23 research outputs found

    A Tverberg type theorem for matroids

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    Let b(M) denote the maximal number of disjoint bases in a matroid M. It is shown that if M is a matroid of rank d+1, then for any continuous map f from the matroidal complex M into the d-dimensional Euclidean space there exist t \geq \sqrt{b(M)}/4 disjoint independent sets \sigma_1,\ldots,\sigma_t \in M such that \bigcap_{i=1}^t f(\sigma_i) \neq \emptyset.Comment: This article is due to be published in the collection of papers "A Journey through Discrete Mathematics. A Tribute to Jiri Matousek" edited by Martin Loebl, Jaroslav Nesetril and Robin Thomas, due to be published by Springe

    Wavelength Tunability of Ion-bombardment Induced Ripples on Sapphire

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    A study of ripple formation on sapphire surfaces by 300-2000 eV Ar+ ion bombardment is presented. Surface characterization by in-situ synchrotron grazing incidence small angle x-ray scattering and ex-situ atomic force microscopy is performed in order to study the wavelength of ripples formed on sapphire (0001) surfaces. We find that the wavelength can be varied over a remarkably wide range-nearly two orders of magnitude-by changing the ion incidence angle. Within the linear theory regime, the ion induced viscous flow smoothing mechanism explains the general trends of the ripple wavelength at low temperature and incidence angles larger than 30. In this model, relaxation is confined to a few-nm thick damaged surface layer. The behavior at high temperature suggests relaxation by surface diffusion. However, strong smoothing is inferred from the observed ripple wavelength near normal incidence, which is not consistent with either surface diffusion or viscous flow relaxation.Comment: Revtex4, 19 pages, 10 figures with JPEG forma

    Estabilidad y compuestos de oxidación volátiles de aceites prensados en frío de semillas de uva, lino y comino negro, afectados por la oxidación térmica

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    The old-pressed oils (CPO) from grape seeds (GSO), flax seeds (FSO) and black cumin seeds (BSO) were analyzed for their fatty acid profiles, tocopherols, total phenolics, bioactives and phenolic compositions. The stability of CPO under thermal oxidation conditions was evaluated. The main fatty acid in FSO was linolenic acid (56.5% of total fatty acids); while GSO and BSO were rich in linoleic acid, which accounted for 66.8 and 56.8%, respectively. GSO was rich in ?-tocopherol (123.0 mg/kg), while ?-tocopherol was a prevalent isomer in FSO and BSO (137.9 and 128.9 mg/kg, respectively). The total phenolic contents in the oils ranged from 554 mg GAE/kg oil (FSO) to 1140 mg GAE/kg oil (BSO). Luteolin, dihydroquercetin and benzoic acids were the dominant bioactives and phenolics in FSO, GSO and BSO, respectively. Based on the oxidative stability index (OSI) value, BSO showed the highest value (6.14 h) among the other oils. The oxidative stability of FSO and BSO were higher than GSO according to peroxide value (PV) and conjugated diene (CD) values of the oils during storage at 60 °C. Hexanal, 2,4-heptadienal and (E,E)-2,4-heptadienal were the major volatile oxidation compounds (VOC) in FSO. Hexanal and (E)-2-heptanal were the main identified VOC in the GSO and BSO under the same oxidation conditions.Los aceites prensados en frío (CPO) de semilla de uva (OSG), semilla de lino (FSO) y semilla de comino negro (BSO) se analizaron para determinar su perfil de ácidos grasos, tocoferoles, compuestos fenólicos totales, compuestos bioactivos y composición fenólica. Se evaluó la estabilidad del CPO en condiciones de oxidación térmica. El ácido graso principal en FSO fue ácido linolénico (56,5%), mientras que GSO y BSO fueron ricos en ácido linoleico que representó el 66,8% y 56,8%, respectivamente. La OSG fue rica en ?-tocoferol (123,0 mg/kg), mientras que el ?-tocoferol fue el tocoferol mayoritario en el FOE y BSO (137,9 y 128,9 mg/kg, respectivamente). El contenido fenólico total de los aceites varió de 554 mg GAE/kg de aceite en FSO a 1140 mg GAE/kg de aceite en BSO. La luteolina, la dihidroquercetina y los ácidos benzoicos fueron los bioactivos y fenólicos dominantes en FSO, GSO y BSO, respectivamente. En base al valor del índice de estabilidad de la oxidación (OSI), BSO mostró el valor más alto (6,14 h) entre los otros aceites. La estabilidad oxidativa de FSO y BSO fue mayor que la OSG según el valor de peróxido (PV) y los valores de dieno conjugado (CD) de los aceites durante el almacenamiento a 60 °C. Hexanal, 2,4-heptadienal y (E, E) -2,4-heptadienal fueron los principales compuestos de oxidación volátiles (VOC) en FSO. Hexanal y (E) -2-heptanal fueron los principales VOC identificados en la OSG y la BSO en las mismas condiciones de oxidación

