1,679 research outputs found

    Initial test results with a single-cylinder rhombic-drive Stirling engine

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    A 6 kW (8 hp), single-cylinder, rhombic-drive Stirling engine was restored to operating condition, and preliminary characterization tests run with hydrogen and helium as the working gases. Initial tests show the engine brake specific fuel consumption (BSFC) with hydrogen working gas to be within the range of BSFC observed by the Army at Fort Belvoir, Virginia, in 1966. The minimum system specific fuel consumption (SFC) observed during the initial tests with hydrogen was 669 g/kW hr (1.1 lb/hpx hr), compared with 620 g/kWx hr (1.02 lb/hpx hr) for the Army tests. However, the engine output power for a given mean compression-space pressure was lower than for the Army tests. The observed output power at a working-space pressure of 5 MPa (725 psig) was 3.27 kW (4.39 hp) for the initial tests and 3.80 kW (5.09 hp) for the Army tests. As expected, the engine power with helium was substantially lower than with hydrogen

    Quantitative detection of _Potato virus Y_ in potato plants and aphids - Discussion of diverse applications in potato research

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    Every year potato growers worldwide complain about severe yield losses caused by _Potato virus Y_ (PVY). Therefore, PVY along with _Potato leafroll virus_ belongs to the most important potato viruses. There are three main strains of PVY: PVY^O^, PVY^N^ and PVY^C^. However, also recombinant forms exist such as PVY^N^Wilga and PVY^NTN^, both of which increase in importance due to their potential to displace the non-recombinant strains at a high percentage. They appear also in mixed infections. In recent years PCR and qPCR assays were developed to differentiate PVY isolates. In order to identify PVY isolates by PCR often large amplicons have to be generated which requires the input of expensive enzymes. On the other hand, qPCR assays until now do not allow the differentiation between PVY^N^Wilga and PVY^NTN^. 

For the discrimination between PVY^O^/PVY^N^Wilga and PVY^N^/PVY^NTN^ a qPCR assay was developed, which allows the differentiation and highly efficient quantification of both strains and recombinants, respectively. For this purpose dual-labeled hydrolysis probes tagged with different fluorophores were designed. The assay is suitable for many different applications, for example safety research on genetically modified (GM) potato plants. The goal of this research is to determine whether genetic modification causes changes in resistance to viruses. Two different GM cultivars were examined for signs of altered resistance to an infection with PVY in comparison to their near-isogenic lines and three reference cultivars. Reference cultivars are included to determine the baselines for resistance and thus to be able to decide if the changes could represent a biological risk. The plants to be investigated were mechanically inoculated with PVY^N^Wilga or PVY^NTN^ and analyzed by means of the developed assay after two weeks. The results of the experiment indicate that the differences in virus titer between the reference cultivars are higher than between the GM potatoes and their isogenic lines. Therefore, in our experiments the GM potato plants showed no alteration in PVY resistance to neither one of the tested strains.

Since _Myzus persicae_ is one of the most important vectors transmitting PVY, the developed assay will also be applied to the quantification of PVY particles in aphids. The displacement of PVY^O^ and PVY^N^ by PVY^N^Wilga and PVY^NTN^ may be due to a difference in efficiency of transmission by _M. persicae_. Therefore, the objective is to test whether more virus particles of the recombinant forms in comparison to the non-recombinant strains PVY^O^ and PVY^N^ bind in the stylets of _M. persicae_. 

A third possible application of the developed assay may be of interest in potato breeding. The exact quantification of PVY particles in plants allows the classification of resistance in potato plants. It is possible to estimate whether a resistance is extreme or not. Extreme resistance is characterized by the absence or presence of very low amounts of virus particles in plants several days after inoculation. When testing the plants for PVY infection by ELISA, often unspecific reactions occur which makes it difficult to differentiate between plants weakly infected and plants very weakly infected. An exact quantification of the PVY titer gives more certainty for the determination of the resistance type.

