65 research outputs found

    Transcendental obstructions to weak approximation on general K3 surfaces

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    We construct an explicit K3 surface over the field of rational numbers that has geometric Picard rank one, and for which there is a transcendental Brauer-Manin obstruction to weak approximation. To do so, we exploit the relationship between polarized K3 surfaces endowed with particular kinds of Brauer classes and cubic fourfolds.Comment: 24 pages, 3 figures, Magma scripts included at the end of the source file

    A 24 Hour Ecotoxicity Test for Acid Mine Drainage Using Hatching Success in Daphnia magna

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    A bioassay utilizing the cladoceran Daphnia magna hatching success is presented for testing the toxicity of acid mine drainage (AMD) sediments. AMD sediments contain complex mixtures of potential toxins and a rapid, sensitive bioassay is valuable for assessing toxicity in the field, particularly after transient environmental events. Daphnia magna was incubated in water exposed to 1. clean sand spiked with different proportions of a mixture of metal salts and 2. sand mixed with different proportions of AMD sediments. Hatching success was linearly related to both the proportion of artificially spiked sediments (r= -0.83; p= 0.0002) and the proportion of AMD sediments (r = -0.74; p= 0.02) that Daphnia magna was exposed to during incubations. No animals hatched during the first 18 hrs of observation under any treatments, so a single observation at 24 h is practical for this assay. The assay should be generally applicable to toxicity testing, particularly when assessing complex mixtures of pollutants in field settings. The novelty of the proposed study lies in the fact that it proposes the fastest ecotoxicity assay that we know of using Dahpnia magna. Potentially, after appropriate calibration for the particular pollutant of interest, it could be used to test for a wide array of aquatic pollutants

    Regenerative peripheral nerve interfaces for real-time, proportional control of a Neuroprosthetic hand

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    Abstract Introduction Regenerative peripheral nerve interfaces (RPNIs) are biological constructs which amplify neural signals and have shown long-term stability in rat models. Real-time control of a neuroprosthesis in rat models has not yet been demonstrated. The purpose of this study was to: a) design and validate a system for translating electromyography (EMG) signals from an RPNI in a rat model into real-time control of a neuroprosthetic hand, and; b) use the system to demonstrate RPNI proportional neuroprosthesis control. Methods Animals were randomly assigned to three experimental groups: (1) Control; (2) Denervated, and; (3) RPNI. In the RPNI group, the extensor digitorum longus (EDL) muscle was dissected free, denervated, transferred to the lateral thigh and neurotized with the residual end of the transected common peroneal nerve. Rats received tactile stimuli to the hind-limb via monofilaments, and electrodes were used to record EMG. Signals were filtered, rectified and integrated using a moving sample window. Processed EMG signals (iEMG) from RPNIs were validated against Control and Denervated group outputs. Results Voluntary reflexive rat movements produced signaling that activated the prosthesis in both the Control and RPNI groups, but produced no activation in the Denervated group. Signal-to-Noise ratio between hind-limb movement and resting iEMG was 3.55 for Controls and 3.81 for RPNIs. Both Control and RPNI groups exhibited a logarithmic iEMG increase with increased monofilament pressure, allowing graded prosthetic hand speed control (R2 = 0.758 and R2 = 0.802, respectively). Conclusion EMG signals were successfully acquired from RPNIs and translated into real-time neuroprosthetic control. Signal contamination from muscles adjacent to the RPNI was minimal. RPNI constructs provided reliable proportional prosthetic hand control.https://deepblue.lib.umich.edu/bitstream/2027.42/146521/1/12984_2018_Article_452.pd

    Determination of the efficacy and side-effect profile of lower doses of intrathecal morphine in patients undergoing total knee arthroplasty

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    <p>Abstract</p> <p>Background</p> <p>Intrathecal (IT) morphine provides excellent post-operative analgesia, but causes multiple side effects including nausea and vomiting (PONV), pruritus and respiratory depression, particularly at higher doses. The lowest effective dose of spinal morphine in patients undergoing total knee arthroplasty is not known.</p> <p>Methods</p> <p>We evaluated the analgesic efficacy and side effect profile of 100 – 300 μg IT morphine in patients undergoing elective total knee replacement in this prospective, randomized, controlled, double-blind study. Sixty patients over the age of 60 undergoing elective knee arthroplasty were enrolled. Patients were randomized to receive spinal anaesthesia with 15 mg Bupivacaine and IT morphine in three groups: (i) 100 μg; (ii) 200 μg; and (iii) 300 μg.</p> <p>Results</p> <p>Both 200 μg and 300 μg IT morphine provided comparable levels of postoperative analgesia. However, patients that received 100 μg had greater pain postoperatively, with higher pain scores and a greater requirement for supplemental morphine. There were no differences between groups with regard to PONV, pruritus, sedation, respiratory depression or urinary retention.</p> <p>Conclusion</p> <p>Both 200 μg and 300 μg provided comparable postoperative analgesia, which was superior to that provided by 100 μg IT morphine in patients undergoing total knee arthroplasty. Based on these findings, we recommend that 200 μg IT morphine be used in these patients.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier NCT00695045</p

