1,458 research outputs found

    Whipping Instabilities in Electrified Liquid Jets

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    A liquid jet may develop different types of instabilities, like the so-called Rayleigh-Plateau instability, which breaks the jet into droplets. However, another type of instabilities may appear when we electrify a liquid jet and induce some charge at his surface. Among them, the most common is the so-called Whipping Instability, which is characterized by violent and fast lashes of the jet. In the submitted fluid dynamic video(see http://hdl.handle.net/1813/11422), we will show an unstable charged glycerine jet in a dielectric liquid bath, which permits an enhanced visualization of the instability. For this reason, it is probably the first time that these phenomena are visualized with enough clarity to analyze features as the effect of the feeding liquid flow rate through the jet or as the surprising spontaneous stabilization at some critical distance to the ground electrode.Comment: 3 pages, no figures, links to videos, Submission to the 26th Gallery of Fluid Motion (2009

    Stability analysis of a grid-connected VSC controlled by SPC

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    In the near future a large part of traditional generation based on conventional synchronous machines (SM) will be replaced by renewable generation based on voltage source converters (VSC). In this sense, power system operators have begun to demand VSC-based power plants be able to participate in the frequency and voltage regulation, and are also interested in services like inertia emulation and damping of power oscillation, functions that today are carried out by large synchronous generators. Therefore, several studies have suggested new ways to control voltage source converters, that try to emulate the behavior of synchronous generators and are known generically as Virtual Synchronous Machines. The synchronous power controller (SPC) is a flexible solution that emulates the classical swing equation of a synchronous machine and improves its response. The SPC inherits the advantages of conventional synchronous generators, while it fixes many of its drawbacks. In this work, a sensitivity analysis of a VSC connected to the grid and controlled by SPC is performed. In this sense, a non-linear mathematical model of the system is first developed. This non-linear model is then linearized, obtaining a linear model from which the eigenvalues and sensitivities of the system to some relevant parameters are calculated. Finally, time-domain simulations are performed to confirm the results of the sensitivity analysis.Postprint (author's final draft

    New records of Pristidactylus nigroiugulus Cei, Scolaro & Videla, 2001 (squamata: Leiosauridae) with a geographic distribution map

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    We provide new geographic records for Pristidactylus nigroiugulus Cei, Scolaro & Videla, 2001 from Argentina. We present the first record for Santa Cruz province and the southernmost records of the species based on lizards collected in the austral summers of 2012/2013 and 2013/2014. Based on a museum specimen, we extend the species distribution to the eastern part of the Somuncurá Plateau. An updated distributional map is included.Fil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Minoli, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Perez, Cristian Hernan Fulvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Gonzalez Marin, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Morando, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentin

    Acute-Stress Biomarkers in Three Octopodidae Species After Bottom Trawling

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    Several Octopodidae species have a great potential for the diversification of worldwide aquaculture. Unfortunately, the lack of stress-related biomarkers in this taxon results an obstacle for its maintenance in conditions where animal welfare is of paramount relevance. In this study, we made a first approach to uncover physiological responses related to fishing capture in Eledone moschata, Eledone cirrhosa, and Octopus vulgaris. Captured octopus from all three species were individually maintained in an aquaculture system onboard of oceanographic vessel in south-western waters of Europe. Haemolymph plasma and muscle were collected in animals at the moment of capture, and recovery was evaluated along a time-course of 48 h in Eledone spp., and 24 h for O. vulgaris. Survival rates of these species captured in spring and autumn were evaluated. Physiological parameters such as plasma pH, total CO2, peroxidase activity, lysozyme, hemocyanin, proteases, pro-phenoloxidase, anti-proteases, free amino acids, lactate and glucose levels, as well as muscle water percentage, free amino acids, lactate, glycogen and glucose values were analyzed. The immune system appears to be compromised in these species due to capture processes, while energy metabolites were mobilized to face the acute-stress situation, but recovery of all described parameters occurs within the first 24 h after capture. Moreover, this situation exerts hydric balance changes, as observed in the muscle water, being these responses depending on the species assessed. In conclusion, three Octopodidae species from south-western waters of Europe have been evaluated for stress-related biomarkers resulting in differentiated mechanisms between species. This study may pave the way to further study the physiology of stress in adult octopuses and develop new methodologies for their growth in aquaculture conditions

    Los mecanismos de control y sanción de las violaciones del derecho internacional humanitario

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    93 p.Los mecanismos de control y sanción en la violación de Derecho Internacional Humanitario durante conflictos armados internacionales o internos, postulamos que son insuficientes para lograr su cometido. Dedicamos parte de este trabajo de investigación a la Organización de las Naciones Unidas y al Comité Internacional de la Cruz Roja en su rol de garantes de tales tratados. Analizamos el tratado del Estatuto de Roma que creo la Corte Penal Internacional, como tribunal permanente y como mecanismo de sanción, sus efectos en Chile, el fallo del Tribunal Constitucional, así como la opinión de la doctrina chilena en búsqueda de vías, de solución . Los tratados internacionales y la opinión de la doctrina nacional e internacional han sido base de nuestro análisis. Finalmente sugerimos mecanismos para lograr un pleno cumplimiento a dichos tratados por parte dela grandes potencias

    Differential in vitro and in vivo effect of barley cysteine and serine protease inhibitors on phytopathogenic microorganisms

