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This work aims to analyze the responses of a group of engineering students related to problems about tangents in a teaching learning process of derivative in a differential calculus course. The methodological design, oriented to a group of 161 students from two Chilean universities, considers different onto-semiotic configurations in problem-situations about tangents. The methodology implemented integrates information and communication technologies in differentiated activities, favoring the use of languages and progressive approach to the meaning of the derivative. The exploratory-type analysis was carried out applying some tools of the onto-semiotic Approach of mathematical knowledge and instruction. Difficulties were found in the concept of function and the Euclidean conception of the tangent line, which brings with it a weak interpretation of the derivative function and its geometric representation. It is concluded that the implementation of the geometric interpretation through information and communication technologies makes it possible to improve the teaching of the derivative.

In 2019, Chile enjoyed high levels of economic freedom, high growth, high wealth by regional standards and a growing and solid middle class. Behind the numbers, the middle class felt insecure, and the country exploded over a small spark—first, there were five months of social unrest, then there was not one, but two constitutional conventions. In the end, the existing constitution prevailed. This paper examines the “Chilean paradox” of simultaneous high levels of income and middle-class dissatisfaction, by analyzing the Chilean middle class. While we can obviously and unfortunately not interview an aggregate such as the middle class, we propose several theories to explain the paradox—ranging from Director’s Law of middle-class redistribution to narrative manipulation. [ABSTRACT FROM AUTHOR]

Copyright of Paradigma is the property of Universidad Pedagogica Experimental Libertador and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Forest fires alter soil microbial communities that are essential to support ecosystem recovery following land burning. These alterations have different responses according to soil abiotic pre- and post-fire conditions and fire severity, among others, and tend to decrease along vegetation recovery over time. Thus, understanding the effects of fires on microbial soil communities is critical to evaluate ecosystem resilience and restoration strategies in fire-prone ecosystems. We studied the state of community-level physiological profiles (CLPPs) and the prokaryotic community structure of rhizosphere and bulk soils from two fire-affected sclerophyll forests (one surveyed 17 months and the other 33 months after fire occurrence) in the Mediterranean climate zone of central Chile. Increases in catabolic activity (by average well color development of CLPPs), especially in the rhizosphere as compared with the bulk soil, were observed in the most recently affected site only. Legacy of land burning was still clearly shaping soil prokaryote community structure, as shown by quantitative PCR (qPCR) and Illumina MiSeq sequencing of the V4 region of the 16S rRNA gene, particularly in the most recent fire-affected site. The qPCR copy numbers and alpha diversity indexes (Shannon and Pielou's evenness) of sequencing data decreased in burned soils at both locations. Beta diversity analyses showed dissimilarity of prokaryote communities at both study sites according to fire occurrence, and NO3– was the common variable explaining community changes for both of them. Acidobacteria and Rokubacteria phyla significantly decreased in burned soils at both locations, while Firmicutes and Actinobacteria increased. These findings provide a better understanding of the resilience of soil prokaryote communities and their physiological conditions in Mediterranean forests of central Chile following different time periods after fire, conditions that likely influence the ecological processes taking place during recovery of fire-affected ecosystems. [ABSTRACT FROM AUTHOR]

This article analyzes the role of women in the public space of a colonial frontier territory in Spanish America, focusing on the female syndics of the Franciscan missions of Valdivia, Chile near the end of the colonial era. The article develops the case study of Clara de Eslava y Lope, who, as a syndic, administered financial matters for the Chillán Franciscan College for the Propagation of the Faith in the Valdivia missions. While Clara de Eslava y Lope's role as a syndic for the Franciscans was not unique in the Hispanic Catholic world, this essay sheds light on the position of female syndics, largely ignored by colonial and early modern historiographies. Through the lens of female syndics, this paper argues that women fulfilled an essential role within the Valdivia Hispanic-Creole population in the late colonial era, influenced not only by their economic power, but also their social recognition, education, and marital status as widows. [ABSTRACT FROM AUTHOR]

