47 research outputs found

    The electrostatic instability for realistic pair distributions in blazar/EBL cascades

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    This work revisits the electrostatic instability for blazar-induced pair beams propagating through IGM with the methods of linear analysis and PIC simulations. We study the impact of the realistic distribution function of pairs resulting from interaction of high-energy gamma-rays with the extragalactic background light. We present analytical and numerical calculations of the linear growth rate of the instability for arbitrary orientation of wave vectors. Our results explicitly demonstrate that the finite angular spread of the beam dramatically affects the growth rate of the waves, leading to fastest growth for wave vectors quasi-parallel to the beam direction and a growth rate at oblique directions that is only by a factor of 2-4 smaller compared to the maximum. To study the non-linear beam relaxation, we performed PIC simulations that take into account a realistic wide-energy distribution of beam particles. The parameters of the simulated beam-plasma system provide an adequate physical picture that can be extrapolated to realistic blazar-induced pairs. In our simulations the beam looses only 1\% percent of its energy, and we analytically estimate that the beam would lose its total energy over about 100100 simulation times. Analytical scaling is then used to extrapolate to the parameters of realistic blazar-induced pair beams. We find that they can dissipate their energy slightly faster by the electrostatic instability than through inverse-Compton scattering. The uncertainties arising from, e.g., details of the primary gamma-ray spectrum are too large to make firm statements for individual blazars, and an analysis based on their specific properties is required.Comment: Accepted for publication in ApJ (2018), in prin

    Revisit of non-linear Landau damping for electrostatic instability driven by blazar-induced pair beams

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    We revisit the effect of non-linear Landau (NL) damping on the electrostatic instability of blazar-induced pair beams, using a realistic pair-beam distribution. We employ a simplified 2D model in k{\bf k}-space to study the evolution of the electric-field spectrum and to calculate the relaxation time of the beam. We demonstrate that the 2D model is an adequate representation of the 3D physics. We find that non-linear Landau damping, once it operates efficiently, transports essentially the entire wave energy to small wavenumbers where wave driving is weak or absent. The relaxation time also strongly depends on the IGM temperature, TIGMT_\mathrm{IGM}, and for TIGM10T_\mathrm{IGM}\ll10 eV, and in the absence of any other damping mechanism, the relaxation time of the pair beam is longer than the inverse Compton (IC) scattering time. The weak late-time beam energy losses arise from the accumulation of wave energy at small kk, that non-linearly drains the wave energy at the resonant k\mathbf{k} of the pair-beam instability. Any other dissipation process operating at small kk would reduce that wave-energy drain and hence lead to stronger pair-beam energy losses. As an example, collisions reduce the relaxation time by an order of magnitude, although their rate is very small. Other non-linear processes, such as the modulation instability, could provide additional damping of the non-resonant waves and dramatically reduce the relaxation time of the pair beam. An accurate description of the spectral evolution of the electrostatic waves is crucial for calculating the relaxation time of the pair beam

    Adsorbed residual oil saturation and phase permeability relationship for oil in Western Siberia productive formations

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    Relevance. Relative phase permeabilities determine oil by water displacement mechanism, efficiency of productive formations flooding, dynamics of producing wells flooding. Relative phase permeabilities curves allow us to estimate the inflow nature according to geophysical well studies. Currently, relative phase permeabilities curves are constructed according to core samples laboratory studies. They are used to select a mathematical model describing the nature of the curves for a given productive reservoir. The most optimal option is to justify the individual relative phase permeabilities curve parameters. This option allows transition from the core sample level to the entire productive reservoir characteristics using geophysical well studies data. Aim. To substantiate a choice of a model describing the change in the relative phase permeability curves using field geophysics data based on the adsorbed residual oil saturation and phase permeability to oil relationship. Objects. Productive layers of individual deposits of the West Siberian oil and gas province, confined to the Lower Cretaceous deposits. Methods. Statistical processing of capillarimetric research data, analysis and substantiation of mathematical models describing relative phase permeability. Results. The paper shows that the permeability to oil at residual water saturation (the starting point of the relative phase permeabilities curve to oil) is determined by the adsorbed residual reservoir oil saturation. The authors have obtained the formula, linking the adsorbed residual oil saturation coefficient with the phase permeability to oil with residual water saturation. The adsorbed residual oil saturation is also closely related to the residual reservoir water saturation. Such relation is carried out through the reservoir clay content. The authors proposed the technique that allows residual oil saturation by type structuring and mobility degree. This technique allows as well as finding out the residual reserves of mobile oil distribution to justify the recovery techniques

