Contextualised Browsing in a Digital Library's Living Lab

Contextualisation has proven to be effective in tailoring \linebreak search results towards the users' information need. While this is true for a basic query search, the usage of contextual session information during exploratory search especially on the level of browsing has so far been underexposed in research. In this paper, we present two approaches that contextualise browsing on the level of structured metadata in a Digital Library (DL), (1) one variant bases on document similarity and (2) one variant utilises implicit session information, such as queries and different document metadata encountered during the session of a users. We evaluate our approaches in a living lab environment using a DL in the social sciences and compare our contextualisation approaches against a non-contextualised approach. For a period of more than three months we analysed 47,444 unique retrieval sessions that contain search activities on the level of browsing. Our results show that a contextualisation of browsing significantly outperforms our baseline in terms of the position of the first clicked item in the result set. The mean rank of the first clicked document (measured as mean first relevant - MFR) was 4.52 using a non-contextualised ranking compared to 3.04 when re-ranking the result lists based on similarity to the previously viewed document. Furthermore, we observed that both contextual approaches show a noticeably higher click-through rate. A contextualisation based on document similarity leads to almost twice as many document views compared to the non-contextualised ranking.Comment: 10 pages, 2 figures, paper accepted at JCDL 201

Launch Facility Requirements for a Liquid Fluorine Upper Stage

In a parallel activity to the development of a liquid fluorine upper stage vehicle, the problems associated with the launch facility must be addressed. This paper describes the factors that must be considered in the design and operation of such a facility. Among the factors discussed are general fluorine system requirements, launch facility requirements, safety considerations, and modification costs. Specific attention is given to storage and transfer, vapor disposal, leak detection, spills, aborts, range safety, and personnel protection

Using willow riparian buffer strips for biomass production and riparian protection

Non-Peer ReviewedThere is increasing interest in the development of willow biomass as a renewable source of energy and woody lignocellulosic feedstock for bioproducts. Riparian buffers have been identified as an effective barrier to soil and nutrient movement from agricultural fields into watercourse. Willows are ideal riparian species in that they are well adapted to growing conditions in riparian zones and they vigorously re-grow following coppicing which allows them to be harvested for biomass in 3-4 year cycles. Characteristically riparian edges are highly productive due to water availability, therefore it is anticipated that willow biomass yield per unit area in riparian zones would be attractive. Research is being conducted to determine if using riparian buffer strips for willow biomass production provides energy alternatives and economic opportunities for land owners, but also leads to environmental benefits such as reduced erosion and nutrient leaching and preservation of water quality

Sociologia moral das dependências motivadas: o caso da dependência amorosa

Este artigo propõe um panorama do procedimento e dos métodos da sociologia moral, que se baseiam em uma etnofilosofia da existência social comum e em uma antropologia natural. A primeira parte do texto situa a sociologia moral em relação ao desenvolvimento contemporâneo das pesquisas empíricas sobre a ética, sobretudo no âmbito da psicologia experimental e evolucionista. A segunda parte apresenta alguns elementos de uma teoria das dependências motivadas aos prazeres e às recompensas, desenvolvida a partir do aporte das neurociências da adição e de pesquisas de campo sobre as condutas aditivas e as tentativas de restabelecimento. A terceira parte propõe uma ilustração do método a partir de uma pesquisa recente sobre a dependência amorosa, feita principalmente a partir de um corpus literário e cinematográfico

First results from Faint Infrared Grism Survey (FIGS): first simultaneous detection of Lyman-alpha emission and Lyman break from a galaxy at z=7.51

Galaxies at high redshifts provide a valuable tool to study cosmic dawn, and therefore it is crucial to reliably identify these galaxies. Here, we present an unambiguous and first simultaneous detection of both the Lyman-alpha emission and the Lyman break from a z = 7.512+/- 0.004 galaxy, observed in the Faint Infrared Grism Survey (FIGS). These spectra, taken with G102 grism on Hubble Space Telescope (HST), show a significant emission line detection (6 sigma) in multiple observational position angles (PA), with total integrated Ly{\alpha} line flux of 1.06+/- 0.12 e10-17erg s-1cm-2. The line flux is nearly a factor of four higher than the previous MOSFIRE spectroscopic observations of faint Ly{\alpha} emission at {\lambda} = 1.0347{\mu}m, yielding z = 7.5078+/- 0.0004. This is consistent with other recent observations implying that ground-based near-infrared spectroscopy underestimates total emission line fluxes, and if confirmed, can have strong implications for reionization studies that are based on ground-based Lyman-{\alpha} measurements. A 4-{\sigma} detection of the NV line in one PA also suggests a weak Active Galactic Nucleus (AGN), potentially making this source the highest-redshift AGN yet found. Thus, this observation from the Hubble Space Telescope clearly demonstrates the sensitivity of the FIGS survey, and the capability of grism spectroscopy to study the epoch of reionization.Comment: Published in ApJL; matches published versio

Internationalization of the curriculum through student-led climate change teaching activity