The objective of this article is to estimate the income and price elasticities of the demand of residential electricity for Argentina, Brazil, Chile y Colombia (ABCM) with the Johansen (1995) procedure for the period 1980-2018 and the simulation of some prospective scenarios to 2030. The results show that the income elasticities of the demand of residential electricity are 1.00, 0.93, 1.01 y de 0.61 and the price elasticities of the demand of residential electricity are -0.16, -0.28, -0.14 and -0.08 for Argentina, Brazil, Chile y Colombia, respectively. Also, there is a positive effect of the temperature around 0.5 for all these countries over the demand of residential electricity confirming the presence of circular causation between de demand of electricity and climate change. [ABSTRACT FROM AUTHOR]

Piscirickettsia salmonis is the causative agent of Piscirickettsiosis, a systemic disease generating high mortality rates in farmed salmon cultures of southern Chile. Proteolytic enzymes are important virulence factors since they play a key role in bacterial invasion and proliferation within the host. Bacteria growing in muscle tissues are known to secrete proteases, but no proteolytic enzymes have been described in P. salmonis to date. A battery of putative protease genes was found in the genomes and available strains of P. salmonis by bioinformatics analyses, and their identity was established through comparison with protease genes in databases. The transcript levels of five candidate genes were analysed by in vitro infection and qPCR. All strains were found to generate protease activity to varying degrees, and this was significantly increased when bacteria infected a salmon cell line. Gene expression of several types of proteases was also evidenced, with the highest levels corresponding to the type 1 secretion system (T1SS), which is also involved in the transport of haemolysin A, although transcripts with significant levels of peptidase M4 (thermolysin) and CLP protease were also found. [ABSTRACT FROM AUTHOR]

The Mesozoic magnetite-(apatite) deposits of the Coastal Cordillera of Chile are interpreted as the product of the crystallization of oxidized iron-rich melts and subsequent hydrothermal alteration produced by related magmatic-hydrothermal systems. These deposits form a regional-scale mineral system controlled by the Atacama Fault System and where the mineralization spans more than 10 km in vertical extent. Individual sub-vertical bodies of massive magnetite coexist with and evolve vertically into pegmatite-, breccia-, and vein-like apatite-actinolite-magnetite/ilmenite rock. The mineralization is always hosted by a hydrothermal aureole of alkali-calcic-iron alteration that includes stockwork-like to disseminated mineralization. The deposits cluster in two groups. Those located in the northern part are mostly vein-like, and are hosted by Jurassic diorite. They have 87Sr/86Sri and εNdi values of 0.7042–0.7062 and + 5.1 to + 7.2, respectively. The southern group includes shallowly emplaced ore lenses in broadly coeval (sub-)volcanic intermediate rocks. They show similar 87Sr/86Sri signatures (0.7033–0.7065, with one value up to 0.7097) and more variable εNdi values (+ 3.9 to + 8.6). As a whole, the Sr-Nd data do not seem to be influenced by the type of crust intruded, but rather, likely track the mixing between a MORB-like reservoir and another source with elevated 87Sr/86Sri (≥ 0.706). The genetic model proposed involves the dehydration of variably altered subducted oceanic crust, the interaction of fluids released from the mantle wedge, the separation of iron-rich melts, and their ascent along transcrustal faults. The broadly coeval intermediate host rocks show a lesser contribution of subducted crust, something that perhaps excludes a genetic relationship between these rocks and the magnetite-(apatite) mineralization. [ABSTRACT FROM AUTHOR]

Objective: Clinical guidelines recommend the use of endocrine therapy (ET) in advanced hormone receptor positive (HR+) human epidermal growth factor receptor type 2 negative (HER2-) breast cancer (BC) patients in the absence of visceral disease or ET resistance. Furthermore, studies indicate similar response and survival rates using ET or cytotoxic chemotherapy (CT).Methods: Herein, we assessed clinical characteristics, type of systemic therapy and survival rates of advanced HR + HER2-BC patients in our database.Results: A total of 172 advanced HR + HER2-BC patients were treated at our institution between 1997 and 2019. Sixty percent received first-line ET (4% received combined ET). Median age of this subset was 55 years (range: 30-86). Similarly, the median age of patients that received CT was 54 years (range: 21-83). Over time, 30% of patients received ET in the 2000-2005 period; this increased to 70% in the 2016-2019 period (p = .045). Overall survival (OS) was 97 months and 51 months for patients treated with ET or CT, respectively (p = .002).Conclusions: To the best of our knowledge this is the first study assessing the use of ET in Chilean advanced HR + HER2-BC patients. Several patients in our institution receive CT without indication. The increase in ET usage over time can be attributed to better and faster immunohistochemical detection methods for Estrogen Receptor (ER), changes in educational and government policies, and a wider variety of ET options. Finally, clinical trials have failed to demonstrate a substantial benefit of CT over ET in this setting. [ABSTRACT FROM AUTHOR]

