A study of search algorithms’ optimization speed

Search algorithms are often compared by the optimization speed achieved on some sets of cost functions. Here some properties of algorithms’ optimization speed are introduced and discussed. In particular, we show that determining whether a set of cost functions F admits a search algorithm having given optimization speed is an NP-complete problem. Further, we derive an explicit formula to calculate the best achievable optimization speed when F is closed under permutation. Finally, we show that the optimization speed achieved by some well-know optimization techniques can be much worse than the best theoretical value, at least on some sets of optimization benchmarks.     

CHANGING BUSINESS MODELS IN INTERNATIONAL BANK FUNDING

This paper investigates the foreign funding mix of globally active banks. Using BIS international banking statistics for a panel of 12 advanced economies, we detect a structural break in international bank funding at the onset of the great financial crisis. In their postbreak business model, banks rely less on cross‐border liabilities and, instead, tap funds from outside their jurisdictions by making more active use of their subsidiaries and branches, as well as interoffice accounts within the same banking group. (JEL C32, F65, G21)     

Total testosterone levels are correlated to metabolic syndrome components

Introduction: Metabolic syndrome (MetS) is a constellation of interrelated risk factors of metabolic origin. Some studies suggest a possible link between low total testosterone (TT) levels and the presence of MetS.

Aim: To analyze the strength and independence of associations between TT and MetS components in non-diabetic men.

Methods: In this cross-sectional study, 143 non-diabetic men older than 40 were analyzed.

Main outcomes measure: Blood samples were collected to evaluate metabolic profile and TT levels. MetS was defined as the presence of three or more of the following characteristics: fasting blood glucose levels?≥?100?mg/dL, triglyceride?≥?150?mg/dL, HDL-c??102?cm.

Results: Mean age of the study population was 61.5?±?8.61 years old. MetS was present in 47.9% of the individuals. Thirty-four men had low TT and MetS was observed in 23 (70%) against 50 (46%) in those with normal TT (≥?300?ng/dL) (OR 4.94, p?p?=?0.03) and HDL-c (Beta: 0.19; p?=?0.04) remained significantly correlated with TT levels.

Conclusions: Low TT levels were associated with MetS diagnosis. Abdominal obesity was the MetS component independently correlated to low TT levels.     

The Effect of Cash Transfers on Fertility: Evidence from Argentina

In 2009 Argentina introduced a large poverty-alleviation program (AUH) that provides monthly cash transfers per child to households without workers in the formal sector. In this paper we study the potential unintended effect of this program on fertility. We apply a difference-in-difference strategy comparing the probability of having a new child among eligible and ineligible mothers both before and after the program inception. The intention to treat estimations suggest a significant positive impact on fertility in households with at least one child (around 2 percentage points), but no significant effect on childless households. Given the short time window since the implementation of the AUH, we are unable to identify whether this positive effect reflects changes in the timing of births or in the equilibrium number of children.     

China’s GDP: Examining provincial disparities (1952–1998)

Accompanying rapid economic growth in China, there have been provincial disparities. This article presents and analyzes the evolution of Chinas provincial GDP per capita disparity between 1952 and 1998. First, an examination of some basic indicators of disparity is carried out, and a test for unconditional convergence is performed to explore the dispersion features. Then, a more comprehensive regression analysis, allowing insights into the evidence of conditional convergence and highlighting the main determinants of growth in two main periods of the recent history of China (i.e., prereform and postreform) is presented. Finally, a discussion and conclusion are provided.     

Control centers design for ergonomics and safety

This paper shows the general design conditions about ergonomics and safety for control centers in the petrochemical process industry. Some of the topics include guidelines for the optimized workstation design, control room layout, building layout, and lighting, acoustical and environmental design. Also takes into account the safety parameters in the control rooms and centers design. The conditions and parameters shown in this paper come from the standards and global advances on this topic on the most recent publications. And also the work was supplemented by field visits of our team to the control center operations in a petrochemical company, and technical literature search efforts. This guideline will be useful to increase the productivity and improve the working conditions at the control rooms.     

Binomial Mixture Modeling of University Credits

The paper reviews finite mixture models for binomial counts with concomitant variables. These models are well known in theory, but they are rarely applied. We use a binomial finite mixture to model the number of credits gained by freshmen during the first year at the School of Economics of the University of Florence. The finite mixture approach allows us to appropriately account for the large number of zeroes and the multimodality of the observed distribution. Moreover, we rely on a concomitant variable specification to investigate the role of student background characteristics and of a compulsory pre-enrollment test in predicting gained credits. In the paper, we deal with model selection, including the choice of the number of components, and we devise numerical and graphical summaries of the model results in order to exploit the information content of the concomitant variable specification. The main finding is that the introduction of the pre-enrollment test gives additional information for student tutoring, even if the predictive power is modest.     

The Money–Happiness Relationship in Transition Countries: Evidence from Albania

With an empirical analysis on a panel of individuals living in a transition country (Albania) we document that the impact of money on happiness does not depend only on the pecuniary outcome but also on aspirations and conditions leading to its determination. Additional factors which matter are the self perceived economic status and the share earned from remittances (and, more weakly, from social assistance). By looking at different sides of the phenomenon we find that these factors affect levels, changes in income and the probability of being “frustrated achievers”. Finally, unlike what happens in developed countries, higher income levels are negatively and not positively correlated with the probability of frustrated achievement thereby supporting the hypothesis that individuals in transition countries are not in the upper side of a concave happiness-income relationship.