Universidad del Norte, Colombia

About: Universidad del Norte, Colombia is a education organization based out in Barranquilla, Colombia. It is known for research contribution in the topics: Population & Context (language use). The organization has 3562 authors who have published 4355 publications receiving 37861 citations. The organization is also known as: University of the North, Colombia & Uninorte.

Monetary and relative scorecards to assess profits in consumer revolving credit

Abstract: This paper presents for the first time a relative profit measure for scoring purposes and compares results with those obtained from monetary scores. The suggested measure is the cumulative profit relative to the outstanding debt. It can also be interpreted as the percentage coverage against default. Monetary and relative measures are compared with both being estimated using direct and indirect methods. Direct scores are obtained from borrower attributes, while indirect scores are predicted using the estimated probabilities of default and repurchase. Results show that specific segments of customers are profitable in both monetary and relative terms. The best performing indirect models use the probabilities of default within 12 months on books. This agrees with existing banking practice of default estimation. Direct models outperform indirect models. Relative scores would be preferred under more conservative standpoints towards default because of unstable conditions and if the aim is to penetrate relatively unknown segments. Further ethical considerations justify their use in an inclusive lending context.

Mid-elevation ecosystems of Panama: future uncertainties in light of past global climatic variability

Abstract: Modern changes in regional climates will result in high ecosystem turnover and substantial biodiversity rearrangements. Understanding these changes requires palaeoecological studies at temporal resolutions comparable to the time window at which modern climate change is occurring. Here we present a multi-proxy, high-resolution record of forest and lake ecosystem change that occurred during the last 1100 years at middle elevations in Panama. From ∼900 to 1400 CE, regional forest and lake ecosystems were characterized by high seasonality, probably associated with both high El Nino activity and higher global temperatures. At ∼1400 CE, an abrupt transition marked the decoupling of forest and lake responses, with forest responding mostly to local patterns of human occupation, and lake trophic status being controlled mostly by the regional precipitation–evaporation balance, possibly associated with solar irradiance. Factors that played important roles in shaping regional ecosystems during the last 1100 years will probably again play critical roles within the coming decades, i.e. higher precipitation seasonality and higher temperatures. Past responses of the system, together with pervasive human activities, suggest that future conditions will simplify mid-elevation forests. Given the importance of these geographical locations as hotspots of biological diversity, substantial losses of global biodiversity are foreseen.

Novel Nanohybrid Structured Regioregular Polyhexylthiophene Blend Films for Photoelectrochemical Energy Applications

Abstract: The present study shows for the first time the novel photoelectrochemical studies on nanohybrid films fabricated by blending regioregular polyhexylthiophene (RRPHTh) conducting polymer with nanodiamond (ND) nanoparticles. The photoelectrochemical properties of ND– RRPHTh nanohybrid films have been compared by blending RRPHTh with zinc oxide (ZnO) and titanium oxide (TiO2) nanoparticles deposited on indium tin oxide (ITO) coated glass plates, n-type silicon, and gold-coated glass substrates. The ND–RRPHTh film has revealed more promising morphological and photoelectrochemical properties than RRPHTh, ZnO–RRPHTh, and TiO–-RRPHTh nanohybrid films. The photoelectrochemical study has shown the photoinduced electron transfer in ND–RRPHTh nanohybrid films where RRPHTh acts as the donor and ND as the acceptor, providing a molecular approach to high-efficiency photoelectrochemical conversion properties. The photoelectrochemical properties of ND–RRPHTh deposited on either n-type silicon or ITO-coated glass plates in...

Drastic Vegetation Change in the Guajira Peninsula (Colombia) during the Neogene

Abstract: Dry biomes occupy ~35% of the landscape in the Neotropics, but these are heavily human-disturbed. In spite of their importance, we still do not fully understand their origins and how they are sustained. The Guajira Peninsula in northern Colombia is dominated by dry biomes and has a rich Neogene fossil record. Here, we have analyzed its changes in vegetation and precipitation during the Neogene using a fossil pollen and spore dataset of 20 samples taken from a well and we also dated the stratigraphic sequence using microfossils. In addition, we analyzed the pollen and spore contents of 10 Holocene samples to establish a modern baseline for comparison with the Neogene as well as a study of the modern vegetation to assess both its spatial distribution and anthropic disturbances during the initial stages of European colonization. The section was dated to span from the latest Oligocene to the early Miocene (~24.2 to 17.3 Ma), with the Oligocene/Miocene boundary being in the lower Uitpa Formation. The early Miocene vegetation is dominated by a rainforest biome with a mean annual precipitation of ~2,000 mm/yr, which strongly contrasts with Guajira's modern xerophytic vegetation and a precipitation of ~300 mm/yr. The shift to the dry modern vegetation probably occurred over the past three millions years, but the mechanism that led to this change is still uncertain. Global circulation models that include the vegetation could explain the ancient climate of Guajira, but further work is required to assess the feedbacks of vegetation, precipitation, and CO2.