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    Protease inhibitors from plants have been involved in defence mechanisms against pests and pathogens. Phytocystatins and trypsin/α-amylase inhibitors are two of the best characterized protease inhibitor families in plants. In barley, thirteen cystatins (HvCPI-1 to 13) and the BTI-CMe trypsin inhibitor have been previously studied. Their capacity to inhibit pest digestive proteases, and the negative in vivo effect caused by plants expressing these inhibitors on pests support the defence function of these proteins. Barley cystatins are also able to inhibit in vitro fungal growth. However, the antifungal effect of these inhibitors in vivo had not been previously tested. Moreover, their in vitro and in vivo effect on plant pathogenous bacteria is still unknown. In order to obtain new insights on this feature, in vitro assays were made against different bacterial and fungal pathogens of plants using the trypsin inhibitor BTI-CMe and the thirteen barley cystatins. Most barley cystatins and the BTI-CMe inhibitor were able to inhibit mycelial growth but no bacterial growth. Transgenic Arabidopsis plants independently expressing the BTI-CMe inhibitor and the cystatin HvCPI-6 were tested against the same bacterial and fungal pathogens. Neither the HvCPI-6 expressing transgenic plants nor the BTI-CMe ones were more resistant to plant pathogen fungi and bacteria than control Arabidopsis plants. The differences observed between the in vitro and in planta assays against phytopathogenic fungi are discusse

    Albendazole-induced granulomatous hepatitis: a case report

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    INTRODUCTION: Drug-related hepatotoxicity is a common medical problem with implications for health systems. It constitutes a cause of acute liver failure and, in many cases, is responsible for the rejection of new pharmacological agents during efficacy and safety studies. Risk factors, as well as pathogenesis of drug-induced liver injury, are poorly understood. The diagnosis of drug-induced liver injury is challenging; it is difficult to define the cause of drug hepatotoxicity due to the heterogeneity of the clinical presentation and the absence of established criteria for accurate and reproducible identification of drug-associated liver toxicity. CASE PRESENTATION: We report the case of a 25-year-old Hispanic woman admitted to our Clinical Hepatology Unit with symptoms of acute hepatitis of unknown etiology. She was diagnosed with albendazole-induced granulomatous hepatitis after ruling out other possible causes, based on laboratory studies, liver biopsy, medical history, detailed drug history, and spontaneous improvement of her liver biochemical profile after medication withdrawal. This diagnosis was supported by the Council for International Organizations of Medical Sciences-Roussel Uclaf Causality Assessment Method, which showed a likely correlation between hepatocellular damage and drug toxicity as the etiology. CONCLUSIONS: Our patient’s suspected diagnosis was albendazole-induced granulomatous hepatitis with confirmatory histologic pattern. This case deserves particular attention due to the wide use of albendazole in our country (Colombia) and the prevalent medical issue of drug-related hepatotoxicity

    The Roco protein family:a functional perspective

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    In this review, we discuss the evolutionary, biochemical, and functional data available for members of the Roco protein family. They are characterized by having a conserved supradomain that contains a Ras-like GTPase domain, called Roc, and a characteristic COR (C-terminal of Roc) domain. A kinase domain and diverse regulatory and protein protein interaction domains are also often found in Roco proteins. First detected in the slime mold Dictyostelium discoideum, they have a broad phylogenetic range, being present in both prokaryotes and eukaryotes. The functions of these proteins are diverse. The best understood are Dictyostelium Rocos, which are involved in cell division, chemotaxis, and development. However, this family has received extensive attention because mutations in one of the human Roco genes (LRRK2) cause familial Parkinson disease. Other human Rocos are involved in epilepsy and cancer. Biochemical data suggest that Roc domains are capable of activating kinase domains intramolecularly. Interestingly, some of the dominant, disease-causing mutations in both the GTPase and kinase domains of LRRK2 increase kinase activity. Thus, Roco proteins may act as stand-alone transduction units, performing roles that were thought so far to require multiple proteins, as occur in the Ras transduction pathway

    Freezing induces an increase in leaf spectral transmittance of forest understorey and alpine forbs

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    Evergreen plants growing at high latitudes or high elevations may experience freezing events in their photosynthetic tissues. Freezing events can have physical and physiological effects on the leaves which alter leaf optical properties affecting remote and proximal sensing parameters. We froze leaves of six alpine plant species (Soldanella alpina, Ranunculus kuepferi, Luzula nutans, Gentiana acaulis, Geum montanum, and Centaurea uniflora) and three evergreen forest understorey species (Hepatica nobilis, Fragaria vesca and Oxalis acetosella), and assessed their spectral transmittance and optically measured pigments, as well as photochemical efficiency of photosystem II (PSII) as an indicator of freezing damage. Upon freezing, leaves of all the species transmitted more photosynthetically active radiation (PAR) and some species had increased ultraviolet-A (UV-A) transmittance. These differences were less pronounced in alpine than in understorey species, which may be related to higher chlorophyll degradation, visible as reduced leaf chlorophyll content upon freezing in the latter species. Among these understorey forbs, the thin leaves of O. acetosella displayed the largest reduction in chlorophyll (−79%). This study provides insights into how freezing changes the leaf optical properties of wild plants which could be used to set a baseline for upscaling optical reflectance data from remote sensing. Changes in leaf transmittance may also serve to indicate photosynthetic sufficiency and physiological tolerance of freezing events, but experimental research is required to establish this functional association.Peer reviewe
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