54 research outputs found

    Free-algebra functors from a coalgebraic perspective

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    Given a set Σ\Sigma of equations, the free-algebra functor FΣF_{\Sigma} associates to each set XX of variables the free algebra FΣ(X)F_{\Sigma}(X) over XX. Extending the notion of \emph{derivative} Σ\Sigma' for an arbitrary set Σ\Sigma of equations, originally defined by Dent, Kearnes, and Szendrei, we show that FΣF_\Sigma preserves preimages if and only if ΣΣ\Sigma \vdash \Sigma', i.e. Σ\Sigma derives its derivative Σ\Sigma'. If FΣF_\Sigma weakly preserves kernel pairs, then every equation p(x,x,y)=q(x,y,y)p(x,x,y)=q(x,y,y) gives rise to a term s(x,y,z,u)s(x,y,z,u) such that p(x,y,z)=s(x,y,z,z)p(x,y,z)=s(x,y,z,z) and q(x,y,z)=s(x,x,y,z)q(x,y,z)=s(x,x,y,z). In this case n-permutable varieties must already be permutable, i.e. Mal'cev. Conversely, if Σ\Sigma defines a Mal'cev variety, then FΣF_\Sigma weakly preserves kernel pairs. As a tool, we prove that arbitrary SetSet-endofunctors FF weakly preserve kernel pairs if and only if they weakly preserve pullbacks of epis

    LEMUR: Large European Module for solar Ultraviolet Research. European contribution to JAXA's Solar-C mission

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    Understanding the solar outer atmosphere requires concerted, simultaneous solar observations from the visible to the vacuum ultraviolet (VUV) and soft X-rays, at high spatial resolution (between 0.1" and 0.3"), at high temporal resolution (on the order of 10 s, i.e., the time scale of chromospheric dynamics), with a wide temperature coverage (0.01 MK to 20 MK, from the chromosphere to the flaring corona), and the capability of measuring magnetic fields through spectropolarimetry at visible and near-infrared wavelengths. Simultaneous spectroscopic measurements sampling the entire temperature range are particularly important. These requirements are fulfilled by the Japanese Solar-C mission (Plan B), composed of a spacecraft in a geosynchronous orbit with a payload providing a significant improvement of imaging and spectropolarimetric capabilities in the UV, visible, and near-infrared with respect to what is available today and foreseen in the near future. The Large European Module for solar Ultraviolet Research (LEMUR), described in this paper, is a large VUV telescope feeding a scientific payload of high-resolution imaging spectrographs and cameras. LEMUR consists of two major components: a VUV solar telescope with a 30 cm diameter mirror and a focal length of 3.6 m, and a focal-plane package composed of VUV spectrometers covering six carefully chosen wavelength ranges between 17 and 127 nm. The LEMUR slit covers 280" on the Sun with 0.14" per pixel sampling. In addition, LEMUR is capable of measuring mass flows velocities (line shifts) down to 2 km/s or better. LEMUR has been proposed to ESA as the European contribution to the Solar C mission.Comment: 35 pages, 14 figures. To appear on Experimental Astronom

    Tone burst-evoked otoacoustic emissions in neonates: normative data

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    <p>Abstract</p> <p>Background</p> <p>Tone-burst otoacoustic emissions (TBOAEs) have not been routinely studied in pediatric populations, although tone burst stimuli have greater frequency specificity compared with click sound stimuli. The present study aimed (1) to determine an appropriate stimulus level for neonatal TBOAE measurements when the stimulus center frequency was 1 kHz, (2) to explore the characteristics of 1 kHz TBOAEs in a neonatal population.</p> <p>Methods</p> <p>A total of 395 normal neonates (745 ears) were recruited. The study consisted of two parts, reflecting the two study aims. Part I included 40 normal neonatal ears, and TBOAE measurement was performed at five stimulus levels in the range 60–80 dB peSPL, with 5 dB incremental steps. Part II investigated the characteristics of the 1 kHz TBOAE response in a large group of 705 neonatal ears, and provided clinical reference criteria based on these characteristics.</p> <p>Results</p> <p>The study provided a series of reference parameters for 1 kHz TBOAE measurement in neonates. Based on the results, a suggested stimulus level and reference criteria for 1 kHz TBOAE measures with neonates were established. In addition, time-frequency analysis of the data gave new insight into the energy distribution of the neonatal TBOAE response.</p> <p>Conclusion</p> <p>TBOAE measures may be a useful method for investigating cochlear function at specific frequency ranges in neonates. However, further studies of both TBOAE time-frequency analysis and measurements in newborns are needed.</p

    Avoiding Treatment Interruptions: What Role Do Australian Community Pharmacists Play?