    Population dynamics of the mediterranean green crab carcinus aestuarii nardo, 1847 (Crustacea: Portunidae) in the gediz delta (İzmir bay, eastern aegean sea) [Dinamika populacije mediteranskog zelenog raka carcinus aestuarii nardo, 1847. (crustacea: portunidae)u delti rijeke gediz (zaljev izmir, isto?no egejsko more)]

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    2-s2.0-85088207805A total of 6265 Mediterranean green crabs Carcinus aestuarii were sampled from the Gediz Delta in the eastern Aegean Sea (Turkey) during 24 sampling surveys with a 15-day interval from November 2014 to October 2015. The overall ratio of males to females was 1.8:1. Males were predominant in all sampling surveys, except in September 2015. The ranges of total weight (W) and carapace width (CW) for all crabs were 0.19–45.74 g and 8–53 mm. Male crabs were, on average, larger and heavier than females. The W–CW relationships were W=0.0004×CW2.88 for females, and W=0.0003×CW2.96 for males. The estimated von Bertalanffy growth parameters for females were: CW?=49 mm, K=0.82 year-1 and t0=-0.9 year, and for males CW?=54 mm, K=0.92 year-1 and t0=0.96 year. The total mortality rates were 2.25 and 2.27 year-1 for females and males, respectively. The breeding season spans from mid fall to early spring peaking in winter. The recruitment of juveniles to the lagoon happens predominantly in summer. The median size at first maturity was 30.6 mm for females and 41.5 mm for males. The average potential fecundity estimate was 63565±36519 oocytes per female crab while the average realized fecundity was 42810±33310 eggs. © 2020, Institute of Oceanography and Fisheries. All rights reserved.Ege Ãœniversitesi: 2014-SUF-016The authors would like to thank Ege University for supporting this study by funds from Ege University Scientific Research Projects Coordination Unit (Project No: 2014-SUF-016)

    Histological investigation of the effects of tenoxicam on pulmonary complications of pneumoperitoneum - Tenoxicam reduces lung injuries caused by pneumoperitoneum

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    Objectives. Pneumoperitoneum increases intra-abdominal pressure and generates oxidative stress, which mediates tissue injury. One of the causes of oxidative stress production is an inflammatory reaction. Taking this into consideration, the current animal study was designed, using tenoxicam before a laparoscopy procedure in order to ascertain whether tenoxicam can prevent lung injury caused by pneumoperitoenum. Material and Methods. Fourteen female Wistar rats were randomly divided into two groups: the tenoxicam group (seven rats) and the control group (seven rats). The tenoxicam group was given two doses (totalling 0.5 mg/kg) of intraperitoneal tenoxicam, and the control group was given 0.5 cc of 0.9% NaCl, 12 hours and 1/2 hour before the operation. Under intra-peritoneal anesthesia, a Veress needle was placed in the peritoneal cavity and a 15 mm-Hg pneumoperitoneum was established and maintained for 20 minutes; the peritoneal gas was then desufflated. The lungs were resected at the 180 th minute from the beginning of the operation and were evaluated histopathologically. Histopathological evaluations including intra-alveolar hemorrhage, alveolar edema, congestion and leukocyte infiltration were carried out for both groups. Results. A statistical comparison of the evaluation scores revealed significant differences between the two groups for intra-alveolar hemorrhage (p = 0.007), alveolar edema (p = 0.023) and congestion (p = 0.005) and a non-significant difference for leukocyte infiltration (p = 0.114). Conclusions. Pneumoperitoneum causes injuries to lung tissue; tenoxicam reduces that damage and protects the lungs by decreasing intra-alveolar hemorrhage, alveolar edema and congestion. © Copyright by Wroclaw Medical University

    Genome-wide Mapping of DNA Synthesis in Saccharomyces cerevisiae Reveals That Mechanisms Preventing Reinitiation of DNA Replication Are Not Redundant

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    To maintain genomic stability, reinitiation of eukaryotic DNA replication within a single cell cycle is blocked by multiple mechanisms that inactivate or remove replication proteins after G1 phase. Consistent with the prevailing notion that these mechanisms are redundant, we previously showed that simultaneous deregulation of three replication proteins, ORC, Cdc6, and Mcm2-7, was necessary to cause detectable bulk re-replication in G2/M phase in Saccharomyces cerevisiae. In this study, we used microarray comparative genomic hybridization (CGH) to provide a more comprehensive and detailed analysis of re-replication. This genome-wide analysis suggests that reinitiation in G2/M phase primarily occurs at a subset of both active and latent origins, but is independent of chromosomal determinants that specify the use and timing of these origins in S phase. We demonstrate that re-replication can be induced within S phase, but differs in amount and location from re-replication in G2/M phase, illustrating the dynamic nature of DNA replication controls. Finally, we show that very limited re-replication can be detected by microarray CGH when only two replication proteins are deregulated, suggesting that the mechanisms blocking re-replication are not redundant. Therefore we propose that eukaryotic re-replication at levels below current detection limits may be more prevalent and a greater source of genomic instability than previously appreciated
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