Variational Bayesian image restoration with group-sparse modeling of wavelet coefficients

In this work, we present a recent wavelet-based image restoration framework based on a group-sparse Gaussian scale mixture model. A hierarchical Bayesian estimation is derived using a combination of variational Bayesian inference and a subband-adaptive majorization–minimization method that simplifies computation of the posterior distribution. We show that both of these iterative methods can converge together without needing nested loops, and thus good solutions can be found rapidly in the non-convex search space. We also integrate our method, variational Bayesian with majorization minimization (VBMM), with tree-structured modeling of the wavelet coefficients. This extension achieves significant gains in performance over the coefficient-sparse version of the algorithm. The experimental results demonstrate that the proposed method and its tree-structured extensions are effective for various imaging applications such as image deconvolution, image superresolution and compressive sensing magnetic resonance imaging (MRI) reconstruction, and that they outperform more conventional sparsity-inducing methods based on the _l1-norm.This is the author accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S1051200415001438

An analysis of requests produced by second language speakers of English and how these requests are received by English first language speakers

Thesis (MPhil)--Stellenbosch University, 2012.ENGLISH ABSTRACT: During the course of my work as Communications lecturer at a multicultural university, I have noticed differences in the manners in which Sesotho-speaking and Afrikaans-speaking students make the same requests to me while speaking English. There exists a possibility that these second language (L2) requests could be deemed inappropriate and/or unintelligible by first language (L1) speakers of English. It is possible that miscommunication may result when requests by one culture group is judged as inappropriate and/or unintelligible by another. The aims of my study were to investigate (i) whether there are indeed differences in the manners in which L1 Sesotho and L1 Afrikaans speakers make requests when speaking English and (ii) how the differences in the (a) politeness, (b) formalness, (c) appropriateness, (d) grammaticality and (e) intelligibility of these requests made by the above-mentioned two groups manifest, as judged by L1 speakers of English. In terms of research methodology, I elicited requests in English from two culturally and linguistically different groups of students (17 L1 Afrikaans and 17 L1 Sesotho) by means of a written scenario completion task. One scenario involved a high imposition situation and the other a low imposition. The requests made by the two groups were then analysed using the Cross Cultural Speech Act Realisation Project (CCSARP) framework of Blum-Kulka, House and Kasper (1989a). Each request was also judged by eight L1 English speakers. Data analysis showed that there are indeed differences in the way in which Afrikaans- and Sesotho-speaking people put forth English requests. In terms of CCSARP categories, the Sesotho speakers used more alerters and more politeness markers than the Afrikaans speakers did. Sesotho and Afrikaans speakers also differed in their responses to high and low imposition situations – for example, Sesotho speakers used more grounders in the low imposition request than in the high imposition request, whereas Afrikaans speakers’ requests showed the reverse pattern. In terms of ratings received by L1 speakers, although Sesotho speakers’ requests were judged as more polite, Afrikaans speakers’ requests were judged as more appropriate and grammatically correct. The findings have implications for curriculum design: By being mindful of the workings of intercultural verbal and nonverbal communication and by acknowledging that people from different cultural backgrounds bring to a conversation certain culturally inherited factors which influence them and the interlocutors, I can use the results of this study to better inform the different L1 groups in my classes how to change their requesting behaviour so as to make requests that are judged by L1 English speakers as being appropriate.AFRIKAANSE OPSOMMING: Tydens my werk as Kommunikasie-dosent aan ‘n multikulturele universiteit het ek verskille opgelet in die manier waarop Sesotho-sprekende en Afrikaanssprekende studente dieselfde versoeke aan my rig wanneer hulle Engels praat. Die moontlikheid bestaan dat hierdie tweedetaal- (T2) versoeke as ontoepaslik en/of onverstaanbaar beskou kan word deur eerstetaal- (T1) sprekers van Engels. Dit is moontlik dat miskommunikasie kan ontstaan wanneer versoeke deur een kultuurgroep as ontoepaslik en/of onverstaanbaar beoordeel word deur ‘n ander kultuurgroep. Die doelstellings van my studie was om die volgende te ondersoek: (i) of daar inderdaad verskille bestaan in die manier waarop T1 Sesotho- en T1 Afrikaanssprekendes versoeke in Engels rig en (ii) hoe verskille in die (a) hoflikheid, (b) formeelheid, (c) toepaslikheid, (d) grammatikaliteit en (e) verstaanbaarheid van hierdie versoeke deur bogenoemde twee groepe manifesteer, soos beoordeel deur T1-sprekers van Engels. In terme van navorsingsmetodologie het ek versoeke in Engels van twee kultureel en talig verskillende groepe studente (17 T1 Afrikaans en 17 T1 Sesotho) ontlok deur gebruik te maak van ‘n geskrewe scenario-voltooiingstaak. Een scenario het ‘n versoek met ‘n hoë afdwingingsvlak (imposition) behels en die ander met ‘n lae afdwingingsvlak. Die versoeke gerig deur die twee groepe is toe geanaliseer deur gebruik te maak van die sogenaamde Cross Cultural Speech Act Realisation Project (CCSARP)-raamwerk van Blum-Kulka, House en Kasper (1989a). Elke versoek is ook deur agt T1-sprekers van Engels beoordeel. Data-analise het aangedui dat daar wel verskille is in die manier waarop Afrikaans- en Sesotho-sprekendes versoeke in Engels rig. In terme van CCSARP-kategorieë het die Sesotho-sprekendes meer attentmakers (alerters) en meer hoflikheidsmerkers as die Afrikaanssprekendes gebruik. Sesotho- en Afrikaanssprekendes het ook verskil in hul reaksie op hoë en lae imposisie-situasies – Sesotho-sprekendes het meer redeverskaffers (grounders) in die lae afdwingingsversoek as in die hoë afdwingingsversoek gebruik terwyl Afrikaanssprekendes die teenoorgestelde gedoen het. Alhoewel die Sesotho-sprekendes se versoeke as meer hoflik beskou is deur die T1-sprekende beoordelaars, is Afrikaanssprekendes se versoeke as meer toepaslik en grammatikaal korrek beskou. Die bevindinge het implikasies vir kurrikulum-ontwerp: Deur bewus te bly van die aard van interkulturele verbale en nie-verbale kommunikasie en deur te erken dat persone van verskillende kulturele agtergronde sekere kultuur-inherente faktore na ‘n gesprek toe bring wat hulle en hulle gespreksgenote beïnvloed, kan ek die resultate van hierdie studie gebruik om die verskillende T1-groepe in my klasse beter in te lig hoe om hul versoekgedrag aan te pas om versoeke te kan rig wat as toepaslik beskou word deur T1-sprekers van Engels

