918 research outputs found
Multi-filter transit observations of WASP-39b and WASP-43b with three San Pedro M\'artir telescopes
Three optical telescopes located at the San Pedro M\'artir National
Observatory were used for the first time to obtain multi-filter defocused
photometry of the transiting extrasolar planets WASP-39b and WASP-43b. We
observed WASP-39b with the 2.12m telescope in the U filter for the first time,
and additional observations were carried out in the R and I filters using the
0.84m telescope. WASP-43b was observed in VRI with the same instrument, and in
the i filter with the robotic 1.50m telescope. We reduced the data using
different pipelines and performed aperture photometry with the help of custom
routines, in order to obtain the light curves. The fit of the light curves
(1.5--2.5mmag rms), and of the period analysis, allowed a revision of the
orbital and physical parameters, revealing for WASP-39b a period ( days) which is seconds larger than
previously reported. Moreover, we find for WASP-43b a planet/star radius
() which is larger in the i filter
with respect to previous works, and that should be confirmed with additional
observations. Finally, we confirm no evidence of constant period variations in
WASP-43b.Comment: 13 pages, 7 figures, accepted in PASP, scheduled for the February 1,
2015 issu
Incentivizing Information Literacy Integration: A Case Study on Faculty–Librarian Collaboration
Frequently, information literacy instruction takes the form of a one-shot library session with minimal collaboration between librarians and teaching faculty. To offer an alternative to this model, librarians implemented the Information Literacy Mini-Grant; an incentivized program inviting teaching faculty to collaborate with librarians to redesign an assignment to integrate information literacy into their course. Following the semester-long collaboration, teaching faculty provided written feedback and participated in a panel discussion to share their experiences with the program. This case study examines teaching faculty’s perceptions of collaborating with librarians in the pilot year of the program. Teaching faculty’s feedback provided insights into their perceptions of librarians, their thoughts regarding librarians’ unique expertise as pedagogical partners, and the challenges of collaborations. This case study considers the successes and challenges of the program and provides recommendations for future faculty-librarian collaborations that position librarians as partners in student learning
Dosimetry characterization of P intravascular brachytherapy source wires using Monte Carlo codes PENELOPE and GEANT4
Monte Carlo calculations using the codes PENELOPE and GEANT4 have been
performed to characterize the dosimetric parameters of the new 20 mm long
catheter based P beta source manufactured by Guidant Corporation. The
dose distribution along the transverse axis and the two dimensional dose rate
table have been calculated. Also, the dose rate at the reference point, the
radial dose function and the anisotropy function were evaluated according to
the adapted TG-60 formalism for cylindrical sources. PENELOPE and GEANT4 codes
were first verified against previous results corresponding to the old 27 mm
Guidant P beta source. The dose rate at the reference point for the
unsheathed 27 mm source in water was calculated to be cGy
s mCi, for PENELOPE, and cGy s
mCi, for GEANT4. For the unsheathed 20 mm source these values were
cGy s mCi and cGy s
mCi, respectively. Also, a comparison with the limited data available on
this new source is shown. We found non negligible differences between the
results obtained with PENELOPE and GEANT4.Comment: 13 pages, 7 figures, 7 tables (accepted for publication in Medical
Physics
Elevated CO\u3csub\u3e2\u3c/sub\u3e further lengthens growing season under warming conditions
Observations of a longer growing season through earlier plant growth in temperate to polar regions have been thought to be a response to climate warming. However, data from experimental warming studies indicate that many species that initiate leaf growth and flowering earlier also reach seed maturation and senesce earlier, shortening their active and reproductive periods. A conceptual model to explain this apparent contradiction, and an analysis of the effect of elevated CO2—which can delay annual life cycle events—on changing season length, have not been tested. Here we show that experimental warming in a temperate grassland led to a longer growing season through earlier leaf emergence by the first species to leaf, often a grass, and constant or delayed senescence by other species that were the last to senesce, supporting the conceptual model. Elevated CO2 further extended growing, but not reproductive, season length in the warmed grassland by conserving water, which enabled most species to remain active longer. Our results suggest that a longer growing season, especially in years or biomes where water is a limiting factor, is not due to warming alone, but also to higher atmospheric CO2 concentrations that extend the active period of plant annual life cycles
Multi-transmission-line-beam interactive system
We construct here a Lagrangian field formulation for a system consisting of
an electron beam interacting with a slow-wave structure modeled by a possibly
non-uniform multiple transmission line (MTL). In the case of a single line we
recover the linear model of a traveling wave tube (TWT) due to J.R. Pierce.
