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The rough teiid or water cork lizard (Echinosaura horrida) is a small reptile from Colombia and Ecuador placed in a genus that contains eight species and well-known phylogenetic relationships. Here we provide a detailed description and illustrations, bone by bone, of its skull, while we discussed its intraspecific variation by comparing high-resolution computed tomography data from two specimens and the variation within the genus by including previously published data from Echinosaura fischerorum. This allowed to propose putative diagnostic character states for Echinosaura horrida and synapomorphies for Echinosaura. In addition, our discussion includes broader comparisons of new character transformations of the jugal, vomer, orbitosphenoid, and hyoid. These characters are important for diagnosing clades at different levels of the Gymnophthalmoidea phylogeny.
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The atlas and axis are the first two vertebrae from the cervical series; these two vertebrae are responsible for neck flexion, extension, and rotation movements, while providing insertion points for muscles and tendons. Amphisbaenia is a group of fossorial squamates known for having four distinctive head shapes, which are related to different excavation methods. However, little is known about the relationship between these different digging patterns and the anatomy and evolution of the atlantoaxial complex. In this study, we used computed microtomography data to describe in detail of the atlantoaxial complex for 15 species, belonging to all six current families of Amphisbaenia. Furthermore, we evaluate evolutionary scenarios of selected characters related to the atlantoaxial complex in the most recent phylogeny for Amphisbaenia, using the criteria of parsimony and maximum likelihood. Our results indicate that the evolutionary pattern of the atlantoaxial complex presents a diversification in its morphology that is not always correlated with the shape of the head. This analysis reinforces the hypothesis of remarkable morphological convergences in the evolutionary history of Amphisbaenia. Additionally, some of the characters studied may represent independent evolution through convergence in some cases (e.g., horizontal axis of the neural column) and parallelism in others (e.g., present or absent from the transverse process).
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BACKGROUND: Preliminary evidence suggests that eccentric strength training (ECC) improves muscle strength and postural control in individuals with stroke; however, the evidence about the effects of ECC in people living with stroke has not been systematically analyzed. OBJECTIVE: To determine the effects of ECC, compared to other exercise modalities (i.e., concentric training), on motor function in individuals with stroke. METHODS: This scoping review was performed according to PRISMA extension for scoping reviews. Until March 2023, a comprehensive search of studies using ECC intervention to improve motor functions in individuals with stroke was performed. Study designs included were randomized and non-randomized controlled trials and quasi-experimental studies using MEDLINE, Web of Science, Rehabilitation & Sports Medicine, PEDro, and OTSeeker databases. Two independent reviewers selected articles based on title and abstract and extracted relevant information from the eligible studies. The results were qualitatively synthesized, and the critical appraisal was performed using the Rob 2.0 and Robins-I tools. RESULTS: Ten studies, with 257 individuals, were analyzed. ECC revealed positive effects on muscle strength, muscular activity, balance, gait speed, and functionality, mainly compared with concentric training, physical therapy, and daily routine. No significant adverse events were reported during ECC. The critical appraisal of individual articles ranged from some to high concern. CONCLUSION: ECC had a greater and positive effect on motor function in individuals with stroke than other exercise modalities. However, the limited number of studies, variability of outcomes, and the risk of bias produced a low certainty of evidence.
