3,676 research outputs found

    The Role of Social Institutions in Determining Aid Effectiveness

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    In recent years, scholars and policymakers have placed growing attention on the issue of aid effectiveness, that is, the efficiency of donor assistance in achieving stated economic and human development objectives. While research has tended to highlight the need for greater capacity building and improved governance as mechanisms to make aid 'effective', the social origins of such mechanisms have not been thoroughly examined. Using the latest cross- country indicator series on aid effectiveness from the OECD and the Indices of Social Development, hosted at the Institute of Social Studies in the Hague, this paper examines the determinants of effective aid spending, and finds a significant effect linking the quality of aid assistance to social institutions relating to public order and trust. These effects are verified when instrumenting social ins

    Inelastic Quantum Transport and Peierls-like Mechanism in Carbon Nanotubes

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    We report on a theoretical study of inelastic quantum transport in (3m,0)(3m,0) carbon nanotubes. By using a many-body description of the electron-phonon interaction in Fock space, a novel mechanism involving optical phonon emission (absorption) is shown to induce an unprecedented energy gap opening at half the phonon energy, ω0/2\hbar\omega_{0}/2, above (below) the charge neutrality point. This mechanism, which is prevented by Pauli blocking at low bias voltages, is activated at bias voltages in the order of ω0\hbar\omega_{0}.Comment: 4 pages, 4 figure

    Follicular lymphoma

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    Methodology of the Indices of Social Development

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    In recent years, international organizations, think-tanks, and the social sciences have contributed to a dramatic expansion in the range of composite indices measuring concepts such as human development, governance, or social capital. This paper discusses challenges faced in the design of composite indices, and suggests the method known as matching pe

    A search in the COS-B data base for correlated time variability in regions containing objects of interest

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    As is well known, association of the gamma-ray sources with celestial objects is, in general, difficult on a pure positional basis, while correlated time variability could obviously provide such proof. This technique can be employed on regions of the gamma-ray sky containing interesting objects of known variability at some wavelength even in the absence of a recognized gamma-ray excess with the aim to extract a weak but predictable signal from the surrounding noise. This technique is applied here on a longer variability time scale, generally of the order of days. Photons coming from the sky regions centered on the various celestial objects considered were selected with energies 100 MeV and with arrival directions within an energy-dependent area of radius of approx 6 deg at 100 MeV. In order to construct a time profile of such photons, their arrival times were grouped in bins of dimensions defined by the available photons number and by the value of the period searched for

    IL2 treatment for cancer: from biology to gene therapy.

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    In this review we shall discuss the biological rationale and the clinical findings obtained using Interleukin 2 (IL2)-based immunotherapy in the management of cancer patients. Objective and long-lived clinical responses have been documented in a proportion of cases, particularly renal cell carcinoma, melanoma and acute myeloid leukaemia. Though encouraging, the clinical use of IL2 has so far been limited by toxicity, as well as by the heterogeneous and unpredictable responses and by the lack of specific anti-tumour effect. These considerations have led to the belief that more sophisticated technologies aimed at introducing the IL2 gene into the neoplastic cells may potentially overcome some of the limitations coupled to the in vivo infusion of high doses of IL2. The data accumulated in animal models and, more recently, also with human tumour cells indicate that the IL2 gene may be successfully inserted into neoplastic cells. The constitutive secretion of IL2 by the tumour cells leads to a reduced or abrogated tumorigenicity in several different tumour models. The evidence that in some experimental tumours the transduction of the IL2 gene into the neoplastic cells may elicit a specific cytotoxic response and confer anti-tumour memory, suggests that vaccination protocols based on this innovative strategy may represent a potential new tool in the management of cancer patients

    Social Institutions as a Form of Intangible Capital

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    In recent years there has been growing interest in including estimates of "intangible" capital, such as knowledge, skills, and institutions, in national asset accounting. In accordance with these efforts, this paper attempts to provide the first worldwide evaluations of "social" institutions, understood as the norms and networks that reduce transaction costs and enable collec

    AC transport in graphene-based Fabry-Perot devices

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    We report on a theoretical study of the effects of time-dependent fields on electronic transport through graphene nanoribbon devices. The Fabry-P\'{e}rot interference pattern is modified by an ac gating in a way that depends strongly on the shape of the graphene edges. While for armchair edges the patterns are found to be regular and can be controlled very efficiently by tuning the ac field, samples with zigzag edges exhibit a much more complex interference pattern due to their peculiar electronic structure. These studies highlight the main role played by geometric details of graphene nanoribbons within the coherent transport regime. We also extend our analysis to noise power response, identifying under which conditions it is possible to minimize the current fluctuations as well as exploring scaling properties of noise with length and width of the systems

    Directional photoelectric current across the bilayer graphene junction

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    A directional photon-assisted resonant chiral tunneling through a bilayer graphene barrier is considered. An external electromagnetic field applied to the barrier switches the transparency TT in the longitudinal direction from its steady state value T=0 to the ideal T=1 at no energy costs. The switch happens because the a.c. field affects the phase correlation between the electrons and holes inside the graphene barrier changing the whole angular dependence of the chiral tunneling (directional photoelectric effect). The suggested phenomena can be implemented in relevant experiments and in various sub-millimeter and far-infrared optical electronic devices.Comment: 7 pages 5 figure

    Imaging of biliary involvement in sarcoidosis: Computed tomography, magnetic resonance cholangiopancreatography, and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging findings

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    Sarcoidosis is a multisystem disease usually affecting the chest, hilar lymph nodes, and lungs, but can potentially involve any organ; therefore, its clinical presentation may vary. Hepato-biliary involvement is rare, and typically asymptomatic; however, it can lead to cirrhosis, and may require liver transplantation. In this report, we present a rare case of a patient affected by sarcoidosis with hepatobiliary involvement. He presented to our hospital complaining of dyspnea triggered by moderate efforts and oppressive thoracic discomfort. Chest X-ray showed multiple bilateral nodular opacities and enlargement of both hilar regions, confirmed by a subsequent total-body computed tomography scan and positron emission tomography, which also revealed cardiac, splenic, and hepatic involvement. Liver function was studied via gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging, and magnetic resonance cholangiopancreatography (MRCP) was also performed. The diagnosis of sarcoidosis was finally achieved via liver biopsy, revealing non-necrotizing granulomas in the periportal space. The patient was treated with prednisone per os, with regression of all lesions at all levels. Although other cases of biliary sarcoidosis have been described, this report provides a complete image set of Gd-EOB-DTPA-enhanced magnetic resonance and MRCP images that is lacking in the English literature, and which may be useful for diagnosis
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