Pseudogaps in Underdoped Cuprates

It has become clear in the past several years that the cuprates show many unusual properties, both in the normal and superconducting states, especially in the underdoped region. In particular, gap-like behavior is observed in magnetic properties, c-axis conductivity and photoemission, whereas in-plane transport properties are only slightly affected by the pseudogap. I shall argue that these experimental evidences must be viewed in the context of the physics of a doped Mott insulator and that they support the notion of spin charge separation. I shall review recent theoretical developments, concentrating on studies based on the t-J model. I shall describe a model based on quasiparticle excitations, which predicts the doping dependence of T_c and anomalous energy-gap-to-T_c ratios. Finally, I shall outline how the model may be derived from a microscopic formulation of the t-J model. After a brief review of the U(1) formulation, I shall explain some of the difficulties encountered there, and how a new SU(2) formulation can resolve some of the difficulties.Comment: 9 pages, 4 figure

Reporting of measures of accuracy in systematic reviews of diagnostic literature

BACKGROUND: There are a variety of ways in which accuracy of clinical tests can be summarised in systematic reviews. Variation in reporting of summary measures has only been assessed in a small survey restricted to meta-analyses of screening studies found in a single database. Therefore, we performed this study to assess the measures of accuracy used for reporting results of primary studies as well as their meta-analysis in systematic reviews of test accuracy studies. METHODS: Relevant reviews on test accuracy were selected from the Database of Abstracts of Reviews of Effectiveness (1994–2000), which electronically searches seven bibliographic databases and manually searches key resources. The structured abstracts of these reviews were screened and information on accuracy measures was extracted from the full texts of 90 relevant reviews, 60 of which used meta-analysis. RESULTS: Sensitivity or specificity was used for reporting the results of primary studies in 65/90 (72%) reviews, predictive values in 26/90 (28%), and likelihood ratios in 20/90 (22%). For meta-analysis, pooled sensitivity or specificity was used in 35/60 (58%) reviews, pooled predictive values in 11/60 (18%), pooled likelihood ratios in 13/60 (22%), and pooled diagnostic odds ratio in 5/60 (8%). Summary ROC was used in 44/60 (73%) of the meta-analyses. There were no significant differences in measures of test accuracy among reviews published earlier (1994–97) and those published later (1998–2000). CONCLUSIONS: There is considerable variation in ways of reporting and summarising results of test accuracy studies in systematic reviews. There is a need for consensus about the best ways of reporting results of test accuracy studies in reviews

Inspection and replacement models for reliability and maintenance: filling in gaps

A thesis submitted in fulfillment of the requirements for the Degree of Doctor of Philosophy, School of Statistics and Actuarial Science, Faculty of Science University of Witwatersrand, Johannesburg. February 2017.The work done in this thesis on finite planning horizon inspection models has demonstrated that with the advent of powerful computers these days it is possible to easily find an optimal inspection schedule when the lifetime distribution is known. For the case of system time to failure following a uniform distribution, a result for the maximum number of inspections for the finite planning models has been derived. If the time to failure follows an exponential distribution, it has been noted that periodically carrying out inspections may not result in maximization of expected profit. For the Weibull distributions family (of which the exponential distribution is a special case), evenly spreading the inspections over a given finite planning horizon may not lead to any serious prejudice in profit. The case of inspection models where inspections are of non-negligible duration has also been explored. The conditions necessary for inspections that are evenly spread over the entire planning horizon to be near-optimal when system time to failure either follows a uniform distribution or exponential distribution have been explored. Finite and infinite planning horizon models where inspections are imperfect have been researched on. Interesting observations on the impact of Type I and Type II errors in inspection have been made. These observations are listed on page 174. A clear and easy to implement road map on how to get an optimal inspection permutation in problems first discussed by Zuckerman (1989) and later reviewed by Qiu (1991) for both the undiscounted and discounted cases has been given. The only challenge envisaged when a system has a large number of components is that of computer memory requirements - which nowadays is fast being overcome. In particular, it has been clearly demonstrated that the impact of repair times and per unit of time repair costs on the optimal inspection permutation cannot be ignored. The ideas and procedures of determining optimal inspection permutations which have been developed in this thesis will no doubt lead to huge cost savings especially for systems where the cost of inspecting components is huge.XL201