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Rodents establish dominance hierarchy as a social ranking system in which one subject acts as dominant over all the other subordinate individuals. Dominance hierarchy regulates food access and mating opportunities, but little is known about its significance in other social behaviors, for instance during collective navigation for foraging or migration. Here, we implemented a simplified goal-directed spatial task in mice, in which animals navigated individually or collectively with their littermates foraging for food. We compared between conditions and found that the social condition exerts significant influence on individual displacement patterns, even when efficient navigation rules leading to reward had been previously learned. Thus, movement patterns and consequent task performance were strongly dependent on contingent social interactions arising during collective displacement, yet their influence on individual behavior was determined by dominance hierarchy. Dominant animals did not behave as leaders during collective displacement; conversely, they were most sensitive to the social environment adjusting their performance accordingly. Social ranking in turn was associated with specific spontaneous neural activity patterns in the prefrontal cortex and hippocampus, with dominant mice showing higher firing rates, larger ripple oscillations, and stronger neuronal entrainment by ripples than subordinate animals. Moreover, dominant animals selectively increased their cortical spiking activity during collective movement, while subordinate mice did not modify their firing rates, consistent with dominant animals being more sensitive to the social context. These results suggest that dominance hierarchy influences behavioral performance during contingent social interactions, likely supported by the coordinated activity in the hippocampal-prefrontal circuit.
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Resumen La embolia de líquido amniótico es una condición catastrófica propia del embarazo que ocurre típicamente durante el parto o justo posterior a este, cuyo sustrato fisiopatológico no ha sido aclarado por completo. Se ha estimado, según cifras de los Estados Unidos, que su incidencia rondaría 1 por cada 12.953 partos, y en el Reino Unido 1 por cada 50.000 partos; sin embargo, estas cifras pueden ser imprecisas debido a que no existen una referencia ni un consenso respecto a los criterios diagnósticos, además de que el cuadro clínico se puede confundir con otras emergencias obstétricas. Se presenta el caso de una paciente sin antecedentes mórbidos que presenta un cuadro de embolia de líquido amniótico no fatal, caracterizado por un estado fetal no tranquilizador durante la inducción del trabajo de parto, seguido de un paro cardiorrespiratorio durante la cesárea de urgencia y la rápida y catastrófica aparición de signos clínicos de una coagulopatía de consumo grave. Se describen además las complicaciones posoperatorias y su manejo, entre ellas un síndrome de Sheehan y la aparición de convulsiones tónico-clónicas generalizadas con alteración de neuroimágenes.
Abstract Amniotic fluid embolism is a catastrophic pregnancy condition that typically occurs during or inmediately after delivery, and whose pathophysiological background has not been fully clarified. According to US records the incidence of amniotic fluid embolism could been around 1 for every 12,953 births and in the United Kingdom 1 for every 50,000 births, however these numbers may be imprecise because there is no gold standard as well as no consensus regarding the diagnostic criteria, in addition that the clinical presentation can be misdiagnosis with other obstetric emergencies. We present the clinical case of a patient without a morbid history who presents with a non-fatal amniotic fluid embolism, characterized by an non-reassuring fetal status during labor induction, followed by cardiorespiratory arrest during emergency cesarean section and the rapid and catastrophic appearance of clinical signs of a severe consumptive coagulopathy. Postoperative complications and their management are also described, including Sheehans syndrome and the appearance of generalized tonic-clonic seizures with impaired neuroimaging.
