231 research outputs found

    Adequate groups of low degree

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    The notion of adequate subgroups was introduced by Jack Thorne [42]. It is a weakening of the notion of big subgroups used in generalizations of the Taylor-Wiles method for proving the automorphy of certain Galois representations. Using this idea, Thorne was able to strengthen many automorphy lifting theorems. It was shown in [22] that if the dimension is small compared to the characteristic then all absolutely irreducible representations are adequate. Here we extend the result by showing that, in almost all cases, absolutely irreducible kG-modules in characteristic p, whose irreducible G+-summands have dimension less than p (where G+ denotes the subgroup of G generated by all p-elements of G), are adequate.Comment: 60 page

    A shortened whole brain radiation therapy protocol for meningoencephalitis of unknown origin in dogs

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    IntroductionA variety of treatment options have been described for canine meningoencephalitis of unknown origin (MUO). Few studies focused on radiation therapy as a second line immunomodulating treatment, implicating its effective use. However, a standard radiation therapy protocol is lacking, and further research will help to evaluate the effect of different dose regimens.MethodsTen dogs diagnosed with MUO based on MRI and CSF findings were prospectively enrolled. The dogs were treated with a shortened whole brain radiation therapy protocol (5 × 4 Gy) in combination with prednisolone. Neurologic changes were quantified using an established scoring scheme. Follow-up MRI and CSF examination was scheduled three months after radiation therapy. Overall survival and time to progression were calculated. Histopathology of the brain was performed in case of death.ResultsSeven dogs were diagnosed de novo and three had a history of relapsing MUO. Neurological status improved in all 10 dogs during radiation therapy, with 4/10 returning to normal shortly after radiation therapy. Three dogs died within the first three months after radiation therapy. At follow-up MRI lesions completely resolved in two dogs, partially resolved in five dogs, and progressed in one dog. After follow-up MRI, dogs were further treated with prednisolone monotherapy (two dogs) and additional immunosuppressant drugs (five dogs). Overall, four dogs showed disease progression, with a mean time to progression of 691 days (95%CI: 396–987) and mean overall survival for all dogs was 723 days (95%CI: 436–1011) (both medians not reached). Histopathology confirmed MUO in three dogs but was suggestive for oligodendroglioma in one dog. Radiation induced side effects were not seen.ConclusionShortened whole-brain radiation therapy could be an additional treatment option for MUO in conjunction to prednisolone, specifically for cases that require rapid relief of symptoms and with relapsing history

    High resolution displacement detection by speckle pattern analysis : accuracy limits in linear displacement speckle metrology

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    We propose a simple reflection measurement setup and a motion evaluation procedure based on a two dimensional recording of subsequent speckle images. The averaging of cross correlation functions is used to measure displacements. We demonstrate experimentally a 10 nm precision on a 50 ÎĽm measurement range limited by systematical errors. An image library is proposed to extend the measurement range. Limitations are given and documented improvements predicted an accuracy better than 5 nm over a range of 150 ÎĽm

    Manifestations of hypertensive encephalopathy in cats

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    Objectives Hypertensive encephalopathy in cats is an important entity but is underestimated in clinical practice. This could be explained, in part, by non-specific clinical signs. The objective of this study was to characterise the clinical manifestations of hypertensive encephalopathy in cats. Methods Cats with systemic hypertension (SHT) recognised by routine screening, associated with underlying predisposing disease or a clinical presentation suggestive of SHT (neurological or non-neurological), were prospectively enrolled over a 2-year period. Confirmation of SHT was based on at least two sets of measurements of systolic blood pressure >160 mmHg by Doppler sphygmomanometry. Results Fifty-six hypertensive cats with a median age of 16.5 years were identified; 31 had neurological signs. In 16/31 cats, neurological abnormalities were the primary complaint. The other 15 cats were first presented to the medicine or ophthalmology service, and neurological disease was recognised based on the cat’s history. The most common neurological signs were ataxia, various manifestations of seizures and altered behaviour. Individual cats also showed paresis, pleurothotonus, cervical ventroflexion, stupor and facial nerve paralysis. In 28/30 cats, retinal lesions were detected. Of these 28 cats, six presented with a primary complaint of visual deficits, and neurological signs were not the primary complaint; nine presented with non-specific medical issues, without suspicion of SHT-induced organ damage; in 13 cats, neurological issues were the primary complaint and fundic abnormalities were detected subsequently. Conclusions and relevance SHT is common in older cats and the brain is an important target organ; however, neurological deficits are commonly ignored in cats with SHT. Gait abnormalities, (partial) seizures and even mild behavioural changes should prompt clinicians to consider the presence of SHT. A fundic examination in cats with suspected hypertensive encephalopathy is a sensitive test to support the diagnosis

    Dynamics of a colloid-stabilized cream

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    We use x-ray photon correlation spectroscopy to investigate the dynamics of a high volume fraction emulsion creaming under gravity. The dodecane-in-water emulsion has interfaces stabilized solely by colloidal particles (silica). The samples were observed soon after mixing: as the emulsion becomes compact we discern two regimes of ageing with a cross-over between them. The young emulsion has faster dynamics associated with creaming in a crowded environment accompanied by local rearrangements. The dynamics slow down for the older emulsion although our studies show that motion is associated with large intermittent events. The relaxation rate, as seen from the intensity autocorrelation function, depends linearly on the wave vector at all times; however, the exponent associated with the line shape changes from 1.5 for young samples to less than 1 as the emulsion ages. The combination of ballisticlike dynamics, an exponent that drops below 1 and large intermittent fluctuations has not been reported before.Comment: 8 pages, 5 figure

    Miniature exoplanet radial velocity array I: design, commissioning, and early photometric results

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    The MINiature Exoplanet Radial Velocity Array (MINERVA) is a US-based observational facility dedicated to the discovery and characterization of exoplanets around a nearby sample of bright stars. MINERVA employs a robotic array of four 0.7 m telescopes outfitted for both high-resolution spec- troscopy and photometry, and is designed for completely autonomous operation. The primary science program is a dedicated radial velocity survey and the secondary science objective is to obtain high precision transit light curves. The modular design of the facility and the flexibility of our hardware allows for both science programs to be pursued simultaneously, while the robotic control software provides a robust and efficient means to carry out nightly observations. In this article, we describe the design of MINERVA including major hardware components, software, and science goals. The telescopes and photometry cameras are characterized at our test facility on the Caltech campus in Pasadena, CA, and their on-sky performance is validated. New observations from our test facility demonstrate sub-mmag photometric precision of one of our radial velocity survey targets, and we present new transit observations and fits of WASP-52b—a known hot-Jupiter with an inflated radius and misaligned orbit. The process of relocating the MINERVA hardware to its final destination at the Fred Lawrence Whipple Observatory in southern Arizona has begun, and science operations are expected to commence within 2015

    Design, motivation, and on-sky tests of an efficient fiber coupling unit for 1-meter class telescopes

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    We present the science motivation, design, and on-sky test data of a high-throughput fiber coupling unit suitable for automated 1-meter class telescopes. The optical and mechanical design of the fiber coupling is detailed and we describe a flexible controller software designed specifically for this unit. The system performance is characterized with a set of numerical simulations, and we present on-sky results that validate the performance of the controller and the expected throughput of the fiber coupling. This unit was designed specifically for the MINERVA array, a robotic observatory consisting of multiple 0.7 m telescopes linked to a single high-resolution stabilized spectrograph for the purpose of exoplanet discovery using high-cadence radial velocimetry. However, this unit could easily be used for general astronomical purposes requiring fiber coupling or precise guiding
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