91 research outputs found

    The theoretical and experimental researches of Pb-Al composite materials extrusion

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    The work presents the analysis of the character of a simultaneous plastic flow of composite material of a hard core-soft sleeve structure. Experimental research work using model composite material Aluminium-Lead and theoretical analysis allowed to identify the initial cracking conditions, its character and localization, depending on geometrical parameters of the composite materials and the extrusion ratio value. It has been shown that the higher the parameters’ values are, the longer the flawless extruded product is (cracking appears in the further stages of the process)

    Efficiency of supplementing saccharomyces cerevisiae var. ellipsoideus for improved growth performance and carcass yield in broilers

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    The use of dietary additives is becoming a very interesting practise to improve animal health and performance in poultry production. Thepax® is a prebiotic that includes inactivated Saccharomyces cerevisiae Var. ellipsoideus cells and nutrients such as vitamins, enzymes, amino acids and short chain polypeptides. The effects of supplementing diet by Thepax® via potable water on growth and carcass yield were studied in broilers. Two treatments, an active with Thepax® and a control treatment, were used on 120 male and female chicks of the Hubbard JV breed. Birds were divided into 6 groups of 20 birds each managed on floor and received the same starter, grower and finisher concentrates based on maize and soybean meal during a 37 days trial period. Thepax®(0.5 ml of the additive for 1 litre of water) was used during only one month. Body weight and daily growth rate seemed to increase by 6.2% and 6.4%, respectively, in birds receiving Thepax® compared to control birds. Feed conversion ratio and water intake were similar (P≥0.201) for both groups of birds. The effect of the additive was important on birds’ health. The mortality rate decreased (P=0.0241) by around 71% in birds receiving Thepax®compared to that in control birds. Furthermore, the active group of birds deposited (P = 0.0172) less abdominal fat (-35.2%) without affecting carcass yield. Positive effects of Thepax® with its structure and composition may be an important additional source of nutrients supports growth and enhance feed ingredients digestibility and beneficial intestinal microflora activity in broilers. In conclusion, Thepax® administered to broilers in drinkable water may improve birds’ health and reduce abdominal fat without compromising carcass yield

    Quantum transport and mobility spectrum of topological carriers in (001) SnTe/PbTe heterojunctions

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    Measurements of magnetotransport in SnTe/PbTe heterojunctions grown by the MBE technique on (001) undoped CdTe substrates were performed. At low magnetic fields, quantum corrections to conductivity were observed that may be attributed to the presence of topological states at the junction interface. For a sample with 5 nm thick SnTe layer, the data analysis suggests that midgap states are actually gapped. However, the phase coherence effects in 10 nm and 20 nm SnTe/PbTe samples are fully explained assuming existence of gapless Dirac cones. Magnetotransport at higher magnetic fields is described in the framework of mobility spectrum analysis (MSA). We demonstrate that the electron- and hole-like peaks observed simultaneously for all SnTe/PbTe heterojunctions may originate from the concave and convex parts of the energy isosurface for topological states -- and not from the existence of quasiparticles both carrying negative and positive charges. This interpretation is supported by numerical calculations of conductivity tensor components for gapless (100) Dirac cones, performed within a classical model and based on the solutions of Boltzmann transport equation. Our approach shows the feasibility of MSA in application to magnetotransport measurements on topological matter

    Regulation of human chorionic gonadotropin beta subunit expression in ovarian cancer

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    Expression of human chorionic gonadotropin beta subunit by cancers is extensively documented, yet regulation of the multiple genes that can code for this protein is poorly understood. The aim of the study was to examine the mechanisms regulating CGB gene expression in ovarian cancer. Expression of CGB genes and SP1, SP3, TFAP2A transcription factor genes was evaluated by RT-qPCR. The methylation status of CGB genes promoter regions was examined by methylation-specific PCR. mRNA arising from multiple CGB genes was detected in both ovarian control and malignant tissues. However, expression of CGB3-9 genes was shown to be significantly higher in malignant than healthy ovarian tissues. CGB1 and CGB2 transcripts were shown to be present in 20% of ovarian cancers, but were not detected in any of the control samples. Malignant tissues were characterized by DNA demethylation of CGB promoter regions. In ovarian cancer CGB expression positively correlated with TFAP2A transcripts level and expression of TFAP2A transcription factor was significantly higher in cancer than in control tissues. In contrast SP3 expression level was significantly lower in ovarian tumours than in control ovarian tissue. In ovarian cancers increased expression of human chorionic gonadotropin beta subunit is associated with demethylation of CGB promoter regions. CGB3-9 expression level strongly correlates with expression of the TFAP2A transcription factor. Presence of mRNA arising from CGB1 and CGB2 genes appears to be a unique feature of a subset of ovarian cancers