In conclusion, the developed assay is an efficient and low-cost method that allows the differentiation and quantification of PVY^O^/PVY^N^Wilga on the one hand and PVY^N^/PVY^NTN^ on the other hand with high throughput. The method can be utilized for a wide range of applications in potato research.
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    The suppression of hidden order and onset of ferromagnetism in URu2Si2 via Re substitution

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    Substitution of Re for Ru in the heavy fermion compound URu2Si2 suppresses the hidden order transition and gives rise to ferromagnetism at higher concentrations. The hidden order transition of URu(2-x)Re(x)Si2, tracked via specific heat and electrical resistivity measurements, decreases in temperature and broadens, and is no longer observed for x>0.1. A critical scaling analysis of the bulk magnetization indicates that the ferromagnetic ordering temperature and ordered moment are suppressed continuously towards zero at a critical concentration of x = 0.15, accompanied by the additional suppression of the critical exponents gamma and (delta-1) towards zero. This unusual trend appears to reflect the underlying interplay between Kondo and ferromagnetic interactions, and perhaps the proximity of the hidden order phase.Comment: 8 pgs, 5 figs, ICM 2009; please refer to Phys. Rev. Lett. 103, 076404 (2009), arXiv:0908.1809 for details on magnetic scaling and phase diagram (reference added to this version

    Interview of John J. McGoldrick, F.S.C., Ph.D.

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    Brother John Joseph McGoldrick (b. 1948), grew up in Southwest Philadelphia with his parents and older brother. Attending Most Blessed Sacrament School and later West Philadelphia Catholic High School for Boys, Brother John was part of a strong Catholic community. It was here at West Philadelphia Catholic High School, where Brother John was introduced to the Christian Brotherhood. It was at this time that he realized that the life of service with the Brotherhood was the type of life he’d like to lead. At the age of fifteen, Brother John attended the junior novitiate and after graduating high school entered the novitiate of the Christian Brothers. He graduated from La Salle in 1971, receiving his bachelor’s degree in History, and planning to become a secondary teacher. He also received his master’s degree with Millersville University in German, and his doctorate degree from Temple University in Communications. During his professional career, he worked at many secondary schools, including Archbishop Carroll High School, La Salle College High School, and Calvert Hall College High School, teaching German, history, and religion courses. For a time period, he also worked at Towson University as an adjunct professor, and Christian Brothers University as the Administrative Assistant to the President, Director of Desktop Services, and Assistant Vice President. Since 2001, Brother John has been working as the Assistant Provost at La Salle University. In his free time, Brother John enjoys taking part in his duties and tasks with the Brothers’ community, traveling, reading, watching movies, and of course attending La Salle basketball games

    Experiencing space–time: the stretched lifeworlds of migrant workers in India

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    In the relatively rare instances when the spatialities of temporary migrant work, workers’ journeys, and labour-market negotiations have been the subject of scholarly attention, there has been little work that integrates time into the analysis. Building on a case study of low-paid and insecure migrant manual workers in the context of rapid economic growth in India, we examine both material and subjective dimensions of these workers’ spatiotemporal experiences. What does it mean to live life stretched out, multiplyattached to places across national space? What kinds of place attachments emerge for people temporarily sojourning in, rather than moving to, new places to reside and work? Our analysis of the spatiotemporalities of migrant workers’ experiences in India suggests that, over time, this group of workers use their own agency to seek to avoid the experience of humiliation and indignity in employment relations. Like David Harvey, we argue that money needs to be integrated into such analysis, along with space and time. The paper sheds light on processes of exclusion, inequality and diff erentiation, unequal power geometries, and social topographies that contrast with neoliberalist narratives of ‘Indian shining

    Development and validation of a method for the detection of altered resistance in transgenic plants against herbivore-pathogen-complexes

