Geology, age and tectonic evolution of the Sierra Maestra Mountains, southeastern Cuba

We summarize the available geological information on the Sierra Maestra Mountains in southeastern Cuba and report new zircon fission track and biotite Ar-Ar ages for this region. Two different and genetically unrelated volcanic arc sequences occur in the Sierra Maestra, one Cretaceous in age (pre-Maastrichtian) and restricted to a few outcrops on the southern coast, and the other Palaeogene in age, forming the main expression of the mountain range. These two sequences are overlain by middle to late Eocene siliciclastic, carbonatic and terrigenous rocks as well as by late Miocene to Quaternary deposits exposed on the southern flank of the mountain range. These rocks are britle deformed and contain extension gashes filled with calcite and karst material. The Palaeogene volcanic arc successions were intruded by calc-alkaline, low- to medium-K tonalites and trondhjemites during the final stages of subduction and subsequent collision of the Caribbean oceanic plate with the North American continental plate. U-Pb SHRIMP single zircon dating of five granitoid plutons yielded 206Pb/238U emplacement ages between 60.5 ± 2.2 and 48.3 ± 0.5 Ma. These granitoids were emplaced at pressures ranging from 1.8 to 3.0 kbar, corresponding to depths of ca. 4.5-8 km. 40Ar/39Ar dating of two biotite concentrates yielded ages of 50 ± 2 and 54 ± 4 Ma, indicating cooling through ca. 300 ºC. Zircon and apatite fission track ages range from 32 ± 3 to 46 ± 4 Ma and 31 ± 10 to 44 ± 13 Ma, respectively, and date cooling through 250 ± 50 ºC and 110 ± 20 ºC. The granitoids are the result of subduction-related magmatism and have geochemical characteristics similar to those of magmas from intra-oceanic island-arcs such as the Izu Bonin-Mariana arc and the New Britain island arc. Major and trace element patterns suggest evolution of these rocks from a single magmatic source. Geochemical features characterize these rocks as typical subduction-related granitoids as found worldwide in intra-oceanic arcs, and they probably formed through fractional crystallization of mantlederived low- to medium-K basalts. Several distinct phases of deformation were recognized in the Sierra Maestra, labelled D1 to D6, which define the transition from collision of the Palaeogene island arc to the formation of the Oriente Transform Wrench Corridor south of Cuba and later movement of the Caribbean plate against the North American plate. The first phase (D1) is related to the intrusion of a set of extensive subparallel, N-trending subvertical basalt-andesite dykes, probably during the early to middle Eocene. Between the late-middle Eocene and early Oligocene (D2), rocks of the Sierra Maestra were deformed by approximately east-west trending folds and north-vergent thrust faults. This deformation (D2) was linked to a shift in the stress regime of the Caribbean plate from mainly NNE-SSW to E-W. This shift in plate motion caused the abandonment of the Nipe-Guacanayabo fault system in the early Oligocene and initiation of a deformation front to the south where the Oriente Transform Wrench corridor is now located. Compressive structures were overprinted by widespread extensional structures (D3), mainly faults with southward-directed normal displacement in the Oligocene to early Miocene. During this period the plate boundary jumped to the Oriente fault. This event was followed by transpressive and transtensive structures (D4-D6) due to further development of the sinistral E-trending Oriente Transform wrench corridor. These structures are consistent with oblique convergence in a wide zone of left-lateral shear along an E-W-oriented transform fault

Actual changes in system of urban planning in post-socialist city: the case of Prague

After the change of political system in Czechoslovakia (1989) came also a lot of social, economical and cultural changes. Today, all the Czech cities stay in front of the biggest change of city planning philosophy in last two decades. Prague, the capital city of Czech Republic, decided for a big institutional transition in 2012. The municipality, in cooperation with Faculty of Architecture CTU in Prague, is preparing completely pioneering methodology for quality commissioning of land use plans and, in cooperation with the new Institute of Planning and Development, is preparing innovative system of city planning. There are new ordinances, laws, regulations, tourist trade strategies and many other documents. Prague, as one of the strongest regions in East-Central Europe, can be seen like a laboratory of current development of post-socialist city. The new methodology of Metropolitan Plan could be a key to success

Impact of discordance between patient's and evaluator's global assessment on treatment outcomes in 14 868 patients with spondyloarthritis

Funding: This work was supported by Novartis. Novartis had no influence on the data collection, statistical analyses, manuscript preparation or decision to submit.Peer reviewedPostprintPostprintPostprintPostprin

Cyanamide mode of action during inhibition of onion (Allium cepa L.) root growth involves disturbances in cell division and cytoskeleton formation

Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2–10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2–6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement

Kinematics of the Southern Rhodope Core Complex (North Greece)

The Southern Rhodope Core Complex is a wide metamorphic dome exhumed in the northern Aegean as a result of large-scale extension from mid-Eocene to mid-Miocene times. Its roughly triangular shape is bordered on the SW by the Jurassic and Cretaceous metamorphic units of the Serbo-Macedonian in the Chalkidiki peninsula and on the N by the eclogite bearing gneisses of the Sideroneron massif. The main foliation of metamorphic rocks is flat lying up to 100 km core complex width. Most rocks display a stretching lineation trending NEâ SW. The Kerdylion detachment zone located at the SW controlled the exhumation of the core complex from middle Eocene to mid-Oligocene. From late Oligocene to mid-Miocene exhumation is located inside the dome and is accompanied by the emplacement of the synkinematic plutons of Vrondou and Symvolon. Since late Miocene times, extensional basin sediments are deposited on top of the exhumed metamorphic and plutonic rocks and controlled by steep normal faults and flat-ramp-type structures. Evidence from Thassos Island is used to illustrate the sequence of deformation from stacking by thrusting of the metamorphic pile to ductile extension and finally to development of extensional Plio-Pleistocene sedimentary basin. Paleomagnetic data indicate that the core complex exhumation is controlled by a 30� dextral rotation of the Chalkidiki block. Extensional displacements are restored using a pole of rotation deduced from the curvature of stretching lineation trends at core complex scale. It is argued that the Rhodope Core Complex has recorded at least 120 km of extension in the North Aegean, since the last 40 My