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Abstract Expanding conservation efforts to private land is paramount to halt biodiversity loss and achieve global conservation targets. Individual landowners can play disproportionately important roles by establishing private parks and managing them with biodiversity‐focused objectives. However, several constraints hinder the expansion of such initiatives, and little is known about their extent, characteristics and keys for success. Here, we provide insights on the conditions that favoured the establishment and conservation outcomes of a private reserve in central Spain whose management has been fully conservation‐oriented for the past two decades. We report on the actions implemented to accomplish four key targets that aimed at protecting and enhancing wildlife populations, and on the landholder's motivations to devote his personal resources to pursue this goal. After acquiring the land, the landowner has made efforts to restore native wildlife populations after decades of poaching and intensive cattle raising. Key actions included re‐establishing degraded vegetation and fostering keystone rabbit populations to sustain carnivore populations. Water bodies are maintained to provide drinking points and foster aquatic animal populations; nest boxes target birds and bats. Many actions resulted from advice from multiple stakeholders, including public administration officers, academics, local residents and NGOs. The estate's formal conservation status has made it a partner in major conservation projects, including repeated releases of captively bred Iberian lynx. The landowner's determination for long‐term conservation was formalised through a legal protected‐area status. The condition that drove the creation of the reserve was the landowner's intrinsic motivation, which resulted from conservation ethic, personal identity and the desire to share and educate about the multiple values of nature. Additionally, several external conditions, such as accessibility and appropriate reserve size (biophysical conditions), the lack of need for economic activities (economic), a positive and pro‐active relationship with multiple stakeholders (social‐cultural), the protected‐area status and the capacity to make decisions independently (governance‐related), have helped sustain the project. The landholder suggests that public policy should reduce the bureaucratic burden to intrinsically motivated landowners and provide them technical advice, trust and financial incentives to expand conservation on private land.

A case study was conducted to explore public secondary school teachers’ perspectives, practices, and experiences concerning the design and implementation of the English curriculum, as well as the professional development offered by the government in order to implement language policies and curriculum guidelines in the city of Medellin, Colombia. The study lasted one year and included a survey, the analysis of curriculum documents from five selected institutions, and focus group interviews as data collection instruments. Results indicate that the initiatives provided by the government have not been effective in supporting teachers in this endeavor as they have been very limited in terms of curriculum design, and reflect a technical view of teacher learning. In addition, several contextual and social factors have tremendously affected the implementation of language policies and curriculum guidelines in schools. Besides, teachers point to several needs, including that they have more time to appropriate and implement reforms, that they be included in policy-making as affected parties, that professional development initiatives be freed from political and economic interests and that they be offered a preparation that combines improving their language proficiency, English teaching methodologies and curriculum design.

The effects of dietary inclusion of silver nanoparticles (NanoAg, <100 nm diameter) on growth performance, gut microbiota, and silver tissue retention was assessed in broilers from 1 to 42 days of age. A total of 870 1-day-old male broilers (Ross 308) were weighted and distributed in 36 floor pens (n = 24) in an environmentally controlled room. The feeding program consisted of two periods (1–21 days and 22 to 42 days of age) and two experimental diets with the same ingredient composition including 2 g kaolin/kg with or without adsorbed NanoAg (10 mg/g kaolin). The experimental design was completely randomized, and the effects of the length of the period in which the birds received NanoAg (none, Ag0; from 1 to 21 days, Ag21; or from 1 to 35 days, Ag35) on growth performance, biodiversity of digestive microbiota and silver retention in body tissues were studied. A common feed without NanoAg was provided to all pens from 36 days onwards. At 21 and 42 days of, one random bird per pen (n = 12) was slaughtered and cecal samples were collected from 9 birds per treatment randomly selected to analyse gut microbiota. Besides, samples of liver and breast muscle were collected to determine silver tissue retention. From 1 to 21 days of age, NanoAg supplementation tended to improve feed conversion ratio (FCR, P = 0.070). From 22 to 35 days of age, FCR tended to be lower (P = 0.072) and average daily gain (ADG) was greater (P < 0.001) in broilers fed Ag21 and Ag35 than in those fed Ag0. Cumulatively, ADG was greater (P < 0.001) for Ag21 and Ag35 than for Ag0, but FCR was unaffected. Caecal microbiota was affected by age of birds, but dietary supplementation with NanoAg did not modify bacterial community structure, diversity and taxa distribution in the caecum neither at 21 nor at 42 days. At 21 days of age, silver retention in liver was 0.591 mg/kg dry tissue in all broilers supplemented with NanoAg. However, at 42 days of age, silver retention in the liver was only detected in two (0.139 mg/kg, n = 2) and 8 (0.183 mg/kg, n = 8) birds fed Ag21 and Ag35, respectively. Silver retention in muscle was exclusively detected at 42 days in two birds (0.124 mg/kg, n = 2) fed Ag35. Irrespective of the supplementation period, NanoAg increased ADG from 1 to 42 d. No silver retention was detected in the liver nor in breast muscle after 21 days of the end of treatment. However, traces of silver might remain in the liver 7 days after removal of NanoAg. Silver supplementation might be a promising strategy to improve growth performance in broilers without expecting any changes in the gut microbiota nor tissue retention after 21 days of NanoAg withdrawal. • Silver nanoparticles at 20 mg/kg from 1 to 35 days improve broiler performance. • Positive response of silver nanoparticles can be achieved by dosing for 21 days. • Silver nanoparticles do not have a major impact on digestive microbiota. • Silver retention in muscle tissue was not detected after 21 days of withdrawal. • Silver retention in liver was detected at low magnitude in several broilers. [ABSTRACT FROM AUTHOR]

