264 research outputs found

    K1,3-covering red and blue points in the plane

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    We say that a finite set of red and blue points in the plane in general position can be K1, 3-covered if the set can be partitioned into subsets of size 4, with 3 points of one color and 1 point of the other color, in such a way that, if at each subset the fourth point is connected by straight-line segments to the same-colored points, then the resulting set of all segments has no crossings. We consider the following problem: Given a set R of r red points and a set B of b blue points in the plane in general position, how many points of R ¿ B can be K1, 3-covered? and we prove the following results: (1) If r = 3g + h and b = 3h + g, for some non-negative integers g and h, then there are point sets R ¿ B, like {1, 3}-equitable sets (i.e., r = 3b or b = 3r) and linearly separable sets, that can be K1, 3-covered. (2) If r = 3g + h, b = 3h + g and the points in R ¿ B are in convex position, then at least r + b - 4 points can be K1, 3-covered, and this bound is tight. (3) There are arbitrarily large point sets R ¿ B in general position, with r = b + 1, such that at most r + b - 5 points can be K1, 3-covered. (4) If b = r = 3b, then at least 9 8 (r + b- 8) points of R ¿ B can be K1, 3-covered. For r > 3b, there are too many red points and at least r - 3b of them will remain uncovered in any K1, 3-covering. Furthermore, in all the cases we provide efficient algorithms to compute the corresponding coverings

    Surface waters of the NW Iberian margin: upwelling on the shelf versus outwelling of upwelled waters from the Rías Baixas

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    A set of hydrographic surveys were carried out in the Ría of Vigo (NW Spain) at 2–4 d intervals during four 2–3 week periods in 1997, covering contrasting seasons. Residual exchange fluxes with the adjacent shelf were estimated with a 2-D, non-steady-state, salinity–temperature weighted box model. Exchange fluxes consist of a steady-state term (dependent on the variability of continental runoff) and a non-steady-state term (dependent on the time changes of density gradients in the embayment). More than 95% of the short-time-scale variability of the exchange fluxes in the middle and outer ría can be explained by the non-steady-state term that, in turns, is correlated (R2>75%) with the offshore Ekman transport. Conversely, 96% of the variability of exchange fluxes in the inner ría rely on the steady-state term. The outer and middle ría are under the direct influence of coastal upwelling, which enhances the positive residual circulation pattern by an order of magnitude: from 10 2 to 10 3 m3s−1. On the contrary, downwelling provokes a reversal of the circulation in the outer ría. The position of the downwelling front along the embayment depends on the relative importance of Ekman transport (Qx, m3s−1km−1) and continental runoff (R, m3s−1). When Qx/ R>7±2 the reversal of the circulation affects the middle ría. Our results are representative for the ‘Rías Baixas’, four large coastal indentations in NW Spain. During the upwelling season (spring and summer), 60% of shelf surface waters off the ‘Rías Baixas’ consist of fresh Eastern North Atlantic Central Water (ENACW) upwelled in situ. The remaining 40% consists of upwelled ENACW that previously enters the rías and it is subsequently outwelled after thermohaline modification. During the downwelling season (autumn and winter), 40% of the warm and salty oceanic subtropic surface water, which piled on the shelf by the predominant southerly winds, enters the rias

    Whole transcriptome approach to evaluate the effect of aluminium hydroxide in ovine encephalon

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    Aluminium hydroxide adjuvants are crucial for livestock and human vaccines. Few studies have analysed their effect on the central nervous system in vivo. In this work, lambs received three different treatments of parallel subcutaneous inoculations during 16 months with aluminium-containing commercial vaccines, an equivalent dose of aluminium hydroxide or mock injections. Brain samples were sequenced by RNA-seq and miRNA-seq for the expression analysis of mRNAs, long non-coding RNAs and microRNAs and three expression comparisons were made. Although few differentially expressed genes were identified, some dysregulated genes by aluminium hydroxide alone were linked to neurological functions, the lncRNA TUNA among them, or were enriched in mitochondrial energy metabolism related functions. In the same way, the miRNA expression was mainly disrupted by the adjuvant alone treatment. Some differentially expressed miRNAs had been previously linked to neurological diseases, oxidative stress and apoptosis. In brief, in this study aluminium hydroxide alone altered the transcriptome of the encephalon to a higher degree than commercial vaccines that present a milder effect. The expression changes in the animals inoculated with aluminium hydroxide suggest mitochondrial disfunction. Further research is needed to elucidate to which extent these changes could have pathological consequences

