1,710 research outputs found
Application of Genetic Algorithms in the Construction of Invertible Substitution Boxes
No full textExisting literature shows that genetic algorithms can be successfully used for automated construction of S-boxes. In this paper we show the usage of genetic algorithm, more specifically NSGA-II, as an aid in designing and testing of invertible substitution boxes which are special case of substitution boxes. Many cryptographic properties of Sboxes are often contradicting each other. It is therefore difficult to find an optimal solution. NSGA-II proved to be a valuable tool in finding a range of solutions from which we can later select an appropriate S-box for a cipher. We also show that we can use NSGA-II to test integration of S-boxes with a cipher and automatically reject S-boxes which make the cipher weak
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Observations of diurnal and spatial variability of radiative forcing by equatorial deep convective clouds
No full textFrom geostationary satellite observations of equatorial Africa and the equatorial east Atlantic during May and June 2000 we explore the radiative forcing by deep convective cloud systems in these regions. Deep convective clouds (DCCs) are associated with a mean radiative forcing relative to non–deep convective areas of −39 W m−2 over the Atlantic Ocean and of +13 W m−2 over equatorial Africa (±10 W m−2 in both cases). We show that over land the timing of the daily cycle of convection relative to the daily cycle in solar illumination and surface temperature significantly affects the mean radiative forcing by DCCs. Displacement of the daily cycle of DCC coverage by 2 hours changes their overall radiative effect by ∼10 W m−2, with implications for the simulation of the radiative balance in this region. The timing of the minimum DCC cover over land, close to noon local time, means that the mean radiative forcing is nearly maximized
Invariant Measures Exist Without a Growth Condition
No full textGiven a non-flat S-unimodal interval map f, we show that there exists C which only depends on the order of the critical point c such that if |Dfn (f(c))|greater than or equal to C for all n sufficiently large, then f admits an absolutely continuous invariant probability measure (acip). As part of the proof we show that if the quotients of successive intervals of the principal nest of f are sufficiently small, then f admits an acip. As a special case, any S-unimodal map with critical order l epsilon having no central returns possesses an acip. These results imply that the summability assumptions in the theorems of Nowicki & van Strien [21] and Martens & Nowicki [17] can be weakened considerably.</p
Decreased haem oxygenase-1 and increased inducible nitric oxide synthase in the lung of severe COPD patients
No full textOxidant/antioxidant imbalance is implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). The current study examined the expression of antioxidant and pro-oxidant enzymes, haem oxygenases; (140) and inducible nitric oxide synthase (iNOS) respectively, in patients with severe COPD and control smokers without lung function impairment. Immunoreactivity for HO-1, HO-2, iNOS and nitric oxide-derived oxidants expressed as nitrotyrosine (N-Tyr) was quantified in peripheral lung. HO-1+ alveolar macrophages were decreased in severe COPD compared to control smokers, whereas no difference was observed in iNOS+ macrophages. In contrast, severe patients had significantly higher numbers of iNOS+ cells in alveolar walls. These iNOS+ cells were identified as type 2 pneumocytes and their number was inversely related to HO-1+ macrophages. There were no significant differences in N-Tyr immunostaining between the two groups. However, the rate of protein nitration in lung tissue was directly related to iNOS expression and associated with lower values of forced expiratory volume in one second/forced vital capacity. HO-2 was constitutively expressed by type 2 pneumocytes and these cells were increased in severe COPD. In conclusion, the results suggest that the enzymes involved in the oxidative stress response may have a different role in the lung defence and that imbalance between haem oxygenase-1 and inducible nitric oxide synthase may be associated with the development of severe impairment in chronic obstructive pulmonary disease patients
Decreased haem oxygenase-1 and increased inducible nitric oxide synthase in the lung of severe COPD patients
No full textInvariant Measures Exist Without a Growth Condition
No full textGiven a non-flat S-unimodal interval map f, we show that there exists C which only depends on the order of the critical point c such that if \Df(n) (f (c))\ greater than or equal to C for all n sufficiently large, then f admits an absolutely continuous invariant probability measure (acip). As part of the proof we show that if the quotients of successive intervals of the principal nest of f are sufficiently small, then f admits an acip. As a special case, any S-unimodal map with critical order l <2 + ε having no central returns possesses an acip. These results imply that the summability assumptions in the theorems of Nowicki & van Strien [21] and Martens & Nowicki [17] can be weakened considerably