This article proposes a measurement solution designed to monitor the instantaneous frequency in power systems. It uses a data acquisition module and a GPS receiver for time stamping and traceability. A Python-based module receives data, computes the frequency, and finally transfers the measurement results to a database. The frequency is calculated with two different methods, which are compared in the article. The stored data is visualized using the Grafana platform, thus demonstrating its potential for comparing scientific data. The system as a whole constitutes an efficient, low-cost solution as a data acquisition system.

This article shows the relevance of educational leadership based on key elements that influence the leader´s behaviour from the perspective of sustainability and due to education´s formative and ethical sense, which makes the leader become an individual having special characteristics, regarding the role of education and guiding educational communities such as students, teachers, parents and people who conduct educational processes. Besides, this issue, which improves organizational quality, climate and culture for individual growth, is reflected in integral formation processes of educational institutions.

En el presente artículo se analiza, si el apocalipsis de la mitología nórdica o “Ragnarök” es realmente el final de los tiempos o del mundo; en la medida en que este cataclismo no afectaría a todos los seres del universo por igual, incluidas las principales divinidades. Por ello, intentaremos dar una interpretación del papel simbólico y clave que juega el Ragnarök en el universo mental escandinavo.

In this article, the author discusses the social justice language teacher education perspective and how it can help language teachers to develop a political view of their work and effect change inside and outside their particular school contexts. To do this, she briefly analyzes various professional development programs for teachers of English in public schools in one city in Colombia to determine how these have or have not contributed to the development of a political perspective in teachers. Finally, she discusses what the implementation of such perspective requires, provides some examples to illustrate how it may look in practice, and discusses some implications for different stakeholders.

Introducción. La resistencia a los carbapenémicos constituye una seria amenaza para la salud pública a nivel mundial, ya que estos antibióticos son una de las últimas opciones terapéuticas contra las bacterias multirresistentes. La caracterización molecular de los brotes causados por bacterias resistentes aporta información relevante para el diseño de estrategias de control de infecciones. Objetivo. Describir las características moleculares de un brote de Klebsiella pneumoniae resistente a carbapenémicos ocurrido en un hospital de alto nivel de complejidad de Medellín entre 2010 y 2011. Materiales y métodos. A partir de una colección de cepas del brote ocurrido en la institución hospitalaria, se recuperaron 84 aislamientos de 32 pacientes infectados y 52 colonizados. La identificación y la sensibilidad de los aislamientos se establecieron mediante el sistema Vitek2®. La detección de carbapenemasas se hizo mediante el test de Hodge modificado y usando la reacción en cadena de la polimerasa. La relación genética entre los aislamientos se evaluó mediante electroforesis en gel de campo pulsado y tipificación de secuencias de locus múltiple. Resultados. Todos los aislamientos analizados fueron multirresistentes; el análisis molecular reveló que todos eran portadores del gen blaKPC-3. El análisis genético mostró que los aislamientos de pacientes infectados y colonizados (58/64 aislamientos) estaban estrechamente relacionados (>80 %) y pertenecían al linaje ST258. Conclusión. Mediante el empleo de técnicas de tipificación molecular fue posible confirmar un brote ocasionado por K. pneumoniae ST258 portador del blaKPC-3 con un perfil de multirresistencia, el cual había sido asociado a uno anterior ocurrido en otro hospital de Medellín. El ST258 es un clon de alto riesgo presente a nivel mundial, lo que debe alertar sobre la posible diseminación de resistencia en el país. El empleo de herramientas moleculares en la vigilancia epidemiológica, es útil para evaluar la diseminación de microorganismos de interés en salud pública.