    The nature of the unresolved extragalactic soft CXB

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    In this paper we investigate the power spectrum of the unresolved 0.5-2 keV CXB with deep Chandra 4 Ms observations in the CDFS. We measured a signal which, on scales >30", is significantly higher than the Shot-Noise and is increasing with the angular scale. We interpreted this signal as the joint contribution of clustered undetected sources like AGN, Galaxies and Inter-Galactic-Medium (IGM). The power of unresolved cosmic sources fluctuations accounts for \sim 12% of the 0.5-2 keV extragalactic CXB. Overall, our modeling predicts that \sim 20% of the unresolved CXB flux is made by low luminosity AGN, \sim 25% by galaxies and \sim 55% by the IGM (Inter Galactic Medium). We do not find any direct evidence of the so called Warm Hot Intergalactic Medium (i.e. matter with 10^5K<T<10^7K and density contrast {\delta} <1000), but we estimated that it could produce about 1/7 of the unresolved CXB. We placed an upper limit to the space density of postulated X-ray-emitting early black hole at z>7.5 and compared it with SMBH evolution models.Comment: 15 pages, 9 figures, accepted by MNRA

    Playing in the academic field: Non-native English-speaking academics in UK business schools

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    This paper draws on Bourdieu's concepts of field, habitus and capital to explore the ways in which working in English as a non-native language influences foreign academics' performance of academic habitus and the level of their symbolic capital necessary for the achievement of success within UK higher education. Empirically, it is based on interviews with 54 non-native English-speaking academics employed in UK business schools. Our findings point to advantages and disadvantages associated with being a non-native English-speaking academic, to strategies deployed by individuals to enhance their linguistic capital, and to the importance of language not merely as a tool of communication but as a key factor enabling individuals to perform academic habitus in the UK academic field. We reflect on whether, and if so, how, the UK academic field is changing as a result of the increased presence within it of non-UK-born academics and, in particular, the fact of their professional functioning in English as a non-native language

    Profaning the sacred in leadership studies: A reading of Murakami's A Wild Sheep Chase

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    The leadership literature is full of stories of heroic self-sacrifice. Sacrificial leadership behaviour, some scholars conclude, is to be recommended. In this article we follow Keith Grint's conceptualization of leadership as necessarily pertaining to the sacred, but-drawing on Giorgio Agamben's notion of profanation-we highlight the need for organization scholars to profane the sacralizations embedded in leadership thinking. One example of this, which guides us throughout the article, is the novel A Wild Sheep Chase, by the Japanese author Haruki Murakami. By means of a thematic reading of the novel, we discuss how it contributes to profaning particular notions of sacrifice and the sacred in leadership thinking. In the novel, self-sacrifice does not function as a way of establishing a leadership position, but as a way to avoid the dangers associated with leadership, and possibly redeem humans from their current collective urge to become leaders. Inspired by Murakami's fictional example, we call organization scholars to engage in profanation of leadership studies and, in doing so, open new vistas for leadership theory and practice. © The Author(s) 2012

    Moving Beyond Mimicry: Developing Hybrid Spaces in Indian Business Schools

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    This article analyses the identity work of Indian management educators and scholars as they seek to establish, maintain and revise a sense of self in the context of business school globalization. We show how globalization, combined with the historical legacy of colonialism, renders Indian scholars precarious in their interactions with Western business schools. Based on a qualitative interview study, we explore how Indian business school scholars perform their identities in the context of neo-colonial relations, which are characterised by the dominance of English language and a pressure to conform to research norms set by globally-ranked journals. Drawing on postcolonial theory, our argument focuses on mimicry as a distinctive form of identity work that involves maintaining difference between Western and non-Western identities by 'Othering' Indian scholars, while simultaneously seeking to transform them. We draw attention to ambivalence within participants' accounts, which we suggest arises because the authority of Western scholarship relies on maintaining non-Western scholars in a position of alterity or 'not quite-ness'. We suggest that hybridity offers an opportunity to disrupt and question current practices of business school globalization and facilitate scholarly engagement that reflects more diverse philosophical positions and worldviews
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