Validation Study Of The Integral-Differential Scheme For Multi-Block Grids

This MS Thesis seeks to validate the accuracy of the Integral-Differential Scheme (IDS). In the attempts to accomplish this task, research efforts were focused on the scheme’s ability to capture the physics of known flow fields, as well as the scheme’s ability to predict the features of flow field quantities that may be derived from experimental measurements. The IDS was developed with the goal of being computationally efficient, from a programming perspective, as well as being numerically accurate, stable, and robust, from a mathematical perspective. The IDS is designed to solve the full Navier-Stokes equations in their integral forms. Unlike traditional control volume schemes, the IDS is built upon two sets of cells: spatial and temporal cells. For 2-D flows, the IDS considers an elementary control volume as a collection of four spatial cells and a single temporal cell. Similar to other explicit CFD schemes, the IDS relies on the use of the Taylor series expansion and other traditional CFD criteria. It is of interest to note that there are previous IDS validation studies which were conducted at North Carolina A&T State University. These past studies mainly focused on the qualitative aspects of the flow field physics. Furthermore, in all cases, they focused on flow field problems that can be represented by single-block grids. In this analysis, the validation studies are focused on multi-block grids in which the physics of the flow field is made complicated due to the presence of shock waves and flow separation zones. Of interest to this MS Thesis are two supersonic flow field problems that are supported by experimental data; namely, the supersonic flow over a rearward-facing step problem and the supersonic flow over a cavity problem. The validation studies conducted herein demonstrated that the IDS was able to predict the experimental data in both cases

Validation Study Of The Integral-Differential Scheme For Multi-Block Grids

This MS Thesis seeks to validate the accuracy of the Integral-Differential Scheme (IDS). In the attempts to accomplish this task, research efforts were focused on the scheme’s ability to capture the physics of known flow fields, as well as the scheme’s ability to predict the features of flow field quantities that may be derived from experimental measurements. The IDS was developed with the goal of being computationally efficient, from a programming perspective, as well as being numerically accurate, stable, and robust, from a mathematical perspective. The IDS is designed to solve the full Navier-Stokes equations in their integral forms. Unlike traditional control volume schemes, the IDS is built upon two sets of cells: spatial and temporal cells. For 2-D flows, the IDS considers an elementary control volume as a collection of four spatial cells and a single temporal cell. Similar to other explicit CFD schemes, the IDS relies on the use of the Taylor series expansion and other traditional CFD criteria. It is of interest to note that there are previous IDS validation studies which were conducted at North Carolina A&T State University. These past studies mainly focused on the qualitative aspects of the flow field physics. Furthermore, in all cases, they focused on flow field problems that can be represented by single-block grids. In this analysis, the validation studies are focused on multi-block grids in which the physics of the flow field is made complicated due to the presence of shock waves and flow separation zones. Of interest to this MS Thesis are two supersonic flow field problems that are supported by experimental data; namely, the supersonic flow over a rearward-facing step problem and the supersonic flow over a cavity problem. The validation studies conducted herein demonstrated that the IDS was able to predict the experimental data in both cases

Tanggapan Perseptual Guru Bahasa Inggris Di SD Se-surakarta Terhadap Kebijakan Pelaksanaan Mata Pelajaran Bahasa Inggris Di Sekolah Dasar

