Cultural Mismatch in Roma Parents’ Perceptions: The Role of Culture, Language, and Traditional Roma Values in Schools

This article draws on data from a two-year qualitative study exploring the factors contributing to Roma students’ disparate outcomes in Bulgaria. I utilize ethnographic observations, oral history, and in-depth interviews with twenty Roma parents to gain understanding of Roma children’s “cultural capital” and relation to formal schools. The article builds on theoretical orientations, generated primarily in the U.S., that emphasize strengths and the need for culturally relevant pedagogy, and explores the possibility to extend these to the case of Roma communities in Europe. The findings indicate that the traditional education of Roma children differs considerably from the mainstream values emphasized in Bulgarian schools. These include the practice of community-based, informal education, child independence, and early participation in adult life, which have the potential to make the transition from home to school problematic. I argue that if educational equity is the goal, policies and practices must shift their current focus from promoting a monocultural Bulgarian curriculum and pedagogical approaches to meaningful incorporation of culturally relevant content and creating educational environments conductive to Roma students’ learning.Cet article se fonde sur des données provenant d’une étude qualitative qui a duré deux ans et qui a porté sur les facteurs qui contribuent aux résultats divergents des étudiants roms en Bulgarie. Mes données reposent sur des observations ethnographiques, l’histoire orale et des entrevues détaillées auprès de vingt parents roms et ce, pour mieux comprendre le « capital culturel » des enfants roms et leur relation aux écoles formelles. L’article s’appuie sur des orientations théoriques issues surtout de milieux américains et qui soulignent l’importance des bienfaits d’une pédagogie pertinente sur le plan culturel, fait valoir le besoin d’une telle approche et explore la possibilité d’appliquer ces orientations au cas des communautés roms en Europe. Les résultats indiquent que l’éducation traditionnelle des enfants roms diffère considérablement des valeurs communément soulignées dans les écoles bulgares; parmi les éléments divergents, notons la pratique d’une éducation informelle et communautaire, l’autonomie des enfants et la participation précoce à la vie adulte – facteurs qui ont le potentiel de rendre difficile la transition de la maison à l’école. J’affirme que si l’objectif est l’équité en matière d’éducation, les politiques et les pratiques doivent se détourner de la promotion d’un curriculum et d’approches pédagogiques homogènes bulgares vers une intégration significative de contenu culturel pertinent et la création de milieux pédagogiques propices à l’apprentissage par les étudiants roms

Consultancy Communities of Practice

The last two decades have witnessed an ongoing effort to re-design the education doctorate to prepare practitioners to conduct research as a key aspect of their practice. As part of the reform, Carnegie Project on the Education Doctorate (CPED) members have tried to ensure the delivery of a relevant practice-based curriculum that prepares practitioners to respond to local needs. This article examines how one U.S. EdD program uses a practice-based pedagogy, called the Group Consultancy Project, to develop students as scholarly practitioners, that is, educational leaders who conduct research to enact positive societal changes. The analysis draws from final consultancy reports and from the responses of 11 students in three consultancy projects. By examining how students learned within the projects, the study reveals that the consultancy model cultivated communities of practice that moved students from a practice community toward a community of scholars and researchers

On the Spectral Properties and Excitation Dynamics of Long-Wavelength Chlorophylls in Higher-Plant Photosystem I

In higher-plant Photosystem I (PSI), the majority of “red” chlorophylls (absorbing at longer wavelengths than the reaction centre P700) are located in the peripheral antenna, but contradicting reports are given about red forms in the core complex. Here we attempt to clarify the spectroscopic characteristics and quantify the red forms in the PSI core complex, which have profound implication on understanding the energy transfer and charge separation dynamics. To this end we compare the steady-state absorption and fluorescence spectra and picosecond time-resolved fluorescence kinetics of isolated PSI core complex and PSI–LHCI supercomplex from Pisum sativum recorded at 77 K. Gaussian decomposition of the absorption spectra revealed a broad band at 705 nm in the core complex with an oscillator strength of three chlorophylls. Additional absorption at 703 nm and 711 nm in PSI–LHCI indicated up to five red chlorophylls in the peripheral antenna. Analysis of fluorescence emission spectra resolved states emitting at 705, 715 and 722 nm in the core and additional states around 705–710 nm and 733 nm in PSI–LHCI. The red states compete with P700 in trapping excitations in the bulk antenna, which occurs on a timescale of ~20 ps. The three red forms in the core have distinct decay kinetics, probably in part determined by the rate of quenching by the oxidized P700. These results affirm that the red chlorophylls in the core complex must not be neglected when interpreting kinetic experimental results of PSI

Time-resolved fluorescence study of excitation energy transfer in the cyanobacterium Anabaena PCC 7120

