higher at their visual maximum. But, it is theoretically predicted that the outer envelope of the nova outflow can become cool enough to form molecules that would be dissociated at high temperatures. We detected strong absorption bands of C2 and CN radicals in the optical spectrum of Nova V2676 Oph, a very slow nova with dust formation. This is the first report of the detection of C2 and the second one of CN in novae during outburst. Although such simple molecules are predicted to form in the envelope of the outflow based on previous studies, there are few reports of their detection. In the case of V2676 Oph, the presence of the molecular envelope is considered to be very transient, lasting several days only

Lamellar corneal injury by bamboo splinters: a case report

<p>Abstract</p> <p>Introduction</p> <p>We report an unusual case of corneal lamellar injury caused by long bamboo splinters.</p> <p>Case presentation</p> <p>A 70-year-old Japanese man visited our hospital with a bamboo injury. Slit lamp examination revealed that a bundle of bamboo splinters had deeply penetrated the corneal stroma of the right eye from the nasal limbus. The splinters were approximately 8 mm in length, but had not perforated the anterior chamber. They were completely removed by superficial corneal incision alongside each splinter with no consequences. The eye has remained healed for 3 months postoperatively.</p> <p>Conclusion</p> <p>The bamboo splinters did not perforate the anterior chamber, although they were long and hard enough to do so. This may be because the spatula-like shape and flexibility of the bamboo splinters allowed them to penetrate the lamellar layer of the corneal stroma with ease, but with no perforation of deeper tissue.</p

Global trends in nasopharyngeal cancer mortality since 1970 and predictions for 2020 : Focus on low-risk areas

Nasopharyngeal cancer (NPC) mortality shows great disparity between endemic high risk areas, where non-keratinizing carcinoma (NKC) histology is prevalent, and non-endemic low risk regions, where the keratinizing squamous cell carcinoma (KSCC) type is more frequent. We used the World Health Organization database to calculate NPC mortality trends from 1970 to 2014 in several countries worldwide. For the European Union (EU), the United States (US) and Japan, we also predicted trends to 2020. In 2012, the highest age-standardized (world standard) rates were in Hong Kong (4.51/100,000 men and 1.15/100,000 women), followed by selected Eastern European countries. The lowest rates were in Northern Europe and Latin America. EU rates were 0.27/100,000 men and 0.09/100,000 women, US rates were 0.20/100,000 men and 0.08/100,000 women and Japanese rates were 0.16/100,000 men and 0.04/100,000 women. NPC mortality trends were favourable for several countries. The decline was 1215% in men and 125% in women between 2002 and 2012 in the EU, 1212% in men and 129% in women in the US and about 1230% in both sexes in Hong Kong and Japan. The favourable patterns in Europe and the United States are predicted to continue. Changes in salted fish and preserved food consumption account for the fall in NKC. Smoking and alcohol prevalence disparities between sexes and geographic areas may explain the different rates and trends observed for KSCC and partially for NKC. Dietary patterns, as well as improvement in management of the disease, may partly account for the observed trends, too

The similarity of the interstellar comet 2I/Borisov to solar system comets from high resolution optical spectroscopy

Aims: 2I/Borisov (hereafter 2I) is the first visibly active interstellar comet observed in the Solar System, allowing us for the first time to sample the composition of a building block from another system. We report on the monitoring of 2I with the Ultraviolet-Visual Echelle Spectrograph, the high-resolution optical spectrograph of the ESO Very Large Telescope at Paranal, for four months from November 15, 2019 to March 16, 2020. Our goal is to characterise the activity and composition of 2I with respect to Solar System comets. Methods: We collected high-resolution spectra at 12 different epochs from 2.1 au pre-perihelion to 2.6 au post-perihelion. Results: On December 24 and 26, 2019, close to perihelion, we detected several OH lines of the 309 nm (0-0) band and derived a water production rate of 2.2 ± 0.2 × 10^26 molecules s^−1. The three [OI] forbidden oxygen lines were detected at different epochs and we derived a green-to-red doublet intensity ratio (G/R) of 0.31 ± 0.05 close to perihelion. The NH_2 ortho and para lines from various bands were measured and allowed us to derive an ortho-to-para abundance ratio (OPR) of 3.21 ± 0.15, corresponding to an OPR and spin temperature of ammonia of 1.11 ± 0.08 and 31 −5/+10 K, respectively. These values are consistent with the values usually measured for Solar System comets. Emission lines of the radicals NH (336 nm), CN (388 nm), CH (431 nm), and C2 (517 nm) were also detected. Several FeI and NiI lines were identified and their intensities were measured to provide a ratio of log (NiI/FeI) = 0.21 ± 0.18, which is in agreement with the value recently found in Solar System comets. Conclusions: Our high spectral resolution observations of 2I/Borisov and the associated measurements of the NH2 OPR and the Ni/Fe abundance ratio are remarkably similar to Solar System comets. Only the G/R ratio is unusually high, but it is consistent with the high abundance ratio of CO/H2O found by other investigators