Forest restoration is most efficient if it can take advantage of facilitative interactions between established vegetation and planted trees. However, positive and negative interactions have been identified in a number of plant communities. After centuries of anthropogenic fires, forest recovery has been extremely slow in southern bog forests previously dominated by the slow‐growing and vulnerable conifer Pilgerodendron uviferum on Chiloé Island, Chile. Today, the landscape is dominated by secondary shrublands with scattered patches of Sphagnum moss and limited natural tree regeneration. We hypothesized that the retention of secondary shrubs facilitates the early performance of P. uviferum restoration plantings by providing better microsite conditions. To test this hypothesis, we compared the response of seedlings planted on sites prepared at two levels of intervention: after shrubs had been removed or where shrubs were retained. Shrub retention showed a nurse‐plant effect on P. uviferum seedlings 4 years after planting, which resulted in reduced physiological stress (measured as Fv/Fm) for seedlings, as well as reduced browsing. Consequently, the seedlings growing in areas with shrub retention had larger height increment and higher vitality than those in areas where shrubs had been removed. Thus, the more open micro‐site conditions created by shrub removal resulted in generally poorer seedling performance, although seedling mortality—which was low overall (approximately 2–4%)—showed no significant difference between the two levels of intervention. These findings have direct implications for the restoration of slow‐growing conifers that can tolerate extreme wet conditions in highly degraded forests. [ABSTRACT FROM AUTHOR]

Copyright of Revista MAD is the property of Revista MAD and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper analyses the main factors involved in the knowledge management of different actors participating in a Chilean port community. The intangible assets participating in the creation of value of the port community, which are expressed in ideas, attitudes, perceptions, experiences, information and knowledge management, are evaluated and classified according to community members’ core competencies. Then, the current situation of public institutions and companies participating in the port community is diagnosed utilizing interviews to experts and relevant actors. The role of the intellectual, structural, and social capital is examined in relation to strategic statements present in the missions of public and private port system companies. The results of the assessment enable to identify the main critical factors in knowledge management, transference, dissemination, collaboration and team work, storage, and best practices. In particular, the Conversation System stage of the Primary Model is analyzed and evaluated, as well as its causes, by actors of the port community and experts. Initiatives fostering collective work and encouraging conversations are proposed. Some of the best practices developed by the port community to create and disseminate stakeholders’ knowledge are presented. Also, a set of knowledge management indicators and indexes is developed and presented. [ABSTRACT FROM AUTHOR]

This paper presents a study of the behaviour of companies participating in Chilean ports of medium size in the processes of creation, transmission and dissemination of knowledge. A diagnosis of the current situation and the identification of the relevant requirements of knowledge management, through surveys and interviews, were carried out by the main actors of the community. The knowledge management processes related to the intellectual, structural, and social capital that have been developed by the different actors involved in the medium-sized port communities are identified. Also, the stage of externalization of knowledge is examined to find the critical factors of knowledge transference. Meanwhile, the role of the knowledge creation process in innovation, generated by public a private institutional systems, is acknowledged. The results of the analysis show that the competitive and efficient management of a port is mainly based on: knowledge sharing and dissemination, collaboration and team work, knowledge storage and best practices. Then, a model that establishes the stages of development for achieving knowledge management in medium-sized port companies is proposed. With respect to information management and learning, the need of a virtual space with available and continuously updated information and knowledge, that will be useful to the members of this community, has been detected. Finally, the challenges and trends related to integrated logistics, port community and collaborative learning networks, logistic platforms and inter-modality, and creation and dissemination of knowledge are observed. [ABSTRACT FROM AUTHOR]

