1,266 research outputs found

    Entrepreneurial intentions among students: towards a re-focused research agenda

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    Purpose – This paper aims to address the need for a re-focused research agenda in relation to graduate entrepreneurship. An important theme for some years has been the effort to monitor attitudes and intentions of students towards starting up their own businesses. It is timely, however, to raise some questions about both the impact of this research and likewise the general approach it has taken in understanding the phenomenon of graduate entrepreneurship. Design/methodology/approach – The paper draws on a large data set (over 8,000 students) from one UK region. Specifically, it presents data from the 2007/2008 Entrepreneurial Intentions (EI) survey within the Yorkshire and Humberside region and reflects back over previous iterations of this research. Findings – The paper identifies three key outcomes. First, it establishes that across all years of the survey a substantial minority of students consistently hold relatively strong start-up intentions. Second, the paper highlights that, despite considerable efforts to increase the numbers moving to start-up, little impact is discernible. Third, the paper suggests that, although the EI survey is useful as a stock-taking exercise, it fails to address critical questions around the impact of higher education on entrepreneurship and the transition from entrepreneurial intent to the act of venture creation. Originality/value – The paper provides an important positioning perspective on the relationship between higher education and graduate entrepreneurship. While highlighting the importance of the EI research, the paper establishes the need for a re-focused research agenda; one that is conceptually robust and with a focus on the student journey from higher education to graduate entrepreneur

    Ground and excited states Gamow-Teller strength distributions of iron isotopes and associated capture rates for core-collapse simulations

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    This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for 54,55,56^{54,55,56}Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic \textit{state-by-state} calculation of GT strength functions and stellar capture rates which greatly increases the reliability of the results. For the first time experimental deformation of nuclei are taken into account. In the core of massive stars isotopes of iron, 54,55,56^{54,55,56}Fe, are considered to be key players in decreasing the electron-to-baryon ratio (YeY_{e}) mainly via electron capture on these nuclide. The structure of the presupernova star is altered both by the changes in YeY_{e} and the entropy of the core material. Results are encouraging and are compared against measurements (where possible) and other calculations. The calculated electron capture rates are in overall good agreement with the shell model results. During the presupernova evolution of massive stars, from oxygen shell burning stages till around end of convective core silicon burning, the calculated electron capture rates on 54^{54}Fe are around three times bigger than the corresponding shell model rates. The calculated positron capture rates, however, are suppressed by two to five orders of magnitude.Comment: 18 pages, 12 figures, 10 table

    rp-Process weak-interaction mediated rates of waiting-point nuclei

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    Electron capture and positron decay rates are calculated for neutron-deficient Kr and Sr waiting point nuclei in stellar matter. The calculation is performed within the framework of pn-QRPA model for rp-process conditions. Fine tuning of particle-particle, particle-hole interaction parameters and a proper choice of the deformation parameter resulted in an accurate reproduction of the measured half-lives. The same model parameters were used to calculate stellar rates. Inclusion of measured Gamow-Teller strength distributions finally led to a reliable calculation of weak rates that reproduced the measured half-lives well under limiting conditions. For the rp-process conditions, electron capture and positron decay rates on 72^{72}Kr and 76^{76}Sr are of comparable magnitude whereas electron capture rates on 78^{78}Sr and 74^{74}Kr are 1--2 orders of magnitude bigger than the corresponding positron decay rates. The pn-QRPA calculated electron capture rates on 74^{74}Kr are bigger than previously calculated. The present calculation strongly suggests that, under rp-process conditions, electron capture rates form an integral part of weak-interaction mediated rates and should not be neglected in nuclear reaction network calculations as done previously.Comment: 13 pages, 4 figures, 4 tables; Astrophysics and Space Science (2012

    Neutrino energy loss rates and positron capture rates on 55^{55}Co for presupernova and supernova physics

