Corporate Social Irresponsibility and Credit Risk Prediction: A Machine Learning Approach

This paper examines the prediction accuracy of various machine learning (ML) algorithms for firm credit risk. It marks the first attempt to leverage data on corporate social irresponsibility (CSI) to better predict credit risk in an ML context. Even though the literature on default and credit risk is vast, the potential explanatory power of CSI for firm credit risk prediction remains unexplored. Previous research has shown that CSI may jeopardize firm survival and thus potentially comes into play in predicting credit risk. We find that prediction accuracy varies considerably between algorithms, with advanced machine learning algorithms (e.?g. random forests) outperforming traditional ones (e.?g. linear regression). Random forest regression achieves an out-of-sample prediction accuracy of 89.75% for adjusted R2 due to the ability of capturing non-linearity and complex interaction effects in the data. We further show that including information on CSI in firm credit risk prediction does not consistently increase prediction accuracy. One possible interpretation of this result is that CSI does not (yet) seem to be systematically reflected in credit ratings, despite prior literature indicating that CSI increases credit risk. Our study contributes to improving firm credit risk predictions using a machine learning design and to exploring how CSI is reflected in credit risk ratings

PROTOCOLOS E METODOLOGIAS DO ENSAIO DE DNA COMETA EM PEIXES: UMA REVISÃO SISTEMÁTICA DE LITERATURA

O Ensaio do DNA Cometa é um dos marcadores mais utilizados para detectar danos no DNA. Essa técnica consiste em englobar células em gel, provocar a lise das membranas e submeter à corrente elétrica, resultando em diferentes deslocamentos que podem indicar a presença de quebras. Diversos contaminantes nos rios e lagos possuem a capacidade de provocar quebras ao DNA de organismos aquáticos. O objetivo deste trabalho foi analisar as metodologias empregadas nos trabalhos de biomonitoramento de ambientes aquáticos que utilizaram o Ensaio de DNA Cometa em peixes. Para isso, realizou-se uma revisão sistemática da literatura, através do Portal de Periódicos da CAPES. A revisão minuciosa dos artigos levantados demonstrou variações sutis nos delineamentos experimentais, a depender dos objetivos de cada trabalho. Também foi possível verificar pequenas variações nas etapas de lise e de coloração, mas os protocolos, em geral, apresentaram certa uniformidade, constatando assim tendências nas adaptações requeridas no uso dessa técnica. Os dados aqui levantados podem auxiliar pesquisadores na padronização das técnicas de Ensaio de DNA Cometa, levando à economia de recursos e de tempo

Proof-of-Mechanism Study of the Phosphodiesterase 10 Inhibitor RG7203 in Patients With Schizophrenia and Negative Symptoms

BACKGROUND:Reduced activation of dopamine D1receptor signaling may be implicated in reward functioning as apotential driver of negative symptoms in schizophrenia. Phosphodiesterase 10A (PDE10A), an enzyme that is highlyexpressed in the striatum, modulates both dopamine D2- and D1-dependent signaling.METHODS:We assessed whether augmentation of D1signaling by the PDE10 inhibitor RG7203 enhances imagingand behavioral markers of reward functions in patients with schizophrenia and negative symptoms. In a 3-period,double-blind, crossover study, we investigated the effects of RG7203 (5 mg and 15 mg doses) and placebo asadjunctive treatment to stable background antipsychotic treatment in patients with chronic schizophrenia withmoderate levels of negative symptoms. Effects on reward functioning and reward-based effortful behavior wereevaluated using the monetary incentive delay task during functional magnetic resonance imaging and the effort-cost-benefit and working memory reinforcement learning tasks.RESULTS:Patients (N= 33; 30 male, mean age6SD 36.667.0 years; Positive and Negative Syndrome Scalenegative symptom factor score 23.063.5 at screening) were assessed at three study centers in the United States; 24patients completed the study. RG7203 at 5 mg significantly increased reward expectation–related activity in themonetary incentive delay task, but in the context of significantly decreased overall activity across all task conditions.CONCLUSIONS:In contrast to our expectations, RG7203 significantly worsened reward-based effortful behavior andindices of reward learning. The results do not support the utility of RG7203 as adjunctive treatment for negativesymptoms in patients with schizophrenia

Thermotropic orientational order of discotic liquid crystals in nanochannels: an optical polarimetry study and a Landau-de Gennes analysis

Optical polarimetry measurements of the orientational order of a discotic liquid crystal based on a pyrene derivative confined in parallelly aligned nanochannels of monolithic, mesoporous alumina, silica, and silicon as a function of temperature, channel radius (3-22 nm) and surface chemistry reveal a competition of radial and axial columnar orders. The evolution of the orientational order parameter of the confined systems is continuous, in contrast to the discontinuous transition in the bulk. For channel radii larger than 10 nm we suggest several, alternative defect structures, which are compatible both with the optical experiments on the collective molecular orientation presented here and with a translational, radial columnar order reported in previous diffraction studies. For smaller channel radii our observations can semi-quantitatively be described by a Landau-de Gennes model with a nematic shell of radially ordered columns (affected by elastic splay deformations) that coexists with an orientationally disordered, isotropic core. For these structures, the cylindrical phase boundaries are predicted to move from the channel walls to the channel centres upon cooling, and vice-versa upon heating, in accord with the pronounced cooling/heating hystereses observed and the scaling behavior of the transition temperatures with the channel diameter. The absence of experimental hints of a paranematic state is consistent with a biquadratic coupling of the splay deformations to the order parameter