    Implementasi Algoritma Advanced Encryption Standard (AES) 128 Untuk Enkripsi dan Dekripsi File Dokumen

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    Keamanan data atau informasi adalah hal yang sangat penting bagi pengguna jaringan internet saat ini. Kasus penyadapan akan pesan atau informasi merupakan salah satu hal yang sangat merugikan, dengan adanya kemungkinan terjadinya kejadian ini, maka perlunya peningkatan dalam hal keamanan pertukaran informasi menjadi penting. Pada saat ini, keamanan pertukaran informasi ini perlu mendapatkan perhatian khusus, maka penelitian ini akan membuat suatu implementasi kriptografi algoritma AES-128 untuk enkripsi dan dekripsi data yang berupa file dokumen (PDF, DOC, TXT). Algoritma Advanced Encryption Standard (AES) dipilih karena memiliki suatu tingkat keamanan pertukaran informasi yang cukup bagus, dan pada penelitian ini diuji coba file dokumen untuk melihat kecepatan waktu yang dibutuhkan selama proses enkripsi dan dekripsi

    Why aggression increases in modern society

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    The article reveals the concept of aggression, considered from the position of different philosophers and scientists who touched upon this topic in their works. Also, the growth of aggression in our time, the prerequisites for this, possible reasons, and modern approaches to understanding this phenomenon are considered.В статье раскрыто понятие агрессии, рассмотрено с позиции различных философов и ученых, затрагивавших эту тему в своих работах. Так же, рассмотрен рост агрессивности в наше время, предпосылки к этому, возможные причины, и современные подходы к пониманию такого явления

    IMMUNOLOGICAL IMBALANCE IN BREAST CANCER AND LUNG CANCER IN POSTMENOPAUSAL WOMEN

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    Previous studies reported some associations between class A antibodies specific for benzo[a]pyrene (IgA-Bp), estradiol (IgA-Es) and progesterone (IgA-Pg) and breast cancer (BC) in women like as with lung cancer (LC) in men. It was suggested that IgA-Bp and IgA-Es may stimulate tumor initiation and promotion, whereas IgA-Pg may inhibit the in vivo human carcinogenesis.The purpose of this study was to identify the suggested associations of such immunological imbalance with BC and LC in postmenopausal women.The serum A-class antibodies specific to benzo[a]pyrene, estradiol and progesterone (IgA-Bp, IgA-Es, IgA- Pg) were studied in 335 healthy women, 824 breast cancer (BC) patients and 127 cases of lung cancer (LC) by means of non-competitive solid phase immunoassay. The following results were obtained: Increased ratio of IgA-Bp and IgA-Es amounts exceeding the IgA-Pg levels was associated with a higher risk of breast cancer (OR = 2.8 and 2.4 respectively, p < 0.0001), and higher risk of LC (OR = 2.9 and 2.8, respectively, p < 0.0001). Conversely, the OR values decreased to 0.3-0.4 for BC and LC if IgA-Pg levels were higher than IgA-Bp and IgA-Es levels (p < 0.0001). These findings confirm the hypothesis that IgA-Bp and IgA-Es are capable to stimulate, and IgA-Pg, to inhibit the BC and LC occurrence n postmenopausal women. The balance between IgA-Bp and IgA-Es, on the one hand, and IgA-Pg, on the other hand, is much more important than individual contents of these antibodies.In conclusion, the phenomenon of “immunological interference” is revealed, i.e., the mutual enhancement of IgA-Bp and IgA-Es effects, thus, probably, stimulating the initial and subsequent events of carcinogenesis initiation and promotion, with a weak anticancer effect of IgA-Pg, and by weakening the mutual procarcinogenic effects of IgA-Bp and IgA-Es by the marked effect of IgA-Pg