Abstract: This study presents a comparative analysis of Information and Computer Technology (ICT) integration in two organizations that combine public and private roles: Office for Harmonization in the Internal Market (OHIM) in the European Union (EU) and the Internal Revenue System (IRS) in Chile. The former registers trademarks and designs in the EU, the latter audits enterprises and individuals in the State of Chile, supervising their compliance with tax laws. Expert knowledge for both institutions is assumed as an organizational asset. Accordingly, OHIM experts and IRS auditors systematically introduce ICT tools for e-government and collaborative work, which is manifest through network and strategic alliances. This study also provides analysis concerning their functions and operations with the integration of ICT, identifying the critical aspects of the technological integration process through SWOT analysis. Then, the Corporative, Business, and Operational Levels frame the criteria for comparing both organizations taking as points of reference outcomes in productivity, effectiveness and efficiency, where the most outstanding differences and similarities are described. Among those critical factors analyzed, governance and coordination issues, budget allocation, and the decision-making process between public-private actors are prominent, as well as their Chiefs’ leadership, business models applied, processes quality, and knowledge management. Finally, the paper considers some tendencies shared by both organizations where the development of ICT goes hand in hand with business models based on human capital, transparency, collaboration among agents and relations with citizens. [Copyright &y& Elsevier]

This article explores two fundamental texts of Chilean poetry of the 80s: Diego Maquieira's La Tirana and Tomás Harris's Cipango in (neo)baroque code, to suggest the redefinition of some of their most representative problematics. These are texts that stress the idea of representation by means of cross-dressing, the baroque costume in the first case, and the deceitfulness of the senses in the second, in the context of a discussion of historical temporality and authoritarianism. [ABSTRACT FROM AUTHOR]

Southern Patagonia is characterized by the presence of numerous shallow ponds with variable trophic and conductivity conditions, and a relatively high species richness of Crustacea. In the present study, published information and data collected in field work on shallow ponds in the Magellan region was reviewed and analysed using co-occurrence of null models, with the aim to determine potential random factors as regulators on crustacean zooplankton assemblages, using a presence-absence matrix. The results of C-score analysis revealed the existence of non-random effects mainly in data collected in 1989-1990 for Torres del Paine National Park, and in data on coastal shallow ponds close to Punta Arenas, collected in October 2006. A different situation is reported for shallow ponds located in other zones of the Magellan region, including also some in the Torres del Paine National Park collected in October 2001, and for shallow ponds close to Porvenir on Tierra del Fuego Island, collected in April 2007. The existence of non-random effects was probably due to markedly different zooplankton assemblages, assumed to be caused mainly by the conductivity gradient and trophic level. Random effects can probably be explained by the condition that a few species occur practically at all localities studied, in many of which species richness is very low. This obviously means the variability in species composition is very limited, yielding similar zooplankton assemblages in the many ponds sampled. Ecological and biogeographical topics are also discussed. [ABSTRACT FROM AUTHOR]

An investigation of bulk-rock and clay-fraction compositions of two sedimentary cores from southern Chile was performed to evaluate the record of temporal climatic changes during the late Quaternary (11 ky and 30 ky BP). The bulk mineralogy shows an abundance of feldspars, mica and quartz, with lesser chlorite, amphibole and pyroxene, and variable amounts of carbonates. The clay fraction consists of illite, chlorite and scarce smectite. Smectite shows platy morphology, an Al-Fe beidellite chemical composition, and is detrital. Smectite, together with biogenic carbonate, increases in levels diagnostic of warmer phases. Increases in smectite are attributed either to the beginning of chemical weathering, allowed by the glacial retreat, or to ice extension and sea-level variations. Warmer climates also favoured the increase of carbonate productivity. Levels diagnostic of colder phases show a large decrease in carbonate, small amounts of smectite and large amounts of chlorite and mica, as the abundance of glaciers reduced the productivity and prevented chemical weathering. [ABSTRACT FROM AUTHOR]

