2,087 research outputs found

    Teaching a New Dog Old Tricks: Resurrecting Multilingual Retrieval Using Zero-shot Learning

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    While billions of non-English speaking users rely on search engines every day, the problem of ad-hoc information retrieval is rarely studied for non-English languages. This is primarily due to a lack of data set that are suitable to train ranking algorithms. In this paper, we tackle the lack of data by leveraging pre-trained multilingual language models to transfer a retrieval system trained on English collections to non-English queries and documents. Our model is evaluated in a zero-shot setting, meaning that we use them to predict relevance scores for query-document pairs in languages never seen during training. Our results show that the proposed approach can significantly outperform unsupervised retrieval techniques for Arabic, Chinese Mandarin, and Spanish. We also show that augmenting the English training collection with some examples from the target language can sometimes improve performance.Comment: ECIR 2020 (short

    Cortical State Fluctuations during Sensory Decision Making

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    In many behavioral tasks, cortex enters a desynchronized state where low-frequency fluctuations in population activity are suppressed. The precise behavioral correlates of desynchronization and its global organization are unclear. One hypothesis holds that desynchronization enhances stimulus coding in the relevant sensory cortex. Another hypothesis holds that desynchronization reflects global arousal, such as task engagement. Here, we trained mice on tasks where task engagement could be distinguished from sensory accuracy. Using widefield calcium imaging, we found that performance-related desynchronization was global and correlated better with engagement than with accuracy. Consistent with this link between desynchronization and engagement, rewards had a long-lasting desynchronizing effect. To determine whether engagement-related state changes depended on the relevant sensory modality, we trained mice on visual and auditory tasks and found that in both cases desynchronization was global, including regions such as somatomotor cortex. We conclude that variations in low-frequency fluctuations are predominately global and related to task engagement

    Aberrant Cortical Activity In Multiple GCaMP6-Expressing Transgenic Mouse Lines

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    Transgenic mouse lines are invaluable tools for neuroscience but as with any technique, care must be taken to ensure that the tool itself does not unduly affect the system under study. Here we report aberrant electrical activity, similar to interictal spikes, and accompanying fluorescence events in some genotypes of transgenic mice expressing GCaMP6 genetically-encoded calcium sensors. These epileptiform events have been observed particularly, but not exclusively, in mice with Emx1-Cre and Ai93 transgenes, across multiple laboratories. The events occur at >0.1 Hz, are very large in amplitude (>1.0 mV local field potentials, >10% df/f widefield imaging signals), and typically cover large regions of cortex. Many properties of neuronal responses and behavior seem normal despite these events, though rare subjects exhibit overt generalized seizures. The underlying mechanisms of this phenomenon remain unclear, but we speculate about possible causes on the basis of diverse observations. We encourage researchers to be aware of these activity patterns while interpreting neuronal recordings from affected mouse lines and when considering which lines to study

    How the other half lives: CRISPR-Cas's influence on bacteriophages

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    CRISPR-Cas is a genetic adaptive immune system unique to prokaryotic cells used to combat phage and plasmid threats. The host cell adapts by incorporating DNA sequences from invading phages or plasmids into its CRISPR locus as spacers. These spacers are expressed as mobile surveillance RNAs that direct CRISPR-associated (Cas) proteins to protect against subsequent attack by the same phages or plasmids. The threat from mobile genetic elements inevitably shapes the CRISPR loci of archaea and bacteria, and simultaneously the CRISPR-Cas immune system drives evolution of these invaders. Here we highlight our recent work, as well as that of others, that seeks to understand phage mechanisms of CRISPR-Cas evasion and conditions for population coexistence of phages with CRISPR-protected prokaryotes.Comment: 24 pages, 8 figure

    Incidence and Risk Factors of Recurrence after Surgery for Pathology-proven Diverticular Disease

