We present multiple epochs of near-IR spectroscopy for a sample of 25 young stars, including T Tauri, Herbig Ae/Be, and FU Ori objects. Using the FSPEC instrument on the Bok 90-inch telescope, we obtained K-band spectra of the Brγ transition of hydrogen, with a resolution of ≈ 3500. Epochs were taken over a span of >1 year, sampling time-spacings of roughly one day, one month, and one year. The majority of our targets show Brγ emission, and in some cases these are the first published detections. Time-variability is seen in approximately half of the targets showing Brγ emission. We compare the observed variability with expectations for rotationally-modulated accretion onto the central stars and time-variable continuum emission or extinction from matter in the inner disk. Our observations are not entirely consistent with models of rotationally-modulated magnetospheric accretion. Further monitoring, over a larger number of epochs, will facilitate more quantitative constraints on variability timescales and amplitudes, and a more conclusive comparison with theoretical models.

Recently, new views of the current status of δ Scuti stars have been developed by Rodríguez & Breger (2001) who carried out an excellent review, listing 8 pre-main-sequence (PMS) δ Scuti candidates and examined the possibility of the existence of PMS δ Scuti variable stars. Here we discuss the nature of 4 stars from their list: 2 said to be members of NGC 2264 and 2 of NGC 6823.

We present near-IR spectra of a sample of T Tauri, Herbig Ae/Be, and FU Ori objects. Using the FSPEC instrument on the Bok 90-inch telescope, we obtained K-band spectra with a resolution of ≈ 3500. Here we present spectra of the ∆v = 2-0 and ∆v = 3-1 bandheads of ro-vibrational transitions of carbon monoxide. We observed these spectra over multiple epochs spaced by a few days and approximately one month. Several of our targets show CO emission or absorption features. However we see little evidence of variability in these features across multiple epochs. We compare our results with previous observations, and discuss the physical implications of non-variable CO emission across the sampled timescales.

Evolution has for the most part used the canonical 20 amino acids of the natural genetic code to construct proteins. While several theories regarding the evolution of the genetic code have been proposed, experimental exploration of these theories has largely been restricted to phylogenetic and computational modeling. The development of orthogonal translation systems has allowed noncanonical amino acids to be inserted at will into proteins. We have taken advantage of these advances to evolve bacteria to accommodate a 21 amino acid genetic code in which the amber codon ambiguously encodes either 3-nitro-L-tyrosine or stop. Such an ambiguous encoding strategy recapitulates numerous models for genetic code expansion, and we find that evolved lineages first accommodate the unnatural amino acid, and then begin to evolve on a neutral landscape where stop codons begin to appear within genes. The resultant lines represent transitional intermediates on the way to the fixation of a functional 21 amino acid code.

Major Depressive Disorder (MDD) is the leading cause of disability worldwide. One of MDD's most troubling symptoms is the loss of reward firing, or anhedonia. Current publications indicate that MTCH‐2, a gene associated with mitochondrial transport, is related to a decrease in firing rates in the hippocampus of mice. Additionally, a GWAS reported a link between MTCH‐2 and neuroticism in humans. Consequently, we hypothesize that a MTCH‐2 related decrease in firing rates in the nucleus accumbens could potentially play a role in the development of depressive symptoms.The C. Elegans MTCH‐1 protein shows a 87% homology to the human MTCH‐2 protein. Here, we examine the relationship between the MTCH‐1 gene and C. Elegans reward firing. Because C. Elegans reward firing levels have been associated with changes in speed change fluidity in past studies, we measure C. Elegans motility as a proxy for reward firing. In this study, we compare motility and gene expression in MTCH‐1 deficient worms and wt worms and further examine MTCH‐1 knockdown to control motility. Together, these data points may indicate a role of MTCH‐2 in depression.Support or Funding InformationThe Nueva SchoolThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.