130 research outputs found

    A large cockroach from the mesosaurbearing Konservat-Lagerstätte (Mangrullo Formation), Late Paleozoic of Uruguay

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    Barona arcuata, n.gen et n.sp., a left forewing of a relatively large cockroach of the Order Blattaria, is described from mesosaur-bearing lagoonal shales of the Mangrullo Formation (north-eastern Uruguay). While most of the insect remains recovered from the Mangrullo Formation come from sandy limestones, associated to scarce isolated mesosaur bones and pygocephalomorph crustaceans, the cockroach wing here described was found in the overlaying green to brownish, gray and dark black shales associated to intercalated bentonites and evaporitic gypsum crystals. Barona arcuata shares some features with typical Late Carboniferous taxa such as its general venation pattern and outline of the wing, four main and powerful veins arising close together from near the base of the wing, Sc simple forked, pectinate, reaching the costal border through a long fork, R and M bifurcating and terminating in the wing margin above and below the apex respectively, short and narrow CuA, and the presence of a broad interspace between CuP and AA. Cross venation seems to be absent or it was not preserved. Some characters might relate Barona arcuata to the Late CarboniferousEarly Permian Neothroblattinidae such as the presence of sigmoidal veins in the anal area, a condition not found in any of the remaining representatives of the Palaeozoic Blattaria. Intriguingly, the Uruguayan blattarian also presents a strong similarity with Qilianiblatta namurensis Zhang, Schneider & Hong, 2012 from the Westphalian of China, clearly a smaller taxon that is also difficult to relate to any of the preexistent families. The apparent plesiomorphic venation pattern of the new species which is reminiscent of that present in the oldest known blattarians, is in agreement with a Permo-Carboniferous (Gzhelian-Asselian) age for the Mangrullo Formation also supported by the presence of a macrofloral assemblage dominated by arborescent lepidondendrids and other lycopsids and the pygocephalid-like morphology of the pygocephalomorph crustaceans from the same levels

    1-D Harmonic Oscillator in Snyder Space, the Classic and the Quantum

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    The 1-D dimension harmonic oscillator in Snyder space is investigated in its classical and quantum versions. The classical trajectory is obtained and the semiclassical quantization from the phase space trajectories is discussed. In the meanwhile, an effective cutoff to high frequencies is found. The quantum version is developed and an equivalent usual harmonic oscillator is obtained through an effective mass and an effective frequency introduced in the model. This modified parameters give us an also modified energy spectra.Comment: 8 pages, 2 figure

    An exact analytical solution for generalized growth models driven by a Markovian dichotomic noise

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    Logistic growth models are recurrent in biology, epidemiology, market models, and neural and social networks. They find important applications in many other fields including laser modelling. In numerous realistic cases the growth rate undergoes stochastic fluctuations and we consider a growth model with a stochastic growth rate modelled via an asymmetric Markovian dichotomic noise. We find an exact analytical solution for the probability distribution providing a powerful tool with applications ranging from biology to astrophysics and laser physics

    Mean pulmonary arterial pressure after percutaneous mitral valvuloplasty predicts long-term adverse outcomes

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    INTRODUCTION AND AIM: Percutaneous mitral valvuloplasty (PMV) is an effective treatment option for mitral stenosis (MS), but its success is assessed on the basis of clinical and echocardiographic outcomes in studies with relatively short follow-up. We aimed to characterize a cohort of patients undergoing PMV with long-term follow-up and to determine independent predictors of post-PMV mitral re-intervention and event-free survival. METHODS: We studied 91 consecutive patients with MS who underwent PMV with a median clinical follow-up duration of 99 months. Two endpoints were considered: post-PMV mitral re-intervention (PMV or mitral surgery) and a composite clinical events endpoint including cardiovascular death, mitral valve re-intervention and hospital admission due to decompensated heart failure. We compared patients who required post-PMV mitral re-intervention with those who did not during follow-up. RESULTS: The study population included 83.5% females and mean age was 48.9±13.9 years. The 1-, 3-, 5-, 7- and 9-year rates of clinical event-free survival were 93.0±2.8%, 86.0±3.9%, 81.0±4.4%, 70.6±5.6%, and 68.4±5.8%, respectively. The 1-, 3-, 5-, 7- and 9-year rates of mitral re-intervention-free survival were 98.8±1.2%, 97.5±1.7%, 92.1±3.1%, 85.5±4.5%, and 85.5±4.5%, respectively. The median time to mitral re-intervention was 6.2 years. Patients who required mitral re-intervention during follow-up were younger (43.3 vs. 51.2 years, p=0.04) and had higher pre- and post-PMV mitral gradient (14.9 vs. 11.5mmHg, p=0.02 and 6.4 vs. 2.1mmHg, p<0.001) and higher post-PMV mean pulmonary artery pressure (mPAP) (30.0 vs. 23.2mmHg, p=0.01). In a Cox proportional hazards model, mPAP ≥25mmHg was the sole predictor of both mitral re-intervention (HR 5.639 [1.246-25.528], p=0.025) and clinical events (HR 3.622 [1.070-12.260], p=0.039). CONCLUSION: In our population, immediate post-PMV mPAP was the sole predictor of post-PMV mitral intervention. These findings may help identify patients in need of closer post-PMV follow-up