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    OBJECTIVE: To explore the reported practice of Australian community pharmacists when dealing with medication supply requests in absence of a valid prescription. METHODS: Self-administered questionnaire was posted to 1490 randomly selected community pharmacies across all Australian states and territories. This sample was estimated to be a 20% of all Australian community pharmacies. RESULTS: Three hundred eighty five pharmacists participated in the study (response rate achieved was 27.9% (there were 111 undelivered questionnaires). Respondents indicated that they were more likely to provide medications to regular customers without a valid prescription compared to non-regular customers (p&lt;0.0001). However, supply was also influenced by the type of prescription and the medication requested. In the case of type of prescription (Standard, Authority or Private) this relates to the complexity/probability of obtaining a valid prescription from the prescriber at a later date (i.e. supply with an anticipated prescription). Decisions to supply and/or not supply related to medication type were more complex. For some cases, including medication with potential for abuse, the practice and/or the method of supply varied significantly according to age and gender of the pharmacist, and pharmacy location (p&lt;0.05). CONCLUSIONS: Although being a regular customer does not guarantee a supply, results of this study reinforce the importance for patients having a regular pharmacy, where pharmacists were more likely to continue medication supply in cases of patients presenting without a valid prescription. We would suggest, more flexible legislation should be implemented to allow pharmacists to continue supplying of medication when obtaining a prescription is not practical

    Locally advanced and recurrent cancer

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    A successful treatment of locally advanced and recurrent rectal cancer is based on the responsibility of the surgeon to perform a radical resection. Planning of treatment starts with imaging with a pelvic MRI and a CT scan of chest and the abdomen. Neoadjuvant chemoradiation is given to achieve downstaging and downsizing. After a waiting period of at least 6 weeks, a total mesorectal excision is performed with often an extra-anatomical extension based on the initial imaging. Reconstruction using several types of pedicled flaps is often necessary to close the defect of the pelvic floor.</p

    Selective phosphodiesterase inhibitors: a promising target for cognition enhancement

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    # The Author(s) 2008. This article is published with open access at Springerlink.com Rationale One of the major complaints most people face during aging is an impairment in cognitive functioning. This has a negative impact on the quality of daily life and is even more prominent in patients suffering from neurodegenerative and psychiatric disorders including Alzheimer’s disease, schizophrenia, and depression. So far, the majority of cognition enhancers are generally targeting one particular neurotransmitter system. However, recently phosphodiesterases (PDEs) have gained increased attention as a potential new target for cognition enhancement. Inhibition of PDEs increases the intracellular availability of the second messengers cGMP and/or cAMP. Objective The aim of this review was to provide an overvie

    Effect of malaria on placental volume measured using three-dimensional ultrasound: a pilot study

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    Background: The presence of malaria parasites and histopathological changes in the placenta are associated with a reduction in birth weight, principally due to intrauterine growth restriction. The aim of this study was to examine the feasibility of studying early pregnancy placental volumes using three-dimensional (3D) ultrasound in a malaria endemic area, as a small volume in the second trimester may be an indicator of intra-uterine growth restriction and placental insufficiency. Methods: Placenta volumes were acquired using a portable ultrasound machine and a 3D ultrasound transducer and estimated using the Virtual Organ Computer-aided AnaLysis (VOCAL) image analysis software package. Intraobserver reliability and limits of agreement of the placenta volume measurements were calculated. Polynomial regression models for the mean and standard deviation as a function of gestational age for the placental volumes of uninfected women were created and tested. Based on these equations each measurement was converted into a z -score. The z-scores of the placental volumes of malaria infected and uninfected women were then compared. Results: Eighty-four women (uninfected = 65; infected = 19) with a posterior placenta delivered congenitally normal, live born, single babies. The mean placental volumes in the uninfected women were modeled to fit 5th, 10th, 50th, 90th and 95th centiles for 14-24 weeks’ gestation. Most placenta volumes in the infected women were below the 50th centile for gestational age; most of those with Plasmodium falciparum were below the 10th centile. The 95% intra-observer limits of agreement for first and second measurements were ± 37.0 mL and ± 25.4 mL at 30 degrees and 15 degrees rotation respectively. Conclusion: The new technique of 3D ultrasound volumetry of the placenta may be useful to improve our understanding of the pathophysiological constraints on foetal growth caused by malaria infection in early pregnancy

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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