Dos nuevos registros para la flora agrostológica de Perú / Two new records for the agrostological flora of Peru

Resumen Se reporta por primera vez la presencia de Piptochaetium bicolor (Vahl) É. Desv. y Trichachne californica var. villosissima (Henrard) Wipff & Shaw para Perú, basada en colecciones realizadas en el ecosistema de formación de lomas costeras del departamento de Arequipa. Se presentan descripciones, fotografías, ilustraciones y una clave taxonómica para cada taxón.

Abstract The presence of Piptochaetium bicolor (Vahl) É. Desv. and Trichachne californica var. villosissima (Henrard) Wipff & Shaw are recorded for the first time from Peru, based upon collections made in the coastal lomas formations ecosystem of the department of Arequipa. Descriptions, photographs, illustrations and a taxonomic key are presented for each taxon.

Medical illustration: a pictorial essay visual illustration of obstetric anal sphincter injuries (OASIS) degrees of severity, a picture is worth a thousand words

Obstetric anal sphincter injury affects about 5.7% of primiparous women who deliver vaginally. Perineal injury during childbirth is a common event with important morbidity associated with third-and-fourth degree perineal tears (also referred to as obstetric anal sphincter injuries -OASIS). As there was a lack of consistency in the classification of a partial anal sphincter injury, with up to 33% of consultant obstetricians classifying a complete or partial tear of the EAS as a second-degree tear. We have proposed simple, digital diagrammatic drawings to visually represent all degrees (grades) of OASIS based on the WHO OASIS classification. (AU)

Edad y crecimiento del pez Fundulus lima (Cyprinodontiformes: Fundulidae) en el río La Purísima, Baja California Sur, México

Introducción: El estudio de la edad y crecimiento en peces es un prerrequisto básico para generar información sobre la longevidad, tasas de crecimiento y estructura poblacional, entre otros atributos, todos ellos para la aplicación de políticas enfocadas en el manejo y conservación poblacional. Evaluamos estos atributos en la sardinilla peninsular en peligro de extinción (Fundulus lima) que habita los oasis de Baja California Sur, con la perspectiva de generar información base de este pez endémico. Objetivo: Determinar la edad, crecimiento somático y estructura de las poblaciones de F. lima en una de las cuencas hidrológicas más importantes de su ámbito de distribución. Métodos: De octubre 2002 a julio 2004 se muestreó F. lima en 4 sitios del río La Purísima por métodos de captura pasiva y activa. Los individuos fueron medidos y pesados en el campo, donde submuestras fueron seleccionadas para el análisis de la edad en escamas. Todos los individuos fueron liberados vivos a sus sitios originales de captura. Estimamos edad, relaciones longitud-peso y longitud-longitud, y estructura poblacional, basados en 802 individuos examinados por técnicas no invasivas. Resultados: El crecimiento somático de F. lima fue alométrico positivo (b > 3.0) en todas las poblaciones estudiadas, con valores de "b" variando de 3.126 (Ojo de Agua) a 3.420 (El Pilón). Tres clases de edad (0, 1 y 2 años) fueron reconocidas, de las cuales la edad 1 fue la más frecuente (49 %). El método polimodal basado en datos de frecuencia de tallas identificó tres clases de edad. Longitudes totales retrocalculadas en edades previas basadas en incrementos de crecimiento en escamas fue entre 38.61 y 68.81 mm para individuos de 1 y 2 años, respectivamente. Conclusiones: Tres clases de edad (0, 1 y 2 años) fueron determinadas para las poblaciones de F. lima en el río La Purísima, basadas en la interpretación de anillos de crecimiento anual en escamas y en la distribución modal de frecuencia de tallas observadas. Todas las poblaciones examinadas demostraron un crecimiento alométrico positivo (b > 3.0).

Introduction: The study of age and growth in fishes is a basic prerequiste to generate information on longevity, growth rates, population structure, among other attributes, all of them for the application of policies focused on the population management and conservation. We evaluated these attributes in the endangered Baja California killifish (Fundulus lima) that inhabits the oases of Baja California Sur, Mexico, with the perspective of generating base information for the conservation of this endemic fish. Objective: To determine the age, somatic growth and population structure of F. lima in one of the most important hydrological basins of its distribution range. Methods: From October 2002 to July 2004 we sampled for F. lima in 4 sites of La Purisima river by using passive and active collection methods. Individuals were measured and weighed in the field, where subsamples were selected for analysis of age based on scales. All of the individuals were released alive to its original sites of capture. We assessed the age, length-weight and length-length relationships and population structure on the basis of 802 individuals examined by non-invasive techniques. Results: The somatic growth of F. lima was of positive allometric type (b > 3.0) in all the populations studied, with values of "b" ranging from 3.126 (Ojo de Agua) to 3.420 (El Pilón). Three age class (0, 1 and 2 years old) were recognized, of which the age 1 year was the most frequent (49 %). The polimodal method based on length-frequency data also identified three age classes. Back-calculated total lengths at previous ages based in increments of growth in scales were 38.61 and 68.81 mm for individuals of 1 and 2 years, respectively. Conclusions: Three age classes (0, 1 and 2 years old) were determined for the populations of F. lima in La Purisima river, based on the interpretation of annual growth rings in scales and in the modal distribution of observed length frequencies. All the populations examined showed a positive allometric growth (b > 3.0).