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Humanos , Feminino , Gravidez , Adulto , Embolia Amniótica/cirurgia , Parada Cardíaca/etiologia , Hipopituitarismo/etiologia , Cesárea , Reanimação Cardiopulmonar , Coagulação Intravascular Disseminada , Emergências , Parada Cardíaca/terapia , Hipopituitarismo/terapiaRESUMO
El linfagioma es considerado por la mayoría de los autores como una neoplasia benigna de los vasos linfáticos, que se puede presentar en cavidad oral. El 75 por ciento de los casos se presentan mayormente en la cabeza y el cuello. Cuando la boca se ve afectada, la lengua es el principal órgano que muestra alteraciones clínicas. El propósito de esta presentación fue describir un caso clínico de linfangioma en tejido gingival, tratado exitosamente mediante extirpación quirúrgica con electrobisturí. Se trata de una paciente de 13 años de edad, que acudió a consulta por presentar sangrado a nivel de la encía de molares inferiores derechos. Durante la anamnesis no se detectaron antecedentes familiares ni personales de interés. Los resultados de los exámenes de laboratorio se encontraron en los rangos normales. A partir de los hallazgos clínicos y radiográficos observados, se establecieron como diagnósticos presuntivos: granuloma piógeno, hemangioma o linfangioma. Se realizó fase higiénica con posterior escisión quirúrgica de la lesión empleando electrobisturí. Se efectuó análisis histopatológico. Se estableció como diagnóstico: linfangioma en encía a nivel de órganos dentales 46 y 47. Se obtuvo una cicatrización excelente 15 días después de la intervención. La localización inusual de este tipo de lesiones en la encía, y su tratamiento exitoso con electrobisturí, lo constituyen en un caso interesante, debido a los escasos reportes que sobre él existen en la literatura científica(AU)
To most authors, lymphangioma is a benign neoplasm of lymphatic vessels which may occur in the oral cavity. In 75 percent of the cases it presents in the head and neck. When the mouth is affected, the tongue is the main organ showing clinical alterations. The purpose of the study was to describe a clinical case of lymphangioma of gingival tissue successfully treated by surgical removal with an electric scalpel. A 13-year-old female patient attended consultation with bleeding from the gingival tissue next to the lower right molars. No personal or family antecedents of interest were detected during history taking. Laboratory results were within normal ranges. Based on clinical and radiographic findings, the following diagnoses were tentatively established: pyogenic granuloma, hemangioma or lymphangioma. Upon cleaning up the area, surgical removal of the lesion was performed using an electric scalpel. Histopathological examination was conducted. The following diagnosis was established: lymphangioma of the gingiva at the level of dental organs 46 and 47. Excellent scarring was obtained 15 days after the intervention. The singularity of this case lies in the unusual location of this type of gingival lesion, its successful treatment with an electric scalpel, and the fact that very few reports about the subject can be found in the literature(AU)
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Humanos , Feminino , Adolescente , Eletrocirurgia/efeitos adversos , Gengiva/lesões , Linfangioma/cirurgia , Linfangioma/diagnóstico por imagemRESUMO
Los quistes del colédoco son una condición médica poco frecuente, la cual se caracteriza por presentar dilatación de la vía biliar intrahepática y extrahepática; se postulan en su etiología la anomalía de la unión pancreático-biliar, lo que favorece el reflujo del jugo pancreático al árbol biliar, y la aganglionosis del árbol biliar. Tiene una amplia gama de presentación de síntomas, y entre los principales se encuentran el dolor abdominal, la ictericia y una masa abdominal palpable. Son lesiones premalignas y, por ende, el tratamiento de elección es la resección quirúrgica completa con seguimiento a largo plazo.
Choledochal cysts are rare pathological conditions characterized by dilatation of the intrahepatic and extrahepatic bile ducts. Postulated etiologies are an abnormal pancreato-biliary junction favoring reflux of pancreatic juice to the biliary tree, and aganglionosis of the biliary tree. They have a wide range of presenting symptoms, the main ones being abdominal pain, jaundice and evident abdominal mass. Choledochal cysts are premalignant lesions, and therefore the treatment of choice is complete surgical resection, which demands long-term follow-up.
