1,501 research outputs found
Comment on "Regularizing capacity of metabolic networks"
In a recent paper, Marr, Muller-Linow and Hutt [Phys. Rev. E 75, 041917
(2007)] investigate an artificial dynamic system on metabolic networks. They
find a less complex time evolution of this dynamic system in real networks,
compared to networks of reference models. The authors argue that this suggests
that metabolic network structure is a major factor behind the stability of
biochemical steady states. We reanalyze the same kind of data using a dynamic
system modeling actual reaction kinetics. The conclusions about stability, from
our analysis, are inconsistent with those of Marr et al. We argue that this
issue calls for a more detailed type of modeling
NNLO QCD corrections to event orientation in e+e- annihilation
We present a new implementation of the NNLO QCD corrections to three-jet final states and related event-shape observables in electron–positron annihilation. Our implementation is based on the antenna subtraction method, and is performed in the NNLOjet framework. The calculation improves upon earlier results by taking into account the full kinematical information on the initial state momenta, thereby allowing the event orientation to be computed to NNLO accuracy. We find the event-orientation distributions at LEP and SLC to be very robust under higher order QCD corrections
Can Action Research Strengthen District Health Management and Improve Health Workforce Performance? A Research Protocol.
The single biggest barrier for countries in sub-Saharan Africa (SSA) to scale up the necessary health services for addressing the three health-related Millennium Development Goals and achieving Universal Health Coverage is the lack of an adequate and well-performing health workforce. This deficit needs to be addressed both by training more new health personnel and by improving the performance of the existing and future health workforce. However, efforts have mostly been focused on training new staff and less on improving the performance of the existing health workforce. The purpose of this paper is to disseminate the protocol for the PERFORM project and reflect on the key challenges encountered during the development of this methodology and how they are being overcome. The overall aim of the PERFORM project is to identify ways of strengthening district management in order to address health workforce inadequacies by improving health workforce performance in SSA. The study will take place in three districts each in Ghana, Tanzania and Uganda using an action research approach. With the support of the country research teams, the district health management teams (DHMTs) will lead on planning, implementation, observation, reflection and redefinition of the activities in the study. Taking into account the national and local human resource (HR) and health systems (HS) policies and practices already in place, 'bundles' of HR/HS strategies that are feasible within the context and affordable within the districts' budget will be developed by the DHMTs to strengthen priority areas of health workforce performance. A comparative analysis of the findings from the three districts in each country will add new knowledge on the effects of these HR/HS bundles on DHMT management and workforce performance and the impact of an action research approach on improving the effectiveness of the DHMTs in implementing these interventions. Different challenges were faced during the development of the methodology. These include the changing context in the study districts, competing with other projects and duties for the time of district managers, complexity of the study design, maintaining the anonymity and confidentiality of study participants as well as how to record the processes during the study. We also discuss how these challenges are being addressed. The dissemination of this research protocol is intended to generate interest in the PERFORM project and also stimulate discussion on the use of action research in complex studies such as this on strengthening district health management to improve health workforce performance
Differential NLO QCD corrections to charged current production at the LHC
Charged current Drell-Yan production at hadron colliders is a benchmark electroweak process. A recent measurement of the W boson mass by the CDF experiment displays a large deviation from the Standard Model prediction. To enable precision phenomenology for this process, we compute the third-order (NLO) QCD corrections to the rapidity distribution in W boson production and to the transverse mass distribution of its decay products. We study kinematic regions relevant for the LHC experiments and assess the numerical magnitude of uncertainties from electroweak input parameters and parton distribution functions
Differential NLO QCD corrections to charged current production at the LHC