In this article, a teacher-researcher and her advisor report on an action-research project aimed at developing student autonomy through the implementation of self-assessment and learning strategies, in an English course for students of different academic programs in a well-known university in Medellín. Affective factors, metacognition, the role of the teacher and linguistic achievement emerged as the main themes related to developing learner autonomy. In this paper the authors aim at a better understanding and discussion on how motivation affects students' decisions regarding planning, monitoring and evaluating their learning, and how this regulation process and the facilitating role of the teacher helps them broaden their learning strategies and improve their linguistic performance.

In response to situations of violence and armed conflict as those present in the Colombian reality, the church’s pastoral commitment should be effective. Then, the suburban pastoral (periphery pastoral), that promotes mercy and compassion as principles of its action, can respond to this reality more comprehensively. This article inquires about this situation and seeks to offer some clues in order to make pastoral action in the big cities, taking into account the reality of displacement. Hopefully, the urban pastoral will be like the Good Samaritan portrayed in the Gospel: it will stop along the way to help those who have fallen as a result of violence in Colombia

The onset and persistence of endodontic infections due to residual biofilm after chemical disinfection promotes secondary bacterial infection. Alternative methods to disinfect operated root canals are a matter of great interest. The aim was to evaluate the antibacterial effectiveness of sodium hypochlorite (NaOCl) at low concentrations activated by the Er,Cr:YSGG laser-activated irrigation (LAI) against 10-day-old intracanal Enterococcus faecalis biofilm. Biofilms were formed inside the root canals and divided into 7 groups (n13): 0.5% NaOCl + Er,Cr:YSGG; Saline + Er,Cr:YSGG; 0.5% NaOCl + syringe irrigation(SI); 2.5% NaOCl + SI; 5% NaOCl + SI; positive and negative controls. Bacterial survivors were counted and specimens visualized under scanning electron and confocal laser scanning microscopy. Treatments with 0.5% NaOCl + Er,Cr:YSGG and 2.5% NaOCl + SI gave a significant reduction in the number of CFU/mm2. Moreover, scanning electron microscopy and confocal laser scanning microscopy imaging confirmed and reinforced bacteriological data. Thus, Er,Cr:YSGG LAI proved to be able to improve the intracanal distribution of 0.5% NaOCl after 60 s of activation, reaching the same level of effectiveness than 2.5% NaOCl. This is regarded as of clinical interest, since working with lower concentrations may contribute to reduce undesired effects.

The highly-changing concept of Power Quality (PQ) needs to be continuously reformulated due to the new schemas of the power grid or Smart Grid (SG). In general, the spectral content is characterized by their averaged or extreme values. However, new PQ events may consist of large variations in amplitude that occur in a short time or small variations in amplitude that take place continuously. Thus, the former second-order techniques are not suitable to monitor the dynamics of the power spectrum. In this work, a strategy based on Spectral Kurtosis (SK) is introduced to detect frequency components with a constant amplitude trend, which accounts for amplitude values’ dispersion related to the mean value of that spectral component. SK has been proven to measure frequency components that follow a constant amplitude trend. Two practical real-life cases have been considered: electric current time-series from an arc furnace and the power grid voltage supply. Both cases confirm that the more concentrated the amplitude values are around the mean value, the lower the SK values are. All this confirms SK as an effective tool for evaluating frequency components with a constant amplitude trend, being able to provide information beyond maximum variation around the mean value and giving a progressive index of value dispersion around the mean amplitude value, for each frequency component.