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Ducto Colédoco , Neoplasias do Sistema Biliar , Cisto do Colédoco , Disfunção do Esfíncter da Ampola HepatopancreáticaRESUMO
El linfoma cutáneo primario difuso de células B grandes tipo pierna (LCPDCBG-TP) constituye el 4% de los linfomas cutáneos primarios (LCP). Presenta un comportamiento agresivo con sobrevida a los cinco años cercana a 55%. La úlcera de Marjolin corresponde al desarrollo de una neoplasia sobre lesiones crónicas, siendo el carcinoma espinocelular el más frecuentemente desarrollado. Presentamos el caso de un paciente de sexo masculino, de 74 años, con insuficiencia venosa crónica bilateral, portador de una úlcera crónica de 15 años de evolución en pierna derecha. Desde hace tres años presenta dos lesiones tumorales exofíticas sobre el fondo de la úlcera, con acelerada progresión en últimos meses, planteándose el diagnóstico de úlcera de Marjolin. La histopatología mostró una proliferación celular atípica difusa de tejido linfoide de tipo blástico. En el análisis inmunohistoquímico se evidenció CD20+, CD10-, MUM1+, Bcl-2+, Bcl-6-, Ki67 90%. Los estudios fueron compatibles con el diagnóstico de LCPDCBG-TP. La valoración imagenológica no evidencia adenopatías profundas, ni visceromegalia. La biopsia de médula ósea no pudo ser completada por dificultades producidas por obesidad e intolerancia al dolor del paciente. Se realizó radioterapia local con una dosis total de 54 Gy, presentando excelente evolución con desaparición de las lesiones tumorales. Las opciones terapéuticas de primera línea para el LCPDCBG-TP son la quimioterapia CHOP asociada a rituximab, con o sin radioterapia agregada. Si el estado del paciente no permite un tratamiento agresivo, se considera realizar monoterapia con rituximab o radioterapia. El presente trabajo corresponde al segundo caso reportado en la literatura a nivel mundial de un LCP que surge como úlcera de Marjolin sobre el lecho de una úlcera venosa crónica, y al primero del subtipo LCPDCBG-TP...
Primary Cutaneous Diffuse Large B-cell Lymphoma, Leg-type (CBCL-LT) accounts for 4% of the primary cutaneous lymphomas (PCL). It is characterized by being aggressive, with a five-year survival rate of around 55%. Marjolins ulcer is a malignant neoplasms arising in an area of chronic lesions, being squamous cell carcinoma the most frequent one.The study presents the case of a 74 year old male patient who suffered from bilateral chronic venous insufficiency, carrier of a chronic ulcer with 15 years of evolution in his right leg. Since three years ago he presents two exophytic lesions on the ulcers bottom, with accelerated progression in the last months, Marjolins ulcer being the possible diagnosis.Histopathology showed an diffuse proliferation of atypical lymphoid cells of blastic type lymphoid cells. Immunohistochemistry evidenced CD20+, CD10-, MUM1+, Bcl-2+, Bcl-6-, Ki67 90%. Studies were compatible with a diagnosis of primary cutaneous diffuse large B-cell Lymphoma, Leg-type. Imagenology assessment failed to evidence deep adenopahties or visceromegally. Bone marrow biopsy could not be completed due to difficulties resulting from the patients obesity and pain intolerance. Local radiation therapy was used with a total dose of 54Gy, evolution being excellent and tumor lesions disappeared. Chemotherapy associated to rituximab is the first line therapy for primary cutaneous diffuse large B-cell Lymphoma, leg-type, with or without radiation therapy.If the patients condition is not compatible with aggressive treatment, then rituximab monotherapy or radiation therapy are considered. This study corresponds to the second case of primary cutaneous lymphoma reported in the global literature, that debuts as Marjolin´s ulcer on a chronic venous lesion, and the first one of the primary cutaneous diffuse large B-cell lymphoma, leg- type sub-type...