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    Proton-neutron quasi-particle random phase approximation (pn-QRPA) theory has recently being used for calculation of stellar weak interaction rates of fpfp-shell nuclide with success. Neutrino losses from proto-neutron stars play a pivotal role to decide if these stars would be crushed into black holes or explode as supernovae. The product of abundance and positron capture rates on 55^{55}Co is substantial and as such can play a role in fine tuning of input parameters of simulation codes specially in the presupernova evolution. Recently we introduced our calculation of capture rates on 55^{55}Co, in a luxurious model space of 7ℏω7 \hbar \omega, employing the pn-QRPA theory with a separable interaction. Simulators, however, may require these rates on a fine scale. Here we present for the first time an expanded calculation of the neutrino energy loss rates and positron capture rates on 55^{55}Co on an extensive temperature-density scale. These type of scale is appropriate for interpolation purposes and of greater utility for simulation codes. The pn-QRPA calculated neutrino energy loss rates are enhanced roughly up to two orders of magnitude compared with the large-scale shell model calculations and favor a lower entropy for the core of massive stars.Comment: 27 pages, 6 figures, 5 table

    Chromosome 9p deletion in clear cell renal cell carcinoma predicts recurrence and survival following surgery

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    BACKGROUND: Wider clinical applications of 9p status in clear cell renal cell carcinoma (ccRCC) are limited owing to the lack of validation and consensus for interphase fluorescent in situ hybridisation (I-FISH) scoring technique. The aim of this study was to analytically validate the applicability of I-FISH in assessing 9p deletion in ccRCC and to clinically assess its long-term prognostic impact following surgical excision of ccRCC. METHODS: Tissue microarrays were constructed from 108 renal cell carcinoma (RCC) tumour paraffin blocks. Interphase fluorescent in situ hybridisation analysis was undertaken based on preset criteria by two independent observers to assess interobserver variability. 9p status in ccRCC tumours was determined and correlated to clinicopathological variables, recurrence-free survival and disease-specific survival. RESULTS: There were 80 ccRCCs with valid 9p scoring and a median follow-up of 95 months. Kappa statistic for interobserver variability was 0.71 (good agreement). 9p deletion was detected in 44% of ccRCCs. 9p loss was associated with higher stage, larger tumours, necrosis, microvascular and renal vein invasion, and higher SSIGN (stage, size, grade and necrosis) score. Patients with 9p-deleted ccRCC were at a higher risk of recurrence (P=0.008) and RCC-specific mortality (P=0.001). On multivariate analysis, 9p deletion was an independent predictor of recurrence (hazard ratio 4.323; P=0.021) and RCC-specific mortality (hazard ratio 4.603; P=0.007). The predictive accuracy of SSIGN score improved from 87.7% to 93.1% by integrating 9p status to the model (P=0.001). CONCLUSIONS: Loss of 9p is associated with aggressive ccRCC and worse prognosis in patients following surgery. Our findings independently confirm the findings of previous reports relying on I-FISH to detect 9p (CDKN2A) deletion

    ASSESSMENT OF TEMPORAL FLOW VARIABILITY OF THE KABUL RIVER

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    Water resources estimation under changing flow regimes is required for planning and smooth distribution of water to provinces. Since the hydrological parameters are changing significantly due to climate change, the changes in the pattern of flow regimes are definite. The objective of present study was to assess the spatial and temporal hydro variability of Indus basin. The data of Kabul river at Nowshera before its confluence with Indus river were collected from Surface water Hydrology Project (SWHP), WAPDA. The seasons were divided as three and six month keeping in view the hydrological cycle. Trends and variation were investigated by applying the Mann-Kendall test and Sen’s method. The presence of trends tested at different significant level, 99.9%, 95% and 90%. The overall analysis indicates that there is more flow variation on seasonal basis as compared to the annual basis. The Kabul river showed decreasing trend in the maximum mean annual discharge, whereas the minimum mean annual discharge showed increasing trend. It was concluded that Kabul river showed decreasing trend in annual mean and maximum discharge, whereas annual minimum discharge showed increasing trend. It was also noticed that Kabul river mean minimum discharge time series decreased during 1961-1985, whereas it increased during 1986-2010. It was also found that annual mean and maximum discharge decreasing rate was greater during 1986-2010. It was further concluded that each decade experienced one or two years of both dry and wet periods and that 2000-2004 was the driest period in the history of Kabul River

    Comparative study of Gamow-Teller strength distributions in the odd-odd nucleus 50V and its impact on electron capture rates in astrophysical environments