Charged current Drell-Yan production at hadron colliders is a benchmark electroweak process. A recent measurement of the W boson mass by the CDF experiment displays a large deviation from the Standard Model prediction. To enable precision phenomenology for this process, we compute the third-order (NLO) QCD corrections to the rapidity distribution in W boson production and to the transverse mass distribution of its decay products. We study kinematic regions relevant for the LHC experiments and assess the numerical magnitude of uncertainties from electroweak input parameters and parton distribution functions
Stirring N-body systems: Universality of end states
We study the evolution of the phase-space of collisionless N-body systems
under repeated stirrings or perturbations. We find convergence towards a
limited solution group, in accordance with Hansen 2010, that is independent of
the initial system and environmental conditions, paying particular attention to
the assumed gravitational paradigm (Newtonian and MOND). We examine the effects
of changes to the perturbation scheme and in doing so identify a large group of
perturbations featuring radial orbit instability (ROI) which always lead to
convergence. The attractor is thus found to be a robust and reproducible effect
under a variety of circumstances
CDK-inhibitor independent cell cycle progression in an experimental haematopoietic stem cell leukaemia despite unaltered Rb-phosphorylation
A CD34-negative haematopoietic progenitor cell line, D064, derived from canine bone marrow stromal cells is able to differentiate into haematopoietic progenitors under the influence of growth factor-mediated signalling. While differentiating, these cells eventually start to express MHC class II molecules (DR homologues) on their surface. The stable transfection of the fibroblast-like wild-type cells with retroviral constructs containing the cDNA for the canine MHC class II DR-genes (DRA and DRB) induces a change in morphology, accelerates cell cycle progression and leads to a loss of anchorage-dependent growth. Transfected cells show features of an immature stem cell leukaemia, such as giant cell formation. In wild-type D064 cells the accumulation of the cyclin-dependent kinase inhibitor (cdki) p27kip-1 induces differentiation, which is dependent upon signalling via the ligand for the tyrosine kinase receptor c-kit (stem cell factor). DR-transfected cells instead apparently grow independently of any growth factor-mediated signals and express high levels of the cdkis p27kip-1 and especially p21waf-1/cip-1, concurrently with accelated cell cycle progression. In contrast to the overexpression of cdkis and despite accelerated cell cycle progression, the expression of the G2/M phase transition kinase p34cdc2 is significantly reduced in DR-transfected and transformed cells as compared to the haematopoietic wild-type cell line D064. This might suggest a possible alternative cell cycle progression pathway in this experimental stem cell leukaemia by by-passing the G0/G1 phase arrest, although retinoblastoma (Rb)-phosphorylation remains unaltered. These results provide evidence that mechanisms normally controlling the cell cycle and early haematopoietic differentiation are disrupted by the constitutive transcription and expression of MHC class II genes (DR) leading to a progression and growth of this experimental stem cell leukaemia independent from cell cycle controlling regulators such as p27 and p21. © 1999 Cancer Research Campaig
Optical data of meteoritic nano-diamonds from far-ultraviolet to far-infrared wavelengths
We have used different spectroscopic techniques to obtain a consistent
quantitative absorption spectrum of a sample of meteoritic nano-diamonds in the
wavelength range from the vacuum ultraviolet (0.12 m) to the far infrared
(100 m). The nano-diamonds have been isolated by a chemical treatment from
the Allende meteorite (Braatz et al.2000). Electron energy loss spectroscopy
(EELS) extends the optical measurements to higher energies and allows the
derivation of the optical constants (n & k) by Kramers-Kronig analysis. The
results can be used to restrain observations and to improve current models of
the environment where the nano-diamonds are expected to have formed. We also
show that the amount of nano-diamond which can be present in space is higher
than previously estimated by Lewis et al. (1989).Comment: 11 pages, 7 figure
Формирование супружеской дезадаптации при сексуальном фобическом неврозе у мужа
Освещены причины, условия формирования и клинические проявления вторичной супружеской дезадаптации при сексуальном фобическом неврозе у мужа. Показана роль биогенных, социогенных и негативных психологических факторов в генезе связанной с рассмотренной формой сексуального расстройства супружеской дезадаптации.The causes, conditions of forming and clinical manifestations of secondary spouse deadaptation in sexual phobic neurosis in the husband are described. The role of biogenic, sociogenic and negative mental factors in the development of spouse deadaptation associated with this form of a sexual disorder is shown
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