    IMMUNOREGULATION OF BLOOD SERUM ESTRADIOL AND PROGESTERONE LEVELS IN POSTMENOPAUSAL WOMEN

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    Specific antibodies against estradiol (Es) and progesterone (Pg) are known to modulate blood serum concentrations of these hormones and their biological effects after immunization of animals. It was suggested that specific IgA-Es and IgA-Pg could influence on Es and Pg levels in human blood serum. The purpose of this study was to identify the suggested correlations between serum Es and Pg and specific IgA-Es and IgA-Pg in postmenopausal healthy women (HW) and breast cancer patients (BCP). The serum levels of Es, Pg, IgA-Es and IgA-Pg were studied in 226 HW and 633 BCP by means of solid-phase immunoassay. The following results were obtained. The levels of Es in BCP (0.25 nmol/l) were higher than in HW (0.16; р < 0.0001). The levels of Pg were lower (0.79 vs 0.87; р < 0.0001), and individual Pg/Es ratios were lower (3.19 vs 6.64; р < 0.0001). Individual IgA-Pg/IgA-Es ratios correlated with decrease of Es (rs = -0.15; p = 0.029), with increase in Pg (rs = 0.38; р < 0.0001), and with increased Pg/Es ratio (rs = 0.29; р < 0.0001) in healthy women. Similar correlations were determined in BCP (correspondingly: rs = -0.14, р < 0.001; rs = 0.1, р = 0.009; rs = 0.15, р < 0.0001). The decrease of Es and increase of Pg and Pg/Es in BCP were less significant than in HW: the a quotients in regression у = ах+b (y = hormones levels and x = antibodies levels) in BCP were 3 to 4-fold lower than in HW. These peciliarities of interrelations between hormones and specific antibody levels were revealed only in ER+/PR+ BCP but not in ER+/PR- and ER-/PR- BCP. In conclusion, we have confirmed a suggestion about participation of specific antibodies in regulation of steroids levels in human blood serum. The immune regulation of hormonal status was weakened in BCP

    ANTIBODIES TO BENZO[A]PYRENE IN SERUM OF PATIENTS WITH NON-SMALL CELL LUNG CANCER

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    The features of immune response to chemical carcinogen benzo[a]pyrene (Bp) at the patients with non-small cell lung cancer (NSCLC) are investigated. The isotypical distinctions in formation of antibodies (Ab) to Bp at the men with NSCLC in comparison with healthy are revealed. There were more often observed the high levels of IgG Ab-Bp at the men with NSCLC. Thus risk of occurrence NSCLC grows almost in 2 times at high levels of Ab-Bp of a class G

    Association of antibodies to benzo[a]pyrene, estradiol and progesterone with gene polymorphisms of cytokines in postmenopausal women

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    Previous studies reported some associations between IgA and IgG antibodies specific to benzo[a] pyrene (Bp), estradiol (Es) and progesterone (Pg), and breast cancer (BC) in postmenopausal women. Likewise, the individual ratios of these antibodies (IgA-Bp/IgA-Pg, IgG-Bp/IgG-Pg, IgG-Es/IgG-Pg, IgG-Es/IgG-Pg) were associated with BC. It was suggested that development of antibodies to chemical carcinogens and steroid hormones was determined by functional polymorphisms of cytokine genes. The purpose of this study was to identify the suggested associations of antibodies to Bp, Es, Pg, and their individual ratios to the following gene polymorphisms: IL1RN (rs4251961), IL1B (rs16944), IL6 (rs1800795, rs1800796, rs1554606), IL8 (rs4073), TNFA (rs1800629) and CD40 (rs6074022) detected in postmenopausal healthy women and BC patients.The serum IgA and IgG antibodies specific to Bp, Es and Pg were studied in 470 healthy women and 995 BC patients by non-competitive solid phase immunoassay. The conjugates of Bp, Es, Pg with bovine serum albumin were used as adsorbed antigen. The goat antibodies against human IgA or IgG conjugated with horseradish peroxidase were used for the detection of bound hapten-specific antibodies. Cytokine gene polymorphisms were analyzed by the real-time PCR.Associations between the studied antibodies and their ratios with the gene polymorphisms in IL1RN (rs4251961), IL6 (rs1800795), TNFA (rs1800629) and CD40 (rs6074022) were found in healthy women. Higher individual ratios of IgA-Bp/IgA-Pg (p = 0.0001), IgG-Bp/IgG-Pg (p < 0.0001), IgG-Es/IgG-Pg (p = 0.0003) were associated with the allele C gene IL1RN. The higher IgG-Es levels were more common in the persons with allele G gene IL6 (p = 0.007), and with C allele of CD40 gene (p = 0.005). The high IgA-Pg levels were associated with A allele gene of TNFA (p = 0.008). Associations of antibodies were found only with genes polymorphisms in CD40 (rs6074022) in BC patients. Higher IgG-Es levels were more common in persons with allele T gene CD40 (p = 0.007).In conclusion, we revealed the participation of cytokines in immune regulation of antibody genesis for environmental chemical carcinogens and endogenous steroid hormones in healthy women and BC patients. The future investigations of antibodies specific to Bp, Es and Pg combined with the analysis genes polymorphisms in cytokines will be useful for detection of the individual hormone-dependent cancer risks in humans
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