Four procedures were employed to extract phosphorus (P) from volcanic soils for 31 P‐NMR experiments. The procedures involve 0.5 M NaOH extraction, 0.5 M NaOH and Chelex 100 cation exchange resin extraction, NaOH‐EDTA extraction, and HCl‐NaOH two step sequential extraction with Chelex 100 clean up. Results showed that inorganic‐P, monoester‐P, diester‐P and pyrophosphate were present. Their detection was dependent on the extraction procedure used. The NaOH procedure gives only a broad and vaguely defined signal with poor signal to noise ratio. The incorporation of Chelex 100 in the extraction enhanced the signal to noise ratio and allowed the distinction of inorganic‐P, monoester‐P, diester‐P and pyrophosphate. The two step sequential extraction involving HCl, NaOH, and Chelex 100 significantly improve the signal to noise ratio. The NaOH‐EDTA extraction procedure is efficient only in samples with low OC contents. When soils have low OC content, any of the four extraction procedures can be successfully used. If the OC and the Fe concentration in the extracted solutions are high, the Chelex 100 became essential in clean up the metallic ions. Both the NaOH and Chelex 100 and the HCl‐NaOH‐Chelex produced satisfactory results and the later procedure by far the best resolved spectra. [ABSTRACT FROM AUTHOR]

Reports on the use of the ORWARE model to analyze the sludge management alternatives in the 5th region, located in central Chile. Stages of the research project; Management alternatives chosen for chemical or biological treatment of sewage and sludge based on digestion, composting or lime stabilization; Need for additional disinfection in the case of discharge to rivers.

The empirical Rothmund-Kornfeld power function approach (in terms of equivalent fractions) was applied to potassium-calcium (K-Ca) exchange equilibrium carried out at 25°C and 0.05 M ionic strength on 4 soils derived from volcanic materials in southern Chile. Results were compared with those obtained by the Gaines-Thomas approach, where a K preference was observed in all samples, with equilibrium constant values ranging from 0.097 to 0.492. The equivalent fraction form of Rothmund-Kornfeld fit the exchange isotherm curves obtained by the Gaines-Thomas convention and provides a good description of experimental exchange data. The exchange equilibrium constants and adsorbed ion activity coefficients calculated with Rothmund-Kornfeld parameters are comparable with those obtained by the Gaines-Thomas approach. [ABSTRACT FROM AUTHOR]

The volcanic ash-derived soils have strong capacity to retain phosphorus (P). The P in 10 virgin Ultisols and Andisols in Southern Chile and their clay size fractions were fractionated into inorganic, fulvic, and humic fractions using an acid and base sequential extraction procedure. These soils had similar mineralogy, and were formed under different climatic conditions, and were under different native vegetation. They are representative of the major agricultural areas. The total content ranges from 733 mg P kg[SUP-1] to 3470 mg P kg[SUP-1]. As groups, Andisols had higher total P concentrations than the Ultisols. The organic P content was linearly correlated to organic carbon (C). In general, soils with higher organic C content had higher percentage of its P in the organic form. Clay size fraction accounted for 35 to 60% of the soil and had significantly higher concentrations of P in all fractions. In the clay fraction, the organic P content was also influence by their organic C. Soil depth did not affect the P distribution neither in the soils nor in the clay fractions. [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) is a complex and heterogeneous disease. In recent decades, The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG) defined GC molecular subtypes. Unfortunately, these systems require high-cost and complex techniques and consequently their impact in the clinic has remained limited. Additionally, most of these studies are based on European, Asian, or North American GC cohorts. Herein, we report a molecular classification of Chilean GC patients into five subtypes, based on immunohistochemical (IHC) and in situ hybridization (ISH) methods. These were Epstein–Barr virus positive (EBV+), mismatch repair-deficient (MMR-D), epithelial to mesenchymal transition (EMT)-like, and accumulated (p53+) or undetected p53 (p53−). Given its lower costs this system has the potential for clinical applicability. Our results confirm relevant molecular alterations previously reported by TCGA and ACRG. We confirm EBV+ and MMR-D patients had the best prognosis and could be candidates for immunotherapy. Conversely, EMT-like displayed the poorest prognosis; our data suggest FGFR2 or KRAS could serve as potential actionable targets for these patients. Finally, we propose a low-cost step-by-step stratification system for GC patients. To the best of our knowledge, this is the first Latin American report on a molecular classification for GC. Pending further validation, this stratification system could be implemented into the routine clinic [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) is a heterogeneous disease. This heterogeneity applies not only to morphological and phenotypic features but also to geographical variations in incidence and mortality rates. As Chile has one of the highest mortality rates within South America, we sought to define a molecular profile of Chilean GCs (ClinicalTrials.gov identifier: NCT03158571/(FORCE1)). Solid tumor samples and clinical data were obtained from 224 patients, with subsets analyzed by tissue microarray (TMA; n = 90) and next generation sequencing (NGS; n = 101). Most demographic and clinical data were in line with previous reports. TMA data indicated that 60% of patients displayed potentially actionable alterations. Furthermore, 20.5% were categorized as having a high tumor mutational burden, and 13% possessed micro-satellite instability (MSI). Results also confirmed previous studies reporting high Epstein-Barr virus (EBV) positivity (13%) in Chilean-derived GC samples suggesting a high proportion of patients could benefit from immunotherapy. As expected, TP53 and PIK3CA were the most frequently altered genes. However, NGS demonstrated the presence of TP53, NRAS, and BRAF variants previously unreported in current GC databases. Finally, using the Kendall method, we report a significant correlation between EBV+ status and programmed death ligand-1 (PDL1)+ and an inverse correlation between p53 mutational status and MSI. Our results suggest that in this Chilean cohort, a high proportion of patients are potential candidates for immunotherapy treatment. To the best of our knowledge, this study is the first in South America to assess the prevalence of actionable targets and to examine a molecular profile of GC patients. [ABSTRACT FROM AUTHOR]

