2,273 research outputs found
On elliptic curves with an isogeny of degree 7
We show that if is an elliptic curve over with a
-rational isogeny of degree 7, then the image of the 7-adic Galois
representation attached to is as large as allowed by the isogeny, except
for the curves with complex multiplication by . The
analogous result with 7 replaced by a prime was proved by the first
author in [7]. The present case has additional interesting
complications. We show that any exceptions correspond to the rational points on
a certain curve of genus 12. We then use the method of Chabauty to show that
the exceptions are exactly the curves with complex multiplication. As a
by-product of one of the key steps in our proof, we determine exactly when
there exist elliptic curves over an arbitrary field of characteristic not 7
with a -rational isogeny of degree 7 and a specified Galois action on the
kernel of the isogeny, and we give a parametric description of such curves.Comment: The revision gives a complete answer to the question considered in
Version 1. Version 3 will appear in the American Journal of Mathematic
Spectral characteristics of dust in planetary nebulae
Some carbon-rich planetary nebulae exhibit a strong broad emission feature beginning at Lambda which is approximately 24 microns and extending to Lambda greater than 30 microns. Thirty to 55 micron spectrophotometry of Ic 418 and NGC 6572, both of which have the strong broad emission feature, allow the wavelength dependence of the emissivity of the dust responsible for the feature to be defined. Comparison with laboratory spectra of candidate materials which are likely to condense in a carbon-rich environment suggests that the feature arises from MgS. The implications of such a strong feature arising from a relatively minor dust constituent are discussed. The environment in which MgS may be found is considered. It is speculated that MgS will be seen in objects with C/O ratios only slightly greater than one, but not in extremely carbon rich objects. In objects with much higher carbon abundances, the formation of CS consumes S so that insufficient MgS can form to exhibit the strong feature. These observations imply that the emergent far infrared spectrum of carbon-rich objects are very different depending on the abundance of the low temperature condensate MgS
A novel 3D multilateration sensor using distributed ultrasonic beacons for indoor navigation
Navigation and guidance systems are a critical part of any autonomous vehicle. In this paper, a novel sensor grid using 40 KHz ultrasonic transmitters is presented for adoption in indoor 3D positioning applications. In the proposed technique, a vehicle measures the arrival time of incoming ultrasonic signals and calculates the position without broadcasting to the grid. This system allows for conducting silent or covert operations and can also be used for the simultaneous navigation of a large number of vehicles. The transmitters and receivers employed are first described. Transmission lobe patterns and receiver directionality determine the geometry of transmitter clusters. Range and accuracy of measurements dictate the number of sensors required to navigate in a given volume. Laboratory experiments were performed in which a small array of transmitters was set up and the sensor system was tested for position accuracy. The prototype system is shown to have a 1-sigma position error of about 16 cm, with errors between 7 and 11 cm in the local horizontal coordinates. This research work provides foundations for the future development of ultrasonic navigation sensors for a variety of autonomous vehicle applications
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Crisaborole Ointment Improves Quality of Life of Patients with Mild to Moderate Atopic Dermatitis and Their Families.