Primer registro en la Península Ibérica de Oobius rudnevi (Nowicki, 1928) (Hymenoptera: Encyrtidae), un parasitoide oófago poco conocido de Cerambyx sp. (Coleoptera: Cerambycidae)
No full textOobius rudnevi (Nowicki, 1928) (Hymenoptera: Encyrtidae) is first reported from Iberia and southern Europe using sentinel eggs. The parasitoid was detected in July 2016 in three oak open woodlands in Extremadura (SW Spain), located in Almendral (La Jara) and Mérida (La Serrana and Cornalvo Natural Park). O. rudnevi para-sitized both the eggs of Cerambyx cerdo Linnaeus, 1758 (its only known host to date) and C. welensii (Küster, 1845), which constitutes a new host-parasitoid association (C. welensii-O. rudnevi). Parasitism rate was quite variable among sites and dates (range 0–93%), with a higher prevalence in C. cerdo than in C. welensii. New studies are conducted in the field and laboratory to explore the ecology, behaviour and parasitic potential of O. rudnevi in Mediterranean oak open woodlands.Se cita por primera vez a Oobius rudnevi (Nowicki, 1928) (Hymenoptera: Encyrtidae) de la Península Ibérica y el sur de Europa usando huevos centinela. El parasitoide se detectó en julio de 2016 en tres dehesas en Extremadura (SO de España), localizadas en Almendral (La Jara) y Mérida (La Serrana y Parque Natural de Cornalvo). O. rudnevi parasitó tanto los huevos de Cerambyx cerdo Linnaeus, 1758 (su único hospedador conocido hasta la fecha) como los de C. welensii (Küster, 1845), lo que supone una nueva asociación hospedador-parasitoide (C. welensii-O. rudnevi). El porcentaje de parasitismo se mostró bastante variable entre sitios y fechas (rango 0–93%), con mayor prevalencia en C. cerdo que en C. welensii. Nuevos estudios se desarrollan en campo y laboratorio para explorar la ecología, comportamiento y potencial parasitario de O. rudnevi en las dehesas mediterráneas de quercíneas
Emotion recognition abilities and empathy of victims of bullying
No full textObjectives: Bullying is a form of systematic abuse by peers with often serious consequences for victims. Few studies have considered the role of emotion recognition abilities and empathic behaviour for different bullying roles. This study investigated physical and relational bullying involvement in relation to basic emotion recognition abilities, and empathic styles in children. Using the framework of the Social Information Processing model, it was expected that victims would have poor emotion recognition abilities, and that bullies would demonstrate low levels of empathy.
Methods: Data was collected from UK children (N = 373) aged 9-11 years who completed a bullying instrument, the Bryant Index of Empathy measurement, and the DANVA (Diagnostic Analysis of Nonverbal Accuracy) to assess emotion recognition abilities. Children were classified into physical and relational bullying roles (bully, victim, bully/victim neutral) for analytical purposes.
Results: While physical victims, bullies and neutrals differed little in their emotion recognition abilities, relational victims were particularly poor in recognising negative emotions of anger and fear in faces. No differences were found in empathy scores, according to bullying roles.
Conclusions: Children who are relationally victimised are poorer in understanding emotional information than bullies and non-involved children. In light of previous research that victims of bullying more frequently experience child abuse, future interventions should consider the importance of emotion and social skills training for these vulnerable children
Endoplasmic Reticulum-Derived Multilamellar Bodies in Oocytes of Mouse Follicle Cultures under Oxidized Low-Density Lipoprotein Treatment
No full textSpanel-Borowski K, Nowicki M, Borlak J, Trapphoff T, Eichenlaub-Ritter U. Endoplasmic Reticulum-Derived Multilamellar Bodies in Oocytes of Mouse Follicle Cultures under Oxidized Low-Density Lipoprotein Treatment. Cells Tissues Organs. 2013;197(1):77-88.Objective: Multilamellar bodies associated with an organized endoplasmic reticulum (ER) arise in various somatic cell types, and a subtype called multivesicular bodies is described in oocytes. Both entities, so far undetermined in significance, may occur in oocytes of follicles under oxidative stress. In preovulatory follicles, oxidative stress appears to be caused by oxidized low-density lipoprotein (ox-LDL). Method: Cultures of preantral mouse follicles were treated with 100 mu g/ml ox-LDL or normal LDL (n-LDL) for 12-48 h or for 12 days during antral follicle growth followed by in vitro ovulation and harvest of cumulus oophorus complexes (COCs) with metaphase II (MII) oocytes on day 13. Preantral follicles, COCs, or MII oocytes were immunostained with anti-tubulin antibody or stained with actin-binding phalloidin for confocal microscopy. Ultrathin sections were prepared for electron microscopy. Results: Preantral follicles exposed to nLDL or ox-LDL developed normally, and MII oocytes in COCs possessed normal spindles with well-aligned chromosomes. In contrast, treated cumulus cells underwent apoptosis. Only the ox-LDL-treated preantral follicle oocytes showed ER-derived multilamellar bodies (EMBs) of type I, consisting of rough ER membranes for the envelope. The MII oocytes of COCs showed type II EMBs consisting of smooth/vesicular ER and were more prominent after ox-LDL than after n-LDL exposure. Degenerating mitochondria were prominent in oocytes of the ox-LDL group and judged as a sign of oxidative stress. Conclusion: Oxidative stress presumably induces damage of proteins and organelles in the oocytes. The EMBs might sequester the damaged structures for oocyte survival. Thus, EMBs could represent a novel form of autophagy. Copyright (C) 2012 S. Karger AG, Base