This research presents a comparative analysis of wind speed forecasting methods applied to perform 1 h-ahead forecasting. The main significant development has been the introduction of low-quality measurements as exogenous information to improve these predictions. Eight prediction models have been assessed; three of these models [persistence, autoregressive integrated moving average (ARIMA) and multiple linear regression] are used as references, and the remaining five, based on neural networks, are evaluated on the basis of two procedures. Firstly, four quality indices are assessed (the Pearson’s correlation coefficient, the index of agreement, the mean absolute error and the mean squared error). Secondly, an analysis of variance test and multiple comparison procedure are conducted. The findings indicate that a backpropagation network with five neurons in the hidden layer is the best model obtained with respect to the reference models. The pair of improvements (mean absolute-mean squared error) obtained are 29.10%–56.54%, 28.15%–53.99% and 4.93%–14.38%, for the persistence, ARIMA and multiple linear regression models, respectively. The experimental results reported in this paper show that traditional agricultural measurements enhance the predictions.

El artículo presenta el resultado del proyecto sobre estrategias de lectura y escritura, como respuesta a la necesidad de implementar una propuesta pedagógica que promueva la lectura crítica de los estudiantes, como aporte al modelo pedagógico en el desarrollo de las competencias transversales de la Universidad EAN (Escuela de Administración de Negocios). Se logró caracterizar las prácticas de enseñanza de la lectura y la escritura de los docentes Eanistas, lo que implica analizar estas prácticas aplicadas desde diferentes disciplinas. Al analizar los resultados obtenidos, se diseñaron dos matrices de estrategias didácticas para la enseñanza de la lectura crítica como parte de la propuesta pedagógica a implementar, sobre cuáles son los criterios que deben orientar a las disciplinas, al trabajar procesos de comprensión y producción de textos con actividades de descripción, recursos, seguimiento del docente y la evaluación.

La anisotropía de susceptibilidad magnética (ASM) es una herramienta útil para el análisis de la fábrica magnética de las rocas y de las deformaciones a que han sido sometidas. Estas fábricas anisotrópicas se expresan matemáticamente como un tensor de segundo orden y geométricamente mediante un elipsoide, cuyos ejes K1, K2, K3 representan respectivamente el eje máximo, intermedio y mínimo, y las relaciones entre ellos determinan los parámetros anisotrópicos que establecen las características del elipsoide. Los resultados obtenidos de ASM en la sección quebrada Sabaleticas en el SW antioqueño indican la existencia de al menos dos eventos deformacionales en el Miembro Superior de la Formación Amagá. Estas deformaciones se pueden correlacionar con las descritas por otros autores en zonas a lo largo del sistema Cauca-Romeral. El análisis global de los resultados, se asocian con depositación, enterramiento y levantamiento de los sedimentos de la cuenca Amagá y la superposición de eventos compresionales.

Very short-term solar forecasts are gaining interest for their application on real-time control of photovoltaic systems. These forecasts are intimately related to the cloud motion that produce variations of the irradiance field on scales of seconds and meters, thus particularly impacting in small photovoltaic systems. Very short-term forecast models must be supported by updated information of the local irradiance field, and solar sensor networks are positioning as the more direct way to obtain these data. The development of solar sensor networks adapted to small-scale systems as microgrids is subject to specific requirements: high updating frequency, high density of measurement points and low investment. This paper proposes a wireless sensor network able to provide snapshots of the irradiance field with an updating frequency of 2 Hz. The network comprised 16 motes regularly distributed over an area of 15 m × 15 m (4 motes × 4 motes, minimum intersensor distance of 5 m). The irradiance values were estimated from illuminance measurements acquired by lux-meters in the network motes. The estimated irradiances were validated with measurements of a secondary standard pyranometer obtaining a mean absolute error of 24.4 W/m 2 and a standard deviation of 36.1 W/m 2 . The network was able to capture the cloud motion and the main features of the irradiance field even with the reduced dimensions of the monitoring area. These results and the low-cost of the measurement devices indicate that this concept of solar sensor networks would be appropriate not only for photovoltaic plants in the range of MW, but also for smaller systems such as the ones installed in microgrids.

This paper presents a higher-order statistics-based approach of detecting transients that uses the fourth-order discrete spectrogram to monitor the power supply in a node of the domestic smart grid. Taking advantage of the mixed time–frequency domain information, the method allows for the transient detection and the subsequent identification of the potential area in which the fault takes place. The proposed method is evaluated through real power-line signals from the Spanish electrical grid. Thanks to the peakedness enhancement capability of the higher-order spectra, the results show that the procedure is able to detect low-level transients, which are likely ignored by the traditional detection procedures, where the concern pertains to power reliability (not oriented to micro grids), and this, by analyzing the duration and frequency content of the electrical perturbation, may indicate prospective faulty states of elements in a grid. Easy to implement in a hand-held instrument, the computational strategy has a 5 Hz resolution in the range 0–500 Hz and a 50 Hz resolution in the range of 0–5 kHz, and could be consequently used by technicians in order to allocate new types of transients originated by the distributed energy resources. Four real-life case-studies illustrate the performance.