    Further results on the cross norm criterion for separability

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    In the present paper the cross norm criterion for separability of density matrices is studied. In the first part of the paper we determine the value of the greatest cross norm for Werner states, for isotropic states and for Bell diagonal states. In the second part we show that the greatest cross norm criterion induces a novel computable separability criterion for bipartite systems. This new criterion is a necessary but in general not a sufficient criterion for separability. It is shown, however, that for all pure states, for Bell diagonal states, for Werner states in dimension d=2 and for isotropic states in arbitrary dimensions the new criterion is necessary and sufficient. Moreover, it is shown that for Werner states in higher dimensions (d greater than 2), the new criterion is only necessary.Comment: REVTeX, 19 page

    Influence of the zro2 crystalline phases on the nature of active sites in pdcu/zro2 catalysts for the methanol steam reforming reaction-an in situ spectroscopic study

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    In this work, the electronic properties of the metal sites in cubic and monoclinic ZrO2 supported Pd and PdCu catalysts have been investigated using CO as probe molecule in in-situ IR studies, and the surface composition of the outermost layers has been studied by APXPS (Ambient Pressure X-ray Photoemission Spectroscopy). The reaction products were followed by mass spectrometry, making it possible to relate the chemical properties of the catalysts under reaction conditions with their selectivity. Combining these techniques, it has been shown that the structure of the support (monoclinic or cubic ZrO2) affects the metal dispersion, mobility, and reorganization of metal sites under methanol steam reforming (MSR) conditions, influencing the oxidation state of surface metal species, with important consequences in the catalytic activity. Correlating the mass spectra of the reaction products with these spectroscopic studies, it was possible to conclude that electropositive metal species play an imperative role for high CO2 and H2 selectivity in the MSR reaction (less CO formation)The research leading to these results has received funding from European Research council project SYNCATMATCH (671093) and from Spanish Ministry of Science, Innovation and Universities with the project “I + D + I research challenges (RTI2018-099668-B-C21)”. This work also was financially supported by: Base Funding-UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy—LEPABE-funded by national funds through the FCT/MCTES (PIDDAC); European Union’s Seventh Framework Program (FP/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement no. 303476.Peer reviewe

    Evaluation of thermo-oxidized Jatropha bio-oil in lubrication of actual wet clutch materials

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    In this work, an assessment of the performance of thermo-oxidated Jatropha oil as a lubricant for actual wet clutch materials was performed and compared with a commercial automatic transmission fluid. For this, Jatropha oil, a commercial automatic transmission fluid and a blend of 20 vol% Jatropha oil–80 vol% automatic transmission fluid were subjected to thermo-oxidative aging at 26 °C and 100 °C, followed by a pin-on-disk testing with disk samples from an actual wet clutch. Evaluation of the film thickness at the sliding interface resulted in a boundary lubrication regime for all the tests. The changes in oxidation, viscosity, and a viscosity index of the samples were evaluated along with friction coefficients at various sliding speeds. Jatropha oil was the most sensitive to thermo-oxidation. Jatropha oil and the blend showed a higher viscosity increase than automatic transmission fluid with thermo-oxidation, while the viscosity index of all oils was decreased considerably, Jatropha oil and the blend being the most reduced. Finally, the anti-shudder property, as measured by the change in the friction coefficient with a sliding speed, of Jatropha oil and automatic transmission fluid was improved by thermo-oxidation at 26 °C but worsened at 100 °C, meanwhile it was barely affected in the blend. Therefore, these results indicate that using pure Jatropha oil as automatic transmission fluid would be unsuitable, but blending it with automatic transmission fluids in specific proportions may be apposite for improving the friction properties of wet clutches even under thermo-oxidative conditions

    Learning resources adaptation in Animal Physiology for students with special educational needs

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    Resúmenes IV Congreso VetDoc de Docencia Veterinaria, León 2017 (6-7 de Julio)[ES] Nuestra labor docente como profesores universitarios debe fundamentarse en promover la diversidad de la educación en el aula prestando más atención al alumnado con necesidades educativas especiales (NEE)

    Manejo expectante de gestación ectópica abdominal tras fecundación in vitro en paciente con salpinguectomía bilateral. Reporte de un caso

