Observations and Modeling of the Companions of Short Period Binary Millisecond Pulsars: Evidence for High-Mass Neutron Stars

We present observations of fields containing eight recently discovered binary millisecond pulsars using the telescopes at MDM Observatory. Optical counterparts to four of these systems are detected, one of which, PSR J2214+3000, is a novel detection. Additionally, we present the fully phase-resolved B, V, and R light curves of the optical counterparts to two objects, PSR J1810+1744 and PSR J2215+5135 for which we employ model fitting using the ELC model of Orosz & Hauschildt (2000) to measure the unknown system parameters. For PSR J1810+1744 we find that the system parameters cannot be fit even assuming that 100% of the spin-down luminosity of the pulsar is irradiating the secondary, and so radial velocity measurements of this object will be required for the complete solution. However, PSR J2215+5135 exhibits light curves that are extremely well constrained using the ELC model and we find that the mass of the neutron star is constrained by these and the radio observations to be greater than 1.75 solar masses at the 3-sigma level. We also find a discrepancy between the model temperature and the measured colors of this object which we interpret as possible evidence for an additional high-temperature source such as a quiescent disk. Given this and the fact that PSR J2214+5135 contains a relatively high mass companion (greater than 0.1 solar masses), we propose that similar to the binary pulsar systems PSR J1023+0038 and IGR J18245-2452, the pulsar may transition between accretion- and rotation-powered modes.Comment: Submitted to ApJ, 12 pages, 5 figures, 2 table

The UV photochemistry of C2N2

The absorption, emission, and photodissociation yield spectra of C2N2 were measured in the 220 and 210 nm region near the 4(0)1 and 1(0)1 4(0)1 bands of the A 1 sigma + from the X 1 sigma + system. The emission spectrum showed very few lines which appeared in the absorption spectrum. Moreover, the emission had 660 ns lifetime and, at 210 nm a very large electronic emission quenching rate. Laser induced fluorescence was used to measure the relative yield of CN radicals as a function of photolysis wavelength. This spectrum seemed to follow the absorption spectrum below the dissociation threshold. Energy in the CN fragments appeared to be statistically distributed

The heat of formation of CN radicals and radiative lifetimes of the A 1 Sigma - state of C2N2

Radiative lifetimes have been measured for the stable vibrational levels of the A 1 sigma - electronic state of C2N2. They range from 1.3 microsec for the 4(sub 0)(sup 1) level to 0.66 microsec for the 1(sub 0)(sup 1) 4(sub 0)(sup 1) level and in general decrease with increasing vibrational excitation. Self-quenching rate constants range from gas kinetic to ten times that. Foreign gas quenching rates are slower. Observation of emission from the 1(sub 0)(sup 1) 4(sub 0)(sup 1) level sets a lower limit for the heat of formation of CN of 439.11 kJ/mol

Photosensitivity, corneal scarring and developmental delay: Xeroderma Pigmentosum in a tropical country

We present the case of an 8 year-old girl in a developing country with significant corneal scarring and multiple cutaneous skin lesions in sun-exposed areas. Neuro-developmental delay had been present since 3 months of age, and taken as a whole the consensus was that this clinical picture was consistent with Xeroderma Pigmentosum (XP). We highlight the difficulties encountered due to the lack of diagnostic and treatment modalities for this child, and offer a brief review of XP, including emerging treatments that show potential

Boston Hospitality Review: Fall 2015

U.S. Lodging Industry Update – Q2 2015 by Daniel Lesser and Jonathan Jaeger of LW Hospitality Advisors® -- Hotel Crowdfunding Grows Up by Joshua Bowman -- Digital Marketing Budgets for Independent Hotels: Continuously Shifting to Remain Competitive in the Online World by Leora Halpern Lanz and Megan Carmichael -- From Patrons to Chefs, a History of Women in Restaurants by Jan Whitaker -- The Bleacher Bar at Fenway Park: Transforming a Former Indoor Batting Cage Into a Unique Eatery and Bar by Graham Ruggie -- Outrageous by Michael Oshin

Encouraging girls in math and science

The objective of this guide is to provide teachers with specific recommendations that can be carried out in the classroom without requiring systemic change. Other school personnel having direct contact with students, such as coaches, counselors, and principals, will also find the guide useful

Comment on "Scrutinizing the carbon cycle and CO2residence time in the atmosphere" by H. Harde

Harde (2017) proposes an alternative accounting scheme for the modern carbon cycle and concludes that only 4.3% of today's atmospheric CO2 is a result of anthropogenic emissions. As we will show, this alternative scheme is too simple, is based on invalid assumptions, and does not address many of the key processes involved in the global carbon cycle that are important on the timescale of interest. Harde (2017) therefore reaches an incorrect conclusion about the role of anthropogenic CO2 emissions. Harde (2017) tries to explain changes in atmospheric CO2 concentration with a single equation, while the most simple model of the carbon cycle must at minimum contain equations of at least two reservoirs (the atmosphere and the surface ocean), which are solved simultaneously. A single equation is fundamentally at odds with basic theory and observations. In the following we will (i) clarify the difference between CO2 atmospheric residence time and adjustment time, (ii) present recently published information about anthropogenic carbon, (iii) present details about the processes that are missing in Harde (2017), (iv) briefly discuss shortcoming in Harde's generalization to paleo timescales, (v) and comment on deficiencies in some of the literature cited in Harde (2017)

Epistasis not needed to explain low dN/dS

An important question in molecular evolution is whether an amino acid that occurs at a given position makes an independent contribution to fitness, or whether its effect depends on the state of other loci in the organism's genome, a phenomenon known as epistasis. In a recent letter to Nature, Breen et al. (2012) argued that epistasis must be "pervasive throughout protein evolution" because the observed ratio between the per-site rates of non-synonymous and synonymous substitutions (dN/dS) is much lower than would be expected in the absence of epistasis. However, when calculating the expected dN/dS ratio in the absence of epistasis, Breen et al. assumed that all amino acids observed in a protein alignment at any particular position have equal fitness. Here, we relax this unrealistic assumption and show that any dN/dS value can in principle be achieved at a site, without epistasis. Furthermore, for all nuclear and chloroplast genes in the Breen et al. dataset, we show that the observed dN/dS values and the observed patterns of amino acid diversity at each site are jointly consistent with a non-epistatic model of protein evolution.Comment: This manuscript is in response to "Epistasis as the primary factor in molecular evolution" by Breen et al. Nature 490, 535-538 (2012