    A mixed methods feasibility study to evaluate the use of a low-intensity, nurse-delivered cognitive behavioural therapy for the treatment of irritable bowel syndrome

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    Introduction: Irritable bowel syndrome (IBS) is characterised by symptoms such as abdominal pain, constipation, diarrhoea and bloating. These symptoms impact on health-related quality of life, result in excess service utilisation and are a significant burden to healthcare systems. Certain mechanisms which underpin IBS can be explained by a biopsychosocial model which is amenable to psychological treatment using techniques such as cognitive behavioural therapy (CBT). While current evidence supports CBT interventions for this group of patients, access to these treatments within the UK healthcare system remains problematic. Methods and analysis: A mixed methods feasibility randomised controlled trial will be used to assess the feasibility of a low-intensity, nurse-delivered guided self-help intervention within secondary care gastrointestinal clinics. A total of 60 participants will be allocated across four treatment conditions consisting of: high-intensity CBT delivered by a fully qualified cognitive behavioural therapist, low-intensity guided self-help delivered by a registered nurse, self-help only without therapist support and a treatment as usual control condition. Participants from each of the intervention arms of the study will be interviewed in order to identify potential barriers and facilitators to the implementation of CBT interventions within clinical practice settings. Quantitative data will be analysed using descriptive statistics only. Qualitative data will be analysed using a group thematic analysis.N/

    Genetic susceptibility of intervertebral disc degeneration among young Finnish adults

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    <p>Abstract</p> <p>Background</p> <p>Disc degeneration (DD) is a common condition that progresses with aging. Although the events leading to DD are not well understood, a significant genetic influence has been found. This study was undertaken to assess the association between relevant candidate gene polymorphisms and moderate DD in a well-defined and characterized cohort of young adults. Focusing on young age can be valuable in determining genetic predisposition to DD.</p> <p>Methods</p> <p>We investigated the associations of existing candidate genes for DD among 538 young adults with a mean age of 19 belonging to the 1986 Northern Finland Birth Cohort. Nineteen single nucleotide polymorphisms (SNP) in 16 genes were genotyped. We evaluated lumbar DD using the modified Pfirrmann classification and a 1.5-T magnetic resonance scanner for imaging.</p> <p>Results</p> <p>Of the 538 individuals studied, 46% had no degeneration, while 54% had DD and 51% of these had moderate DD. The risk of DD was significantly higher in subjects with an allele G of <it>IL6 </it>SNPs rs1800795 (OR 1.45, 95% CI 1.07-1.96) and rs1800797 (OR 1.37, 95% CI 1.02-1.85) in the additive inheritance model. The role of <it>IL6 </it>was further supported by the haplotype analysis, which resulted in an association between the GGG haplotype (SNPs rs1800797, rs1800796 and rs1800795) and DD with an OR of 1.51 (95% CI 1.11-2.04). In addition, we observed an association between DD and two other polymorphisms, <it>SKT </it>rs16924573 (OR 0.27 95% CI 0.07-0.96) and <it>CILP </it>rs2073711 in women (OR 2.04, 95% CI 1.07-3.89).</p> <p>Conclusion</p> <p>Our results indicate that <it>IL6</it>, <it>SKT </it>and <it>CILP </it>are involved in the etiology of DD among young adults.</p

    Opening the Gate to Money Market Fund Reform

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    Effect of phytosterol supplementation on Acartia egg production (PhytosterolsZooplank project)

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    Dataset: Sterols and Acartia egg productionThis dataset includes viable egg production of the copepod Acartia tonsa that were fed a diet supplemented with a variety of phytosterols at two food concentrations. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/724158NSF Division of Ocean Sciences (NSF OCE) OCE-1061973, NSF Division of Ocean Sciences (NSF OCE) OCE-106195
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