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    ANTECEDENTES El embarazo ectópico abdominal es el menos habitual de los embarazos ectópicos, con una prevalencia situada entre el 0.9 - 1.4%. La mortalidad materna es elevada, alcanzando un 20% y la viabilidad fetal mínima. El manejo médico en estas situaciones es complicado ya que no está bien establecido debido a su baja frecuencia. CASO CLÍNICO Mujer de 35 años, con antecedente de esterilidad por endometriosis y salpinguectomía bilateral. Tras 5 fecundaciones in vitro (FIV) consigue una primera gestación, con finalización mediante cesárea por no progresión de parto. Acude a urgencias en su segundo embarazo, logrado tras 3 (FIV), con edad gestacional de 7 semanas. Presenta sangrado vaginal escaso y la ecografía demuestra a nivel de Douglas y hacia fosa iliaca izquierda un saco gestacional de 3 cm con embrión sin latido cardiaco de 5 mm. El nivel de ß-hcg es de 1477 mUI/ml. Se diagnostica de gestación ectópica abdominal y se opta por actitud expectante dada la estabilidad clínica de la paciente. En un control a las 48h la ß-Hcg es de 464 mUI/ml y la paciente se mantiene estable. En controles posteriores se observan niveles descendentes de ß-Hcg y tras un mes la resolución es completa. CONCLUSIÓN El embarazo ectópico abdominal es una entidad poco frecuente pero con una alta tasa de mortalidad. Aunque lo más común es optar por un abordaje quirúrgico es necesario individualizar cada caso y basarse en la clínica y las diferentes pruebas diagnósticas para seleccionar aquellos casos que se pueden beneficiar de un manejo conservador. BACKGROUND Abdominal ectopic pregnancy accounts for only 0.9-1.4% of all ectopic pregnancies. The maternal mortality rate is high (up to 20%) and fetal viability mínimum. The managment, specially the conservatory management of these cases is difficult because of our limited experiencie due to its low frecuency. CASE PRESENTATION 35-year-old woman, with history of sterility due to endometriosis that required bilateral laparoscopic salpinguectomy. Her first pregnancy (after 5 in vitro fertilization cicles (IVF)) finalized with a caesarean section because of to the lack of labour progresion. She was admitted to our emergency department during her second pregnancy (after 3 IVF cicles), with 7 weeks of gestational age. She had a little vaginal bleeding. Ultrasound scan showed a 5mm gestational sac with a 3mm embryo without cardiac activity in the pouch of Douglas. The ß-Hcg level was 1477mUI/ml. The final diagnosis was ectopic abdominal pregnancy and it was decided to undertake an expectant management because she was clinically stable. The ß-Hcg level after 48 hours was 464 mUI/ml. In subsequent examinations ß-Hcg showed descending levels and after one month the resolution was completed. CONCLUSION Abdominal ectopic pregnancy is very infrequent but it has a high mortality rate. The most common approach is surgical but it is necessary to study all signs and diagnostic tests to select patients that could get profit from a conservatory management

    Lacustrine stromatolites: Useful structures for environmental interpretation – an example from the Miocene Ebro Basin

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    The significance of stromatolites as depositional environmental indicators and the underlying causes of lamination in the lacustrine realm are poorly understood. Stromatolites in a ca 600 m thick Miocene succession in the Ebro Basin are good candidates to shed light on these issues because they are intimately related to other lacustrine carbonate and sulphate facies, grew under variable environmental conditions and show distinct lamination patterns. These stromatolites are associated with wave-related, clastic-carbonate laminated limestones. Both facies consist of calcite and variable amounts of dolomite. Thin planar stromatolites (up to 10 cm thick and less than 6 m long) occurred in very shallow water. These stromatolites represented first biological colonization after: (i) subaerial exposure in the palustrine environment (i.e. at the beginning of deepening cycles); or (ii) erosion due to surge action, then coating very irregular surfaces on laminated limestones (i.e. through shallowing or deepening cycles). Sometimes they are associated with evaporative pumping. Stratiform stromatolites (10 to 30 cm high and tens of metres long) and domed stromatolites (10 to 30 cm high and long) developed in deeper settings, between the surge periods that produced hummocky cross-stratification and horizontal lamination offshore. Changes in stromatolite lamina shape, and thus in the growth forms through time, can be attributed to changes in water depth, whereas variations in lamina continuity are linked to water energy and sediment supply. Growth of the stromatolites resulted from in situ calcite precipitation and capture of minor amounts of fine-grained carbonate particles. Based on texture, four types of simple laminae are distinguished. The simple micrite and microsparite laminae can be grouped into light and dark composite laminae, which represent, respectively, high and low Precipitation/Evaporation ratio periods. Different lamination patterns provide new ideas for the interpretation of microbial laminations as a function of variations in climate-dependent parameters (primarily the Precipitation/Evaporation ratio) over variable timescales
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