215 research outputs found
Proper orthogonal decomposition analysis of a turbulent swirling self-excited premixed flame
Thermoacoustic oscillations constitute a serious threat to the integrity of combustion systems. The goal of the present work is to determine the effect of the equivalence ratio (Ļ), inlet flow velocity (U), and burner geometry on the characteristics of the self-excited oscillations and to reveal the dominant mechanisms. It also focuses on the data post-processing aiming at extracting information about the dynamics that are not captured through classical ensemble-averaging, and hence the Proper Orthogonal Decomposition technique is used. Experiments were conducted with a fully-premixed air/methane flame stabilized on a conical bluff body. Self-excited acoustic instabilities were induced by extending the length of the combustion chamber downstream of the bluff body. The flame was visualised using OH* chemiluminescence and OH PLIF at 5 kHz. Proper Orthogonal Decomposition (POD) and Fast Fourier Transform analysis were conducted on the imaging data. A strong effect of the chamber length was found, which primarily drove the generation of acoustic oscillation and flame-vortex interaction. Significant differences in the flame roll-up were found when either the burner geometry or the equivalence ratio was altered. Changes were detected in the frequency of oscillations, which showed a general trend to increase with Ļ and U and decrease with the length of the duct. Analysis of the POD modes allowed an estimate of the convection speed of the flame structures associated with the dominant frequency and it was found that this convection speed was about 1.5 U for most conditions studied
Babylon is Fallen, is Fallen: Southern Morality in \u3cem\u3eGo Set A Watchman\u3c/em\u3e
A crucial theme throughout Go Set a Watchman by Harper Lee is the struggle between individual morality and collective consciousness, as exemplified by black and white relations in the American South. In this thesis, I explore the biblical concept of a āwatchmanā as referenced in the novelās title and what conclusions can be drawn from delving into the literary and biblical contexts of this allusion. I utilize this as a framework to explore how and why the characters of Watchman exist in such fragmented, defensive states as opposed to their Mockingbird counterparts, and what these differences imply regarding the importance or nonimportance of individual culpability in societal ethical failures. In examining Jean Louiseās childhood as compared to her adulthood, I seek to understand how such hostile race consciousness and morality coexist in the white, largely churchgoing South. By studying the differences in the novels along with the titleās greater meaning, I level charges of collective culpability against the novelsā main characters, then argue for or against them, in an attempt to greater comprehend who can be held guilty and who remains innocent in the battle between the Southās collective and individual consciences
Experimental Determination of the Insulating Ability of Corn By-Products
This article proposes and experimentally tests a way to better utilize renewable agricultural products that, if successful, will increase revenue for agricultural producers, decrease the amount and cost of disposal of non-renewable products, and decrease the amount of non-renewable products that need to be produced. In this article the insulating ability of ground corn cobs is compared, by experimental tests, to typical fiberglass, cellulose, and Rock Wool insulation. The study found that the insulating ability of ground corn cobs is not as great when compared to typical insulations, but using a greater thickness of insulation made from ground corn cobs or combining this insulation with typical insulations may be beneficial. In conclusion it is valuable to know how the insulating ability of ground corn cobs compares with typical insulations to determine if further research in this area is beneficial and to stimulate other possible ways to use renewable agricultural products
Structural diversity in the AdoMet radical enzyme superfamily
AdoMet radical enzymes are involved in processes such as cofactor biosynthesis, anaerobic metabolism, and natural product biosynthesis. These enzymes utilize the reductive cleavage of S-adenosylmethionine (AdoMet) to afford l-methionine and a transient 5ā²-deoxyadenosyl radical, which subsequently generates a substrate radical species. By harnessing radical reactivity, the AdoMet radical enzyme superfamily is responsible for an incredible diversity of chemical transformations. Structural analysis reveals that family members adopt a full or partial Triose-phosphate Isomerase Mutase (TIM) barrel protein fold, containing core motifs responsible for binding a catalytic [4Feā4S] cluster and AdoMet. Here we evaluate over twenty structures of AdoMet radical enzymes and classify them into two categories: ātraditionalā and āThiC-likeā (named for the structure of 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate synthase (ThiC)). In light of new structural data, we reexamine the ātraditionalā structural motifs responsible for binding the [4Feā4S] cluster and AdoMet, and compare and contrast these motifs with the ThiC case. We also review how structural data combine with biochemical, spectroscopic, and computational data to help us understand key features of this enzyme superfamily, such as the energetics, the triggering, and the molecular mechanisms of AdoMet reductive cleavage. This article is part of a Special Issue entitled: Radical SAM Enzymes and Radical Enzymology.Wellcome Trust (London, England) (091162/Z/10/Z)National Science Foundation (U.S.) (NSF Grant MCB-0543833)Howard Hughes Medical Institute (Investigator
