The Play Behaviours of Roma Children in Transylvania

The Roma children of Transylvania are probably the most materially deprived in Europe. They often live in one-room shacks made from wood and mud, with no running water, no sanitation, and sometimes no heating. Many rely on charity for their food and medicines. But, are they play deprived? This paper summarises an observational study of the play behaviours of children in a small Roma village. It highlights the striking contrast between the abject poverty that characterises their lives and the general happiness of the children. These children live their limited lives to the full. They ‘play everywhere and with everything’, but not in the generally accepted sense of that phrase. The usual niceties of privacy, personal possessions and property boundaries are irrelevant here. Their play is rich in imagination and creativity; it is living proof of Nicholson’s theory of loose parts

Morphological docking of secretory vesicles

Calcium-dependent secretion of neurotransmitters and hormones is essential for brain function and neuroendocrine-signaling. Prior to exocytosis, neurotransmitter-containing vesicles dock to the target membrane. In electron micrographs of neurons and neuroendocrine cells, like chromaffin cells many synaptic vesicles (SVs) and large dense-core vesicles (LDCVs) are docked. For many years the molecular identity of the morphologically docked state was unknown. Recently, we resolved the minimal docking machinery in adrenal medullary chromaffin cells using embryonic mouse model systems together with electron-microscopic analyses and also found that docking is controlled by the sub-membrane filamentous (F-)actin. Currently it is unclear if the same docking machinery operates in synapses. Here, I will review our docking assay that led to the identification of the LDCV docking machinery in chromaffin cells and also discuss whether identical docking proteins are required for SV docking in synapses

Inelastic scattering of light by magnetic excitons in the pseudo Ising antiferromagnets K2CoF4 and Rb2CoF4

In addition to previously reported phonon Raman scattering, we have observed inelastic light scattering by magnetic excitons in K2CoF 4 and Rb2CoF4 ; the polarized spectra have been studied at low temperatures under an applied magnetic field up to about 5 teslas. The results are interpreted on the basis of a multilevel propagating exciton model deduced from a Hamiltonian including the single ion spin-orbit coupling, the low symmetry crystal field and a nearest neighbours Heisenberg exchange interaction, acting in the 4Γ+4 (Oh) ground state of Co 2+. From the lowest exciton study we derive a value of the tetragonal crystal field Δ (— 425 cm-1 and — 635 cm -1, respectively in K2CoF4 and Rb2CoF 4) and of the isotropic exchange parameter J ( — 11.55 cm-1 and — 9.65 cm-1, respectively in K 2CoF4 and Rb2CoF4). The remaining features of the spectra, which include one and two exciton scattering, are partly interpreted using the above model with these values. The derived J values are close to previous determinations in KCoF3 and RbCoF 3, as expected. The Ising character, which is caused by the low symmetry crystal field, is found to be less marked when evaluated from the magnon dispersion results than it was indicated by previous magnetic measurements, and this has been confirmed by recent inelastic neutron scattering data in Rb2CoF 4.Outre l'effet Raman dû aux phonons, antérieurement signalé, nous observons la diffusion inélastique de la lumière liée aux excitons magnétiques dans K2CoF4 et Rb2CoF4 ; les spectres polarisés ont été étudiés à basse température en présence d'un champ magnétique pouvant atteindre 5 teslas environ. Nous interprétons les résultats au moyen d'un modèle multi-excitonique déduit d'un Hamiltonien tenant compte du couplage spin-orbite, du champ cristallin de basse symétrie et d'une interaction d'échange de type Heisenberg, perturbant l'état fondamental 4Γ+4 (Oh) des ions Co2+. De l'étude de l'exciton de plus basse énergie, nous déduisons la valeur du champ cristallin quadratique Δ (— 425 cm-1 et — 635 cm -1, respectivement pour K2CoF4 et Rb2CoF 4) ainsi que celle du paramètre d'échange isotrope J (— 11,55 cm-1 et — 9,65 cm-1, respectivement pour K2CoF4 et Rb2CoF4). Le reste du spectre, qui contient des contributions à la diffusion par un et par deux excitons, est partiellement interprété, grâce au modèle ci-dessus décrit, pour les valeurs ainsi déterminées des paramètres Δ et J, dont il dépend. Les valeurs de J sont voisines de celles qui ont été antérieurement trouvées pour KCoF 3 et RbCoF3, comme prévu. Le comportement de type Ising, qui provient du champ cristallin de basse symétrie apparaît moins marqué lorsqu'on l'évalue à partir de la courbe de dispersion des magnons que ne le laissaient prévoir d'anciennes mesures magnétiques, résultat confirmé par une récente étude de diffusion inélastique de neutrons dans Rb2CoF4

