Threat and the majority identity.

This study grapples with the question of majority–minority relations in conflict-ridden societies. The ethnographic study analyzed data gathered in a dialogue course conducted at an Israeli university among Jewish and Palestinian students, all citizens of the State of Israel. The authors identified 4 different and interrelated components of threat as these were perceived by the Jews participating in the dialogue: a permanent existential threat, the realistic threat from Palestinians, the threat to Jewish hegemony in the State of Israel, and the threat to the moral worth of the Jews’ national identity. The authors describe each of these components, how they interrelate, and also the changes undergone by the Jewish participants in the dialogue. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling and fuzzy control of the engine coolant conditioning system in an IC engine test bed

Mechanical and thermodynamical performance of internal combustion engines is significantly affected by the engine working temperature. In an engine test bed, the internal combustion engines are tested in different operating conditions using a dynamometer. It is required that the engine temperature be controlled precisely, particularly in transient states. This precise control can be achieved by an engine coolant conditioning system mainly consisting of a heat exchanger, a control valve, and a controller. In this study, constitutive equations of the system are derived first. These differential equations show the second-order nonlinear time-varying dynamics of the system. The model is validated with the experimental data providing satisfactory results. After presenting the dynamic equations of the system, a fuzzy controller is designed based on our prior knowledge of the system. The fuzzy rules and the membership functions are derived by a trial and error and heuristic method. Because of the nonlinear nature of the system the fuzzy rules are set to satisfy the requirements of the temperature control for different operating conditions of the engine. The performance of the fuzzy controller is compared with a PI one for different transient conditions. The results of the simulation show the better performance of the fuzzy controller. The main advantages of the fuzzy controller are the shorter settling time, smaller overshoot, and improved performance especially in the transient states of the system.     

Is (−)-Catechin a Novel Weapon of Spotted Knapweed (<Emphasis Type="Italic">Centaurea stoebe</Emphasis>)?

The novel weapons hypothesis states that some invasive weed species owe part of their success as invaders to allelopathy mediated by allelochemicals that are new to the native species. Presumably, no resistance has evolved among the native species to this new allelochemical (i.e., the novel weapon). In their native habitat, however, the plants that co-evolved with these invasive species have theoretically evolved defenses that obviate the allelochemical advantage. Previous studies have claimed that catechin is such a novel weapon of spotted knapweed (Centaurea stoebe = C. maculosa), an invasive species in the non-native habitat of North America. These studies indicated that (−)-catechin is more phytotoxic than (+)-catechin. Other studies have not found sufficient catechin in field soils to support this theory. We report that (−)-catechin and (+)-catechin are essentially equal, but poorly phytotoxic to a variety of plant species in bioassays without soil. In a dose/response experiment with Montana soils, we found the lowest dose for a growth reduction of two native Montana grasses (Koeleria macrantha and Festuca idahoensis) by a racemic mixture of (±)-catechin that ranged from about 25 to 50 mM, concentrations, orders of magnitude higher than expected in nature. Autoclaving the soil before adding the catechin did not affect the activity of catechin. We found (−)-catechin to be a potent antioxidant, in contrast to a previous claim that it acts as an allelochemical by causing oxidative stress. Our findings suggest that catechin is not a novel weapon of spotted knapweed and that other allelochemical(s) or alternative mechanisms must be found to explain the success of this species as an invader in North America.     

Transverse electric and transverse magnetic pulsed-beam decomposition of time-dependent aperture fields

The present contribution is concerned with applying beam-type expansion to a planar aperture time-dependent (TD) electromagnetic field in which the propagating elements, the electromagnetic pulsed-beams, are a priori decomposed into transverse electric (TE) and transverse magnetic (TM) field polarizations. The propagating field is described as a discrete superposition of tilted, shifted, and delayed TE and TM electromagnetic pulsed-beam propagators over the frame spectral lattice. These waveobjects are evaluated by using TD plane-wave spectral representations. Explicit asymptotic expressions for electromagnetic isodiffracting pulsed-quadratic beam propagators are presented, as well as a numerical example.     

房地产业拆迁还建问题的优化模型

通过对房地产商时常面临的使用新建房屋偿还被拆迁房屋面积(简称还建)问题进行定性分析和定量研究,提出了解决此类问题的合理的房屋拆迁还建优化模型,并应用该模型、使用WINQSB软件对具体的还建问题进行计算,得出解决方案。     

An active protein kinase A (PKA) is involved in meiotic arrest of rat growing oocytes