Acute traumatic abdominal wall hernia

Although blunt abdominal trauma is frequent, traumatic abdominal wall hernias (TAWH) are rare. We describe a large TAWH with associated intra-abdominal lesions that were caused by high-energy trauma. The diagnosis was missed by clinical examination but was subsequently revealed by a computed tomography (CT) scan. Repair consisted of an open anatomical reconstruction of the abdominal wall layers with reinforcement by an intraperitoneal composite mesh. The patient recovered well and the results of a post-operative CT scan are presented

Evaluation of a new model of care for people with complications of diabetic retinopathy : The EMERALD Study

Objectives The increasing diabetes prevalence and advent of new treatments for its major visual-threatening complications (diabetic macular edema [DME] and proliferative diabetic retinopathy [PDR]), which require frequent and life-long follow-up, have markedly increased hospital demands. Resulting delays in the evaluation/treatment of patients are leading to sight loss. Strategies to increase capacity of medical retina clinics are urgently needed. EMERALD tested diagnostic accuracy, acceptability and costs of a new health care pathway for people with previously treated DME/PDR. Design Prospective, multicentric, case-referent, cross-sectional, diagnostic accuracy study, undertaken in 13 hospitals in the United Kingdom. Participants Adults with type 1 or 2 diabetes and previously successfully treated DME/PDR who, at the time of enrolment, had active or inactive disease. Methods A new health care pathway entailing multimodal imaging (spectral domain optical coherence tomography [SD-OCT] for DME, and 7-field Early Treatment Diabetic Retinopathy Study [ETDRS] and ultra-wide-field fundus images [UWF] for PDR) interpreted by trained non-medical staff (ophthalmic graders) to detect re-activation of disease was compared with the current standard care (ophthalmologists face-to-face examination). Main outcome measures Primary outcome: sensitivity of the new pathway. Secondary outcomes: specificity; agreement between pathways; costs; acceptability; proportions requiring subsequent ophthalmologist assessment, unable to undergo imaging, with inadequate images/indeterminate findings. Results The new pathway had sensitivity of 97% (95% confidence interval [CI] 92-99%) and specificity of 31% (95% CI 23-40%) to detect DME. For PDR, sensitivity and specificity using 7-field ETDRS (85%, 95% CI 77-91%; 48%; 95% CI 41-56%, respectively) or UWF (83%, 95% CI 75-89%; 54%; 95% CI 46-61%, respectively) were comparable. For detection of high risk PDR sensitivity and specificity were higher when using UWF images (87%, 95% CI 78-93%; 49% 95% CI 42-56%, respectively for UWF, versus 80%, 95% CI 69-88%; 40% CI 34-47%, respectively, for 7-field ETDRS). Participants preferred ophthalmologist’s assessments; in their absence, wished immediate feedback by graders, maintaining periodic ophthalmologist evaluations. When compared with the current standard care, the new pathway could save £1,390/100 DME visits and between £461-£1,189/100 PDR visits. Conclusion The new ophthalmic grader pathway has acceptable sensitivity and would release resources. Users’ suggestions should guide implementatio

