1,922 research outputs found
NETT Regularization for Compressed Sensing Photoacoustic Tomography
No full textWe discuss several methods for image reconstruction in compressed sensing photoacoustic tomography (CS-PAT). In particular, we apply the deep learning method of [H. Li, J. Schwab, S. Antholzer, and M. Haltmeier. NETT: Solving Inverse Problems with Deep Neural Networks (2018), arXiv:1803.00092], which is based on a learned regularizer, for the first time to the CS-PAT problem. We propose a network architecture and training strategy for the NETT that we expect to be useful for other inverse problems as well. All algorithms are compared and evaluated on simulated data, and validated using experimental data for two different types of phantoms. The results on the one the hand indicate great potential of deep learning methods, and on the other hand show that significant future work is required to improve their performance on real-word data
Norsk kjendisjournalistikk på nett
No full textKjendisjournalistikken har inntatt nyhetsmediene for lengst, og særlig i tabloidpressens
nettaviser vies det mye plass til slikt stoff. Denne artikkelen ser på
hvordan kjendisjournalistikken i de to norske nettavisene VG Nett og Dagbladet.
no har endret seg fra 2005 til 2014. Endringene i journalistikken sees i sammenheng
med flere strukturelle endringer den norske mediebransjen har gjennomgått
i løpet av det siste tiåret: Finanskrisen som førte til at inntektene hos
mediebedriftene stupte, etableringen av sosiale medier, økt globalisering og
nye medieplattformer.This is an Open Access article
distributed under the terms of the Creative Commons CC-BY-NC 4.0 License
(http://creativecommons.org/licenses/by-nc/4.0/), allowing third parties to copy and
redistribute the material in any medium or format and to remix, transform, and build upon the
material for non-commercial use, provided the original author and source are credited
The relevance of perceived academic control and achievement emotions for undergraduate academic success
No full textHigh dropout rates within tertiary education worldwide document challenges students have to overcome in order to succeed (e.g., OECD, 2012). For instance, they have to uphold motivation for the long term (e.g., Robbins et al., 2004). Thereby, one relevant motivational aspect is the subjective perception of control over one’s own academic outcomes, or in other words, perceived academic control (e.g., Perry, 1991). Particularly freshman students who are required to adjust to a new learning setting of university may ‘feel out of control’ (e.g., Perry et al., 2001). Unfortunately, the long-term relevance of perceived academic control remains unknown. Besides motivational aspects, the tertiary educational challenges trigger various achievement emotions (e.g., Pekrun & Stephens, 2010), which have impact themselves on students’ grades (e.g., Pekrun et al., 2017) and interact with perceived academic control (e.g., Pekrun, 2006). Thereby, experiences of achievement emotions depend on the habitual tendency (trait) and the situational impact (state, e.g., Nett et al., 2017). Overall, the aim of the present dissertation was to provide insight into the relevance of perceived academic control for undergraduate academic success, under the consideration of achievement emotions. In order to accomplish this aim, three scientific studies were conducted. Methodically, those studies used two field-based longitudinal datasets to achieve high external validity. They were obtained within the everyday student life of various study majors at Ulm University. The tow field-based datasets were an experience sampling study with 98 participants and an annual questionnaire with 1009 participants. Here, established scales were used (Pekrun et al., 2011; Perry et al., 2001). Overall from a statistical perspective, this dissertation used structural equation modelling approaches including moderated mediations (Study I), stable trait autoregressive trait state models (Study II), and a latent change score model combined with a discrete time survival analysis (Study III). The first research objective focused on the relation of PAC and academic success. Thereby Study III acknowledged a rather long-term and small negative change in undergraduate university PAC. Further, the reduction of university dropout intention (Study I) and dropout behaviour (Study III) through high or increasing PAC were addressed and Study III emphasized the positive effect of PAC on grades and vice versa. The second research objective focused on achievement emotions and their relevance for academic success. Thereby Study II broadened the trait-state debate of achievement emotions. Study I acknowledged the relevance of trait achievement emotions for dropout intention and Study II emphasized the relevance of rather stable variance components of the current negative emotional experience on grades. The third research objective focused on the triad of PAC, achievement emotions, and academic success. Study I acknowledged the partial reciprocal relations between PAC and achievement emotions, particularly for negative emotions such as anxiety or anger. Study II showed partially how PAC influences achievement emotions, which subsequently influences PAC and grades. In sum, the long-term decrease of perceived academic control broadens prior research by showing its relevance for late dropout, mediated by grades, and long-term reciprocal relations with achievement (Weiner, 1985, 2018). However, the results reveal the need for action regarding supporting at-risk students who may dropout or potential poor achievers mostly for freshman students, particularly as the present study indicates a possible over-estimation (e.g., Ruthig et al., 2007) or missing causal search (e.g., Stupnisky et al., 2011). Further, the present dissertation adds previous experiences as a third emotional variance component which is relevant for students’ grades and possibly for explaining how state becomes trait through new statistical analysis for experience sampling data. Additionally, the present dissertation questions the long-term impact of emotions on achievement and takes a first step to analyze their impact on dropout. Overall, this dissertation highlights the contribution of perceived academic control to the known relevance of motivation for academic success (e.g., Bean & Eaton, 2001; Heublein et al., 2017; Robbins et al., 2004) and provides a framework for future research, namely the PACES model
