The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
A Cusano - One of the best experts on this subject based on the ideXlab platform.
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Experimental Evidence of guided resonances in photonic crystals with aperiodically ordered supercells
Optics Letters, 2010Co-Authors: Armando Ricciardi, Marco Pisco, Ilaria Gallina, Stefania Campopiano, Vincenzo Galdi, Liam O Faolain, T F Krauss, A CusanoAbstract:We report on the first Experimental Evidence of guided resonances (GRs) in photonic crystal slabs based on aperiodically ordered supercells. Using Ammann–Beenker (quasiperiodic, eightfold symmetric) tiling geometry, we present our study on the fabrication, Experimental characterization, and full-wave numerical simulation of two representative structures (with different filling parameters) operating at near-IR wavelengths (1300–1600nm). Our results show a fairly good agreement between measurements and numerical predictions and pave the way for the development of new strategies (based on, e.g., the lattice symmetry breaking) for GR engineering.
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Experimental Evidence of guided resonances in photonic crystals with aperiodically ordered supercells
arXiv: Optics, 2010Co-Authors: Armando Ricciardi, Marco Pisco, Ilaria Gallina, Stefania Campopiano, Vincenzo Galdi, Liam O Faolain, T F Krauss, A CusanoAbstract:We report on the first Experimental Evidence of guided resonances (GRs) in photonic crystal slabs based on aperiodically-ordered supercells. Using the Ammann-Beenker (quasiperiodic, 8-fold symmetric) tiling geometry, we present our study on the fabrication, Experimental characterization, and full-wave numerical simulation of two representative structures (with different filling parameters) operating at near-infrared wavelengths (1300-1600 nm). Our results show a fairly good agreement between measurements and numerical predictions, and pave the way for the development of new strategies (based, e.g., on the lattice symmetry breaking) for GR engineering.
Roland Brosch - One of the best experts on this subject based on the ideXlab platform.
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key Experimental Evidence of chromosomal dna transfer among selected tuberculosis causing mycobacteria
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Eva C. Boritsch, Alexandre Pawlik, Philip Supply, Christiane Bouchier, Varun Khanna, Nadine Honore, Victor H Navas, Torsten Seemann, Timothy P Stinear, Roland BroschAbstract:Abstract Horizontal gene transfer (HGT) is a major driving force of bacterial diversification and evolution. For tuberculosis-causing mycobacteria, the impact of HGT in the emergence and distribution of dominant lineages remains a matter of debate. Here, by using fluorescence-assisted mating assays and whole genome sequencing, we present unique Experimental Evidence of chromosomal DNA transfer between tubercle bacilli of the early-branching Mycobacterium canettii clade. We found that the obtained recombinants had received multiple donor-derived DNA fragments in the size range of 100 bp to 118 kbp, fragments large enough to contain whole operons. Although the transfer frequency between M. canettii strains was low and no transfer could be observed among classical Mycobacterium tuberculosis complex (MTBC) strains, our study provides the proof of concept for genetic exchange in tubercle bacilli. This outstanding, now Experimentally validated phenomenon presumably played a key role in the early evolution of the MTBC toward pathogenicity. Moreover, our findings also provide important information for the risk evaluation of potential transfer of drug resistance and fitness mutations among clinically relevant mycobacterial strains.
Karthik Muralidharan - One of the best experts on this subject based on the ideXlab platform.
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disrupting education Experimental Evidence on technology aided instruction in india
Social Science Research Network, 2017Co-Authors: Karthik Muralidharan, Abhijeet Singh, Alejandro GanimianAbstract:We present Experimental Evidence on the impact of a technology-aided after-school instruction program on learning outcomes in middle school grades in urban India, using a lottery that provided students with a voucher to cover program costs. A key feature of the program was its ability to individually customize educational content to match the level and rate of progress of each student. We find that lottery winners had large increases in test scores of 0.36σ in math and 0.22σ in Hindi over just a 4.5-month period. IV estimates suggest that attending the program for 90 days would increase math and Hindi test scores by 0.59σ and 0.36σ respectively. We find similar absolute test score gains for all students, but the relative gain was much greater for academically-weaker students because their rate of learning in the control group was close to zero. We show that the program precisely targets instruction to students' preparation level, thus catering effectively to the very wide variation in student learning levels within a single grade. The program was highly cost-effective, both in terms of productivity per dollar and unit of time. Our results suggest that well-designed technology-aided instruction programs can sharply improve productivity in delivering education.Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.