Structural and metamorphic evolution of an ocean-continent transition (OCT) zone mélange deformed under HP conditions during Alpine subduction (Western Italian Alps)

We report on the structural architecture and metamorphic evolution of a m\ue9lange, developed originally in an ocean-continent transition (OCT) zone along the boundary between the continental crust of the Sesia-Lanzo (SLZ) and the oceanic Piemonte Zones (PZ) in the axial part of the Western Alps. All these units were deformed together under high-pressure conditions. The m\ue9lange consists of thin layers of calcschist, fine-grained gneiss, quartzite, minor metabasic rocks and serpentinite, and occurs all along the western margin of southern SLZ, extending from Santanel klippe to Lanzo Massif, over a distance of 50 km (Spalla et al., 1983; Battiston et al., 1984). Calcschist rocks range from phyllites to carbonatic schists and marbles; fine-grained gneisses of continental origin (very similar to those of SLZ) include phengitic white mica, chlorite, \ub1 garnet \ub1 albite and relict allanite. Thinly layered quartzites are white mica- and garnet-bearing. Metabasic rocks consist of metagabbros and metabasalts with minor mylonitic serpentinites. All these lithologies of the m\ue9lange unit and the rocks of SLZ and PZ together underwent four episodes of deformation, giving rise to a complex regional tectonostratigraphy. The earliest deformational structures are represented by up to ten meter-scale isoclinal rootless folds. The metamorphic mineral assemblages marking successive foliations indicate that all rock units in the m\ue9lange, SLZ and PZ (Spalla et al., 1983; Benciolini et al., 1984) experienced an early eclogite facies imprint, followed by re-equilibration under blueschist facies conditions, and that they were finally widely retrogressed under greenschist facies conditions during the last two deformational episodes (D3 and D4 structures). The strong synmetamorphic deformation of this m\ue9lange prevents an unequivocal interpretation of its origin; hence, we envisage two possible scenarios: i) the present day configuration of these thin, intermingled layers, including rootless refolded isoclinal folds, is entirely due to transposition that occurred in a mantle wedge at the early stages of deformation under eclogite facies conditions during active subduction; ii) a detrital origin of these alternating layers of terrigeneous and carbonaceous rocks corresponds to a primary sequence of an extensionally-thinned continental margin near an OCT that was reworked in the Alpine subduction system. Battiston P., Benciolini L., Dal Piaz G. V., De Vecchi G., Marchi G., Martin S., Polino R. & Tartarotti P. - (1984) - Mem. Soc. Geol. It. 29, 209-232. Benciolini L., Martin S. & Tartarotti P. - (1984) - Mem. Soc. Geol. Ital. 29, 127-151. Spalla M. I., De Maria L., Gosso G., Miletto M. & Pognante U. - (1983) - Mem. Soc. Geol. Ital. 26, 499-514

Structural and metamorphic evolution of an ocean-continent transition (OCT) zone m\ue9lange deformed under HP conditions during Alpine subduction (Western Italian Alps).