This qualitative descriptive study aims to describe how the perceptual response of teachersof English in primary schools towards the government policy related to the implementationof English subjects in elementary school. Population of this research is Englishteachers at the elementary school in Surakarta and takes a sample of English teachersfrom primary schools in partnership with UMS PGSD as many as 20 teachers ofEnglish. Methods of data collection in this study using observations, interviews anddocumentation, and analysis with interactive analysis. In this research, the elementaryteachers as research respondents divided into two groups of teachers who have educationalbackgrounds of English and non-English language. These two groups, dividedinto four categories. The first category are teachers who have a background in Englisheducation with teaching experience less than or equal to ten years. The second categoryare teachers with educational background in English with teaching experience morethan ten years. The third categoryare teachers with backgrounds non English with teachingexperience less than ten years. The fourth category are teachers with backgroundsnon English with teaching experience more than ten years. The findings found in perceptualresponse from the four categories of teachers, show that basically they comprehendthat the implementation of English subjects in elementary school is very importantdue to many reasons. The teachers agree toward the implementation of Englishsubject at elementary school as long as it is conducted seriously and in a professionalways rather than as a additional curriculum

Adoption of Free Open Source Geographic Information System Solution for Health Sector in Zanzibar Tanzania

\ud The study aims at developing in-depth understanding on how Open Source Geographic Information System technology is used to provide solutions for data visualization in the health sector of Zanzibar, Tanzania. The study focuses on implementing the health visualization solutions for the purpose of bridging the gap during the transition period from proprietary software to the Free Open-Source Software using Key Indicator Data System. The developed tool facilitates data integration between the two District Health Information Software versions and hence served as a gateway solution during the transition process. Implementation challenges that include outdated spatial data and the reluctance of the key users in coping with the new Geographical Information System technologies were also identified. Participatory action research and interviews were used in understanding the requirements for the new tool to facilitate the smooth system development for better health service delivery.\u

Insect infestation sources in stored maize grain; what is more important resident versus incoming infestation?

Most studies targeted pest control inside stores; incognisant of the population dynamics in the store vicinity; leading to product re-infestation. Distinction between storage insect pest source and sink grain patches is important for effective pest management strategies. We examined the role of resident versus incoming insect infestation in phosphine-fumigated closed or open and unfumigated closed or open maize farm stores. Grain quality measurements were recorded over 32 weeks for two storage seasons. Whether open or closed, fumigated grain had significantly lower (p < 0.001) grain damage and lower grain weight loss (p < 0.05) than unfumigated grain. Fumigated open stores had significantly higher (p= 0.004) grain damage and weight loss than closed ones. Grain damage was higher in unfumigated-closed than fumigated-open, evidence that resident infestation inflicted higher food loss than incoming infestation. Prostephanus truncatus, Cryptolestes ferrugineus and Tribolium castaneum had significantly higher populations (p < 0.001, p = 0.018 and p = 0.001; respectively) at bottom levels of unfumigated and fumigated grain (T. castaneum). Sitotroga cerealella and Sitophilus zeamais were significantly higher (p < 0.001) at the top of closed than open unfumigated compartments. Grain suffers less infestation and quality loss when it is a sink patch than when it is a source patch. Population build-up and ‘settling’ to inflict significant food loss takes longer for incoming compared to resident infestation. These results have ecological implications on postharvest IPM.Most studies targeted pest control inside stores; incognisant of the population dynamics in the store vicinity; leading to product re-infestation. Distinction between storage insect pest source and sink grain patches is important for effective pest management strategies. We examined the role of resident versus incoming insect infestation in phosphine-fumigated closed or open and unfumigated closed or open maize farm stores. Grain quality measurements were recorded over 32 weeks for two storage seasons. Whether open or closed, fumigated grain had significantly lower (p < 0.001) grain damage and lower grain weight loss (p < 0.05) than unfumigated grain. Fumigated open stores had significantly higher (p= 0.004) grain damage and weight loss than closed ones. Grain damage was higher in unfumigated-closed than fumigated-open, evidence that resident infestation inflicted higher food loss than incoming infestation. Prostephanus truncatus, Cryptolestes ferrugineus and Tribolium castaneum had significantly higher populations (p < 0.001, p = 0.018 and p = 0.001; respectively) at bottom levels of unfumigated and fumigated grain (T. castaneum). Sitotroga cerealella and Sitophilus zeamais were significantly higher (p < 0.001) at the top of closed than open unfumigated compartments. Grain suffers less infestation and quality loss when it is a sink patch than when it is a source patch. Population build-up and ‘settling’ to inflict significant food loss takes longer for incoming compared to resident infestation. These results have ecological implications on postharvest IPM