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2010): "Contract Teachers: Experimental Evidence from India
2016Co-Authors: Karthik Muralidharan, Venkatesh SundararamanAbstract:Abstract: The large-scale expansion of primary schooling in developing countries has led to the increasing use of non-civil-service contract teachers who are hired locally by the school, are not professionally trained, have fixed-term renewable contracts, and are paid much lower salaries than regular civil-service teachers. This has been a controversial policy, but there is limited Evidence on the effectiveness of contract teachers in improving student learning. We present Experimental Evidence on the impact of contract teachers using data from an 'as is ' expansion of contract-teacher hiring across a representative sample of 100 randomly-selected government-run rural primary schools in the Indian state of Andhra Pradesh. At the end of two years, students in schools with an extra contract teacher performed significantly better than those in comparison schools by 0.16σ and 0.15σ, in math and language tests respectively. Contract teachers were also much less likely to be absent from school than civil-service teachers (18 % vs. 27%). Combining the Experimental reduction in school-level pupil-teacher ratio (PTR) induced by the provision of an extra contract teacher, with high-quality panel data estimates of the impact of reducing PTR with a regular civil-service teacher, we show that contract teachers are not only effective at improving student learning outcomes, but that they are no less effective at doing so than regular civil-service teachers who ar
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disrupting education Experimental Evidence on technology aided instruction in india
Research Papers in Economics, 2016Co-Authors: Karthik Muralidharan, Abhijeet Singh, Alejandro GanimianAbstract:We present Experimental Evidence on the impact of a technology-aided after-school instruction program on learning outcomes in middle school grades in urban India, using a lottery that provided students with a voucher to cover program costs. A key feature of the program was its ability to individually customize educational content to match the level and rate of progress of each student. We find that lottery winners had large increases in test scores of 0.36o in math and 0.22o in Hindi over just a 4.5-month period. IV estimates suggest that attending the program for 90 days would increase math and Hindi test scores by 0.59o and 0.36o respectively. We find similar absolute test score gains for all students, but the relative gain was much greater for academically-weaker students because their rate of learning in the control group was close to zero. We show that the program was able to effectively cater to the very wide variation in student learning levels within a single grade by precisely targeting instruction to the level of student preparation. The program was highly cost-effective, both in terms of productivity per dollar and unit of time. Our results suggest that well-designed technology-aided instruction programs can sharply improve productivity in delivering education.
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teacher performance pay Experimental Evidence from india
Journal of Political Economy, 2011Co-Authors: Karthik Muralidharan, Venkatesh SundararamanAbstract:This brief summarizes the results of a gender impact evaluation study, entitled Teacher performance pay : Experimental Evidence from India, conducted in August 2005 in India. The study observed the impact of a teacher performance pay program implemented across a large representative sample of government-run rural primary schools in the Indian state of Andhra Pradesh on the student and school level. After two years, students in incentive schools performed significantly better than control schools. The mean treatment effect is 0.22 standard deviations. There are significant improvements across the performance distribution. Additionally there were no observations of adverse consequences, given that students also do better in non-incentivized subjects. The main mechanism of impact is increased teacher effort conditional on the teacher being present. The student's gender does not have a significant effect on the impact of the intervention. Funding for the study derived from the Andhra Pradesh, Department for International Development (DFID), Azim Premji Foundation, and the Spanish Impact Evaluation Fund.
Alejandro Ganimian - One of the best experts on this subject based on the ideXlab platform.