Internationalization of the curriculum is important in today's globalized environment, with the increasingly interdisciplinary nature of complex issues, such as climate change, requiring students to think beyond their disciplinary and cultural boundaries. Here we introduce a novel cross-discipline and cross-country activity with the overall goal to expose students to an international environmental problem (climate change) that requires an awareness of different perspectives, so as to contribute to their development of responsible global citizenship through internationalization of the curriculum. Students studying in Australia and the United States of America completed an anonymous survey on their climate change perceptions, and then the students discussed the results via a live video link. The survey results provided the catalyst for students to reflect on the ecological impact of their different lifestyles. The students could demonstrate their critical thinking skills and develop cross disciplinary thinking by exploring the vexed issue of climate change science, perceptions, and culture. Overall, the survey was simple to implement and the tutorial was successful despite the different time zones. Our activity achieved the broader goal of internationalization of student learning and enhanced our students' ability to view problems from different angles and helped foster boundary-crossing skills

Onset of Cosmic Reionization: Evidence of An Ionized Bubble Merely 680 Myrs after the Big Bang

While most of the inter-galactic medium (IGM) today is permeated by ionized hydrogen, it was largely filled with neutral hydrogen for the first 700 million years after the Big Bang. The process that ionized the IGM (cosmic reionization) is expected to be spatially inhomogeneous, with fainter galaxies playing a significant role. However, we still have only a few direct constraints on the reionization process. Here we report the first spectroscopic confirmation of two galaxies and very likely a third galaxy in a group (hereafter EGS77) at redshift z = 7.7, merely 680 Myrs after the Big Bang. The physical separation among the three members is < 0.7 Mpc. We estimate the radius of ionized bubble of the brightest galaxy to be about 1.02 Mpc, and show that the individual ionized bubbles formed by all three galaxies likely overlap significantly, forming a large yet localized ionized region, which leads to the spatial inhomogeneity in the reionization process. It is striking that two of three galaxies in EGS77 are quite faint in the continuum, thanks to our selection of reionizing sources using their Lyman-alpha line emission. Indeed, one is the faintest spectroscopically confirmed galaxy yet discovered at such high redshifts. Our observations provide direct constraints in the process of cosmic reionization, and allow us to investigate the properties of sources responsible for reionizing the universe.Comment: Submitted after addressing referee's comment

Discovery of a z = 7.452 High Equivalent Width Ly\u3b1 Emitter from the Hubble Space Telescope Faint Infrared Grism Survey

We present the results of an unbiased search for Ly\u3b1 emission from continuum-selected 5.6 &lt; z &lt; 8.7 galaxies. Our data set consists of 160 orbits of G102 slitless grism spectroscopy obtained with the Hubble Space Telescope(HST)/WFC3 as part of the Faint Infrared Grism Survey (FIGS; PI: Malhotra), which obtains deep slitless spectra of all sources in four fields, and was designed to minimize contamination in observations of previously identified high-redshift galaxy candidates. The FIGS data can potentially spectroscopically confirm the redshifts of galaxies, and as Ly\u3b1 emission is resonantly scattered by neutral gas, FIGS can also constrain the ionization state of the intergalactic medium during the epoch of reionization. These data have sufficient depth to detect Ly\u3b1 emission in this epoch, as Tilvi et al. have published the FIGS detection of previously known Ly\u3b1 emission at z = 7.51. The FIGS data use five separate roll angles of HST to mitigate the contamination by nearby galaxies. We created a method that accounts for and removes the contamination from surrounding galaxies and also removes any dispersed continuum light from each individual spectrum. We searched for significant (&gt;4\u3c3) emission lines using two different automated detection methods, free of any visual inspection biases. Applying these methods on photometrically selected high-redshift candidates between 5.6 &lt; z &lt; 8.7, we find two emission lines, one previously published by Tilvi et al., (2016) and a new line at 1.028 \u3bcm, which we identify as Ly\u3b1 at z = 7.452 \ub1 0.003. This newly spectroscopically confirmed galaxy has the highest Ly\u3b1 rest-frame equivalent width (EWLy\u3b1) yet published at z &gt; 7 (140.3 \ub1 19.0 -)

FIGS-Faint Infrared Grism Survey: Description and Data Reduction

The Faint Infrared Grism Survey (FIGS) is a deep Hubble Space Telescope (HST) WFC3/IR (Wide Field Camera 3 Infrared) slitless spectroscopic survey of four deep fields. Two fields are located in the Great Observatories Origins Deep Survey-North (GOODS-N) area and two fields are located in the Great Observatories Origins Deep Survey-South (GOODS-S) area. One of the southern fields selected is the Hubble Ultra Deep Field. Each of these four fields were observed using the WFC3/G102 grism (0.8 μm–1.15 μm continuous coverage) with a total exposure time of 40 orbits (≈100 kilo-seconds) per field. This reaches a $3\sigma$ continuum depth of $\approx 26$ AB magnitudes and probes emission lines to $\sim {10}^{-17}\,\mathrm{erg}\,{{\rm{s}}}^{-1}\,{\mathrm{cm}}^{-2}$. This paper details the four FIGS fields and the overall observational strategy of the project. A detailed description of the Simulation Based Extraction (SBE) method used to extract and combine over 10,000 spectra of over 2000 distinct sources brighter than ${m}_{F105W}=26.5$ mag is provided. High fidelity simulations of the observations is shown to significantly improve the background subtraction process, the spectral contamination estimates, and the final flux calibration. This allows for the combination of multiple spectra to produce a final high quality, deep, 1D spectra for each object in the survey