3,278 research outputs found
Peano Corto and Peano Basso: A Study of local induction in the context of weak theories
No full textIn this paper we study local induction w.r.t. Σ1-formulas over the weak arithmetic PA- The local induction scheme, which was introduced in, says roughly this: for any virtual class X that is progressive, i.e., is closed under zero and successor, and for any non-empty virtual class Y that is definable by a Σ1-formula without parameters, the intersection of X and Y is non-empty. In other words, we have, for all Σ1-sentences S, that S implies SX, whenever X is progressive. Since, in the weak context, we have (at least) two definitions of Σ1, we obtain two minimal theories of local induction w.r.t. Σ1-formulas, which we call Peano Corto and Peano Basso. In the paper we give careful definitions of Peano Corto and Peano Basso. We establish their naturalness both by giving a model theoretic characterization and by providing an equivalent formulation in terms of a sentential reflection scheme. The theories Peano Corto and Peano Basso occupy a salient place among the sequential theories on the boundary between weak and strong theories. They bring together a powerful collection of principles that is locally interpretable in PA- Moreover, they have an important role as examples of various phenomena in the metamathematics of arithmetical (and, more generally, sequential) theories. We illustrate this by studying their behavior w.r.t. interpretability, model interpretability and local interpretability. In many ways the theories are more like Peano arithmetic or Zermelo Fraenkel set theory, than like finitely axiomatized theories as Elementary Arithmetic, |Σ1 and ACA0. On the one hand, Peano Corto and Peano Basso are very weak: they are locally cut-interpretable in PA- On the other hand, they behave as if they were strong: they are not contained in any consistent finitely axiomatized arithmetical theory, however strong. Moreover, they extend IΠ1-, the theory of parameter-free Π1-induction
Economic and environmental evaluation of site-specific tillage in a maize crop in NE Italy
No full textThe integration of site-specific management principles and conservation tillage practices is a rather unex- ploited field of research despite their economical and environmental benefits. The objectives of this research were: (1) to investigate the farm economic net return of three conservation tillage practices (NIT – Non-Inversion Tillage, MT – Minimum Tillage and NT – No-Tillage) performed at variable intensity within predefined management zones; the HS – area with a consistently higher yield and LS – area with a consistently low yield, of a maize (Zea mays, L.) field in NE-Italy (2) to identify the most economically sound tillage practice for each management zone using long-term simulation results; (3) to assess the environmental impact of the three tillage systems with regards to soil organic carbon changes, CO2 losses and nitrate leaching using the SALUS model.
Field trials were carried out on an 8-ha flat field, situated near Rovigo, NE Italy, on maize (Z. mays, L.). The farm gross margin was higher for NT in the year of study as well as the long-term simulated scenarios that resulted in higher yields over time. The NT tillage practices resulted in higher economic return in the both the HS and LS areas. Total soil carbon was higher in NT due to the crop residues retained on the surface. Nitrate leaching was higher in for the MT and for the LS area
Author Attributions in Medieval Text Collections: An Exploration
No full textThis article examines the role and function of author attributions in multi-text manuscripts containing Dutch, English, French or German short verse narratives. The findings represent one strand of the investigations undertaken by the cross-European project ‘The Dynamics of the Medieval Manuscript’, which analysed the dissemination of short verse narratives and the principles of organisation underlying the compilation of text collections. Whilst short verse narratives are more commonly disseminated anonymously, there are manuscripts in which authorship is repeatedly attributed to a text or corpus. Through six case studies, this article explores medieval concepts of authorship and how they relate to constructions of authority, whether regarding an empirical figure or a literary construction. In addition, it looks at how authorship plays a role in manuscript compilation, and at the effects of attributions (by author and/or compiler) on reception. The case studies include manuscripts from the thirteenth to fifteenth centuries, produced in a range of social and cultural contexts, and featuring some of the most important European authors of short verse narratives: Rutebeuf, Baudouin de Condé, Der Striker, Konrad von Würzberg, Willem of Hildegaersberch, and Geoffrey Chaucer. The preliminary findings contribute to our understanding of author attributions in text collections from across northern Europe and point towards future lines of enquiry into the role of authorship in medieval textual dissemination
Analyzing the effects of climate variability on spatial pattern of yield in a maize-wheat-soybean rotation