Since a properly chosen MTL can approximate a real waveguide structure with any
desired accuracy, the proposed model can be used in particular for design
optimization. Furthermore, the Lagrangian formulation provides for: (i) a clear
identification of the mathematical source of amplification, (ii) exact
expressions for the conserved energy and its flux distributions obtained from
the Noether theorem. In the case of uniform MTLs we carry out an exhaustive
analysis of eigenmodes and find sharp conditions on the parameters of the
system to provide for amplifying regimes
VizieR Online Data Catalog: WASP-39b and WASP-43b light curves (Ricci+, 2015)
The instrument comes with a set of standard UBVRI Johnson filters among others. We present observations carried out using the VRI filters. Light curves of WASP-39b were obtained with the 0.84m telescope in R and I bands and with the 2.12m telescope in the U band. Light curves of WASP-43b were obtained with the 0.84m telescope in VRI bands and with the 1.50m telescope in the Gunn-i band. (2 data files
Foodways in transition: food plants, diet and local perceptions of change in a Costa Rican Ngäbe community
Background
Indigenous populations are undergoing rapid ethnobiological, nutritional and socioeconomic transitions while being increasingly integrated into modernizing societies. To better understand the dynamics of these transitions, this article aims to characterize the cultural domain of food plants and analyze its relation with current day diets, and the local perceptions of changes given amongst the Ngäbe people of Southern Conte-Burica, Costa Rica, as production of food plants by its residents is hypothesized to be drastically in recession with an decreased local production in the area and new conservation and development paradigms being implemented.
Methods
Extensive freelisting, interviews and workshops were used to collect the data from 72 participants on their knowledge of food plants, their current dietary practices and their perceptions of change in local foodways, while cultural domain analysis, descriptive statistical analyses and development of fundamental explanatory themes were employed to analyze the data.
Results
Results show a food plants domain composed of 140 species, of which 85 % grow in the area, with a medium level of cultural consensus, and some age-based variation. Although many plants still grow in the area, in many key species a decrease on local production–even abandonment–was found, with much reduced cultivation areas. Yet, the domain appears to be largely theoretical, with little evidence of use; and the diet today is predominantly dependent on foods bought from the store (more than 50 % of basic ingredients), many of which were not salient or not even recognized as ‘food plants’ in freelists exercises. While changes in the importance of food plants were largely deemed a result of changes in cultural preferences for store bought processed food stuffs and changing values associated with farming and being food self-sufficient, Ngäbe were also aware of how changing household livelihood activities, and the subsequent loss of knowledge and use of food plants, were in fact being driven by changes in social and political policies, despite increases in forest cover and biodiversity.
Conclusions
Ngäbe foodways are changing in different and somewhat disconnected ways: knowledge of food plants is varied, reflecting most relevant changes in dietary practices such as lower cultivation areas and greater dependence on food from stores by all families. We attribute dietary shifts to socioeconomic and political changes in recent decades, in particular to a reduction of local production of food, new economic structures and agents related to the State and globalization
Inclusive production of and mesons in charged current interactions
The inclusive production of the meson resonances ,
and in neutrino-nucleus charged current interactions has been
studied with the NOMAD detector exposed to the wide band neutrino beam
generated by 450 GeV protons at the CERN SPS. For the first time the
meson is observed in neutrino interactions. The statistical
significance of its observation is 6 standard deviations. The presence of
in neutrino interactions is reliably established. The average
multiplicity of these three resonances is measured as a function of several
kinematic variables. The experimental results are compared to the
multiplicities obtained from a simulation based on the Lund model. In addition,
the average multiplicity of in antineutrino - nucleus
interactions is measured.Comment: 23 pages, 14 figures, 8 tables. To appear in Nucl. Phys.
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