La relación entre contabilidad y fiscalidad ha sido una tradición en Colombia, pues es notable la influencia ejercida por las instituciones de carácter público encargadas del control impositivo, en la normativa sobre la cual descansa la práctica contable del país. Si bien se han hecho esfuerzos por separar las dos dimensiones, aún hoy estas permanecen. Con la propuesta de adoptar Normas Internacionales de Contabilidad (NIC), se hace necesario separar las dos esferas. Pero las diferencias en los métodos de cálculo y valoración afectan los resultados de la empresa y por tanto su efecto impositivo. Se trata pues del análisis de esta problemática en aras de garantizar los niveles de recaudo y evitar distorsiones en el mercado.

This article presents the results of a qualitative study that explored the development of knowledge, skills and attitudes of a group of foreign language teacher educators and pre-service teachers through their participation in a study group. Sources of data included minutes of meetings, observations, tape recorded meetings, self-assessment forms and interviews. The fi ndings show that teachers developed knowledge about the subject matter and research. Moreover, they developed skills such as research skills, critical thinking and collaborative work, and attitudes such as initiative, commitment, positive attitude towards research, and risk taking. It is concluded that the use of study groups can be an effective strategy for the professional development of teachers. Received: 06-04-07 / Accepted: 06-08-07 How to reference this article: Sierra Piedrahita, A. M. (2007). Developing Knowledge, Skills and Attitudes through a Study Group: A Study on Teachers’ Professional Development. Íkala. 12(1), pp. 279 – 305.

Inflammatory bowel disease (IBD) is rarely associated with obesity, as malabsorption is a common feature of these diseases (1). However, some patients may experience morbid obesity and associated complications refractory to dietary treatment and benefit from bariatric surgery. It has even been postulated that surgery may result in improvement of IBD by reducing inflammatory markers (2). However, patients may experience a higher incidence of complications following surgery in the context of immunosuppressive therapy and prior malabsorption. Therefore, if surgery is performed, careful patient selection and individualization of technique are essential. We present a patient diagnosed with ulcerative colitis who presented severe protein malnutrition after bariatric surgery type bilio-pancreatic diversion and review the available literature. [ABSTRACT FROM AUTHOR]

Inflammatory bowel disease (IBD) is rarely associated with obesity, as malabsorption is a common feature of these diseases (1). However, some patients may experience morbid obesity and associated complications refractory to dietary treatment and benefit from bariatric surgery. It has even been postulated that surgery may result in improvement of IBD by reducing inflammatory markers (2). However, patients may experience a higher incidence of complications following surgery in the con-text of immunosuppressive therapy and prior malabsorption. Therefore, if surgery is performed, careful patient selection and individualization of technique are essential. We present a patient diagnosed with ulcerative colitis who presented severe protein malnutrition after bariatric surgery type bilio-pancreatic diversion and review the available literature. [ABSTRACT FROM AUTHOR]

RESUMEN Introducción: el propofol, administrado por el endoscopista con una enfermera entrenada, ha evolucionado como alternativa a la monitorización anestésica y es cada vez más frecuente en la práctica clínica habitual, incluso en endoscopia avanzada. Objetivo: evaluar la seguridad de la sedación profunda con propofol controlada por el endoscopista en pacientes sometidos a colangiopancreatografía retrógrada endoscópica (CPRE). Material y métodos: estudio prospectivo en los pacientes a los que se les realizó CPRE bajo sedación profunda con propofol. Se incluyeron diferentes variables relacionadas con el paciente y se registraron los datos iniciales y finales de la saturación de oxígeno (SatO2), la tensión arterial (TA), y la frecuencia cardiaca (FC) para determinar la presencia de eventos adversos a la sedación (hipoxemia, hipotensión o bradicardia). Resultados: un total de 661 pacientes fueron sometidos a CPRE bajo sedación con propofol durante un periodo de 24 meses. La tasa de eventos adversos registrada fue del 9,7%. La más frecuente fue la hipoxemia (5,7%), seguida de la bradicardia (2,4%) y de la hipotensión (1,6%). En el análisis univariante, la aparición de eventos adversos a la sedación (EAS) se asoció a una clasificación de ASA ≥ III (p = 0,026), a pacientes de edad más avanzada (p = 0,009), mayor IMC (p = 0,002) y a un tiempo de exploración más prolongado (p = 0,034). La dosis de inducción de propofol también se relacionó con mayor probabilidad de eventos adversos (p = 0,045), pero no la dosis total de propofol administrado (p = 0,153). En el análisis de regresión logística multivariante, la edad, el índice de masa corporal (IMC) y la duración de la exploración se registran como predictores independientes de EAS (p < 0,05). Conclusión: la sedación profunda con propofol controlada por personal de endoscopia entrenado es un método seguro en procedimientos endoscópicos complejos como la CPRE.

