Gambelia copeii

Number of Pages: 8Integrative BiologyGeological Science

The Search for Million Degree Gas Through The NVII Hyperfine Line

Gas in the million degree range occurs in a variety of astronomical environments, and it may be the main component of the elusive missing baryons at low redshift. The NVII ion is found in this material and it has a hyperfine spin-flip transition with a rest frequency of 53.042 GHz, which can be observed for z > 0.1, when it is shifted into a suitably transparent radio band. We used the 42-48 GHz spectrometer on the Green Bank Telescope to search for both emission and absorption from this NVII transmission. For absorption studies, 3C273, 3C 279, 3C 345, and 4C+39.25 were observed but no feature were seen above the 5 sigma level. For emission line studies, we observed Abell 1835, Abell 2390 and the star-forming galaxy PKS 1345+12, but no features were seen exceeding 5 sigma. We examine whether the strongest emission feature, in Abell 2390 (3.7 sigma), and the strongest absorption feature, toward 4C+39.25 (3.8 sigma), might be expected from theoretical models. The emission feature would require ~1E10 Msolar of 1E6 K gas, which is inconsistent with X-ray limits for the O VII Kalpha line, so it is unlikely to be real. The NVII absorption feature requires a NVII column of 6E16 cm^-2, higher than model predictions by at least an order of magnitude, which makes it inconsistent with model expectations. The individual observations were less than 1 hr in length, so for lengthy observations, we show that NVII absorption line observations can begin to be useful in in the search for hot intergalactic gas.Comment: 27 total pages; 16 figures; Accepted for publication in The Astrophysical Journa

DATA SHARING PRACTICES AND ATTITUDES OF SCIENTISTS IN THE GULF COOPERATION COUNCIL (GCC) COUNTRIES

Advances in science and technology over the last century have brought dramatic changes to most societies of the world, with a parallel increase in the amounts of research data being produced. Scientific progress in the Middle East geographic region of the world has, in general, lagged far behind Western countries during this same time period. Several Gulf Cooperation Council (GCC) Persian Gulf countries of the Middle East have recently made huge investments in developing their educational and research capacities, with the goal of establishing a culture and practice of scientific innovation. Several recent studies looking at data sharing and re-use among scientists in North America and Europe have insisted that sharing data is central to the goals of scientific progress. Using the Diffusion of Innovation Theory as a framework, this research looked at the data sharing practices and perspectives of scientists in the Middle East, through the lens of the four main elements of this theory: the innovation, communication channels, time, and the social system. The analysis of this phenomenon may provide a clearer understanding of data sharing as part of the emerging practice of conducting scientific research and its importance to the region. A mixed-methods research approach, using semi-structured interviews and an online survey, was conducted with scientific researchers in GCC nations. A separate analysis was conducted for the country of Qatar

The Effect of Rutin on Swine Serum Cholesterol and Lipoproteins

A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Jimmy R. Salyer on May 8, 1979

Observation of narrow fluorescence from doubly driven four-level atoms at room temperature

Unusually narrow fluorescence peaks are seen from Rubidium-85 atoms under the action of two driving laser fields that are in a three dimensional molasses configuration. One of the lasers is held at a fixed detuning from the "cooling" transition, while the other is scanned across the "repumping" transitions. The fluorescence peaks are split into symmetric pairs, with the seperation within a pair increasing with the detuning of the cooling laser. For large detunings additional small peaks are seen. A simple model is proposed to explain these experimental observations.Comment: 8 pages, 4 figures, needs epl.cl

On the electromagnetic form factors of the proton from generalized Skyrme models

We compare the prediction of Skyrme-like effective Lagrangians with data for electromagnetic form factors of proton and consider the possibility of fixing the parameters of these higher-order Lagrangians. Our results indicate that one or two-parameter models can lead to better agreement with the data but more accurate determination of the effective Lagragian faces theoretical uncertainties.Comment: 8 pages, 2 figures, revte

Training Curricula for Open Domain Answer Re-Ranking

In precision-oriented tasks like answer ranking, it is more important to rank many relevant answers highly than to retrieve all relevant answers. It follows that a good ranking strategy would be to learn how to identify the easiest correct answers first (i.e., assign a high ranking score to answers that have characteristics that usually indicate relevance, and a low ranking score to those with characteristics that do not), before incorporating more complex logic to handle difficult cases (e.g., semantic matching or reasoning). In this work, we apply this idea to the training of neural answer rankers using curriculum learning. We propose several heuristics to estimate the difficulty of a given training sample. We show that the proposed heuristics can be used to build a training curriculum that down-weights difficult samples early in the training process. As the training process progresses, our approach gradually shifts to weighting all samples equally, regardless of difficulty. We present a comprehensive evaluation of our proposed idea on three answer ranking datasets. Results show that our approach leads to superior performance of two leading neural ranking architectures, namely BERT and ConvKNRM, using both pointwise and pairwise losses. When applied to a BERT-based ranker, our method yields up to a 4% improvement in MRR and a 9% improvement in P@1 (compared to the model trained without a curriculum). This results in models that can achieve comparable performance to more expensive state-of-the-art techniques.Comment: Accepted at SIGIR 2020 (long