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disrupting education Experimental Evidence on technology aided instruction in india
Social Science Research Network, 2017Co-Authors: Karthik Muralidharan, Abhijeet Singh, Alejandro GanimianAbstract:We present Experimental Evidence on the impact of a technology-aided after-school instruction program on learning outcomes in middle school grades in urban India, using a lottery that provided students with a voucher to cover program costs. A key feature of the program was its ability to individually customize educational content to match the level and rate of progress of each student. We find that lottery winners had large increases in test scores of 0.36σ in math and 0.22σ in Hindi over just a 4.5-month period. IV estimates suggest that attending the program for 90 days would increase math and Hindi test scores by 0.59σ and 0.36σ respectively. We find similar absolute test score gains for all students, but the relative gain was much greater for academically-weaker students because their rate of learning in the control group was close to zero. We show that the program precisely targets instruction to students' preparation level, thus catering effectively to the very wide variation in student learning levels within a single grade. The program was highly cost-effective, both in terms of productivity per dollar and unit of time. Our results suggest that well-designed technology-aided instruction programs can sharply improve productivity in delivering education.Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.
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disrupting education Experimental Evidence on technology aided instruction in india
Research Papers in Economics, 2016Co-Authors: Karthik Muralidharan, Abhijeet Singh, Alejandro GanimianAbstract:We present Experimental Evidence on the impact of a technology-aided after-school instruction program on learning outcomes in middle school grades in urban India, using a lottery that provided students with a voucher to cover program costs. A key feature of the program was its ability to individually customize educational content to match the level and rate of progress of each student. We find that lottery winners had large increases in test scores of 0.36o in math and 0.22o in Hindi over just a 4.5-month period. IV estimates suggest that attending the program for 90 days would increase math and Hindi test scores by 0.59o and 0.36o respectively. We find similar absolute test score gains for all students, but the relative gain was much greater for academically-weaker students because their rate of learning in the control group was close to zero. We show that the program was able to effectively cater to the very wide variation in student learning levels within a single grade by precisely targeting instruction to the level of student preparation. The program was highly cost-effective, both in terms of productivity per dollar and unit of time. Our results suggest that well-designed technology-aided instruction programs can sharply improve productivity in delivering education.
Armando Ricciardi - One of the best experts on this subject based on the ideXlab platform.
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Experimental Evidence of guided resonances in photonic crystals with aperiodically ordered supercells
Optics Letters, 2010Co-Authors: Armando Ricciardi, Marco Pisco, Ilaria Gallina, Stefania Campopiano, Vincenzo Galdi, Liam O Faolain, T F Krauss, A CusanoAbstract:We report on the first Experimental Evidence of guided resonances (GRs) in photonic crystal slabs based on aperiodically ordered supercells. Using Ammann–Beenker (quasiperiodic, eightfold symmetric) tiling geometry, we present our study on the fabrication, Experimental characterization, and full-wave numerical simulation of two representative structures (with different filling parameters) operating at near-IR wavelengths (1300–1600nm). Our results show a fairly good agreement between measurements and numerical predictions and pave the way for the development of new strategies (based on, e.g., the lattice symmetry breaking) for GR engineering.
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Experimental Evidence of guided resonances in photonic crystals with aperiodically ordered supercells
arXiv: Optics, 2010Co-Authors: Armando Ricciardi, Marco Pisco, Ilaria Gallina, Stefania Campopiano, Vincenzo Galdi, Liam O Faolain, T F Krauss, A CusanoAbstract:We report on the first Experimental Evidence of guided resonances (GRs) in photonic crystal slabs based on aperiodically-ordered supercells. Using the Ammann-Beenker (quasiperiodic, 8-fold symmetric) tiling geometry, we present our study on the fabrication, Experimental characterization, and full-wave numerical simulation of two representative structures (with different filling parameters) operating at near-infrared wavelengths (1300-1600 nm). Our results show a fairly good agreement between measurements and numerical predictions, and pave the way for the development of new strategies (based, e.g., on the lattice symmetry breaking) for GR engineering.