Excitation energy transfer (EET) and trapping in Anabaena variabilis (PCC 7120) intact cells, isolated phycobilisomes (PBS) and photosystem I (PSI) complexes have been studied by picosecond time-resolved fluorescence spectroscopy at room temperature. Global analysis of the time-resolved fluorescence kinetics revealed two lifetimes of spectral equilibration in the isolated PBS, 30–35 ps and 110–130 ps, assigned primarily to energy transfer within the rods and between the rods and the allophycocyanin core, respectively. An additional intrinsic kinetic component with a lifetime of 500–700 ps was found, representing non-radiative decay or energy transfer in the core. Isolated tetrameric PSI complexes exhibited biexponential fluorescence decay kinetics with lifetimes of about 10 ps and 40 ps, representing equilibration between the bulk antenna chlorophylls with low-energy “red” states and trapping of the equilibrated excitations, respectively. The cascade of EET in the PBS and in PSI could be resolved in intact filaments as well. Virtually all energy absorbed by the PBS was transferred to the photosystems on a timescale of 180–190 ps

Far-red fluorescence:A direct spectroscopic marker for LHCII oligomer formation in non-photochemical quenching

AbstractTime-resolved fluorescence on oligomers of the main light-harvesting complex from higher plants indicate that in vitro oligomerization leads to the formation of a weakly coupled inter-trimer chlorophyll–chlorophyll (Chl) exciton state which converts in tens of ps into a state which is spectrally broad and has a strongly far-red enhanced fluorescence spectrum. Both its lifetime and spectrum show striking similarity with a 400ps fluorescence component appearing in intact leaves of Arabidopsis when non-photochemical quenching (NPQ) is induced. The fluorescence components with high far-red/red ratio are thus a characteristic marker for NPQ conditions in vivo. The far-red emitting state is shown to be an emissive Chl–Chl charge transfer state which plays a crucial part in the quenching

Photobleaching of Chlorophyll in Light-Harvesting Complex II Increases in Lipid Environment

Excess light causes damage to the photosynthetic apparatus of plants and algae primarily via reactive oxygen species. Singlet oxygen can be formed by interaction of chlorophyll (Chl) triplet states, especially in the Photosystem II reaction center, with oxygen. Whether Chls in the light-harvesting antenna complexes play direct role in oxidative photodamage is less clear. In this work, light-induced photobleaching of Chls in the major trimeric light-harvesting complex II (LHCII) is investigated in different molecular environments - protein aggregates, embedded in detergent micelles or in reconstituted membranes (proteoliposomes). The effects of intense light treatment were analyzed by absorption and circular dichroism spectroscopy, steady-state and time-resolved fluorescence and EPR spectroscopy. The rate and quantum yield of photobleaching was estimated from the light-induced Chl absorption changes. Photobleaching occurred mainly in Chl a and was accompanied by strong fluorescence quenching of the remaining unbleached Chls. The rate of photobleaching increased by 140% when LHCII was embedded in lipid membranes, compared to detergent-solubilized LHCII. Removing oxygen from the medium or adding antioxidants largely suppressed the bleaching, confirming its oxidative mechanism. Singlet oxygen formation was monitored by EPR spectroscopy using spin traps and spin labels to detect singlet oxygen directly and indirectly, respectively. The quantum yield of Chlaphotobleaching in membranes and detergent was found to be 3.4 x 10(-5)and 1.4 x 10(-5), respectively. These values compare well with the yields of ROS production estimated from spin-trap EPR spectroscopy (around 4 x 10(-5)and 2 x 10(-5)). A kinetic model is proposed, quantifying the generation of Chl and carotenoid triplet states and singlet oxygen. The high quantum yield of photobleaching, especially in the lipid membrane, suggest that direct photodamage of the antenna occurs with rates relevant to photoinhibitionin vivo. The results represent further evidence that the molecular environment of LHCII has profound impact on its functional characteristics, including, among others, the susceptibility to photodamage

Multiscale photosynthetic exciton transfer

Photosynthetic light harvesting provides a natural blueprint for bioengineered and biomimetic solar energy and light detection technologies. Recent evidence suggests some individual light harvesting protein complexes (LHCs) and LHC subunits efficiently transfer excitons towards chemical reaction centers (RCs) via an interplay between excitonic quantum coherence, resonant protein vibrations, and thermal decoherence. The role of coherence in vivo is unclear however, where excitons are transferred through multi-LHC/RC aggregates over distances typically large compared with intra-LHC scales. Here we assess the possibility of long-range coherent transfer in a simple chromophore network with disordered site and transfer coupling energies. Through renormalization we find that, surprisingly, decoherence is diminished at larger scales, and long-range coherence is facilitated by chromophoric clustering. Conversely, static disorder in the site energies grows with length scale, forcing localization. Our results suggest sustained coherent exciton transfer may be possible over distances large compared with nearest-neighbour (n-n) chromophore separations, at physiological temperatures, in a clustered network with small static disorder. This may support findings suggesting long-range coherence in algal chloroplasts, and provides a framework for engineering large chromophore or quantum dot high-temperature exciton transfer networks.Comment: 9 pages, 6 figures. A significantly updated version is now published online by Nature Physics (2012