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    Enhanced or reduced uptake of viruses by vectors and changes in resistance level can be sensitive indicators for metabolic changes in transgenic plants caused by the new trait and not observed by conventional methods. In addition, the plant transformation process itself can lead to such changes. To be able to investigate this hypothesis in cereals we decided to use two highly important insect-transmitted viruses infecting them - _Barley yellow dwarf virus_ (BYDV) and _Wheat dwarf virus_ (WDV). Corresponding molecular tools for their quantification in plants as well as virus vectors had to be developed. 
Both viruses cause similar symptoms: dwarfing, stunting, leaf discoloration leading to yield losses or death of plant. BYDV (_Luteoviridae_) is one of the most important cereal-infecting viruses worldwide causing substantial yield losses. In Germany, the strain PAV is widespread. It is transmitted by the aphids _Rhopalosiphum padi_ and _Sitobion avenae_ in a persistent manner. WDV (_Geminiviridae_) is found in Germany since the early 1990s and has gained importance over the last years. It is transmitted by the leafhopper _Psammotettix alienus_ in a persistent manner. 
Real-time PCR is the state of the art method for specific detection of viruses even in minor quantities. It allows exact quantification of the virus content of plants and vectors and is hence suited to monitor changes of it. We developed qPCR assays for WDV and RT-qPCR assays for BYDV-PAV based on TaqMan probe technology as well as the DNA-binding dye SybrGreen. The qPCR assays proved to be more sensitive than DAS-ELISA. For example, WDV is detected even at dilutions of 1:10^8^, whereas the corresponding threshold for ELISA is about 1:10^4^. As nucleic acid extraction procedures proved to be time consuming and expensive, detection methods are adopted now for immunocapture procedures. 
These methods will be applied to the analysis of several transgenic wheat lines.
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    Scentinformatics: Mining of Structure-Odor Relationships and Scent-related Medical Effects for Mono-Molecular Odorants

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    In this dissertation, we address the unique challenge of establishing predictive relationshipsbetween chemical structure and scent properties of monomolecular odorants, in order to supportthe discovery of new odorants with targeted properties. This challenge is both difficult and excitingbecause unlike traditional medicinal agents tested in biological assays, scent properties arecharacterized by verbal descriptors rather than traditional quantitative metrics such as bindingconstants or dose-response curves. Thus, the stated challenge requires novel ways of quantifyingand harmonizing verbal scent descriptors of odorants to enable the use of cheminformatictechniques for scent research. In Chapter 1, we establish a natural language processing-basedtechnique for harmonizing subjective scent perception-based data. In Chapter 2, we build andvalidate Quantitative Structure-Odor Relationship models to predict standardized scent profilesfrom chemical structures. In Chapter 3, we develop a knowledge graph database that integratesbiomedical and scent-perceptual data linked to odorants, to enable the exploration of links betweenolfactory processes and biomedical phenomena. The processes detailed in the three chapters ofthis dissertation form a singular workflow designed to support odorant discovery research. Theprotocols developed in this thesis are made publicly available athttps://figshare.com/projects/AJT_Dissertation_UNC_CH_ESOP_CBMC_2022/137364.Doctor of Philosoph

    The effects of foreign language programmes in early childhood education and care: a systematic review

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    This systematic review investigates the effects of foreign language programmes in early childhood education and care (ECEC), which are increasingly popular. Foreign language ECEC centres familiarise very young children with a foreign language, and in general also expose them to the majority language. This review synthesises research on the effects of foreign language ECEC on children’s development of the foreign language, majority language, first language, and wellbeing, as well as programme-related and child-related factors that influence language development and wellbeing. The reviewed studies indicate that foreign language ECEC fosters foreign language development, without negatively impacting the majority and first language. Children can experience positive wellbeing in these programmes, but only if programmes are play-based and if the language policy is not too strict. Some studies report that programme characteristics, such as input quantity, language policy, and teacher strategies, modulate the effects of foreign language ECEC on language development and wellbeing. Few of the reviewed studies examined child characteristics, but the available findings indicate that children’s age, as well as their temperament and in-class behaviour, are related to foreign language learning. However, these findings need to be interpreted with caution, because research into foreign language ECEC is still in its infancy

    BinCam:designing for engagement with Facebook for behavior change

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    Abstract. In this paper we continue work to investigate how we can engage young adults in behaviors of recycling and the prevention of food waste through social media and persuasive and ubiquitous computing systems. Our previous work with BinCam, a two-part design combining a system for the collection of waste-related behaviors with a Facebook application, suggested that although this ubiquitous system could raise awareness of recycling behavior, engagement with social media remained low. In this paper we reconsider our design in terms of engagement, examining both the theoretical and practical ways in which engagement can be designed for. This paper presents findings from a new user study exploring the redesign of the social media interface following this analysis. By incorporating elements of gamification, social support and improved data visualization, we contribute insights on the relative potential of these techniques to engage individuals across the lifespan of a system’s deployment
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