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    Gamow-Teller (GT) strength transitions are an ideal probe for testing nuclear structure models. In addition to nuclear structure, GT transitions in nuclei directly affect the early phases of Type Ia and Type-II supernovae core collapse since the electron capture rates are partly determined by these GT transitions. In astrophysics, GT transitions provide an important input for model calculations and element formation during the explosive phase of a massive star at the end of its life-time. Recent nucleosynthesis calculations show that odd-odd and odd-A nuclei cause the largest contribution in the rate of change of lepton-to-baryon ratio. In the present manuscript, we have calculated the GT strength distributions and electron capture rates for odd-odd nucleus 50V by using the pn-QRPA theory. At present 50V is the first experimentally available odd-odd nucleus in fp-shell nuclei. We also compare our GT strength distribution with the recently measured results of a 50V(d,2He)50Ti experiment, with the earlier work of Fuller, Fowler, and Newman (referred to as FFN) and subsequently with the large-scale shell model calculations. One curious finding of the paper is that the Brink's hypothesis, usually employed in large-scale shell model calculations, is not a good approximation to use at least in the case of 50V. SNe Ia model calculations performed using FFN rates result in overproduction of 50Ti, and were brought to a much acceptable value by employing shell model results. It might be interesting to study how the composition of the ejecta using presently reported QRPA rates compare with the observed abundances.Comment: 16 pages, 5 figure

    Discrimination of healthy and cancer cells of the bladder by metabolic state, based on autofluorescence

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    Bladder cancer is among the most common cancers worldwide (4th in men). It is responsible for high patient morbidity and displays rapid recurrence and progression. Lack of sensitivity of gold standard techniques (white light cystoscopy, voided urine cytology) means many early treatable cases are missed. The result is a large number of advanced cases of bladder cancer which require extensive treatment and monitoring. For this reason, bladder cancer is the single most expensive cancer to treat on a per patient basis. In recent years, autofluorescence spectroscopy has begun to shed light into disease research. Of particular interest in cancer research are the fluorescent metabolic cofactors NADH and FAD. Early in tumour development, cancer cells often undergo a metabolic shift (the Warburg effect) resulting in increased NADH. The ratio of NADH to FAD ("redox ratio") can therefore be used as an indicator of the metabolic status of cells. Redox ratio measurements have been used to differentiate between healthy and cancer breast cells and to monitor cellular responses to therapies. Here, we have demonstrated, using healthy and bladder cancer cell lines, a statistically significant difference in the redox ratio of bladder cancer cells, indicative of a metabolic shift. To do this we customised a standard flow cytometer to excite and record fluorescence specifically from NADH and FAD, along with a method for automatically calculating the redox ratio of individual cells within large populations. These results could inform the design of novel probes and screening systems for the early detection of bladder cancer

    Quantitative proteomics in resected renal cancer tissue for biomarker discovery and profiling

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    <b>Background:</b>Β Β Proteomics-based approaches for biomarker discovery are promising strategies used in cancer research. We present state-of-art label-free quantitative proteomics method to assess proteome of renal cell carcinoma (RCC) compared with noncancer renal tissues.<p></p> <b>Methods:</b>Β Β Fresh frozen tissue samples from eight primary RCC lesions and autologous adjacent normal renal tissues were obtained from surgically resected tumour-bearing kidneys. Proteins were extracted by complete solubilisation of tissues using filter-aided sample preparation (FASP) method. Trypsin digested proteins were analysed using quantitative label-free proteomics approach followed by data interpretation and pathways analysis.<p></p> <b>Results:</b>Β Β A total of 1761 proteins were identified and quantified with high confidence (MASCOT ion score threshold of 35 and P-value <0.05). Of these, 596 proteins were identified as differentially expressed between cancer and noncancer tissues. Two upregulated proteins in tumour samples (adipose differentiation-related protein and Coronin 1A) were further validated by immunohistochemistry. Pathway analysis using IPA, KOBAS 2.0, DAVID functional annotation and FLink tools showed enrichment of many cancer-related biological processes and pathways such as oxidative phosphorylation, glycolysis and amino acid synthetic pathways.<p></p> <b>Conclusions:<b>Β Β Our study identified a number of differentially expressed proteins and pathways using label-free proteomics approach in RCC compared with normal tissue samples. Two proteins validated in this study are the focus of on-going research in a large cohort of patients.<p></p&gt
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