No full textThe identification of homogeneous management zones within a field is crucial for variable rate application of agronomic inputs. This study 12 proposed a methodology to identify homogeneous management zones within a 8 ha field, based on the stability of measured and simulated yield 13 patterns in a maize–soybean–wheat crop rotation in north-east Italy. Crop growth and yield were simulated over a 14-year period (1989–2002) using 14 CERES-Maize, CROPGRO-Soybean and CERES-Wheat models to account for weather effects on yield spatial patterns. The overlay of long-term 15 assessments of yield spatial and temporal data allowed for the identification of two stable zones with different yield levels, one with greater yield 16 (called HS for high and stable yield) and one with lower yield (called LS for low and stable yield). The size of the HS zone identified using 14 17 years of simulated yield was smaller than the one obtained when considering only yield monitor data taken during the 5-year crop rotation. The LS 18 zone was larger when using simulated data, confirming that the consistency of temporal stability increased by increasing the years considered. The 19 models were able to closely simulate yield across the field when site-specific inputs were used, showing potential for use in yield map interpretation 20 in the context of precision agriculture. Results showed that a combination of GIS tools and crop growth simulation models can be used to identify 21 temporally stable zones, which is a fundamental prerequisite for adopting variable rate technologies
Batch Bayesian Learning of Large-Scale LS-SVMs Based on Low-rank Tensor Networks
No full textLeast Squares Support Vector Machines (LS-SVMs) are state-of-the-art learning algorithms that have been widely used for pattern recognition. The solution for an LS-SVM is found by solving a system of linear equations, which involves the computational complexity of O(N^3). When datasets get larger, solving LS-SVM problems with standard methods becomes burdensome or even unfeasible. The Tensor Train (TT) decomposition provides an approach to representing data in highly compressed formats without loss of accuracy. By converting vectors and matrices in the TT format, the storage and computational requirements can be greatly reduced. In this thesis, we develop a Bayesian learning method in the TT format to solve large-scale LS-SVM problems, which involves the computation of a matrix inverse. This method allows us to include the information we know about the model parameters in the prior distribution. As a result, we are able to obtain a probability distribution of the parameters, which enables us to construct confidence levels of the predictions. In the numerical experiment, we show that the developed method performs competitively with the current methods.Mechanical Engineering | Systems and Contro
Additive Manufacturing: Polymers Applicable for Laser Sintering (LS)
No full textAbstractAdditive Manufacturing (AM) is close to become a production technique changing the way of part fabrication in future. Enhanced complexity and personalized features are aimed. The expectations in AM for the future are enormous and betimes it is considered as kind of the next industrial revolution. Laser Sintering (LS) of polymer powders is one component of the AM production techniques. However materials successfully applicable to Laser Sintering (LS) are very limited today. The presentation picks up this topic and gives a short introduction on the material available today. Important factors of polymer powders, their significance for effective LS processing and analytical approaches to access those values are presented in the main part. Concurrently the exceptional position of polyamide 12 powders is this connection is outlined
The Social Cost-of-Living: Welfare Foundations and Estimation
No full textWe present a new class of social cost-of-living indices and a nonparametric framework for estimating these and other social cost-of- living indices. Common social cost-of-living indices can be understood as aggregator functions of approximations of individual cost-of-living indices. The Consumer Price Index (CPI) is the expenditure-weighted average of first-order approximations of each individual’s cost-of-living index. This is troubling for three reasons. First, it has not been shown to have a welfare economic foundation for the case where agents are heterogeneous (as they clearly are.) Second, it uses an expenditure-weighted average which downweights the experience of poor households relative to rich households. Finally, it uses only first-order approximations of each individual’s cost-of-living index, and thus ignores substitution effects. We propose a “common-scaling” social cost-of-living index, which is defined as the single scaling to everyone’s expenditure which holds social welfare constant across a price change. Our approach has an explicit social welfare foundation and allows us to choose the weights on the costs of rich and poor households. We also give a unique solution for the welfare function for the case where the weights are independent of household expenditure. A first order approximation of our social cost-of- living index nests as special cases commonly used indices such as the CPI. We also provide a nonparametric method for estimating second- order approximations (which account for substitution effects).Inflation, Social cost-of-living, Demand, Average Derivatives
Short- and long-term changes in bone mineral density of the lumbar spine after parathyroidectomy in patients with primary hyperparathyroidism