IntroductionThe impact of crisaborole ointment, a nonsteroidal phosphodiesterase 4 inhibitor for the treatment of mild to moderate atopic dermatitis (AD), on quality of life (QoL) was assessed in two identically designed phase 3 studies (AD-301: NCT02118766; AD-302: NCT02118792, both at http://www.clinicaltrials.gov ).MethodsIn both studies, patients aged ≥ 2 years with mild to moderate AD per the Investigator's Static Global Assessment were randomly assigned 2:1 to receive crisaborole or vehicle twice daily for 28 days. QoL was assessed using the Children's Dermatology Life Quality Index (CDLQI) (2-15 years), the Dermatology Life Quality Index (DLQI) (≥ 16 years), and the Dermatitis Family Impact Questionnaire (DFI) (parents/caregivers/family of patients aged 2-17 years). Established QoL score severity bands provided clinical context.ResultsGreater mean improvement in QoL was observed in crisaborole-treated patients than in vehicle-treated patients at day 29 [mean change from baseline (∆BL), CDLQI: - 4.6 vs. - 3.0; P < 0.001; DLQI: - 5.2 vs. - 3.5; P = 0.015]. At baseline, more than half the patients had a "moderate effect" or higher of AD on QoL. At day 29, there was a trend toward more crisaborole- than vehicle-treated patients having "small effect" to "no effect", The QoL of parents/caregivers/family improved more for crisaborole-treated than for vehicle-treated patients (∆BL, DFI: - 3.7 vs. - 2.7; P = 0.003).ConclusionCrisaborole treatment results in clinically meaningful improvement in QoL for patients and their parents/caregivers/families.Trial registrationAD-301: http://www.clinicaltrials.gov , NCT02118766; AD-302: http://www.clinicaltrials.gov , NCT02118792.FundingAnacor Pharmaceuticals, Inc., a wholly owned subsidiary of Pfizer Inc., New York, NY
A Near-Infrared Spectrometer to Measure Zodiacal Light Absorption Spectrum
We have developed a high throughput infrared spectrometer for zodiacal light fraunhofer lines measurements. The instrument is based on a cryogenic dual silicon Fabry-Perot etalon which is designed to achieve high signal to noise Fraunhofer line profile measurements. Very large aperture silicon Fabry-Perot etalons and fast camera optics make these measurements possible. The results of the absorption line profile measurements will provide a model free measure of the zodiacal Light intensity in the near infrared. The knowledge of the zodiacal light brightness is crucial for accurate subtraction of zodiacal light foreground for accurate measure of the extragalactic background light after the subtraction of zodiacal light foreground. We present the final design of the instrument and the first results of its performance
Log-normal distributions of suspended particles in the open ocean
A scanning electron microscope-electron microprobe technique was used to chemically distinguish and size particles as fine as 0.2/µm on GEOSECS suspended matter filters from the open ocean…
Future perspectives on treatment with erythropoiesis-stimulating agents in high-risk patients
Patients with chronic kidney disease (CKD) have a high burden of mortality and cardiovascular morbidity. Additional strategies to modulate cardiovascular risk in this population are needed. Anaemia has been associated with adverse outcomes in CKD populations, and the ability to modify this parameter with the use of erythropoiesis-stimulating agents has been a topic of much debate. Data on the effects of anaemia correction on cardiovascular outcomes and survival in CKD have been both discordant and controversial. It is hoped that the ongoing Trial to Reduce cardiovascular Events with Aranesp Therapy (TREAT) will help to redress the current clinical gaps and the uncertainty over the optimal management of anaemia in patients with CKD and type 2 diabetes mellitus. Anaemia is also increasingly being recognized as an important comorbid condition in patients with symptomatic heart failure. The ongoing Reduction of Events with Darbepoetin alfa in Heart Failure (RED-HFTM) trial is designed to determine whether the treatment of anaemia improves outcomes in such patients
Optical Properties of Iron Silicates in the Infrared to Millimeter as a Function of Temperatures and Wavelength
The Optical Properties of Astronomical Silicates with Infrared Techniques
(OPASI-T) program utilizes multiple instruments to provide spectral data over a
wide range of temperature and wavelengths. Experimental methods include Vector
Network Analyzer (VNA) and Fourier Transform Spectroscopy (FTS) transmission,
and reflection/scattering measurements. From this data, we can determine the
optical parameters for the index of refraction, \textit{n}, and the absorption
coefficient, \textit{k}. The analysis of the laboratory transmittance data for
each sample type is based upon different mathematical models, which are applied
to each data set according to their degree of coherence. Presented here are
results from iron silicate dust grain analogs, in several sample preparations
and at temperatures ranging from 5--300 K, across the infrared and millimeter
portion of the spectrum (from 2.5--10,000 \mic\ or 4,000--1 \wvn).Comment: Revised manuscript submitted to Ap
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