Attitudinal factors among elementary school teacher education students

In second or foreign language learning, attitudinal factors were one of the key factors that determine language success and achievement. In Indonesia, foreign language (English) has been taught since elementary school, however research showed most Indonesian language learners in English showed unsatisfactorily result. This research aimed at disclosing the students’ attitudinal factors in learning foreign language by exploring their first experience in learning foreign language. This qualitative study employed exploratory case study design to interview students’ attitudinal factors by exploring the students past experience at first time learning foreign language. These students were from different education unit background when they were in elementary school. This study applied thematic analysis to interpret and analyze the data. The findings showed in case of attitudinal factors were categorized into three components that were cognitive, affective, and behavior. In case of cognitive and affective components, those who had good experiences felt happy in their first experience in foreign language and the vice versa. However, both were having similar learning behavior when they serve as an English teacher, they adopted particular learning behavior that was able to make students enjoy the foreign language learning

Analisis Kesulitan Belajar Matematika Anak Tunagrahita Kelas 4 di SD Negeri

Penelitian ini bertujuan mengalisis penyebab kesulitan belajar matematika yang dialami anak tunagrahita di SD Negeri. Penelitian ini menerapkan pendekatan kualitatif, metode deskriptif, dengan model fenomenologi. Keabsahan data diperkuat dengan menggunakan metode tes. Model interaktif dari Miles dan Huberman diterapkan untuk menganalisis data. Penelitian ini berdasar pada teori kesulitan belajar matematika oleh Lerner, didukung dengan teori ketunagrahitaan  oleh Efendi. Hasil penelitian ini, yakni : 1) kesulitan mengenal dan memahami simbol, disebabkan karena lemahnya daya ingat. 2) gangguan hubungan keruangan, disebabkan karena kemampuan berinteraksi anak tunagrahita. 3) gangguan dalam membaca bahasa matematika, disebabkan oleh keterbatasan kemampuan bahasa tunagrahita secara alamiah dan adanya gangguan konsentrasi. Hasil penelitian ini diharapkan dapat menjadi pertimbangan dalam memilih strategi dan model belajar bagi peyelenggara pendidikan inklusi.Penelitian ini bertujuan untuk mengalisis penyebab kesulitan belajar matematika yang dialami anak tunagrahita kelas 4 Penelitian ini menerapkan pendekatan kualitatif metode deskriptif dengan model fenomenologi. Data diperoleh berdasarkan hasil observasi, wawancara, dan dokumentasi pada seorang siswi tunagrahita kelas 4 SD negeri. Untuk memperkuat keabsahan data peneliti melakukan metode tes untuk mereview kemampuan siswa dalam pembelajan matematika. Model analisis data yang diterapkan pada penelitian ini yakni model interaktif dari Miles dan Huberman, yakni mereduksi data, menyajikan data, dan menyimpulkan. Penelitian ini berdasar pada teori karakteristik kesulitan belajar matematika yang dikemukakan oleh Lerner dan didukung dengan teori ketunagrahitaan yang dikemukakan oleh Efendi. Hasil penelitian ini antara lain : 1) kesulitan mengenal dan memahami simbol, disebabkan karena lemahnya daya ingat anak tunagrahita. 2) gangguan hubungan keruangan, disebabkan karena rendahnya kemampuan berinteraksi anak tunagrahita. 3) gangguan dalam membaca bahasa matematika yang disebabkan oleh keterbatasan kemampuan bahasa tunagrahita secara alamiah dan adanya gangguan konsentrasi