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    Contains fulltext : 69776.pdf (publisher's version ) (Closed access)BACKGROUND: Diverticular disease is a common problem in Western countries. Rationale for elective surgery is to prevent recurrent complicated diverticulitis and to reduce emergency procedures. Recurrent diverticulitis occurs in about 10% after resection. The pathogenesis for recurrence is not completely understood. We studied the incidence and risk factors for recurrence and the overall morbidity and mortality of surgical therapy for diverticular disease. METHODS: Medical records of 183 consecutive patients with pathology-proven diverticulitis were eligible for evaluation. Mean duration of follow-up was 7.2 years. Number of preoperative episodes, emergency or elective surgeries, type of operation, level of anastomosis, postoperative complications, persistent postoperative pain, complications associated with colostomy reversal, and recurrent diverticulitis were noted. The Kaplan-Meier method was used to calculate the cumulative probability of recurrence. Cox regression was used to identify possible risk factors for recurrence. RESULTS: The incidence of recurrence was 8.7%, with an estimated risk of recurrence over a 15-year period of 16%. Risk factors associated with recurrence were (younger) age (p < 0.02) and the persistence of postoperative pain (p < 0.005). Persistent abdominal pain after surgery was present in 22%. Eighty percent of patients who needed emergency surgery for acute diverticulitis had no manifestation of diverticular disease prior to surgery. In addition, recurrent diverticulitis was not associated with a higher percentage of emergency procedures. CONCLUSION: Estimated risk of recurrence is high and abdominal complaints after surgical therapy for diverticulitis are frequent. Younger age and persistence of postoperative symptoms predict recurrent diverticulitis after resection. The clinical implication of these findings needs further investigation. The results of this study support the careful selection of patients for surgery for diverticulitis

    Contrasting the Percutaneous Nerve Evaluation Versus Staged Implantation in Sacral Neuromodulation

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    Sacral neuromodulation is increasingly used for the treatment of voiding dysfunction, pelvic pain syndromes, and gastrointestinal disorders. While increased use of this technology has led to a greater understanding of its potential as well as its limitations, difficulty persists in identifying the patients that will benefit most. Either of two trial stimulation techniques is performed before placement of a permanent neuromodulator: the monopolar percutaneous nerve evaluation and the tined quadripolar staged trial. The preponderance of recent literature asserts the superior sensitivity of the staged trial over percutaneous nerve evaluation. However, the techniques offer disparate advantages, and other issues, such as cost-effectiveness, remain largely unexplored. The role of sacral neuromodulation will continue to expand as physicians and patients become increasingly aware of its therapeutic potential. Widespread adoption of this clinically superior technique will most rapidly help the greatest number of patients

    Large-scale validation of methods for cytotoxic T-lymphocyte epitope prediction

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    <p>Abstract</p> <p>Background</p> <p>Reliable predictions of Cytotoxic T lymphocyte (CTL) epitopes are essential for rational vaccine design. Most importantly, they can minimize the experimental effort needed to identify epitopes. NetCTL is a web-based tool designed for predicting human CTL epitopes in any given protein. It does so by integrating predictions of proteasomal cleavage, TAP transport efficiency, and MHC class I affinity. At least four other methods have been developed recently that likewise attempt to predict CTL epitopes: EpiJen, MAPPP, MHC-pathway, and WAPP. In order to compare the performance of prediction methods, objective benchmarks and standardized performance measures are needed. Here, we develop such large-scale benchmark and corresponding performance measures and report the performance of an updated version 1.2 of NetCTL in comparison with the four other methods.</p> <p>Results</p> <p>We define a number of performance measures that can handle the different types of output data from the five methods. We use two evaluation datasets consisting of known HIV CTL epitopes and their source proteins. The source proteins are split into all possible 9 mers and except for annotated epitopes; all other 9 mers are considered non-epitopes. In the RANK measure, we compare two methods at a time and count how often each of the methods rank the epitope highest. In another measure, we find the specificity of the methods at three predefined sensitivity values. Lastly, for each method, we calculate the percentage of known epitopes that rank within the 5% peptides with the highest predicted score.</p> <p>Conclusion</p> <p>NetCTL-1.2 is demonstrated to have a higher predictive performance than EpiJen, MAPPP, MHC-pathway, and WAPP on all performance measures. The higher performance of NetCTL-1.2 as compared to EpiJen and MHC-pathway is, however, not statistically significant on all measures. In the large-scale benchmark calculation consisting of 216 known HIV epitopes covering all 12 recognized HLA supertypes, the NetCTL-1.2 method was shown to have a sensitivity among the 5% top-scoring peptides above 0.72. On this dataset, the best of the other methods achieved a sensitivity of 0.64. The NetCTL-1.2 method is available at <url>http://www.cbs.dtu.dk/services/NetCTL</url>.</p> <p>All used datasets are available at <url>http://www.cbs.dtu.dk/suppl/immunology/CTL-1.2.php</url>.</p

