Study of the Van der Pol Oscillator with Fractional Derivatives

In this paper we propose a modified version of the classical Van der Pol oscillator by introducing fractional-order time derivatives into the state-space model. The resulting fractional-order Van der Pol oscillator is analyzed in the time and frequency domains, by using phase portraits, spectral analysis and bifurcation diagrams. The fractional-order dynamics is illustrated through numerical simulations of the proposed schemes by using approximations to fractional-order operators. Finally, the analysis is extended to the forced Van der Pol oscillator.N/

Exploring frailty-related biomarkers and potential influence of environmental factors

Recent evidence advocates that healthy ageing may be possible, with morbidity compressed to later years. One area of concern is the burden of environmentally induced disease in susceptible populations. Older adults are a well-recognized susceptible population due to the decline of immune defences and the burden of multiple chronic diseases. As a susceptible population, the burden of environmentally induced disease and lifestyle factors is an increasing concern. Frailty is an age-related syndrome expected to increase over the next decades given the observed demographic shift. This syndrome has been identified to be the most common condition leading to disability, institutionalization and death in the older adults and the risk factors associated with its development are yet to be clarified. The main aim of the present study is to investigate a relation between frailty status, biomarkers and environmental exposures

Intensification of heterogeneous photocatalysis by applying a kenics® static mixer as catalyst support

Despite scientific community’s efforts, overcoming mass and photon transfer limitations remain a main challenge for heterogeneous photocatalysis with immobilized catalysts. Here, a Kenics® static mixer was used for the first time as catalyst support for heterogeneous photocatalysis in tubular reactors. This permitted not only to take advantage of the enhanced mass transfer supplied by the intense mixing, but also to provide a total illumination of the photocatalyst surface area with front-irradiation mechanism by using sunlight combined with compound parabolic collectors. Stainless steel Kenics® static mixers were coated with TiO2 or Fe2O3 photocatalyst and applied for oxytetracycline (OTC) degradation in aqueous solutions. The photocatalytic efficiency was evaluated as a function of different parameters: (i) catalyst deposition technique (dip coating or spray coating), (ii) photocatalyst film thickness, (iii) oxidant (H2O2) concentration, and (iv) number of static mixing elements.info:eu-repo/semantics/publishedVersio

Analysis and optimization of propagation losses in LiNbO3 optical waveguides produced by swift heavy-ion irradiation

The propagation losses (PL) of lithium niobate optical planar waveguides fabricated by swift heavy-ion irradiation (SHI), an alternative to conventional ion implantation, have been investigated and optimized. For waveguide fabrication, congruently melting LiNbO3 substrates were irradiated with F ions at 20 MeV or 30 MeV and fluences in the range 1013–1014 cm−2. The influence of the temperature and time of post-irradiation annealing treatments has been systematically studied. Optimum propagation losses lower than 0.5 dB/cm have been obtained for both TE and TM modes, after a two-stage annealing treatment at 350 and 375∘C. Possible loss mechanisms are discussed

Recomendacoes de inseticidas para utilizacao no Programa de Manejo de Pragas da Soja safra 1982/83 nos Estados de Mato Grosso do Sul, Parana e Sao Paulo.

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Spatiotemporal variability of modern precipitation δ18O in the central Andes and implications for paleoclimate and paleoaltimetry estimates

Understanding the patterns of rainfall isotopic composition in the central Andes is hindered by sparse observations. Despite limited observational data, stable isotope tracers have been commonly used to constrain modern‐to‐ancient Andean atmospheric processes, as well as to reconstruct paleoclimate and paleoaltimetry histories. Here, we present isotopic compositions of precipitation (δ18Op and δDp) from 11 micrometeorological stations located throughout the Bolivian Altiplano and along its eastern flank at ~21.5°S. We collected and isotopically analyzed 293 monthly bulk precipitation samples (August 2008 to April 2013). δ18Op values ranged from −28.0‰ to 9.6‰, with prominent seasonal cycles expressed at all stations. We observed a strong relationship between the δ18Op and elevation, though it varies widely in time and space. Constraints on air sourcing estimated from atmospheric back trajectory calculations indicate that continental‐scale climate dynamics control the interannual variability in δ18Op, with upwind precipitation anomalies having the largest effect. The impact of precipitation anomalies in distant air source regions to the central Andes is in turn modulated by the Bolivian High. The importance of the Bolivian High is most clearly observed on the southern Bolivian Altiplano. However, monthly variability among Altiplano stations can exceed 10‰ in δ18Op on the plateau and cannot be explained by elevation or source variability, indicating a nontrivial role for local scale effects on short timescales. The strong influence of atmospheric circulation on central Andean δ18Op requires that paleoclimate and paleoaltimetry studies consider the role of South American atmospheric paleocirculation in their interpretation of stable isotopic values as proxies.Key PointsFive‐year record of central Andes precipitation isotopic compositionPrecipitation isotopes are elevation dependent, but vary in space and timePrecipitation isotope variability is related to large‐scale climate dynamicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111974/1/jgrd52161.pd