Construction of a large scale integrated map of macrophage pathogen recognition and effector systems

<p>Abstract</p> <p>Background</p> <p>In an effort to better understand the molecular networks that underpin macrophage activation we have been assembling a map of relevant pathways. Manual curation of the published literature was carried out in order to define the components of these pathways and the interactions between them. This information has been assembled into a large integrated directional network and represented graphically using the modified Edinburgh Pathway Notation (mEPN) scheme.</p> <p>Results</p> <p>The diagram includes detailed views of the toll-like receptor (TLR) pathways, other pathogen recognition systems, NF-kappa-B, apoptosis, interferon signalling, MAP-kinase cascades, MHC antigen presentation and proteasome assembly, as well as selected views of the transcriptional networks they regulate. The integrated pathway includes a total of 496 unique proteins, the complexes formed between them and the processes in which they are involved. This produces a network of 2,170 nodes connected by 2,553 edges.</p> <p>Conclusions</p> <p>The pathway diagram is a navigable visual aid for displaying a consensus view of the pathway information available for these systems. It is also a valuable resource for computational modelling and aid in the interpretation of functional genomics data. We envisage that this work will be of value to those interested in macrophage biology and also contribute to the ongoing Systems Biology community effort to develop a standard notation scheme for the graphical representation of biological pathways.</p

Mechanistic aspects of NF-κB regulation: The emerging role of phosphorylation and proteolysis

Members of the NF-KB transcription factor family serve as a prototypical model of inducible transcription factors. As discussed below, NF-KB activity is primarily regulated by a group of structurally related proteins collectively referred to as IKB (for recent reviews on NF-KB and IKB, see Beg and Baldwin, 1993; Gilmore and Morin, 1993; Siebenlist et al., 1994; Baeuerle and Henkel, 1994; Thanos and Maniatis, 1995). The NF-KB transcription factor family is an important component in a variety of biological processes, most notably inflammation and immune responses. The requirement for NF-KB in these processes is indicated by its ability to regulate genes whose products are critical for these cellular events. These products include cytokines, immunoreceptors, cell adhesion molecules, and acute phase proteins (Siebenlist et al., 1994; Baeuerle and Henkel, 1994). In addition, recent research has shown dramatically that mice containing targeted disruptions of NF-KB subunits are compromised in various aspects of immune function and inflammatory responses (Weih et al., 1995; Sha et al., 1995; Burkly et al., 1995; Kontgen et al., 1995; also see Thanos and Maniatis, 1995). A number of pathogenic viruses, including the human immunodeficiency virus, also subvert NF-KB activity for the expression of essential viral genes (Nabel and Baltimore, 1987; Siebenlist et al., 1994; Baeuerle and Henkel, 1994). Finally, genetic alterations in the structure or expression of genes encoding NF-KB and IKB family members can render these proteins oncogenic, demonstrating an intimate relationship between NF-~Bfunction and normal cellular proliferation (Siebenlist et al., 1994; Baeuerle and Henkel, 1994). In this review, we discuss the mechanisms regulating NF-KB activity. A particular emphasis has been placed on recent studies, which more clearly define how various modifications to IKB, specifically inducible phosphorylation, ubiquitination, and proteasome-driven degradation, contribute to NF-KB activation

Smart guns -- handgun identification

Kahr Arms wishes to implement a new means of identifying handguns into the production process. A recently passed law in Massachusetts requires an identification number to be located on the gun that is hidden from plain view and resists alteration by unauthorized individuals. The goal of this project is to establish a suitable means of identification that adheres to the laws of Massachusetts, and to provide recommendations that will aid in implementing the device into the production process