Effects of OASIS iris expander in phacoemulsification surgery of cataract with small pupil / 眼科新进展

Objective To assess the outcomes of OASIS iris expander in phacoemulsification surgery of cataract with small pupil.Methods A prospective case-control study was conducted in 22 microcoria cataract patients (22 eyes).And they were randomly divided into group A and B,in which the pupils of group A were dilated by tearing instruments in 13 eyes,and the pupils of group B were dilated using OASIS iris expander in 9 eyes.All patient underwent phacoemulsification with 3.2 mm clear corneal incision and were followed up at postoperative 1 week,1 month,3 months and 6 months.Finally,the best corrected visual acuity (BCVA),intraocular pressure (IOP),corneal endothelial cell counts,pupil size before and after surgery were recorded and analyzed by an independent sample t test.Results All procedures were completed successfully by the same skilled doctor.Intraocular lenses were implanted in capsule completely,and no complications occurred.At 6 months after operation,patients'BCVA in group A (0.41 ± 0.30) and group B (0.77 ± 0.23) was significantly higher than that in group A (0.17 ±0.14) and group B (0.16 ±0.14) before operation,but there was no statistical difference between the two groups (all P ＞0.05);whereas there was no significant change in the IOP of group A and B at 6 months after operation (1 kPa =7.5 mmHg) and before operation [(14.22 ±6.00) mmHg vs.(15.70 ± 5.70) mmHg)] (all P ＞ 0.05).Moreover,corneal endothelial cell counts in group A [(1486 ±718) cells · mm-2] and B [(1246 ±516)cells · mm-2] were significantly smaller than those before operation [(2498 ±564)cells · mm-2 vs.[(2424 ± 640) cells · mm-2],with no significant difference (P=0.091).The postoperative diameter of the pupil in group A [(4.00 ±0.88) mm] and group B [(4.70 ± 1.57) mm] after operation was larger than that in group A [(2.30 ±0.35)mm] and group B [(1.94 ±0.50)mm] before operation,and there was no statistical difference between the two groups (all P ＞0.05).Conclusions OASIS iris expander can help to dilate and hold pupils and does not affect the postoperative visual acuity and intraocular pressure in mlcrocoria cataract phacoemulsification.The postoperative pupils become larger,and it is necessary to pay attention to protect corneal endothelial cell during usage of OASIS iris expander.

Effect of built-in type OASIS iris expander in phacoemulsification surgery for cataract with small pupil / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To observe the effect of built-in type OASIS iris expander in phacoemulsification surgery for cataract with small pupil. <p>METHODS: Totally 44 cataract patients with small pupil were treated in our hospital from January 2016 to October 2017 were randomly divided into the control group(22 cases, 31 eyes)and the observation group(22 cases, 30 eyes). The patients in control group was treated by conventional phacoemulsification surgery, within surgery the small pupils were dilated by cleavage and lens position hook; the patients in observation group use OASIS iris expander within surgery. The best corrected visual acuity(BCVA), corneal endothelial cell counts, pupil size, intraocular pressure(IOP)of two groups before and after surgery were compared and analyzed, and the application effect of built-in type OASIS iris expander was evaluated. <p>RESULTS: At 1mo after operation, the BCVA of the two groups were significantly improved, and the BCVA of the observation group(0.09±0.04)was significantly better than that of the control group(0.20±0.03), the difference was statistically significant(<i>P</i><0.05). At 1mo after operation, the corneal endothelial cell counts of the two groups were significantly decreased, but the corneal endothelial cell counts of the observation group(2455.77±52.98/mm²)were significantly higher than those of the control group(2298.94±49.12/mm²), the difference was statistically significant(<i>P</i><0.05). At 1mo after operation, the pupil diameter of the two groups was enlarged(<i>P</i><0.05), and the pupil diameter of the observation group(3.52±1.14mm)was larger than that of the control group(3.15±1.02mm, <i>P</i>>0.05). At 6mo after operation, the pupil diameter of the two groups was significantly enlarged(<i>P</i><0.05), but there was no significant difference in the pupil diameter between the two groups(<i>P</i>>0.05). At 1mo after operation, intraocular pressure in both groups was lower than that before operation(<i>P</i><0.05), and the intraocular pressure in observation group(13.40±1.73mmHg)was lower than that in control group(13.93±1.98mmHg, <i>P</i>>0.05). At 6mo after operation, intraocular pressure in both groups was lower than that before operation and 1mo after operation(<i>P</i><0.05), but there was no significant difference in intraocular pressure between the two groups at 6mo after operation(<i>P</i>>0.05). <p>CONCLUSION: The OASIS built-in iris dilator can improve the best corrected visual acuity, reduce intraocular pressure and expand pupil diameter in small pupil phacoemulsification.