Recomendações de inseticidas para utilização no programa de manejo de pragas da soja - safra 1981/82 - nos Estados do Paraná, São Paulo e Mato Grosso do Sul.

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“Dilatation” of the left renal vein on computed tomography in children: A normal variant

Compression of the left renal vein (LRV) between the superior mesenteric artery and the aorta is thought to be a cause of hematuria, periureteral and gonadal varices, and varicocele (“Nutcracker phenomenon”). Previous investigators have suggested that this diagnosis can be made on computed tomography when the LRV ratio ≥1.5 (the diameter of the LRV proximal to the aorto-mesenteric angle divided by the diameter of the LRV distal to the aorto-mesenteric angle). This study was designed to establish the normal range for the LRV ratio on CT in children. The LRV ratio was measured in thirty-nine consecutive children undergoing intravenously enhanced CT of the abdomen. None of the children had hematuria on urinalysis immediately before or after the CT. Children with any known abnormality involving the kidneys, adrenal glands, IVC, or renal or gonadal veins were excluded. The patients ranged in age from 3.4 to 18.5 years (mean=10.6 years). LRV ratio ranged from 0.78 to 2.00 (mean=1.46; S.D.=0.312). Twenty of the 39 children (51.3%) had a LRV ratio ≥1.50. The conclusion is that the normal range for the LRV ration is too wide for it to be useful in diagnosing LRV entrapment and that a LRV ratio ≥1.5 on CT is normal in children.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46695/1/247_2005_Article_BF02018620.pd

Rotura distal del tendón de la porción larga del bíceps braquial. ¿por qué está aumentado su incidencia? ¿Cuándo se debe reparar?

Introduction and objectives: The breaking of the distal biceps tendon is rare and represents only 3% of all breakings of this tendon. However, for the last decade this percentage has increased up to 10%. They are characteristic of middle-aged men with a predominance of the dominant arm. Local risk factor (high functional demand) and systemic ones (smoking, dyslipidemia, steroids, analogies, obesity) are associated with this pathology. Our goal is to analyze the risk factors which are associated with this condition and evaluate the results after surgical repair of the tendon. Materials and methods: Retrospective study of 13 patients diagnosed with distal biceps tendon breaking in our hospital from May 2012 to January 2014. All patients were treated surgically with anatomic reattachment single trak (69, 23 % with Endobutton''s technique and 30, 77 % remembering using harpoons). There have been assessed factors such us potential risk factors, joint mobility, early and late complications and the patient''s degree of satisfaction (scale Karunakar). Their clinical follow-up was carried out for at least 6 months after the surgery. Result: All patients were male, with an average age of 42, 69 years, the 92, 3 % were in the dominant arm, 76, 92 % of the patients usually exercised the biceps while training and 53, 84 % were taking medication for dyslipidemia. The results obtained after the treatment were excellent, shawing that all patients were satisfied with it. Conclusion: The risk factors that are known so far such us smoking, dyslipidemia, steroids, anabolics and obesity do not justify the increase in the currents incidence rate. Regular exercise involving the biceps brachial muscle in patients with risk factors increases the probability of breaking the distal biceps tendon and anatomic reattachment anterior approach is a correct treatment option

Influence of ligand structure and molecular geometry on the properties of d6 polypyridinic transition metal complexes

Different strategies to improve the excited state properties of polypyridinic complexes by varying ligand structure and molecular geometry are described. Bidentate and tetradentate ligands based on fragments as dipyrido[3,2-a:2′,3′-c]phenazine, dppz, and pyrazino[2,3-f][1,10]-phenanthroline, ppl, have been used. Quinonic residues were fused to these basic units to improve acceptor properties. Photophysical studies were performed in order to test theoretical predictions