The development of SOFC with perovskite electrodes by co-sintering and co-casting method
No full textThe Solid Oxide Fuel Cells (SOFCs) were produced with various geometries by tape casting and co-sintering. Tape casting is a cheap and easily scalable method employed on a large scale for thin layers preparation. In the project, a sequential casting technique was developed where all the function layers in SOFC assembly were cast on each other; co-casting gave a strong interface and reduced electrolyte thickness. Co-sintering further simplified cells manufacturing and reduced processing time and energy demand, making fuel cells more profitable and suitable for mass production. The crucial factor for co-sintering of various-material tapes is to ensure that they have close shrinkage profiles during the sintering step, which usually differ due to individual properties of ceramic materials and pore former’s concentration in the slurry. The minor differences create stress between layers, leading to delamination and cracks in the cell’s structure. By controlling the composition of the slurry, particle size distribution and sintering temperature, it was possible to produce a cell without any internal structural defects.
The developed method was used to produce SOFC with alternative SOFCRoll geometry and the small tubular cells. SOFCRoll gives the possibility to extend the surface area while keeping the volume low. Up to 27.75 cm² of surface area was incorporated in a spiral structure, with a volume of about 2.5 cm³, thus giving better applicability where size reduction is required and a more robust structure; however, the cell was suffered a performance loss due to complications with the current collection and gas distribution. The structure modification and co-sintering of the current collector with high Ni content into otherwise unavailable part of the cell allowed for optimal use of 12 cm² surface area in the smaller version of the cell. Tubular cells are known for their high mechanical and thermal resistance. Tubular cell's surface area was up to 7 cm², much lower than in SOFCRoll but more accessible for gas and current collector. The combination of a small tubular design with thermally and redox stable alternative perovskite fuel electrode gave a highly durable device; without noticeable degradation after testing in extreme conditions.
Through the project, composite electrodes were mainly used, co-cast, and co-sintered with electrolyte at 1350 °C. The state-of-art yttria-stabilised zirconia (Zr₀.₈₄Y₀.₁₆O₁.₉₂, YSZ) was used as the electrolyte, which offers good performance and commercial availability. The co-sintered active fuel electrode contained the nickel-doped lanthanum calcium titanate (La₀.₄₃Ca₀.₃₇Ni₀.₀₆Ti₀.₉₄O[sub](3-γ), LCNT) and YSZ. The co-sintered oxygen electrode was a composite of lanthanum strontium manganate ((La₀.₈Sr₀.₂)₀.₉₅MnO₃, LSM) and YSZ. LCNT belongs to the family of new alternative materials proposed to replace highly active but prone to degradation state-of-the-art Ni/YSZ composite. Thanks to its mixed ionic and electronic properties (MIEC) and the possibility of exsolving nickel nanoparticles on its surface, LCNT offers a high activity for hydrogen oxidation whilst possessing great thermal shock and redox resistance as a fully ceramic electrode.
Despite the successful co-sintering of the LCNT/YSZ fuel electrode and LSM/YSZ oxygen electrode into a SOFCRoll and tubular structure, due to limitations related to the sintering temperature and composition, electrodes showed a significant ohmic and polarisation resistance.
In the following experiment, the composite electrodes were replaced. For the development of the next generation of tubular cells, the active material was impregnated into a co-sintered porous YSZ backbone. For impregnated electrodes, LCNT was impregnated on a porous YSZ backbone for the fuel hydrogen side, while on the air electrode, a lanthanum strontium ferrite (La₀.₈Sr₀.₂FeO₃, LSF). The impregnated electrodes were sintered at a much lower temperature than in state-of-the-art methods, giving more active spatial microstructures with a large surface area. Using this technique in co-sintered cells simplified manufacturing and made a broader range of materials available.
This work contains complete procedures for producing SOFC with various designs, including planar, tubular, and SOFCRoll, by the outlined methods. In addition, it seeks to determine a mechanism of their functionality based on electrochemical tests and DRT analysis
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