No full textThe aims of this study were (1) to analyze whether correlations exist between lumbar spine (LS) bone mineral density (BMD) and the main preoperative biochemical parameters in a large population of patients with primary hyperparathyroidism (HPT); and (2) to evaluate the LS-BMD changes after parathyroidectomy (PTx) at long-term follow-up. Sixty-two patients (median age 57 years, range 23-82 years) with confirmed primary HPT underwent LS osteodensitometry by dual-energy X-ray absorptiometry with BMD measurements at the L2-L4 region before surgery and at 1 year and 2 years after successful PTx. Three groups of patients were considered: Group A (men, n = 14, 22.6%), Group B (premenopausal women, n = 12, 19.3%), and Group C (postmenopausal women, n = 36, 58.1%). There were no linear correlations (P = NS) among the main biochemical parameters, the age of the patients, and their baseline LS-BMD values that were significantly (P < 0.01) lower in Group C patients. At 2-year follow-up the LS-BMD improved by 13.0%, 11.5%, and 11.7% in Groups A, B, and C, respectively (P = NS). In order to compare groups with the same linear relationship between age and LS-BMD, a subgroup of postmenopausal patients aged < or = 60 years (Group C2) was considered. ANOVA showed that the improvement of the LS-BMD at 1- and 2-year follow-up was higher (P = 0.002) in Group B than in Group C2 patients. The result was confirmed by using the Mann-Whitney U-test (P = 0.0078). Improvement of LS-BMD after successful PTx was significantly (P < 0.01) higher in premenopausal women, suggesting a possible role of estrogen hormone in complete bone remodeling
The Social Cost-of-Living: Welfare Foundations and Estimation
No full textWe present a new class of social cost-of-living indices and a nonparametric framework for estimating these and other social cost-of-living indices. Common social cost-of-living indices can be understood as aggregator functions of approximations of individual cost-of-living indices. The Consumer Price Index (CPI) is the expenditure-weighted average of first-order approximations of each individual’s cost-of-living index. This is troubling for three reasons. First, it has not been shown to have a welfare economic foundation for the case where agents are heterogeneous (as they clearly are.) Second, it uses an expenditure-weighted average which downweights the experience of poor households relative to rich households. Finally, it uses only first-order approximations of each individual’s cost-of-living index, and thus ignores substitution effects. We propose a “common-scaling” social cost-of-living index, which is defined as the single scaling to everyone’s expenditure which holds social welfare constant across a price change. Our approach has an explicit social welfare foundation and allows us to choose the weights on the costs of rich and poor households. We also give a unique solution for the welfare function for the case where the weights are independent of household expenditure. A first order approximation of our social cost-of-living index nests as special cases commonly used indices such as the CPI. We also provide a nonparametric method for estimating second-order approximations (which account for substitution effects).Inflation, Social cost-of-living, Demand, Average derivatives
Relationship between bone mineral density, PTH, 25(OH)D and IGF-1 serum levels in elderly men with osteoporosis: results from a preliminary study
No full textBackground: Osteoporosis is relatively rare among men, but represents one of the leading causes of morbidity and mortality among elderly men. The precocious recognition of patients at increased risk of fracture is still a challenge for physicians. In this preliminary study we evaluated the relationship between bone mineral density (BMD), parathyroid hormone (PTH), 25-Hydroxyvitamin D [25(OH)D] and insulin-like growth factor-1 (IGF-1) serum levels in a group of osteoporotic men (≥65 years old).
Patients and Methods: A group of 15 elderly men (median age 68 years, range 65-74 years) with confirmed osteoporosis (LS T-score below ‒2SD) underwent PTH, 25(OH)D and IGF-1 serum levels measurement. As previously reported, PTH was analyzed by an immunometric assay (Intact PTH Bridge, Adaltis, Bologna, Italy) with a detection limit 10 pg/mL and inter- and intra-assay CV of 4% and 3.5%, respectively. 25(OH)D was determined by a radioimmunoassay (RIA) (25-hydroxyvitamin D 125I RIA kit, DiaSorin, Stillwater, MN, USA), detection limit 5 nmol/L and inter- and intra-assay CV of 9%. Serum IGF-I was measured by a immunoradiometric method (IGF-1 kit, Immunotech, Marseille, France) with detection limit 10 ng/mL and inter- and intra-assay CV of 11% and 4%, respectively. The evaluation of lumbar spine (LS) bone mineral density (BMD) was obtained with dual-energy X-ray absorptiometry (DXA) in all patients.
Results: The results were the following: LS-BMD=0.777±0.060 g/cm2, PTH=75.2±8.3 pg/mL, 25(OH)D=365.1±134.4 nmol/L, IGF-1=201.3±55.3 ng/mL. No correlation was found between age and LS-BMD (R=‒0.034, p=0.91), PTH (R=0.276, p=0.31), 25(OH)D (R=‒0.235, p=0.40), IGF-1 (R=0.219, p=0.43). No correlation between 25(OH)D and BMD (R=0.278, p=0.32), PTH (R=0.036, p=0.88), IGF-1 (R=0.032, p=0.91), and between IGF-1 and PTH (R=0.292, p=0.29). There was e significant inverse relationship between BMD and both PTH (R=‒0.511, p=0.047) and IGF-1 (R=‒0.662, p=0.007)
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