O linfoma cutâneo primário difuso de células B grandes tipo perna (LCPDCBG-TP) corresponde ao 4% dos linfomas cutâneos primários (LCP). Apresenta comportamento agressivo com sobrevida de aproximadamente 55% aos cinco anos. A úlcera de Marjolin corresponde ao desenvolvimento de uma neoplasia sobre lesões crônicas, sendo o carcinoma espinocelular o mais frequente. Apresentamos o caso de um paciente de sexo masculino, de 74 anos, com insuficiência venosa crônica bilateral, portador de uma úlcera crônica de 15 anos de evolução na perna direita. Apresenta, desde três anos atrás, duas lesões tumorais exofíticas sobre o fundo da úlcera, com progressão acelerada nos últimos meses, quando se propôs o diagnóstico de úlcera de Marjolin. A histopatologia mostrou uma proliferação celular atípica difusa de tecido linfoide de tipo blástico. Nos exames imunohistoquímicos foram observados CD20+, CD10-, MUM1+, Bcl-2+, Bcl-6-, Ki67 90%. Os exames eram compatíveis com o diagnóstico de LCPDCBG- TP. A avaliação imagenológica não mostrou adenopatias profundas, nem visceromegalia. A biopsia de medula óssea não pode ser completada por dificuldades devidas a intolerância à dor e a obesidade do paciente. Foi realizado tratamento com radioterapia local com uma dose total de 54Gy, apresentando excelente evolução com desaparecimento das lesões tumorais. As opções terapêuticas de primeira línea para o LCPDCBG-TP são a quimioterapia CHOP associada à rituximab, com ou sem radioterapia. Se o estado do paciente não permite tratamento agressivo, deve-se considerar monoterapia com rituximab ou radioterapia. Este trabalho corresponde ao segundo caso informado na literatura mundial de um LCP que surge como úlcera de Marjolin sobre o leito de uma úlcera venosa crônica, e o primeiro do subtipo LCPDCBG-TP...
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Carcinoma de Células Escamosas , Linfoma , Úlcera VaricosaRESUMO
Objetivo: diseñar, fabricar y realizar pruebas de un prototipo de sistema electromecánico para mejorar la atención a pacientes hospitalizados, con sobrepeso o problemas de movilidad, en los servicios de enfermería. Material y métodos: estudio de investigación experimental, como base de prueba, realizado por los profesores de las facultades de Enfermería de la Universidad Peruana Cayetano Heredia y Ingeniería Mecánica de la Universidad Nacional de Ingeniería. Se partió de la realidad de los servicios de un hospital del Ministerio de Salud-Lima. Resultados: se presentó el prototipo integrando la camilla recta, la balanza electrónica y el sistema de comunicación vía bluetooth, cuyas funcionalidades (lectura de pesos, uso y manejo del sistema integrado) fueron explicadas al personal de la Facultad de Enfermería para su posterior validación con los pacientes. Conclusiones: el prototipo de sistema bioingenieril contribuye a mejorar la calidad de atención en el pesaje y en el traslado de manera segura y cómoda de pacientes hospitalizados y evitar lesiones físicas al personal de salud.
Objetive: Design, manufacture and testing of a prototype of electromechanical system to improve care to hospitalized patients, overweight or problems of mobility in nursing services. Material and Methods: Study of experimental research, as a basis for testing, conducted by professors from the faculties of Nursing of the Cayetano Heredia Peruvian University and Mechanical Engineering of the National University of Engineering. It departed from the reality of the services of a hospital of the Ministry of health-Lima. Results: Presented the prototype integrating the stretcher straight, the electronic scale and the communication system via bluetooth, whose capabilities (weights, use and management of the integrated reading) were explained to the staff of the school of nursing for further validation with patients.Conclusions. The prototype bioingenieril system contributes to improve the quality of care at the weigh-in and in the transfer of safe and comfortable way of hospitalized patients and prevent injury to health personnel.
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Bioengenharia , Ergonomia , Movimentação e Reposicionamento de Pacientes , Serviço Hospitalar de Enfermagem , Sobrepeso , Ensaio ClínicoRESUMO
La psoriasis es una enfermedad de filiación inmunológica, frecuente a nivel mundial. En población europea y en EE.UU. reporta una prevalencia del 0,6 al 4%. No hay reportes en Uruguay. La forma clásica de presentación es la vulgar en placas. Si bien en la mayoría de los casos es paucisintomática y las terapias tópicas permiten su control (psoriasis leve), en una proporción importante de casos es capaz de afectar severamente la calidad de vida al generalizarse o asociar afectación de otros órganos, o en casos extremos inclusive llevar a la muerte. El objetivo principal de este artículo es brindar recomendaciones unificadas sobre el tratamiento de la psoriasis vulgar en placas moderada y severa. En esta parte se discuten tratamientos sistémicos ‘convencionales’, priorizando la fototerapia, metotrexato, ciclosporina A y retinoides. Aquí no se incluirán las terapias dirigidas contra blancos moleculares (llamadas ‘terapias biológicas’) que ya constituyen alternativas convencionales en los países desarrollados.
