Emplacement of Jurassic - Lower Cretaceous radiolarites of the Nicoya Complex (Costa Rica)

We present a new model to explain the origin, emplacement and stratigraphy of the Nicoya Complex in the NW part of the Nicoya Peninsula (Costa Rica) based on twenty-five years of field work, accompanied with the evolution of geochemical, vulcanological, petrological, sedimentological and paleontological paradigms. The igneous-sedimentary relation, together with radiolarian biochronology of the NW-Nicoya Peninsula is re-examined. We interpret the Nicoya Complex as a cross-section of a fragment of the Late Cretaceous Caribbean Plateau, in which the deepest levels are exposed in the NW-Nicoya Peninsula. Over 50% of the igneous rocks are intrusive (gabbros and in less proportion plagiogranites) which have a single mantle source; the remainder are basalts with a similar geochemical signature. Ar39/Ar40 radioisotopic whole rock and plagioclase ages range throughout the area from 84 to 83 Ma (Santonian) for the intrusives, and from 139 to 88 Ma (Berriasian-Turonian) for the basalts. In contrast, Mn-radiolarites that crop out in the area are older in age, Bajocian (Middle Jurassic) to Albian (middle Cretaceous). These Mn-radiolaritic blocks are set in a "matrix" of multiple gabbros and diabases intrusions. Chilled margins of magmatites, and hydrothermal baking and leaching of the radiolarites confirm the Ar39/Ar40 dating of igneous rocks being consistently younger than most of the radiolarian cherts. No Jurassic magmatic basement has been identified on the Nicoya Peninsula. We interpret the Jurassic-Cretaceous chert sediment pile to have been disrupted and detached from its original basement by multiple magmatic events that occurred during the formation of the Caribbean Plateau. Coniacian-Santonian (Late Cretaceous), Fe-rich radiolarites are largely synchronous and associated with late phases of the Plateau.

The Variscan evolution in the External massifs of the Alps and place in their Variscan framework

In the general discussion on the Variscan evolution of central Europe the pre-Mesozoic basement of the Alps is, in many cases, only included with hesitation. Relatively well-preserved from Alpine metamorphism, the Alpine External massifs can serve as an excellent example of evolution of the Variscan basement, including the earliest Gondwana-derived microcontinents with Cadomian relics. Testifying to the evolution at the Gondwana margin, at least since the Cambrian, such pieces took part in the birth of the Rheic Ocean. After the separation of Avalonia, the remaining Gondwana border was continuously transformed through crustal extension with contemporaneous separation of continental blocks composing future Pangea, but the opening of Palaeotethys had only a reduced significance since the Devonian. The Variscan evolution in the External domain is characterised by an early HP-evolution with subsequent granulitic decompression melts. During Visean crustal shortening, the areas of future formation of migmatites and intrusion of monzodioritic magmas in a general strike-slip regime, were probably in a lower plate situation, whereas the so called monometamorphic areas may have been in an upper plate position of the nappe pile. During the Latest Carboniferous, the emplacement of the youngest granites was associated with the strike-slip faulting and crustal extension at lower crustal levels, whereas, at the surface, detrital sediments accumulated in intramontaneous transtensional basins on a strongly eroded surface. To cite this article: J.R von Raumer et al., C. R. Geoscience 341 (2009). (C) 2008 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

An overview of conservative treatment for lower back pain

This article summarizes the available evidence on the management of patients with subacute or chronic low back pain. The largest part is devoted to nonspecific low back pain but the models of spinal stenosis and disk herniation/sciatica are also specifically addressed. The authors point out the limited evidence available and the importance of a tailored approach for the individual patient. As the effect sizes of most therapies are rather small (close to that of a placebo), patients' preferences and other variables important for individualized management are highlighted. The task for the practitioner is difficult and awareness of this is important. Some speculation regarding potential future ways of improving patient care are presented.

