1,914 research outputs found

    Dealing with unexpected shocks to the budget

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    In this paper we assess the impact of unexpected shocks to real interest rates and GDP on government budgets for nine European Union countries. Shocks are estimated as onestep-ahead forecast errors arising from a recursive bivariate VAR model. To assess the impact on the budgets we use available information on budgetary sensitivities with respect to the business cycle and estimate the sensitivities to changes in interest rates on the basis of the maturity structure of public debts. Our analysis is relevant, in particular, to define what safety margins are needed to avoid the deficit exceeding the 3 per cent Maastricht threshold. The approach followed in this paper differs in two respects from standard analyses aiming at defining budgetary positions that satisfy the Stability and Growth Pact. First, whereas the latter examine only fluctuations in economic activity, we also consider fluctuations in interest rates. Second, whereas standard analyses focus on deviations from trends and define margins for the medium-term cyclically adjusted balance, we examine unexpected shocks and define margins for nominal balances. The results point to significant differences in the required margins across countries, depending on the amplitude of past shocks, the magnitude of automatic stabilizers and the size and maturity structure of the debt. In the case of Italy, the country with the highest debt/GDP ratio and the largest fraction of short-term debt, the impact of unexpected shocks to interest rates may be quite substantial. However, when shocks to interest rates and GDP are considered jointly, other countries (Belgium and Finland) seem to require larger margins.budgeting, Stability and Growth Pact, forecast errors

    Tolerance versus synaptic noise in dense associative memories

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    The retrieval capabilities of associative neural networks are known to be impaired by fast noise, which endows neuron behavior with some degree of stochasticity, and by slow noise, due to interference among stored memories; here, we allow for another source of noise, referred to as “synaptic noise,” which may stem from i. corrupted information provided during learning, ii. shortcomings occurring in the learning stage, or iii. flaws occurring in the storing stage, and which accordingly affects the couplings among neurons. Indeed, we prove that this kind of noise can also yield to a break-down of retrieval and, just like the slow noise, its effect can be softened by relying on density, namely by allowing p-body interactions among neurons

    Tolerance versus synaptic noise in dense associative memories

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    The retrieval capabilities of associative neural networks can be impaired by different kinds of noise: the fast noise (which makes neurons more prone to failure), the slow noise (stemming from interference among stored memories), and synaptic noise (due to possible flaws during the learning or the storing stage). In this work we consider dense associative neural networks, where neurons can interact in pp-plets, in the absence of fast noise, and we investigate the interplay of slow and synaptic noise. In particular, leveraging on the duality between associative neural networks and restricted Boltzmann machines, we analyze the effect of corrupted information, imperfect learning and storing errors. For p=2p=2 (corresponding to the Hopfield model) any source of synaptic noise breaks-down retrieval if the number of memories KK scales as the network size. For p>2p>2, in the relatively low-load regime KNK \sim N, synaptic noise is tolerated up to a certain bound, depending on the density of the structure.Comment: 11 pages, 7 figure

    The Role of Mesothelin Expression in Serous Ovarian Carcinoma: Impacts on Diagnosis, Prognosis, and Therapeutic Targets

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    Mesothelin (MSLN) is a protein expressed in the mesothelial cell lining of the pleura,peritoneum, and pericardium; its biological functions in normal cells are still unknown. Experimental studies using knockout mice have suggested that this molecule does not play an important role in development and reproduction. In contrast, it has been observed that this molecule is produced in abnormal amounts in several malignant neoplasms, such as mesotheliomas and pancreatic adenocarcinomas. Many molecular studies have also demonstrated that mesothelin is overexpressed in HSOCs. Here, we discuss the current knowledge of mesothelin and focus on its role in clinical and pathological diagnoses, as well as its impact on the prognosis of HSOC. Moreover, regarding the binding of MSLN to the ovarian cancer antigen CA125, which has been demonstrated in many studies, we also report on signal transduction pathways that may play an important role in the spread and neoplasticprogression of this lethal neoplasm. Given that mesothelin is overexpressed in many solid tumours and has antigenic properties, this molecule could be considered an antigenic target for the treatment of many malignancies. Consequently, we also review the literature to report on mesothelin-targeting therapies for HSOC that have been recently investigated in many clinical studies

    A case of ovarian psammocarcinoma with homolateral serous cystoadenofibroma and thecoma associated with Brenner tumour and cystoadenofibroma of the contralateral ovary

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    Psammocarcinoma of the ovary is a rare serous neoplasm, with only 32 cases reported in the international literature. Characteristically, this tumour shows extensive formation ofpsammoma bodies, low-grade cytological features, and invasion of the ovarian stroma, peritoneum or intraperitoneal viscera. The behaviour of this entity is unpredictable, with benign, low malignant and metastatic potential. Herein the authors report a case ofpsammocarcinoma of the ovary with homolateral serous cystoadenofibroma and thecoma, which were associated with Brenner tumour and adenofibroma of the contralateral ovary, in a 78-year-old woman. Thus, this example shows an unpredictable tumour associated with multiple benign epithelial neoplasms and a benign stromal tumour. Moreover, this example of psammocarcinoma is very interesting because it measures only 1.5 x 0.5 x 1.5 cm and, to the best of the author's knowledge, represents the smallest case ofpsammocarcinoma described so far in the literature

    Terrestrial Laser Scanner Resolution: Numerical Simulations and Experiments on Spatial Sampling Optimization

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    An empirical approach is proposed in order to evaluate the largest spot spacing allowing the appropriate resolution to recognize the required surface details in a terrestrial laser scanner (TLS) survey. The suitable combination of laser beam divergence and spot spacing for the effective scanning angular resolution has been studied by numerical simulation experiments with an artificial target taken from distances between 25 m and 100 m, and observations of real surfaces. The tests have been performed by using the Optech ILRIS-3D instrument. Results show that the discrimination of elements smaller than a third of the beam divergence (D) is not possible and that the ratio between the used spot-spacing (ss) and the element size (TS) is linearly related to the acquisition range. The zero and first order parameters of this linear trend are computed and used to solve for the maximum efficient ss at defined ranges for a defined TS. Despite the fact that the parameters are obtained for the Optech ILRIS-3D scanner case, and depend on its specific technical data and performances, the proposed method has general validity and it can be used to estimate the corresponding parameters for other instruments. The obtained results allow the optimization of a TLS survey in terms of acquisition time and surface details recognition
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