Reinitiation of meiosis in meiotically competent, fully grown mammalian oocytes is governed by a fall in intraoocyte cAMP concentrations and the subsequent inactivation of protein kinase A (PKA). A similar reduction in intraoocyte cAMP concentrations in growing, meiotically incompetent rat oocytes not leading to resumption of meiosis, questions the involvement of PKA in the regulation of meiosis at this early stage of oocyte development. We examined the possibility of whether PKA activity maintains growing oocytes in meiotic arrest and further explored the mode of activation of PKA under conditions of relatively low cAMP concentrations. Our experiment demonstrated that inactivation of PKA stimulates growing rat oocytes to resume meiosis, and elevates the activity of their maturation-promoting factor (MPF). We also found that the expressions of type I and type II regulatory subunits (RI and RII) of PKA are higher in growing and fully grown oocytes, respectively. In addition, we revealed that the common 1:1 ratio between the regulatory (R) and catalytic (C) subunits of PKA is apparently not abrogated and, in accordance PKA activity in growing oocyte-cell extract is fully dependent on cAMP. Finally, we identified in growing oocytes, the A kinase anchoring protein (AKAP) 140, which was previously depicted in fully grown oocytes. We conclude that an active PKA prevents growing oocytes from resuming meiosis. Our findings further suggest that relatively high abundance of the PKAI isoform and/or its subcellular compartmentalization, through interaction with AKAP140, could possibly account for the high basal PKA activity at relatively low intraoocyte cAMP concentrations.     

Lead Zirconate Titanate Particle Dispersion in Thick-Film Ink Formulations

Diverse device applications for lead zirconate titanate (PZT) ceramics in thick-film form are currently in active development. In the present study, the particle dispersion properties of thick-film ink formulations containing PZT powder have been determined using rheological measurements. Although all of the eight commercially available dispersants tested are more effective than the terpineol solvent alone in decreasing attractive interparticle forces in suspensions, the best dispersant identified for hard and soft PZT powders is a phosphate ester oligomer. This dispersant is extremely efficient, and its use in thick-film ink formulations results in viscosity decreases of 50% at low shear rates (10 s⁻¹) and 30% at high shear rates (100 s⁻¹) compared with current ink formulations containing no dispersant. The effects upon rheology of the order of addition of components in the processing of inks have been studied, with the most effective processing route using a fugitive solvent that probably facilitates uniform coverage of the particle surfaces by the dispersant molecules. Modeling of the rheological profiles of inks indicates that the use of a dispersant decreases the depth of the primary minimum in the interparticle potential by a factor of 3. Demonstrated advantages of the use of a dispersant in PZT thick-film inks include improved microstructural homogeneity in the green body and the ability to formulate printable inks with higher solids loadings. No adverse effects of the dispersant upon the dielectric and piezoelectric properties of bulk PZT samples are found following burnout and sintering.     

Preparation and Characterization of KNbO3 Ceramics

The processing and characterization of electrical properties of potassium niobate ceramic, KNbO₃ (KN) have been studied. The difficulty of obtaining dense samples by conventional methods limits the knowledge on electrical properties of this material. In this paper, a complete route for processing of KN with density over 94% is described. Piezoelectric and dielectric data are presented. It is observed that the major problem concerning the density is related to incorrect stoichiometry, which is believed to be a more critical issue for this system compared with other electro-ceramics.     

非洲猪瘟疫情下中国猪肉价格波动性研究——基于 ARCH 族和 BVAR 模型

2018 年 8 月开始传入我国的非洲猪瘟疫情对我国的猪肉市场产生了持续性冲击,使得猪肉价格大幅度上涨,突破了历史最高值。选取2000 年 1 月至 2020 年 3 月的月度数据,采用 ARCH 族模型研究了猪肉价格波动的集簇性、高风险高回报性和非对称性;使用贝叶斯VAR 模型、脉冲响应和方差分解研究了玉米价格、城镇居民人均可支配收入、人民币兑美元汇率和猪疫情指数对猪肉价格的影响。得到的结论是猪肉价格条件方差存在波动“成群”现象;猪肉价格存在高风险高回报的特点;“利好消息”比“利空消息”能够带来更大的波动。玉米价格和汇率水平对猪肉价格有较强的正向影响,可支配收入对猪肉价格的正向影响作用较弱,而猪疫情对猪肉价格存在较强的负向影响。对于猪肉价格的波动贡献率从大到小依次是自身、汇率水平、城镇居民可支配收入、玉米价格和猪疫情指数。最后,提出了相应的解决对策。     

Assessment of Edible Fungi and Films Bio-Based Material Simulating Expanded Polystyrene

Expanded polystyrene (EPS) contains benzene and styrene, posing a risk to human health. Research objective was to create and evaluate a bio-based material that mimics EPS physical and mechanical properties; this material was developed from crop residues (Triticum sp.), fungi (Pleurotus sp.), and edible films (carrageenan, chitosan, and xanthan gum). Treatments differed in the type of film applied over the bio-based material, and physical and mechanical properties were evaluated. Compressive and flexural strength ranged from 20 to 60 kPa and 4.6 to 17.9 kPa, respectively; dimensional stability and relative density ranged from 5.1 to 7.3% and 178.7 to 198.9 kg m^?3, respectively. The bio-based material does not pose to be an alternative to EPS yet, and further researches must assess water absorption and biodegradability.