Characterization of CYP115 As a Gibberellin 3-Oxidase Indicates That Certain Rhizobia Can Produce Bioactive Gibberellin A4
No full textThe gibberellin (GA) phytohormones are produced not only by plants but also by fungi and bacteria. Previous characterization of a cytochrome P450 (CYP)-rich GA biosynthetic operon found in many symbiotic, nitrogen-fixing rhizobia led to the elucidation of bacterial GA biosynthesis and implicated GA9 as the final product. However, GA9 does not exhibit hormonal/biological activity and presumably requires further transformation to elicit an effect in the legume host plant. Some rhizobia that contain the GA operon also possess an additional CYP (CYP115), and here we show that this acts as a GA 3-oxidase to produce bioactive GA4 from GA9. This is the first GA 3-oxidase identified for rhizobia, and provides a more complete scheme for biosynthesis of bioactive GAs in bacteria. Furthermore, phylogenetic analyses suggest that rhizobia acquired CYP115 independently of the core GA operon, adding further complexity to the horizontal gene transfer of GA biosynthetic enzymes among bacteria.This article is published as Nett, Ryan S., Tiffany Contreras, and Reuben J. Peters. "Characterization of CYP115 as a gibberellin 3-oxidase indicates that certain rhizobia can produce bioactive gibberellin A4." ACS chemical biology 12, no. 4 (2017): 912-917. doi: 10.1021/acschembio.6b01038. Posted with permission.</p
CT Metrics of Airway Disease and Emphysema in Severe COPD
No full textBackground: CT scan measures of emphysema and airway disease have been correlated with lung function in cohorts of subjects with a range of COPD severity. The contribution of CT scan-assessed airway disease to objective measures of lung function and respiratory symptoms such as dyspnea in severe emphysema is less clear. Methods: Using data from 338 subjects in the National Emphysema Treatment Trial (NETT) Genetics Ancillary Study, densitometric measures of emphysema using a threshold of −950 Hounsfield units (%LAA-950) and airway wall phenotypes of the wall thickness (WT) and the square root of wall area (SRWA) of a 10-mm luminal perimeter airway were calculated for each subject. Linear regression analysis was performed for outcome variables FEV1 and percent predicted value of FEV1 with CT scan measures of emphysema and airway disease. Results: In univariate analysis, there were significant negative correlations between %LAA-950 and both the WT (r = −0.28, p = 0.0001) and SRWA (r = −0.19, p = 0.0008). Airway wall thickness was weakly but significantly correlated with postbronchodilator FEV1% predicted (R = −0.12, p = 0.02). Multivariate analysis showed significant associations between either WT or SRWA (β = −5.2, p = 0.009; β = −2.6, p = 0.008, respectively) and %LAA-950 (β = −10.6, p = 0.03) with the postbronchodilator FEV1% predicted. Male subjects exhibited significantly thicker airway wall phenotypes (p = 0.007 for WT and p = 0.0006 for SRWA). Conclusions: Airway disease and emphysema detected by CT scanning are inversely related in patients with severe COPD. Airway wall phenotypes were influenced by gender and associated with lung function in subjects with severe emphysema.Lewis Katz School of MedicinePulmonary and Critical Care Medicin
Preliminary Investigations of the Electrical Tree Growth at Frequencies of 50 Hz and 2.2 kHz by means of Partial Discharge Analysis
No full textDuring fault situations within high voltage direct current (HVDC) links, transient overvoltages with frequency components of several kHz, can occur and incept electrical trees inside the cable insulation. Since the relationship between applied voltage and frequency and the growth of the electrical trees is not completely understood, a deeper investigation is necessary. In particular, starting from cross-linked polyethylene (XLPE) samples obtained from a commercial HVDC cable, electrical treeing tests have been performed by applying a voltage level with two different frequencies: 50 Hz and 2.2 kHz. During the tests, the partial discharge (PD) activity has been monitored. The obtained results show that the time to breakdown obtained from the samples subjected to the 50 Hz power supply is shorter than those obtained with 2.2 kHz. Analyzing the PD activity and the sample by means of digital microscope, different tree shapes were visible, which influence the degradation time of the performed test. The obtained results of this preliminary study suggest that increasing the frequency does not necessarily lead to a reduction of the time to breakdown but influences the shape and the growth of the electrical trees
Archivare auf qype: Werler Stadtarchivar Heinrich J. Deisting
No full textveryarrant aus Ense dürfte am 14.12.2008 die erste qype-Besprechung eines Archivaren gegeben haben: "Sehr nett und hilfsbereit. Werde in den nächsten Tagen nochmal dorthin , um mir historisches Material für eine Facharbeit zu besorgen. 5/5 Punkten!" Link: http://www.qype.com/place/383737-Stadtarchivar-Heinrich-J-Deisting-Wer
Implementation of the Exception From Informed Consent Regulations in a Large Multicenter Emergency Clinical Trials Network: The RAMPART Experience
No full textClinical trials investigating therapies for acutely and critically ill and injured patients in the earliest phases of treatment often can only be performed under regulations allowing for exception from informed consent (EFIC) for emergency research. Implementation of these regulations in multicenter clinical trials involves special challenges and opportunities. The Rapid Anticonvulsant Medication Prior to Arrival Trial (RAMPART), the first EFIC trial conducted by the Neurological Emergencies Treatment Trials (NETT) network, combined centralized resources and coordination with retention of local control and flexibility to facilitate compliance with the EFIC regulations. Specific methods used by the NETT included common tools for community consultation and public disclosure, sharing of experiences and knowledge, and reporting of aggregate results. Tracking of community consultation and public disclosure activities and feedback facilitates empirical research on EFIC methods in the network and supports quality improvements for future NETT trials. The NETT model used in RAMPART demonstrates how EFIC may be effectively performed in established clinical trial networks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91139/1/j.1553-2712.2012.01328.x.pd
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