8,371 research outputs found
A Quantitative Non-radial Oscillation Model for the Subpulses in PSR B0943+10
In this paper, we analyze time series measurements of PSR B0943+10 and fit
them with a non-radial oscillation model. The model we apply was first
developed for total intensity measurements in an earlier paper, and expanded to
encompass linear polarization in a companion paper to this one. We use PSR
B0943+10 for the initial tests of our model because it has a simple geometry,
it has been exhaustively studied in the literature, and its behavior is
well-documented. As prelude to quantitative fitting, we have reanalyzed
previously published archival data of PSR B0943+10 and uncovered subtle but
significant behavior that is difficult to explain in the framework of the
drifting spark model. Our fits of a non-radial oscillation model are able to
successfully reproduce the observed behavior in this pulsar.Comment: 45 pages, 16 figures, accepted Ap
Weed Infestation: A Service Learning Capstone Project
Infestation of weeds can be most upsetting to anyone who finds themselves dealing with them. Whether they are in your garden, lawn, or you pass by them thinking they are a pretty flower, weeds definitely make their appearance in most places. For ranchers, weeds can take a huge toll on them and their operation. Since I live on a ranch it was only fit for me to create a project that would not only benefit myself and other ranchers in the Harney County community. My project was about the importance of weed control. It is a huge part of ranching life and is a big problem in the Harney County ranching community. The sole purpose of this project was to gather information regarding the destruction of weeds through research and interviews around the community and online. I want this project to be successful for years to come and not to stop after this class. This is a project I am dearly passionate about and I truly want to fix using the research and interviews within the ranching community. My main purpose was to engage the community, educate the community and get the community more involved in controlling the infestation of weeds that seems to be affecting our soil, crops and cattle production. It will take the entire ranching community in working together to solve this problem. One can see the impact that weeds have on ranchers, but this is an issue that can be turned around if everyone is willing to do their part in fixing it. Three keywords that I would choose to describe my project would be; innovative, creative, and necessary
A precise description of the p-adic valuation of the number of alternating sign matrices
Following Sun and Moll, we study v_p(T(N)), the p-adic valuation of the
counting function of the alternating sign matrices. We find an exact analytic
expression for it that exhibits the fluctuating behaviour, by means of Fourier
coefficients. The method is the Mellin-Perron technique, which is familiar in
the analysis of the sum-of-digits function and related quantities
Planar laser-induced fluorescence imaging of OH in the exhaust of a bi-propellant thruster
Planar laser-induced fluorescence imaging of the hydroxyl radical has been performed on the flow produced by the exhaust of a subscale H2/O2 fueled bi-propellant rocket engine. Measurements were made to test the feasibility of OH (0,0) and (3,0) excitation strategies by using injection seeded XeCl and KrF excimer lasers, respectively. The flow is produced with hydrogen and oxygen reacting at a combustor chamber pressure of 5 atm which then exhausts to the ambient. The hydroxyl concentration in the exhaust flow is approximately 8 percent. Fluorescence images obtained by pumping the Q1(3) transition in the (0,0) band exhibited very high signals but also showed the effect of laser beam absorption. To obtain images when pumping the P1(8) transition in the (3,0) band it was necessary to use exceptionally fast imaging optics and unacceptably high intensifier gains. The result was single-shot images which displayed a signal-to-noise ratio of order unity or less when measured on a per pixel basis
Doping-induced quantum cross-over in ErTiSnO
We present the results of the investigation of magnetic properties of the
ErTiSnO series. For small doping values the ordering
temperature decreases linearly with while the moment configuration remains
the same as in the parent compound. Around doping level we
observe a change in the behavior, where the ordering temperature starts to
increase and new magnetic Bragg peaks appear. For the first time we present
evidence of a long-range order (LRO) in ErSnO () below
mK. It is revealed that the moment configuration corresponds to a