Abstract: The environmental geochemical behaviour of the rhyolitic ashes from the 2008 eruption of Chaitén volcano, Southern Chile, has been studied. After the bulk characterisation, the potential contribution to the regional geochemical fluxes was examined using: i) single batch leaching tests to provide a rapid screening of the implied major and trace elements; and ii) column experiments to evaluate the temporal mobility of leached elements. The environmental concerns of these ashes are related to the fine grained component present in each sample (independent of distance from the source), in particular the presence of cristobalite, and the geochemical hazards posed by ash–water interaction. Leaching experiments show the fast dissolution of surface salts and aerosols, which dominate over glass dissolution during the first steps of the ash–water interaction. Chaitén ashes could transfer to the environment more than 1×1010 g or 10,000metric tonnes (mt) of Cl, S, Ca, Na, Si, and K; between 1000 and 10,000mt of F, Mg, and Al; between 100 and 1000mt of As, Pb, P, Fe, Sr, Zn, Mn, and Br; between 10 and 100mt of Ba, Li, Ti, Ni, Nb, Cu, Rb, Zr, V, Mo, Co, and Sc; and less than 10mt of Cr, Sb, Ce, Ga, Cs, and Y. These results show the fertilising potential of the ashes (e.g., providing Ca and Fe) but also the input of potentially toxic trace elements (e.g., F and As) in the regional geochemical mass balance. The Chaitén results evidence lower potentials for poisoning and fertilising than low silica ashes due to the lower contents released of practically all elements. [Copyright &y& Elsevier]

Column leaching experiments were conducted to test the ability of Chilean volcanic soils in retaining the mineral constituents and metals in sewage sludge and sludge ash that were incorporated into the soils. Small or negligible amounts of the total content of Pb, Fe, Cr, Mn, Cd, and Zn (0 to <2%), and more significant amounts of mineral constituents such as Na (7–9%), Ca (7–13%), PO4 (4–10%), and SO4 (39–46%) in the sludge and sludge ash were readily soluble. When they were incorporated on the surface layer of the soils and leached with 12 pore volumes of water over a 3 month period of time, less than 0. 1% of the total amount of heavy metals and PO4 in the sludge and sludge ash were collected in the drainage water. Cation exchange selectivity, specific anion adsorption and solubility are the processes that cause the reduction of leaching. The volcanic soils were capable of retaining the mineral constituents, P, and metals in applied sewage sludge and sludge ash and gradually released them as nutrients for plant growth. [Copyright &y& Elsevier]

Hematopoietic precursors transplantation is a therapeutic alternative for leukemia, some metabolic diseases and some immune deficiency syndromes. In its allogeneic variety leukemia eradication is based in the conditioning prior to transplantation and the allograñ effect against leukemia. Umbilical cord blood is an alternative source of hematopoietic precursors when there are no HLA compatible relatives available. Between 2003 and 2007 we have performed five umbilical cord blood transplant in adult patients in a University hospital. All patients had malignant diseases. Conditioning protocols were ablative in all except in one patient and in all, more than one unit of umbilical cord blood was used. Hematopoietic engraftment was confirmed in all patients and the main complications registered were infectious and associated to immunosuppression.