1,651 research outputs found

    Sharp weighted bounds for one-sided and multiple integral operators

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    In this paper we establish sharp weighted bounds (Buckley type theorems) for one{sided maximal and fractional integral operators in terms of one{sided ApA_p characteristics. Appropriate sharp bounds for strong maximal functions, multiple potentials and singular integrals are derived

    Effect of Biofertilizer and Plant Spacing on Growth, Yield and Fruit Quality of Brinjal (Solanum melongena L.)

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    A field experiment “effect of biofertilizer and plant spacing on growth, yield and fruit quality of brinjal” was carried out. Four Biofertilizer levels (B1:0, B2: 6.5, B3: 8.5 and B4: 10.5L ha-1) and four Plant spacing (S1: 60×30, S2: 60×60, S3: 60×90 and S4: 60×120cm) were used. A Randomize Complete Block Design (RCBD) with split-plot arrangement was used in such a way that biofertilizer levels were subjected to main plots and plant spacing was allotted to sub plots. Biofertilizers and plant spacing significantly (P≤0.05) affected most of the attributes studied. Among the Biofertilizer treatments, maximum plant height (108.72cm), number of leaves plant-1(135.33), leaf area (90.73cm2), fruit weight (99.36gm), yield plant-1 (1.77kg), total yield (37.21tons ha-1), fruit pH (5.59), vitamin C (3.00mg) and fruit firmness (2.06kg cm-2) were recorded in biofertilizer application @6.5L ha-1. In case of different plant spacing maximum plant height (102.35cm), number of  leaves plant-1 (123.45), leaf area (86.41cm2), fruit weight plant-1 (89.54gm), yield plant-1 (1.63kg), total yield (40.64tons ha-1), fruit pH (5.44), vitamin C (2.70mg) and fruit firmness (2.05kg cm-2) were recorded in 60x60 cm. It is concluded that biofertilizer application @6.5 L ha-1 with plant spacing 60x60 cm increased the qualitative and quantitative attributes of brinjal. Keywords: Brinjal, biofertilizer, plant spacing, growth, yield, quality

    Graphene field-effect transistors for high frequency applications

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    Rapid development of wireless and internet communications requires development of new generation high frequency electronics based on new device concepts and new materials. The very high intrinsic velocity of charge carriers in graphene makes it promising new channel material for high frequency electronics.In this thesis, the graphene field-effect transistors (GFETs) are fabricated using chemical vapor deposition (CVD) graphene and investigated for high frequency electronics applications. The characterization and simulation of high frequency performance of the state-of-the-art GFETs devices are given. A modified fabrication process is used. This allows for preserving intrinsic graphene properties in the GFET channel and, simultaneously, achieving extremely low graphene/metal contact resistance. As a result, GFETs with state-of-the-art high frequency performance were fabricated and used in further analysis for development of GFETs with continuously improved performance.In particular, the dependencies between the material quality and the high-field high-frequency performance of GFETs fabricated on Si chip have been studied. It was shown, that the low-field carrier mobility can be selected as the material quality parameter. The high-frequency performance of GFETs is characterized by fT and fmax. The surface distribution of the graphene/dielectric material quality across the chip has been exploited as a tool to study the dependencies of GFET high-frequency performance on the material quality. The fT and fmax increase in the range of 20-40 GHz with low-field mobility in the range of 600-2000 cm2/V s. The dependencies are analyzed by combining the models of the drain resistance, carrier velocity, saturation velocity and small-signal equivalent circuit. Additionally, this allows for clarifying the effects of the equivalent-circuit parameters, such as contact resistance (Rc), transconductance (gm) and differential drain conductance (gds), on the fT and fmax. The observed variations of fT and fmax are mainly governed by corresponding variations of gm and gds. Analysis allows for identifying a most promising approach for improving the GFET high-frequency performance, which is selection of adjacent dielectric materials with optical phonon energy higher than that of SiO2, resulting in higher saturation velocity and, hence, higher fT and fmax

    “EFFECT OF IRRADIATION ON THE IMMUNOREGULATORY FUNCTIONS EXERTED BY TUMOUR FIBROBLASTS ON MACROPHAGES”

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    Summary Background/aim of the study: Carcinoma-associated fibroblasts (CAFs) represents a heterogeneous population of cells and are considered one of the dominant stromal component of solid tumours, performing a crucial role in tumour proliferation and metastasis. The main objective of this study was to investigate the immunoregulatory features of CAFs isolated from non-small cell lung carcinomas on macrophages and the potential effects of ionizing radiation on observed effects. Methods: The study comprise primary cultures of CAFs isolated from freshly resected NSCLC (Non Small Lung Cancer) tumours (n=8) and monocyte-derived macrophages prepared from peripheral blood of healthy donors. The experimental settings included both co-cultures and incubations of macrophages with CAF-conditioned medium. Moreover, CAF-mediated effects were studied in both uncommitted and M1-polarized macrophages. Functional assays to study macrophage polarisation included expression of cell surface markers by flow cytometry, production of nitric oxide by flow cytometry and secretion of inflammatory cytokines by ELISA. Results: All functional assays illustrated that CAFs both in co-culture and by conditioned medium, promote changes on uncommitted macrophages (M0) that harmonize with both M1 and M2 phenotypes. CAFs, both in co-culture and by conditioned medium, could inhibit some of the pro-inflammatory features of M1 macrophages as demonstrated by strong inhibition of nitric oxide production, strong inhibition of proinflammatory cytokines secretion and a reduction of some M1 surface markers. Importantly, radiation given at high dose (1x18 Gy) or in fractioned regimens (3x6 Gy) is not able to modify substantially the immunoregulatory features exerted by CAFs over macrophages in vitro. Last, protein expression analyses in CAF supernatants show that both irradiated and non-irradiated CAFs produced approximately the same levels of cytokines. Conclusion: This study display that CAFs-derived soluble factors mediate measurable changes on uncomitted macrophages (M0) and down-regulate pro-inflammatory features of M1 polarized macrophages, even though the soluble factors accountable for this shift remains unknown. On the other hand, this study also illustrates that low dose fractioned radiotherapy and single high dose radiotherapy do not curtail the immunosuppressive effect of CAFs

    Labor Market and the Job Nationalization Policy: A Trajectory of Hospitality and Tourism Strategy in Saudi Arabia

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    Saudi Arabia has a long history of dependence on foreign workers at all levels within their private sector economies. Saudi Arabia, along with Gulf states such as the UAE, are now pursuing active policies of nationalization within their labor markets in an effort to reduce dependence on foreign labor and engage the national population more actively in the workforce. The purpose of this paper is to present the latest issues relating to job nationalization in the Saudi Arabian labor market. The Saudi Arabian government, in this context, acts to ensure that certain quotas of Saudi national employees are required of private businesses in accordance with the size of their workforce as well as their performance in the field of the economy where they are located. This paper attempts to review the strategy of job nationalization known as “Saudization” and elaborate on the “Nitaqat” scheme. The discussion addresses policy procedures and highlights various impediments that exist in their implementation process. This paper extends the work of other researchers by focusing on the job nationalization policy in Saudi Arabia, and especially on discussion of the “Saudization” policy and the “Nitaqat” scheme in the context of the hospitality and tourism sector
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