10,910 research outputs found

    Is friction responsible for the reduction of fusion rates far below the Coulomb barrier?

    Full text link
    The fusion of two interacting heavy ions traditionally has been interpreted in terms of the penetration of the projectile into the target. Observed rates well below the Coulomb barrier are considerably lower than estimates obtained from penetration factors. One approach in the analysis of the data invokes coupling to non-elastic channels in the scattering as the source of the depletion. Another is to analyze those data in terms of tunneling in semi-classical models, with the observed depletion being taken as evidence of a ``friction'' under the barrier. A complementary approach is to consider such tunneling in terms of a fully quantal model. We investigate tunneling with both one-dimensional and three-dimensional models in a fully quantal approach to investigate possible sources for such a friction. We find that the observed phenomenon may not be explained by friction. However, we find that under certain conditions tunneling may be enhanced or diminished by up to 50%, which finds analogy with observation, without the invocation of a friction under the barrier.Comment: 18 pages, 15 figures embedde

    A FAMILY OF CATION ATPASE-LIKE MOLECULES FROM PLASMODIUM-FALCIPARUM

    Get PDF
    Abstract. We report the nucleotide and derived amino acid sequence of the ATPase 1 gene from Plasmodium falciparum. The amino acid sequence shares homology with the family of "P-type cation transloeating ATPases in conserved regions important for nucleotide binding, conformational change, or phosphorylation. The gene, which is present on chromosome 5, has a product longer than any other reported for a P-type ATPase. Interstrain analysis from 12 parasite isolates by the polymerase chain reaction reveals that a 330-bp nucleotide sequence encoding three cytoplasmic regions conserved in cation ATPases (regions a-c) is of constant length. By contrast, another 360-bp sequence which is one of four regions we refer to as

    Observables in the Decays of B to Two Vector Mesons

    Full text link
    In general there are nine observables in the decay of a B meson to two vector mesons defined in terms of polarization correlations of these mesons. Only six of these can be detected via the subsequent decay angular distributions because of parity conservation in those decays. The remaining three require the measurement of the spin polarization of one of the decay products.Comment: 12 pages, no figur

    Top Notch Targeting Strategies in Cancer: A Detailed Overview of Recent Insights and Current Perspectives.

    Full text link
    Evolutionarily conserved Notch plays a critical role in embryonic development and cellular self-renewal. It has both tumour suppressor and oncogenic activity, the latter of which is widely described. Notch-activating mutations are associated with haematological malignancies and several solid tumours including breast, lung and adenoid cystic carcinoma. Moreover, upregulation of Notch receptors and ligands and aberrant Notch signalling is frequently observed in cancer. It is involved in cancer hallmarks including proliferation, survival, migration, angiogenesis, cancer stem cell renewal, metastasis and drug resistance. It is a key component of cell-to-cell interactions between cancer cells and cells of the tumour microenvironment, such as endothelial cells, immune cells and fibroblasts. Notch displays diverse crosstalk with many other oncogenic signalling pathways, and may drive acquired resistance to targeted therapies as well as resistance to standard chemo/radiation therapy. The past 10 years have seen the emergence of different classes of drugs therapeutically targeting Notch including receptor/ligand antibodies, gamma secretase inhibitors (GSI) and most recently, the development of Notch transcription complex inhibitors. It is an exciting time for Notch research with over 70 cancer clinical trials registered and the first-ever Phase III trial of a Notch GSI, nirogacestat, currently at the recruitment stage

    A qualitative study to investigate why patients accept or decline a copy of their referral letter from their GP

    Get PDF
    Background: Our practice in Northumberland has offered patients copies of their clinical referral letters for almost 3 years. However, many patients declined this offer and this qualitative study was conducted to determine why almost 80% of patients offered a copy of their referral letter opted not to receive one. Aim: To discover why some patients accepted and others declined a copy of the letter written from GP to specialist. Design of study: A qualitative focus-group study. Setting: General practice in Northumberland. Method: Three focus groups of referred patients were created, and discussions were taped, transcribed and analysed for major themes. Results: The patients chose to accept or decline a copy of their referral letter for diverse reasons. However, most felt that the ability to choose for themselves whether to have a copy or not was essential. Conclusions: The concept of trust in their GP was a major theme that patients related was often behind their decision to decline a copy of their letter. These results, if transferable, may have implications for the application of this policy