Introduction: Smoking can play a key role in SARS-CoV-2 infection and in the course of the disease. Previous studies have conflicting or inconclusive results on the prevalence of smoking and the severity of the coronavirus disease (COVID-19)., Methods: Observational, multicenter, retrospective cohort study of 14,260 patients admitted for COVID-19 in Spanish hospitals between February and September 2020. Their clinical characteristics were recorded and the patients were classified into a smoking group (active or former smokers) or a non-smoking group (never smokers). The patients were followed up to one month after discharge. Differences between groups were analysed. A multivariate logistic regression and Kapplan Meier curves analysed the relationship between smoking and in-hospital mortality., Results: The median age was 68.6 (55.8-79.1) years, with 57.7% of males. Smoking patients were older (69.9 (59.6-78.0 years)), more frequently male (80.3%) and with higher Charlson index (4 (2-6)) than non-smoking patients. Smoking patients presented a worse evolution, with a higher rate of admission to the intensive care unit (ICU) (10.4 vs. 8.1%), higher in-hospital mortality (22.5 vs. 16.4%) and readmission at one month (5.8 vs. 4.0%) than in non-smoking patients. After multivariate analysis, smoking remained associated with these events., Conclusions: Active or past smoking is an independent predictor of poor prognosis in patients with COVID-19. It is associated with higher ICU admissions and in-hospital mortality., (© 2021 Elsevier España, S.L.U. All rights reserved.)

The aim of this study was to analyze the presence of lithogenic metabolic factors in the blood and urine of patients with osteopenia versus osteoporosis. This is a cross-sectional study including 67 patients who were divided into two groups according to the presence of either osteopenia or osteoporosis as measured by bone densitometry: group 1-40 patients with osteopenia (22 men and 18 women) and group 2-27 patients with osteoporosis (13 men and 14 women). Metabolic studies were performed on the blood and urine; statistical analysis was performed comparing means and conducting linear correlation and multivariate analyses with SPSS. Statistical significance was considered to be p ≤ 0.05. The mean age of patients in group 1 was 52.9 ± 12.8 years versus 50.3 ± 11.4 in group 2; the difference was not statistically significant. In group 2, higher levels of osteocalcin, β-crosslaps, urinary calcium, fasting urine calcium/creatinine, 24 h urine calcium/creatinine and 24 h oxaluria were observed compared to group 1. In the multivariate analysis, only the β-crosslaps and urinary calcium were independently associated with osteoporosis. It would be advisable to determine the urinary calcium levels in patients with osteoporosis since altered levels may necessitate modifying the diagnostic and therapeutic approach to osteoporosis.

Aim: To analyze and compare the expression of MTNR1A receptor in normal and pathological major and minor salivary glands., Materials and Methods: Twenty samples of major and minor salivary glands and 10 with Warthin's tumor were studied. Expression of the MTNR1A receptor (goat polyclonal antibody raised against a peptide mapping at the N-terminus of MEL-1A R of human origin) was analyzed., Results: The excretory ducts of major salivary glands demonstrated intense intracytoplasmic positivity but scant cytoplasmic membrane positivity for MTNR1A. The studied Warthin's tumors showed intense cytoplasmic positivity for MT1 receptor in all cylindrical epithelial cells lining spaces and a less intense positivity in basal cells. The lymphoid component accompanying the tumor was negative for MT1 receptor., Conclusion: Intense intracytoplasmic positivity for the MTNR1A receptor in the excretory ducts of human major and minor salivary glands and Warthin's tumor was found. The intense expression of MTNR1A receptors observed in this study in the excretory ducts of major and minor salivary glands may be related to salivary regulation.