Palmer-Chalker type with a value of the magnetic moment significantly
renormalized compared to . We discuss our results in the framework of a
possible quantum phase transition occurring close to .Comment: accepted in PRB Rapi
Proper Motion of the Faint Star near KIC 8462852 (Boyajian's Star) - Not a Binary System
A faint star located 2 arcsec from KIC 8462852 was discovered in Keck 10 m
adaptive optics imaging in the near-infrared (NIR) in 2014 by Boyajian et
al. (2016). The closeness of the star to KIC 8462852 suggested the two could
constitute a binary, which might have implications for the cause of the
brightness dips seen by {\it Kepler} (Boyajian et al. (2016) and in
ground-based optical studies Boyajian et al. (2018). Here, NIR imaging in 2017
using the Mimir instrument resolved the pair and enabled measuring their
separation. The faint star had moved milliarcsec (mas) relative to
KIC 8462852 since 2014. The relative proper motion of the faint star is mas yr, for a tangential velocity of km s if
it is at the same 390 pc distance as KIC 8462852. Circular velocity at the 750
AU current projected separation is km s, hence the star pair
cannot be bound.Comment: 10 pages, 2 figure
Magnetic Field Uniformity Across the GF 9-2 YSO, L1082C Dense Core, and GF 9 Filamentary Dark Cloud
The orientation of the magnetic field (B-field) in the filamentary dark cloud
GF 9 was traced from the periphery of the cloud into the L1082C dense core that
contains the low-mass, low-luminosity Class 0 young stellar object (YSO) GF 9-2
(IRAS 20503+6006). This was done using SOFIA HAWC+ dust thermal emission
polarimetry (TEP) at 216 um in combination with Mimir near-infrared background
starlight polarimetry (BSP) conducted at H-band (1.6 um) and K-band (2.2 um).
These observations were augmented with published I-band (0.77 um) BSP and
Planck 850 um TEP to probe B-field orientations with offset from the YSO in a
range spanning 6000 AU to 3 pc. No strong B-field orientation change with
offset was found, indicating remarkable uniformity of the B-field from the
cloud edge to the YSO environs. This finding disagrees with weak-field models
of cloud core and YSO formation. The continuity of inferred B-field
orientations for both TEP and BSP probes is strong evidence that both are
sampling a common B-field that uniformly threads the cloud, core, and YSO
region. Bayesian analysis of Gaia DR2 stars matched to the Mimir BSP stars
finds a distance to GF 9 of 270 +/- 10 pc. No strong wavelength dependence of
B-field orientation angle was found, contrary to previous claims.Comment: 18 pages, 6 figures ApJ, accepte
The efficacy of halofantrine in the treatment of acute malaria in nonimmune travelers
A multicenter prospective trial was performed to investigate the efficacy and the tolerability of halofantrine in nonimmune patients with malaria imported from areas with drug-resistant falciparum parasites (mainly Africa). Forty-five of the 74 subjects were treated with a one-day regimen (3 x 500 mg) of halofantrine, and the other 29 received the same regimen with an additional treatment on day 7. In the second group, a 100% efficacy rate was demonstrated, but in the group receiving the one-day regimen, four recrudescences were observed in patients with falciparum malaria. Only five mild adverse reactions were seen, which disappeared spontaneously after the end of the treatment. We conclude that halofantrine is highly effective in curing malaria in nonimmune subjects. The treatment scheme for such persons should include an additional treatment on day 7 for nonimmune individuals. This drug was well tolerated in our patients, indicating that halofantrine will be useful in the treatment of multidrug-resistant malaria in nonimmune persons
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Primary care physician practices in the diagnosis, treatment and management of men with chronic prostatitis/chronic pelvic pain syndrome.
To describe practice patterns of primary care physicians (PCPs) for the diagnosis, treatment and management of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), we surveyed 556 PCPs in Boston, Chicago, and Los Angeles (RR=52%). Only 62% reported ever seeing a patient like the one described in the vignette. In all, 16% were 'not at all' familiar with CP/CPPS, and 48% were 'not at all' familiar with the National Institutes of Health classification scheme. PCPs reported practice patterns regarding CP/CPPS, which are not supported by evidence. Although studies suggest that CP/CPPS is common, many PCPs reported little or no familiarity, important knowledge deficits and limited experience in managing men with this syndrome
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