We report on the structural architecture and metamorphic evolution of a m\ue9lange, developed originally in an ocean-continent transition (OCT) zone along the boundary between the continental crust of the Sesia-Lanzo (SLZ) and the oceanic Piemonte Zones (PZ) in the axial part of the Western Alps. All these units were deformed together under high-pressure conditions. The m\ue9lange consists of thin layers of calcschist, fine-grained gneiss, quartzite, minor metabasic rocks and serpentinite, and occurs all along the western margin of southern SLZ, extending from Santanel klippe to Lanzo Massif, over a distance of 50 km (Spalla et al., 1983; Battiston et al., 1984). Calcschist rocks range from phyllites to carbonatic schists and marbles; fine-grained gneisses of continental origin (very similar to those of SLZ) include phengitic white mica, chlorite, \ub1 garnet \ub1 albite and relict allanite. Thinly layered quartzites are white mica- and garnet-bearing. Metabasic rocks consist of metagabbros and metabasalts with minor mylonitic serpentinites. All these lithologies of the m\ue9lange unit and the rocks of SLZ and PZ together underwent four episodes of deformation, giving rise to a complex regional tectonostratigraphy. The earliest deformational structures are represented by up to ten meter-scale isoclinal rootless folds. The metamorphic mineral assemblages marking successive foliations indicate that all rock units in the m\ue9lange, SLZ and PZ (Spalla et al., 1983; Benciolini et al., 1984) experienced an early eclogite facies imprint, followed by re-equilibration under blueschist facies conditions, and that they were finally widely retrogressed under greenschist facies conditions during the last two deformational episodes (D3 and D4 structures). The strong synmetamorphic deformation of this m\ue9lange prevents an unequivocal interpretation of its origin; hence, we envisage two possible scenarios: i) the present day configuration of these thin, intermingled layers, including rootless refolded isoclinal folds, is entirely due to transposition that occurred in a mantle wedge at the early stages of deformation under eclogite facies conditions during active subduction; ii) a detrital origin of these alternating layers of terrigeneous and carbonaceous rocks corresponds to a primary sequence of an extensionally-thinned continental margin near an OCT that was reworked in the Alpine subduction system

Structural and metamorphic evolution of an ocean-continent transition (OCT) zone m\ue9lange deformed under HP conditions during Alpine subduction (Western Italian Alps)

We report on the structural architecture and metamorphic evolution of a mélange, developed originally in an ocean-continent transition (OCT) zone along the boundary between the continental crust of the Sesia-Lanzo (SLZ) and the oceanic Piemonte Zones (PZ) in the axial part of the Western Alps. All these units were deformed together under high-pressure conditions. The mélange consists of thin layers of calcschist, fine-grained gneiss, quartzite, minor metabasic rocks and serpentinite, and occurs all along the western margin of southern SLZ, extending from Santanel klippe to Lanzo Massif, over a distance of 50 km (Spalla et al., 1983; Battiston et al., 1984). Calcschist rocks range from phyllites to carbonatic schists and marbles; fine-grained gneisses of continental origin (very similar to those of SLZ) include phengitic white mica, chlorite, ± garnet ± albite and relict allanite. Thinly layered quartzites are white mica- and garnet-bearing. Metabasic rocks consist of metagabbros and metabasalts with minor mylonitic serpentinites. All these lithologies of the mélange unit and the rocks of SLZ and PZ together underwent four episodes of deformation, giving rise to a complex regional tectonostratigraphy. The earliest deformational structures are represented by up to ten meter-scale isoclinal rootless folds. The metamorphic mineral assemblages marking successive foliations indicate that all rock units in the mélange, SLZ and PZ (Spalla et al., 1983; Benciolini et al., 1984) experienced an early eclogite facies imprint, followed by re-equilibration under blueschist facies conditions, and that they were finally widely retrogressed under greenschist facies conditions during the last two deformational episodes (D3 and D4 structures). The strong synmetamorphic deformation of this mélange prevents an unequivocal interpretation of its origin; hence, we envisage two possible scenarios: i) the present day configuration of these thin, intermingled layers, including rootless refolded isoclinal folds, is entirely due to transposition that occurred in a mantle wedge at the early stages of deformation under eclogite facies conditions during active subduction; ii) a detrital origin of these alternating layers of terrigeneous and carbonaceous rocks corresponds to a primary sequence of an extensionally-thinned continental margin near an OCT that was reworked in the Alpine subduction system