Probing 5f-state configurations in URu2Si2 with U L3-edge resonant x-ray emission spectroscopy

Resonant x-ray emission spectroscopy (RXES) was employed at the U L3 absorption edge and the La1 emission line to explore the 5f occupancy, nf, and the degree of 5f orbital delocalization in the hidden order compound URu2Si2. By comparing to suitable reference materials such as UF4, UCd11, and alpha-U, we conclude that the 5f orbital in URu2Si2 is at least partially delocalized with nf = 2.87 +/- 0.08, and does not change with temperature down to 10 K within the estimated error. These results place further constraints on theoretical explanations of the hidden order, especially those requiring a localized f2 ground state.Comment: 11 pages,7 figure

Predicted Colors and Flux Densities of Protostars in the Herschel PACS and SPIRE Filters

Upcoming surveys with the Herschel Space Observatory will yield far-IR photometry of large samples of young stellar objects, which will require careful interpretation. We investigate the color and luminosity diagnostics based on Herschel broad-band filters to identify and discern the properties of low-mass protostars. We compute a grid of 2,016 protostars in various physical congurations, present the expected flux densities and flux density ratios for this grid of protostars, and compare Herschel observations of three protostars to the model results. These provide useful constraints on the range of colors and fluxes of protostar in the Herschel filters. We find that Herschel data alone is likely a useful diagnostic of the envelope properties of young starsComment: Part of HOPS KP papers to the Herschel special A&A issu

High efficiency GaAs-Ge tandem solar cells grown by MOCVD

High conversion efficiency and low weight are obviously desirable for solar cells intended for space applications. One promising structure is GaAs on Ge. The advantages of using Ge wafers as substrates include the following: they offer high efficiency by forming a two-junction tandem cell; low weight combined with superior strength allows usage of thin (3 mil) wafers; and they are a good substrate for GaAs, being lattice matched, thermal expansion matched, and available as large-area wafers

Physiological and morphological responses of 'Irukandji' polyps to thermal and osmotic conditions: consequences for niche profiling

The Irukandji jellyfish (Carukia barnesi) is a medically important species. While the medusa stage of this species is well known, due to its highly venomous sting, the benthic polyp has core roles in regulating both the timing and abundance of medusa making it a research priority. However, due to their small size, Carukia barnesi polyps have never been found in situ and, basic ecological knowledge surrounding this life stage is limited. In this study we adopt a lab-based approach, utilizing physiological tolerance as a functional tool, to gain new insights into the in situ location for Carukia barnesi polyps. The physiological tolerance of Carukia barnesi polyps was characterized by measuring the oxygen consumption rates of polyps exposed to different salinity/temperature combinations. A total of nine salinities and seven temperatures were investigated, ranging from 11 °C/16‰ to 34 °C/42.5‰, encompassing the spectrum of environments experienced on the Great Barrier Reef. Polyps were also monitored for morphological changes such as asexual reproduction, polyp deterioration, and mortality. Salinity did not have a significant effect on oxygen consumption rates, with Carukia barnesi polyps displaying a significant tolerance to a wide range of salinities. The effect of temperature, however, was statistically significant with oxygen °consumption rates increasing alongside water temperature. There was no statistical evidence to support an interactive effect between salinity and temperature. Based on these results, we conclude that the polyp stage of this species is likely located in an environment with stable temperatures and fluctuating salinities and, consequently, future endeavors aimed at locating this life stage should expand targeted survey areas outside stable oceanic environments, typical of medusa, and encompass dynamic environments such as estuaries and submarine freshwater upwellings

Increasing Campus Sense of Belonging through LLC Participation: To Gems Camp We Go

Gemstone seeks to develop students’ research and collaboration skills, foster leadership opportunities, and provide a sense of belonging on a large campus utilizing the Best Practices Model (BPM) and a variety of high impact practices (HIPs), like a Gemstone-specific orientation program called Gems Camp. While studies have demonstrated that LLCs increase students’ sense of belonging, the goal of this study is to explicitly test via propensity score matching if (a) enrollment in the Gemstone Honors Program increases sense of belonging compared to university students not in Gemstone and (b) attendance at Gems Camp increases sense of belonging in Gemstone students. Gemstone students (N=221) had an increased sense of belonging compared to matched university students (N=221). Moreover, Gemstone students who attended Gems Camp (N=92) had an increased sense of belonging compared to matched Gemstone students who did not attend Gems Camp (N=92). In conclusion, the Gemstone Honors Program is an example of an LLC with scaffolded high impact practices, such as intentional first year programming, undergraduate research, and collaborative projects, that promotes an increase in students’ sense of belonging, providing a model for other LLCs to consider in their programming efforts

Financial Transaction Tax: Small is Beautiful

The case for taxing financial transactions merely to raise more revenues from the financial sector is not particularly strong. Better alternatives to tax the financial sector are likely to be available. However, a tax on financial transactions could be justified in order to limit socially undesirable transactions when more direct means of doing so are unavailable for political or practical reasons. Some financial transactions are indeed likely to do more harm than good, especially when they contribute to the systemic risk of the financial system. However, such a financial transaction tax should be very small, much smaller than the negative externalities in question, because it is a blunt instrument that also drives out socially useful transactions. There is a case for taxing over-the-counter derivative transactions at a somewhat higher rate than exchange-based derivative transactions. More targeted remedies to drive out socially undesirable transactions should be sought in parallel, which would allow, after their implementation, to reduce or even phase out financialtransaction taxes