The composition of the protosolar disk and the formation conditions for comets

Conditions in the protosolar nebula have left their mark in the composition of cometary volatiles, thought to be some of the most pristine material in the solar system. Cometary compositions represent the end point of processing that began in the parent molecular cloud core and continued through the collapse of that core to form the protosun and the solar nebula, and finally during the evolution of the solar nebula itself as the cometary bodies were accreting. Disentangling the effects of the various epochs on the final composition of a comet is complicated. But comets are not the only source of information about the solar nebula. Protostellar disks around young stars similar to the protosun provide a way of investigating the evolution of disks similar to the solar nebula while they are in the process of evolving to form their own solar systems. In this way we can learn about the physical and chemical conditions under which comets formed, and about the types of dynamical processing that shaped the solar system we see today. This paper summarizes some recent contributions to our understanding of both cometary volatiles and the composition, structure and evolution of protostellar disks.Comment: To appear in Space Science Reviews. The final publication is available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-

Globally FF-regular and log Fano varieties

We prove that every globally $F$-regular variety is log Fano. In other words, if a prime characteristic variety $X$ is globally $F$-regular, then it admits an effective \bQ-divisor $\Delta$ such that $-K_X - \Delta$ is ample and $(X, \Delta)$ has controlled (Kawamata log terminal, in fact globally $F$-regular) singularities. A weak form of this result can be viewed as a prime characteristic analog of de Fernex and Hacon's new point of view on Kawamata log terminal singularities in the non-\bQ-Gorenstein case. We also prove a converse statement in characteristic zero: every log Fano variety has globally $F$-regular type. Our techniques apply also to $F$-split varieties, which we show to satisfy a "log Calabi-Yau" condition. We also prove a Kawamata-Viehweg vanishing theorem for globally $F$-regular pairs.Comment: 31 pages, minor changes throughout. The presentation of section 5 improved. To appear in Advances in Mathematic

Water in Comets 71P/Clark and C/2004 B1 (LINEAR) with Spitzer

We present 5.5 to 7.6 micron spectra of comets 71P/Clark (2006 May 27.56 UT, r_h = 1.57 AU pre-perihelion) and C/2004 B1 (LINEAR) (2005 October 15.22 UT, r_h = 2.21 AU pre-perihelion and 2006 May 16.22 UT, r_h = 2.06 AU post-perihelion) obtained with the Spitzer Space Telescope. The nu_2 vibrational band of water is detected with a signal-to-noise ratio of 11 to 50. Fitting the spectra using a fluorescence model of water emission yields a water rotational temperature of < 18 K for 71P/Clark and approximately less than or equivalent to 14 +/- 2 K (pre-perihelion) and 23 +/- 4 K (post-perihelion) for C/2004 B1 (LINEAR). The water ortho-to-para ratio in C/2004 B1 (LINEAR) is measured to be 2.31 +/- 0.18, which corresponds to a spin temperature of 26^{+3}_{-2} K. Water production rates are derived. The agreement between the water model and the measurements is good, as previously found for Spitzer spectra of C/2003 K4 (LINEAR). The Spitzer spectra of these three comets do not show any evidence for emission from PAHs and carbonate minerals, in contrast to results reported for comets 9P/Tempel~1 and C/1995 O1 (Hale-Bopp).Comment: 16 pages, 1 table, 7 figures, ApJ accepted 200