Psoriasis is a common worldwide disease and is considered of immune affiliation. In Europe and the U.S. population reported a prevalence of 0.6 to 4%. There are no reports of Uruguay prevalence. The classic presentation is vulgar plates. Although in most cases the disease is paucisymptomatic and topical therapies allows control (mild psoriasis), in a significant proportion can severely affect quality of life associated with generalized psoriasis or involvement of other organs. Even lead to death. The main objective of this article is to provide unified guidelines on the treatment of chronic plaque psoriasis with moderate to severe presentation. This part discusses systemic ‘conventional’ treatments, giving priority to phototherapy, methotrexate, cyclosporin A and retinoids. The so called ‘Biologic Therapies’ wich are already conventional alternatives in developed countries, will be the subject of Part II of these recommendations.
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Diffuse idiopathic skeletal hyperostosis (DISH) is an under-diagnosed condition producing flowing ossification of the antero-lateral ligaments of the spine. Affecting predominantly males over 65years old, it is an unusual cause of dysphagia and dysphonia. We report a 45-year-old mole with a three years history of dysphonia and three months of dysphagia. The initial diagnosis was gastroesophageal reflux, and an endoscopy ruled out esophageal luminal pathology. Cervical spine radiographs showed ossification of the cervical anterior longitudinal ligament with large, prominent osteophytes from C3 to C6, producing esophageal and upper airway compression; these images were compatible with DISH. Cervical osteophyte resection resulted in complete resolution of symptoms. DISH should be considered in the differential diagnosis of dysphagia and dysphonia.
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Humanos , Masculino , Transtornos de Deglutição/etiologia , Hiperostose Esquelética Difusa Idiopática/complicações , Transtornos de Deglutição , Hiperostose Esquelética Difusa Idiopática/cirurgiaRESUMO
Exchange rate and market liberalization policies put in place by recent Chilean administrations with the stated goal of promoting exports in both traditional and non-traditional sectors have resulted in a relative boom for the aquacultural activities in particular. The farming of salmon is well known, and less traditional exports in this area are beginning to play a larger role in the performance of the Chilean economy as a whole. This papers objective is the analysis of the performance of the Chilean aquacultural exports for the period 1995-2005, as a complement of a previous work on agricultural exports. The performance of several indicators of specialization (revealed comparative advantage and contribution to the trade balance), commerce structure (share of exports of the selected items to the total of exports) and competitiveness (indices of sector participation and market share) of each export category was analyzed. Eleven categories of the Harmonized System were reduced to six: salmon, fish fillets, seaweed, scallops, mussels and aquatic invertebrates. The performance of the worlds top exporter in each category was also included in the analysis. A relatively high level of specialization of aquacultural exports for Chile and its main competitors in almost all categories, with exceptions, is inferred. Trends in competitiveness that may help take remedial measures where needed are revealed. These results may prove useful for those responsible of implementing policies with beneficial effect for the sector and the economy as a whole.