    Rayleigh-Ritz Calculation of Effective Potential Far From Equilibrium

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    We demonstrate the utility of a Rayleigh-Ritz scheme recently proposed to compute the nonequilibrium effective potential nonperturbatively in a strong noise regime far from equilibrium. A simple Kramers model of an ionic conductor is used to illustrate the efficiency of the method.Comment: 4 pages, Latex (Version 2.09), 2 figures (Postscript), tar+gzip+uuencoded. Submitted to Phys. Rev. Let

    Self-consistency in Theories with a Minimal Length

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    The aim of this paper is to clarify the relation between three different approaches of theories with a minimal length scale: A modification of the Lorentz-group in the 'Deformed Special Relativity', theories with a 'Generalized Uncertainty Principle' and those with 'Modified Dispersion Relations'. It is shown that the first two are equivalent, how they can be translated into each other, and how the third can be obtained from them. An adequate theory with a minimal length scale requires all three features to be present.Comment: typos corrected, published with new title following referee's advic

    Resultados da utilização rotineira de catéteres 4F no cateterismo diagnóstico num laboratório de hemodinâmica

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    INTRODUCTION: Complications at the site of vascular access are the most common adverse events in cardiac catheterization. The use of small gauge catheters may reduce this risk and allow earlier ambulation, the main disadvantage according to some authors being inferior image quality. The aim of our study was to evaluate the safety and image quality of 4 French diagnostic catheters. METHODS: We performed a retrospective study of 1656 patients who underwent diagnostic cardiac catheterization with 4F catheters via the femoral artery between January 2006 and December 2007, and analyzed the complications during and immediately after the procedure. The quality of the films was assessed in 125 consecutive patients from this group, who were also followed up on average one month after hospital discharge. RESULTS: Cardiac catheterization with 4F catheters was technically possible in all cases. Patients were able to ambulate and were discharged from hospital on average four and six hours respectively after the procedure. Complications during or immediately after the procedure occurred in 5.8% of cases. In the subgroup with clinical follow-up, there was minor bleeding at the access site in 16.4% and hematoma in 14.4%; in the latter group, only one patient had major hematoma requiring therapeutic intervention. No other major complications were recorded and the patients resumed their daily activities on average 7 days after discharge. Image analysis revealed that most of the films were of good quality. Conclusion: The use of 4F catheters for diagnostic cardiac catheterization via the femoral approach enables rapid hemostasis and early ambulation, with a low incidence of complications at the access site. This type of catheter provides good quality images and there were no problems in their handling. 4F catheters are therefore a good option to consider for cardiac catheterization, especially when no therapeutic procedures are expected

    Upcycling spent brewery grains through the production of carbon adsorbents: application to the removal of carbamazepine from water

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    Spent brewery grains, a by-product of the brewing process, were used as precursor of biochars and activated carbons to be applied to the removal of pharmaceuticals from water. Biochars were obtained by pyrolysis of the raw materials, while activated carbons were produced by adding a previous chemical activation step. The influence of using different precursors (from distinct fermentation processes), activating agents (potassium hydroxide, sodium hydroxide, and phosphoric acid), pyrolysis temperatures, and residence times was assessed. The adsorbents were physicochemically characterized and applied to the removal of the antiepileptic carbamazepine from water. Potassium hydroxide activation produced the materials with the most promising properties and adsorptive removals, with specific surface areas up to 1120 m2 g-1 and maximum adsorption capacities up to 190 ± 27 mg g-1 in ultrapure water. The adsorption capacity suffered a reduction of < 70% in wastewater, allowing to evaluate the impact of realistic matrices on the efficiency of the materials.publishe

    Microsporogenesis in Brachiaria brizantha (Poaceae) as a selection tool for breeding.

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    The genus Brachiaria comprises more than 100 species and is the single most important genus of forage grass in the tropics. Brachiaria brizantha , widely used in Brazilian pastures for beef and dairy production, is native to tropical Africa. As a subsidy to the breeding program underway in Brazil, cytological studies were employed to determine the chromosome number and to evaluate microsporogenesis in 46 accessions of this species available at Embrapa Beef Cattle (Brazil)
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