Web-based counseling for problem gambling: exploring motivations and recommendations
Background:For highly stigmatized disorders, such as problem gambling, Web-based counseling has the potential to address common barriers to treatment, including issues of shame and stigma. Despite the exponential growth in the uptake of immediate synchronous Web-based counseling (ie, provided without appointment), little is known about why people choose this service over other modes of treatment.Objective:The aim of the current study was to determine motivations for choosing and recommending Web-based counseling over telephone or face-to-face services.Methods:The study involved 233 Australian participants who had completed an online counseling session for problem gambling on the Gambling Help Online website between November 2010 and February 2012. Participants were all classified as problem gamblers, with a greater proportion of males (57.4%) and 60.4% younger than 40 years of age. Participants completed open-ended questions about their reasons for choosing online counseling over other modes (ie, face-to-face and telephone), as well as reasons for recommending the service to others.Results:A content analysis revealed 4 themes related to confidentiality/anonymity (reported by 27.0%), convenience/accessibility (50.9%), service system access (34.2%), and a preference for the therapeutic medium (26.6%). Few participants reported helpful professional support as a reason for accessing counseling online, but 43.2% of participants stated that this was a reason for recommending the service.Those older than 40 years were more likely than younger people in the sample to use Web-based counseling as an entry point into the service system (<italic>P</italic>=.045), whereas those engaged in nonstrategic gambling (eg, machine gambling) were more likely to access online counseling as an entry into the service system than those engaged in strategic gambling (ie, cards, sports; <italic>P</italic>=.01). Participants older than 40 years were more likely to recommend the service because of its potential for confidentiality and anonymity (<italic>P</italic>=.04), whereas those younger than 40 years were more likely to recommend the service due to it being helpful (<italic>P</italic>=.02).Conclusions:This study provides important information about why online counseling for gambling is attractive to people with problem gambling, thereby informing the development of targeted online programs, campaigns, and promotional material.</div
Problematizing the Adoption and Implementation of Athlete Development āModelsā: A Foucauldian-Inspired Analysis of the Long-Term Athlete Development Framework
The purpose of this paper is to problematize the continued adoption and implementation of Long-Term Athlete Development (LTAD) framework (Balyi et al., 2005; 2014) as an increasingly orthodox conception of the athlete development process and for underpinning and designing sport coaching practice. In adopting a post-structuralist, Foucauldian perspective and drawing upon empirical interview data with Balyi and colleagues, senior government officials and sport administrators, our analysis examines some of the potential limitations for adopting and implementing LTAD as a conception of the athlete development process. In particular, we highlight the potential issues and contradictions linked to adopting such conceptions, namely their (mis)use as mechanisms of social control (i.e. governmentality), delimiting the ability of athletes and sport practitioners to think otherwise (i.e. disciplining and docility), and the potential to marginalize alternative ways of thinking. We conclude with a discussion of the implications for managerial and coaching practice
Structural elements of an NRPS cyclization domain and its intermodule docking domain
Epothilones are thiazole-containing natural products with anticancer activity that are biosynthesized by polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) enzymes EpoAāF. A cyclization domain of EpoB (Cy) assembles the thiazole functionality from an acetyl group and L-cysteine via condensation, cyclization, and dehydration. The PKS carrier protein of EpoA contributes the acetyl moiety, guided by a docking domain, whereas an NRPS EpoB carrier protein contributes L-cysteine. To visualize the structure of a cyclization domain with an accompanying docking domain, we solved a 2.03-Ć
resolution structure of this bidomain EpoB unit, comprising residues M1-Q497 (62 kDa) of the 160-kDa EpoB protein. We find that the N-terminal docking domain is connected to the V-shaped Cy domain by a 20-residue linker but otherwise makes no contacts to Cy. Molecular dynamic simulations and additional crystal structures reveal a high degree of flexibility for this docking domain, emphasizing the modular nature of the components of PKS-NRPS hybrid systems. These structures further reveal two 20-Ć
