Credit scoring: Does XGboost outperform logistic regression?A test on Italian SMEs

The old-fashioned logistic regression is still the most used method for credit scoring. Recent developments have evolved new instruments coming from the machine learning approach, including random forests. In this paper, we tested the efficiency of logistic regression and XGBoost methods for default forecasting on a sample of 35,535 cases from 7 different business sectors of Italian SMEs, on a set of 28 banking variables and 55 balance sheet ratios for verifying which approach is better supporting the lending decisions. With this aim, we developed an efficiency index for measuring each model's capability to correctly select good borrowers, balancing the different effects of refusing the loan to a good customer and lending to a defaulter. Also, we computed the balancing spread to quantify the different models' efficiency in terms of credit costs for the borrower firms. Results show that different sectors report different results. However, generally speaking, the two methods report similar capabilities, while the cutoff setting can make a substantial difference in the actual use of those models for lending decisions

India - Effective incentives in India's agriculture : cotton, groundnuts, wheat and rice

This study explicity considers the possibilities of international trade in evaluating the impact of incentives in agriculture. Specifically, the study estimates three standard coefficients (ratios): (a) the nominal protection coefficient (NPC); (b) the effective protection coefficient (EPC); and (c) the effective subsidy coefficient (ESC). The study also includes estimates of the nominal protection coefficient adjusted for a premium on foreign exchange (ANPC) and some discussion of how such a premium would affect the EPCs and ESCs. Four commodities are covered in this study; wheat, rice, cotton and groundnuts. The estimates for the protection coefficients for the four commodities for the 1980s are summarized, and estimates of comparable domestic and world prices are given. Cotton, and to a lesser extent wheat and rice, have been disprotected during the 1980s while groundnuts have received substantial protection. The study also raises a number of important issues that deserve further research.Economic Theory&Research,Environmental Economics&Policies,Crops&Crop Management Systems,Agricultural Research,Access to Markets

Landscaping with fluxes and the E8 Yukawa Point in F-theory

Integrality in the Hodge theory of Calabi-Yau fourfolds is essential to find the vacuum structure and the anomaly cancellation mechanism of four dimensional F-theory compactifications. We use the Griffiths-Frobenius geometry and homological mirror symmetry to fix the integral monodromy basis in the primitive horizontal subspace of Calabi-Yau fourfolds. The Gamma class and supersymmetric localization calculations in the 2d gauged linear sigma model on the hemisphere are used to check and extend this method. The result allows us to study the superpotential and the Weil-Petersson metric and an associated tt* structure over the full complex moduli space of compact fourfolds for the first time. We show that integral fluxes can drive the theory to N=1 supersymmetric vacua at orbifold points and argue that fluxes can be chosen that fix the complex moduli of F-theory compactifications at gauge enhancements including such with U(1) factors. Given the mechanism it is natural to start with the most generic complex structure families of elliptic Calabi-Yau 4-fold fibrations over a given base. We classify these families in toric ambient spaces and among them the ones with heterotic duals. The method also applies to the creating of matter and Yukawa structures in F-theory. We construct two SU(5) models in F-theory with a Yukawa point that have a point on the base with an $E_8$-type singularity on the fiber and explore their embeddings in the global models. The explicit resolution of the singularity introduce a higher dimensional fiber and leads to novel features.Comment: 150 page

The Peruvian upwelling ecosystem: dynamics and interactions

Upwelling, Ecosystems, Fishery biology, Fishery oceanography, Conferences, Peru,

Goddard's Astrophysics Science Division Annual Report 2013

The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radio wavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for two orbiting astrophysics missions Fermi Gamma-ray Space Telescope and Swift as well as the Science Support Center for Fermi. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, space-based interferometry, high contrast imaging techniques to search for exoplanets, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. The overriding goals of ASD are to carry out cutting-edge scientific research, provide Project Scientist support for spaceflight missions, implement the goals of the NASA Strategic Plan, serve and support the astronomical community, and enable future missions by conceiving new concepts and inventing new technologies