    H\u3csup\u3e+\u3c/sup\u3e/OH\u3csup\u3e-\u3c/sup\u3e Excretion and Nutrient Uptake in Upper and Lower Parts of Lupin (\u3cem\u3eLupinus angustifolius\u3c/em\u3e L.) Root Systems

    Get PDF
    The cultivation of narrow-leafed lupins (Lupinus angustifolius L.) increase rates of subsoil acidification, and this is thought to be partly related to their pattern of nutrient uptake and H+/OH- excretion. The main hypothesis of this study was that H+ and OH- excretion is not distributed evenly over the entire length of the root system but is limited to zones where excess cation or anion uptake occur. Seedlings of nodulated lupins were grown in solution culture using vertically split pots that allowed the upper and lower zones of the root system to be supplied with varying concentrations of K+ and NO-3. Net H+/OH- excretion was equated to the addition of NaOH/HCl required to maintain a constant pH in the nutrient solution during a 4-d treatment period and nutrient uptake was measured by depletion from solution in each zone of the split pots. The excess of cation over anion uptake was positively correlated with H+ excretion in each rooting zone. In zones where K+ was supplied at 1200 µM, cation uptake was dominated by K+ and up to twice as much H+ was excreted than in zones where K+ was absent. In zones where NO-3 was supplied at 750 µM, the anion/cation uptake was balanced, however H+ excretion continued to occur in the zone. When NO-3 was supplied at 5000 µM, anion uptake exceeded cation uptake but there was no OH- excretion. Organic acid anions may be excreted by lupins to maintain their internal electroneutrality when anion uptake exceeds cation uptake. Rhizosphere pH would not increase unless the pKa of the excreted organic anions was greater than the external pH

    Fixed Asset Accounting Software Evaluation: A Structured Methodology For The Mid-Market Firm

    Get PDF
    Packaged software evaluation represents a major decision for business.  It involves a number of quantitative as well as qualitative attributes in choosing among system alternatives.  This paper illustrates an evaluation methodology for accounting software selection, specifically a fixed asset system.  The methodology incorporates three stages:  1) software screening; 2) detail package evaluation; and, 3) confirmation and design (also known as a test drive).  Initially, developing a short list through screening of accounting software determines whether an appropriate package exists and narrows the field of available fixed asset products for detailed consideration.  The second stage determines which of the remaining fixed asset systems (the finalists) best meets the needs of the organization, from both functional and technical perspectives. The final stage, or phase, compares user requirements with the features of the selected fixed asset software by determining how these requirements will be satisfied by specific applications built using the fixed asset software.  The methodology also controls for the possibility that no fixed asset software product is suitable and that such a system must be constructed on a custom basis. No other reported evaluation and selection approach offers this device.  A case example demonstrating the applicability of the suggested methodology is given for a mid-sized hospital organization representing the largest market segment for accounting software

    Product Service System Innovation in the Smart City

    Get PDF
    Product service systems (PSS) may usefully form part of the mix of innovations necessary to move society toward more sustainable futures. However, despite such potential, PSS implementation is highly uneven and limited. Drawing on an alternate socio-technical perspective of innovation, this paper provides fresh insights, on among other things the role of context in PSS innovation, to address this issue. Case study research is presented focusing on a use orientated PSS in an urban environment: the Copenhagen city bike scheme. The paper shows that PSS innovation is a situated complex process, shaped by actors and knowledge from other locales. It argues that further research is needed to investigate how actors interests shape PSS innovation. It recommends that institutional spaces should be provided in governance landscapes associated with urban environments to enable legitimate PSS concepts to co-evolve in light of locally articulated sustainability principles and priorities
    corecore