Las políticas cambiarias y de libre mercado introducidas por los últimos gobiernos de Chile con el objetivo expreso de promover las exportaciones de productos tradicionales y no tradicionales, han tenido como consecuencia, en particular, un relativo auge de la acuicultura. El cultivo del salmón es de renombre, y exportaciones menos conocidas de este sector tienen una importancia cada vez mayor en el comportamiento global de la economía chilena. El objetivo de este artículo es el análisis del comportamiento de las exportaciones acuícolas chilenas para el periodo 1995-2005, como complemento de un trabajo anterior sobre las exportaciones agrícolas chilenas. Se analizó el comportamiento de varios indicadores de especialización (ventaja comparativa revelada y contribución a la balanza comercial), estructura de comercio (participación de la exportación de los productos seleccionados en el total de las exportaciones) y competitividad (índices de participación sectorial y de cuota de mercado) en cada categoría exportada. Once categorías del Sistema Armonizado fueron reducidas a seis: salmón, filete de pescado, algas, ostiones, mejillones e invertebrados acuáticos. Además, se analizó el comportamiento del principal país exportador y competidor de Chile en cada categoría seleccionada. Los resultados permiten concluir que, excepciones aparte, las exportaciones acuícolas tanto de Chile como de sus principales competidores gozan de un relativamente alto grado de especialización. También muestran tendencias en la competitividad que pueden ayudar a tomar medidas correctivas donde se necesite. Estos resultados pueden ser útiles a aquellos responsables de implementar políticas con beneficio para el sector y para la economía en general.
As políticas cambiárias e de livre mercado introduzidas pelos últimos governos do Chile com o objetivo expresso de promover as exportações de produtos tradicionais e não tradicionais, têm tido como conseqüência, em particular, um relativo auge da aqüicultura. O cultivo do salmão é de renome, e exportações menos conhecidas deste setor têm uma importância cada vez maior no comportamento global da economia chilena. O objetivo deste artigo é a análise do comportamento das exportações aqüícolas chilenas para o período 1995-2005, como complemento de um trabalho anterior sobre as exportações agrícolas chilenas. Analisou-se o comportamento de vários indicadores de especialização (vantagem comparativa revelada e contribuição à balança comercial), estrutura de comercio (participação da exportação dos produtos selecionados no total das exportações) e competitividade (índices de participação setorial e de quota de mercado) em cada categoria exportada. Onze categorias do Sistema Harmonizado foram reduzidas a seis: salmão, filete de peixe, algas, ostras, mexilhões e invertebrados aquáticos. Além disso, se analisou o comportamento do principal país exportador e competidor de Chile em cada categoria selecionada. Os resultados permitem concluir que, exceções aparte, as exportações aqüícolas tanto de Chile como de seus principais competidores contam com um relativamente alto grau de especialização. Também mostram tendências na competitividade que podem ajudar a tomar medidas corretivas onde necessárias. Estes resultados podem ser úteis para os responsáveis na implementação de políticas com beneficio para o sector e para a economia em geral.
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El éxito relativo de la economía chilena se ha debido en gran medida a la aplicación por parte del gobierno de políticas tanto cambiaria como de apertura económica orientadas a favorecer el desarrollo de actividades exportadoras en sectores tradicionales y no tradicionales, para hacer de ellas el motor del crecimiento económico. El sector agropecuario en el país se ha llegado a situar como un componente clave en la economía. Este trabajo analiza el comportamiento de las exportaciones del sector agrícola para el período 1994-2004, con base en una serie de indicadores que dan cuenta de la especialización, la estructura del comercio y la competitividad de las exportaciones. Se estudiaron siete categorías arancelarias del Sistema Armonizado (2002). Para analizar la especialización de las exportaciones se utilizaron tres indicadores, la ventaja comparativa revelada, el índice de la contribución a la balanza comercial y el de comercio intra-industrial. La estructura de comercio fue analizada en base a la participación de las exportaciones de los productos seleccionados en el total exportado. La competitividad se estudió por medio de los índices de participación sectorial y participación de mercado. Los resultados muestran un alto nivel de especialización de las exportaciones agrícolas y un incremento de las ventajas comparativas de los aguacates, las uvas y el vino. En cuanto a la competitividad, el estudio reveló un incremento en la cuota de mercado en la mayoría de los destinos considerados. Las categorías más débiles en este aspecto son las hortalizas y las frutas y verduras elaboradas, que no han sido capaces de posicionarse casi en ningún mercado.