2,836 research outputs found
Short-term Response of Holcus lanatus L. (Common Velvetgrass) to Chemical and Manual Control at Yosemite National Park, USA
One of the highest priority invasive species at both Yosemite and Sequoia and Kings Canyon national parks is Holcus lanatus L. (common velvetgrass), a perennial bunchgrass that invades mid-elevation montane meadows. Despite velvetgrass being a high priority species, there is little information available on control techniques. The goal of this project was to evaluate the short-term response of a single application of common chemical and manual velvetgrass control techniques. The study was conducted at three montane sites in Yosemite National Park. Glyphosate spotspray treatments were applied at 0.5, 1.0, 1.5, and 2.0% concentrations, and compared with hand pulling to evaluate effects on cover of common velvetgrass, cover of other plant species, and community species richness. Posttreatment year 1 cover of common velvetgrass was 12.1% 6 1.6 in control plots, 6.3% 6 1.5 averaged over the four chemical treatments (all chemical treatments performed similarly), and 13.6% 6 1.7 for handpulled plots. This represents an approximately 50% reduction in common velvetgrass cover in chemically- treated plots recoded posttreatment year 1 and no statistically significant reduction in hand pulled plots compared with controls. However, there was no treatment effect in posttreatment year 2, and all herbicide application rates performed similarly. In addition, there were no significant treatment effects on nontarget species or species richness. These results suggest that for this level of infestation and habitat type, (1) one year of hand pulling is not an effective control method and (2) glyphosate provides some level of control in the short-term without impact to nontarget plant species, but the effect is temporary as a single year of glyphosate treatment is ineffective over a twoyear period
Polarization dOTF: on-sky focal plane wavefront sensing
The differential Optical Transfer Function (dOTF) is a focal plane wavefront
sensing method that uses a diversity in the pupil plane to generate two
different focal plane images. The difference of their Fourier transforms
recovers the complex amplitude of the pupil down to the spatial scale of the
diversity. We produce two simultaneous PSF images with diversity using a
polarizing filter at the edge of the telescope pupil, and a polarization camera
to simultaneously record the two images. Here we present the first on-sky
demonstration of polarization dOTF at the 1.0m South African Astronomical
Observatory telescope in Sutherland, and our attempt to validate it with
simultaneous Shack-Hartmann wavefront sensor images.Comment: 11 pages, 9 figures, Proc. SPIE Vol. 991
Four decades of open language science:the CHILDES Project
The Child Language Data Exchange System (CHILDES), created by Brain MacWhinney and Catherine Snow in 1984, is one of the earliest Open Science and data sharing initiatives in child language development research, and probably in developmental psychology and the behavioral sciences more generally. It is the cornerstone of TalkBank––a repository of transcripts, audio, and video files of natural language samples. Here we highlight how the CHILDES Project served as a trailblazer for the language development research community by being the first initiative to introduce a Big Data approach, encouraging and facilitating crosslinguistic data collection and championing science collaboration through open access to data and analysis tools. We conclude with an outlook on the future of CHILDES and suggestions for where child language development researchers might turn their attention when collecting and donating observational data. Understanding the many paths to language will require expanding CHILDES to increase representation of culturally and neurally diverse populations, finding solutions to the challenge of promoting Open Science practices while safeguarding participant agency and privacy, and leveraging AI tools for automated transcription and data analysis
Debye relaxation in high magnetic fields
Dielectric relaxation is universal in characterizing polar liquids and
solids, insulators, and semiconductors, and the theoretical models are well
developed. However, in high magnetic fields, previously unknown aspects of
dielectric relaxation can be revealed and exploited. Here, we report low
temperature dielectric relaxation measurements in lightly doped silicon in high
dc magnetic fields B both parallel and perpendicular to the applied ac electric
field E. For B//E, we observe a temperature and magnetic field dependent
dielectric dispersion e(w)characteristic of conventional Debye relaxation where
the free carrier concentration is dependent on thermal dopant ionization,
magnetic freeze-out, and/or magnetic localization effects. However, for BperpE,
anomalous dispersion emerges in e(w) with increasing magnetic field. It is
shown that the Debye formalism can be simply extended by adding the Lorentz
force to describe the general response of a dielectric in crossed magnetic and
electric fields. Moreover, we predict and observe a new transverse dielectric
response EH perp B perp E not previously described in magneto-dielectric
measurements. The new formalism allows the determination of the mobility and
the ability to discriminate between magnetic localization/freeze out and
Lorentz force effects in the magneto-dielectric response.Comment: 19 pages, 6 figure
A randomized controlled trial to evaluate the effect of a new skincare regimen on skin barrier function in those with podoconiosis in Ethiopia.
BACKGROUND: Podoconiosis affects an estimated 3 million people in Ethiopia with a further 19 million at risk. Volcanic soil and pathogens enter skin breaches in the feet causing inflammation, lymphoedema and hyperkeratosis. There is no robust evidence on optimal podoconiosis skincare regimens to improve skin barrier function (SBF). OBJECTIVES: To evaluate the effectiveness of a new, low-cost, evidence-based intervention to improve SBF in the lower limbs of those with podoconiosis. METHODS: A randomized controlled trial (NCT02839772) was conducted over 3 months in two podoconiosis clinics (n = 193). The intervention comprised 2% (v/v) glycerine added to a reduced volume of soaking water. The control group received the current skincare regimen. Primary outcome measures were transepidermal water loss (TEWL) and stratum corneum hydration (SCH) at four specific sites on the lower limbs. RESULTS: Improvement in SBF was observed in both groups across all measurement sites and time points, although this was significantly greater in the experimental group. TEWL reduced in both groups at all sites. For example, on top of the foot the estimated group difference in TEWL at visit 4 was 1·751 [standard error (SE) = 0·0390] in favour of the experimental group [t = 3·15, degrees of freedom (df) = 189·58, P = 0·002, 95% confidence interval (CI) 0·066-2·85], indicating a greater reduction in TEWL in the experimental group. Similarly, at the same site the estimated group difference in SCH at visit 4 was -2·041 (SE = 0·572) in favour of the experimental group (t = -3·56, df = 186·74, P < 0·001, 95% CI -3·16 to -0·91), indicating a greater increase in SCH in the experimental group. There were also significantly greater reductions in odour, number of wounds and largest foot circumference in the experimental vs. the control group. CONCLUSIONS: The addition of 2% (v/v) glycerol to a reduced volume (83% reduction) of soaking water significantly improved SBF
A Pilot Survey for the HO Southern Galactic Plane Survey (HOPS)
We describe observations with the Mopra radiotelescope designed to assess the
feasibility of the HO maser southern Galactic plane survey (HOPS). We
mapped two one-square-degree regions along the Galactic plane using the new 12
mm receiver and the UNSW Mopra spectrometer (MOPS). We covered the entire
spectrum between 19.5 and 27.5 GHz using this setup with the main aims of
finding out which spectral lines can be detected with a quick mapping survey.
We report on detected emission from HO masers, NH inversion transitions
(1,1), (2,2) and (3,3), HCN (3-2), as well as several radio recombination
lines.Comment: accepted by PAS
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