Biodiversity of rhizobia associated with cowpea cultivars in soils of the lower half of the São Francisco River Valley

The biodiversity of rhizobium in soils of the São Francisco Valley is unknown and can be studied using cowpea as trap plants. The objective of this study was to verify the diversity of diazotrophic bacteria that nodulate cowpea in soils of the lower half of the São Francisco River Valley by morphological and genotypic characterization. Seven soil samples (A1, A2, A3, A4, C1, C2 and MC) were collected to capture bacteria associated to five cowpea cultivars (IPA 206, BRS Pujante, BRS Marataoã, Canapu Roxo, and Sempre Verde), in a 5x7 factorial design with three replications. Thirty days after plant emergence, the nodules were collected and the bacteria isolated and analyzed in relation to their growth characteristics in YMA medium. The 581 isolates were grouped in 49 morphologic groups. Of this total, 62.3 % formed colonies in up to three days, 33.4 % grew from the 6th day on, and 4.3 % began to grow 4 to 5 days after incubation. Regarding the formation of acids and alkalis, 63 % acidified the medium, 12 % made it alkaline and 25 % maintained the medium at neutral pH. The highest diversity was observed in the A3 sample and in isolates associated with the cultivars Canapu Roxo and BRS Pujante. Thirty-eight representative isolates were chosen for the genotypic characterization, clustered in four groups based on the restriction analysis of 16s rDNA. This grouping was strongly correlated with the sampling site; 13 rhizobium isolates had an electrophoretic profile distinct from the standard rhizobium strains used in this study.

Groundwater Availability Modeling of the Lower Dakota Aquifer in Northwest Iowa, October 2008

The 2007 Iowa General Assembly, recognizing the increased demand for water to support the growth of industries and municipalities, approved funding for the first year of a multi-year evaluation and modeling of Iowa’s major aquifers by the Iowa Department of Natural Resources. The task of conducting this evaluation and modeling was assigned to the Iowa Geological and Water Survey (IGWS). The first aquifer to be studied was the Lower Dakota aquifer in a sixteen county area of northwest Iowa.

Exact lower bounds to the ground-state energy of spin systems: The two-dimensional S=1/2 antiferromagnetic Heisenberg model

We present a very simple but fairly unknown method to obtain exact lower bounds to the ground-state energy of any Hamiltonian that can be partitioned into a sum of sub-Hamiltonians. The technique is applied, in particular, to the two-dimensional spin-1/2 antiferromagnetic Heisenberg model. Reasonably good results are easily obtained and the extension of the method to other systems is straightforward.

A Prognostic Score to Identify Low-risk Outpatients with Acute Deep Vein Thrombosis in the Lower Limbs.

BACKGROUND: No prior studies have identified which patients with deep vein thrombosis in the lower limbs are at a low risk for adverse events within the first week of therapy. METHODS: We used data from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) to identify patients at low risk for the composite outcome of pulmonary embolism, major bleeding, or death within the first week. We built a prognostic score and compared it with the decision to treat patients at home. RESULTS: As of December 2013, 15,280 outpatients with deep vein thrombosis had been enrolled. Overall, 5164 patients (34%) were treated at home. Of these, 12 (0.23%) had pulmonary embolism, 8 (0.15%) bled, and 4 (0.08%) died. On multivariable analysis, chronic heart failure, recent immobility, recent bleeding, cancer, renal insufficiency, and abnormal platelet count independently predicted the risk for the composite outcome. Among 11,430 patients (75%) considered to be at low risk, 15 (0.13%) suffered pulmonary embolism, 22 (0.19%) bled, and 8 (0.07%) died. The C-statistic was 0.61 (95% confidence interval [CI], 0.57-0.65) for the decision to treat patients at home and 0.76 (95% CI, 0.72-0.79) for the score (P = .003). Net reclassification improvement was 41% (P < .001). Integrated discrimination improvement was 0.034 for the score and 0.015 for the clinical decision (P < .001). CONCLUSIONS: Using 6 easily available variables, we identified outpatients with deep vein thrombosis at low risk for adverse events within the first week. These data may help to safely treat more patients at home. This score, however, should be validated.