-long channels that run from distant sites on the Cy domain to the active site at the core of the enzyme, allowing two carrier proteins to dock with Cy and deliver their substrates simultaneously. Through mutagenesis and activity assays, catalytic residues N335 and D449 have been identified. Surprisingly, these residues do not map to the location of the conserved HHxxxDG motif in the structurally homologous NRPS condensation (C) domain. Thus, although both C and Cy domains have the same basic fold, their active sites appear distinct
Structural elements of an NRPS cyclization domain and its intermodule docking domain
Epothilones are thiazole-containing natural products with anticancer activity that are biosynthesized by polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) enzymes EpoA-F. A cyclization domain of EpoB (Cy) assembles the thiazole functionality from an acetyl group and l-cysteine via condensation, cyclization, and dehydration. The PKS carrier protein of EpoA contributes the acetyl moiety, guided by a docking domain, whereas an NRPS EpoB carrier protein contributes l-cysteine. To visualize the structure of a cyclization domain with an accompanying docking domain, we solved a 2.03-A resolution structure of this bidomain EpoB unit, comprising residues M1-Q497 (62 kDa) of the 160-kDa EpoB protein. We find that the N-terminal docking domain is connected to the V-shaped Cy domain by a 20-residue linker but otherwise makes no contacts to Cy. Molecular dynamic simulations and additional crystal structures reveal a high degree of flexibility for this docking domain, emphasizing the modular nature of the components of PKS-NRPS hybrid systems. These structures further reveal two 20-A-long channels that run from distant sites on the Cy domain to the active site at the core of the enzyme, allowing two carrier proteins to dock with Cy and deliver their substrates simultaneously. Through mutagenesis and activity assays, catalytic residues N335 and D449 have been identified. Surprisingly, these residues do not map to the location of the conserved HHxxxDG motif in the structurally homologous NRPS condensation (C) domain. Thus, although both C and Cy domains have the same basic fold, their active sites appear distinct
KBG syndrome
KBG syndrome is a rare condition characterised by a typical facial dysmorphism, macrodontia of the upper central incisors, skeletal (mainly costovertebral) anomalies and developmental delay. To date, KBG syndrome has been reported in 45 patients. Clinical features observed in more than half of patients that may support the diagnosis are short stature, electroencephalogram (EEG) anomalies (with or without seizures) and abnormal hair implantation. Cutaneous syndactyly, webbed short neck, cryptorchidism, hearing loss, palatal defects, strabismus and congenital heart defects are less common findings. Autosomal dominant transmission has been observed in some families, and it is predominantly the mother, often showing a milder clinical picture, that transmits the disease. The diagnosis is currently based solely on clinical findings as the aetiology is unknown. The final diagnosis is generally achieved after the eruption of upper permanent central incisors at 7ā8 years of age when the management of possible congenital anomalies should have been already planned. A full developmental assessment should be done at diagnosis and, if delays are noted, an infant stimulation program should be initiated. Subsequent management and follow-up should include an EEG, complete orthodontic evaluation, skeletal investigation with particular regard to spine curvatures and limb asymmetry, hearing testing and ophthalmologic assessment
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Barriers to Treatment for Female Problem Gamblers: A UK Perspective
There is a paucity of research in the UK which examines problem gambling and that which does exist is mainly quantitative, focuses on male samples and fails to look at treatment seeking populations or obstacles preventing problem gamblers from seeking treatment. This paper presents findings from part of a larger qualitative study that explored the experience of treatment for female problem gamblers. Data were collected using semi-structured interviews with eight women who had received individual cognitive-behavioural therapy in the National Health Service for their gambling problem. An interpretative phenomenological analysis approach was applied in the research process, identifying three main themes, of which the subtheme āBarriers to Treatmentā is examined here. Internal and external barriers to treatment organically emerged in all female participantsā accounts and appear to have an impact on service utilisation. Input directly from gamblers can be combined with findings from other studies to devise better ways of reaching female problem gamblers. A better understanding of barriers to treatment can also provide valuable direction for future research and suggest applications in clinical service provision and treatment planning
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