    Pemetrexed Induced Thymidylate Synthase Inhibition in Non-Small Cell Lung Cancer Patients: A Pilot Study with 3 '-Deoxy-3 '-[F-18]fluorothymidine Positron Emission Tomography

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    OBJECTIVES: Pemetrexed is a thymidylate synthase (TS) inhibitor and is effective in non-small cell lung cancer (NSCLC). 3'-deoxy-3'-[¹⁸F]fluorothymidine (¹⁸F-FLT), a proliferation marker, could potentially identify tumor specific TS-inhibition. The aim of this study was to investigate the effect of pemetrexed-induced TS-inhibition on ¹⁸F-FLT uptake 4 hours after pemetrexed administration in metastatic NSCLC patients. METHODS: Fourteen NSCLC patients underwent dynamic ¹⁸F-FLT positron emission tomography (PET) scans at baseline and 4 hours after the first dose of pemetrexed. Volumes of interest were defined with a 41%, 50% and 70% threshold of the maximum pixel. Kinetic analysis and simplified measures were performed. At one, two, four and six hours after pemetrexed, plasma deoxyuridine was measured as systemic indicator of TS-inhibition. Tumor response measured with response evaluation criteria in solid tumors (RECIST), time to progression (TTP) and overall survival (OS) were determined. RESULTS: Eleven patients had evaluable ¹⁸F-FLT PET scans at baseline and 4 hours after pemetrexed. Two patients had increased ¹⁸F-FLT uptake of 35% and 31% after pemetrexed, whereas two other patients had decreased uptake of 31%. In the remaining seven patients ¹⁸F-FLT uptake did not change beyond test-retest borders. In all patients deoxyuridine levels raised after administration of pemetrexed, implicating pemetrexed-induced TS-inhibition. ¹⁸F-FLT uptake in bone marrow was significantly increased 4 hours after pemetrexed administration. Six weeks after the start of treatment 5 patients had partial response, 4 stable disease and 2 progressive disease. Median TTP was 4.2 months (range 3.0-7.4 months); median OS was 13.0 months (range 5.1-30.8 months). Changes in ¹⁸F-FLT uptake were not predictive for tumor response, TTP or OS. CONCLUSIONS: Measuring TS-inhibition in a clinical setting 4 hours after pemetrexed revealed a non-systematic change in ¹⁸F-FLT uptake within the tumor. No significant association with tumor response, TTP or OS was observed

    Particulate air pollution and chronic ischemic heart disease in the eastern United States: a county level ecological study using satellite aerosol data

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    <p>Abstract</p> <p>Background</p> <p>There are several known factors that cause ischemic heart disease. However, the part played by air pollution still remains something of a mystery. Recent attention has focused on the chronic effect of particulate matter on heart disease. Satellite-derived aerosol optical depth (AOD) was found to be correlated with <it>PM</it><sub>2.5 </sub>in the eastern US. The objective of this study was to examine if there is an association between aerosol air pollution as indicated by AOD and chronic ischemic heart disease (CIHD) in the eastern US.</p> <p>Methods</p> <p>An ecological geographic study method was employed. Race and age standardized mortality rate (SMR) of CIHD was computed for each of the 2306 counties for the time period 2003–2004. A mean AOD raster grid for the same period was derived from Moderate Resolution Imaging Spectrometer (MODIS) aerosol data and the average AOD was calculated for each county. A bivariate Moran's I scatter plot, a map of local indicator of spatial association (LISA) clusters, and three regression models (ordinary least square, spatial lag, and spatial error) were used to analyze the relationship between AOD and CIHD SMR.</p> <p>Results</p> <p>The global Moran's I value is 0.2673 (<it>p </it>= 0.001), indicating an overall positive spatial correlation of CIHD SMR and AOD. The entire study area is dominated by spatial clusters of AOD against SMR (high AOD and high SMR in the east, and low AOD and low SMR in the west) (permutations = 999, <it>p </it>= 0.05). Of the three regression models, the spatial error model achieved the best fit (R<sup>2 </sup>= 0.28). The effect of AOD is positive and significant (beta = 0.7774, p = 0.01).</p> <p>Conclusion</p> <p>Aerosol particle pollution has adverse effect on CIHD mortality risk in the eastern US. High risk of CIHD mortality was found in areas with elevated levels of outdoor aerosol air pollution as indicated by satellite derived AOD. The evidence of the association would support targeting of policy interventions on such areas to reduce air pollution levels. Remote sensing AOD data could be used as an alternative health-related indictor of air quality.</p
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