The study of the value of Oxford Acute Severity of Illness Score in assessing the severity of critical illness patients: a single-center analysis of 470 cases / 中华急诊医学杂志

Objective To explore the value of Oxford acute severity of illness score in evaluating the severity and prognosis of critical illness patients.Methods All adult patients admitted to the Department of Critical Care Medicine from August 2012 to July 2014 were retrospectively analyzed.The severity in survivors and non-survivors was evaluated by using Oxford acute severity of illness score and APACHE Ⅲ score,and then statistic analysis were performed.Results Of 470 patients,321 (68.297％) were male,the range of age and ((x) ±s) age were 18 to 97 years and (59 ± 18) years respectively,and 123 patients (26.170％) were in non-survivors group and 347 patients in survivors group.The area under the ROC of Oxford acute severity of illness score was 0.760 (95％ CI:0.712-0.808,P ＜ 0.001),and Youden index was biggest when Oxford acute severity of illness score was 30.5.The area under the ROC of APACHE Ⅲ score was 0.844 (95％ CI:0.806-0.882,P ＜ 0.01),and Youden index was biggest when APACHE Ⅲ score was 70.5.Mortality was high (above 70％) as Oxford acute severity of illness score increased (＞ 40),and Spearman r was 0.976 (P ＜ 0.01).Conclusions Oxford Acute Severity of Illness Score was useful to evaluating the severity and prognosis of critical illness patients and it was easy in clinical practice.

The Effects of Age, Gender and Head Size on the Cortical Thickness of Brain

OBJECTIVES: Standardization of head size is essential for the volume study. Cortical thickness analyses are increasingly being used in many fields of neuroscience. However, it is not established whether head size correction should be done for thickness study. METHODS: Using the Open Access Series of Imaging Studies data, we determined cortical thickness of 316 cognitively normal participants aged 18-94 with FreeSurfer. The association between head size and cortical thickness of whole cortical mantle and in each lobe among age tertile groups was assessed. Estimated total intracranial volume (eTIV) was calculated for determining head size. RESULTS: Across all participants, cortical thickness in whole brain except some areas in cingulate and insula decreased with aging. eTIV had positive correlation with the thickness of frontal, parietal, occipital and whole brain areas. However, the age effect was not shown in whole brain of the first tertile group and in cingulate areas of the third tertile group. eTIV had negative correlation with the thickness of cingulate in the third tertile group. Gender effects were shown in some areas in third tertile group, but it would be due to difference of head size. CONCLUSIONS: These findings suggest that head size standardization might be done especially in older population and in studies of paralimbic areas.

Evaluation of self-perceived dental aesthetics and orthodontictreatment need among young adults / Avaliação da autopercepção da estética dental e da necessidade detratamento ortodôntico entre pacientes adultos jovens

Objectives: The aim of the study was to assess the self-perception of dental aesthetics and orthodontic treatment need in a group of young adults. Materials and methods: Perception of dental aesthetics and orthodontic treatment need was assessed among 189 first year university undergraduates using the Oral Aesthetic Subjective Impact Scale (OASIS), a visual analogue scale (VAS), and the Aesthetic component (AC) scale of the Index of Orthodontic treatment Need (IOTN). Data analysis was done using SPSS version 11.0. Descriptive statistics and Chi-square tests were used. One way analysis of variance (ANOVA) was used to identify differences in the mean VAS and OASIS scores according to perceived orthodontic treatment need on the AC scale of IOTN. The relationship between the various scales was examined using correlation tests. Statistical significance was set as p < 0.05. Results: The mean OASIS and VAS scores were 13.61 ± 5.98 and 75.64 ± 18.40 respectively. According to the AC scale of IOTN, 86.8% of participants rated themselves as having no need for treatment, 7.4% borderline need and 5.8% great need for orthodontic treatment. Comparison of mean OASIS and VAS scores according to the AC category showed a trend towards higher mean OASIS scores and lower VAS scores with greater treatment need. ANOVA showed there were significant differences between the AC groups in mean OASIS and VAS scores. Spearman‘s correlation tests between the 3 scales gave low results. Conclusion: There was a low correlation between the OASIS, VAS and AC scale of IOTN in evaluating self-perception of dental aesthetics and orthodontic treatment need. The OASIS and VAS were able to discriminate between participants with different degrees of treatment need.

Objetivos: O objetivo do estudo foi avaliar a autopercepção da estética dentária e necessidade de tratamento ortodôntico em um grupo de adultos jovens. Materiais e métodos: A percepção da estética e a necessidade de tratamento ortodôntico foram avaliadas entre 189 estudantes universitários do primeiro ano, usando a Escala Ortodôntica de Impacto Subjetivo (OASIS), uma escala visual analógica (VAS), e a Escala de Componente Estético (AC) do Índice de Necessidade de Tratamento Ortodôntico (IOTN). A análise dos dados foi feita usando SPSS versão 11.0. Estatística descritiva e Qui-quadrado foram utilizados. Análise de variância (ANOVA) foi utilizada para identificar diferenças entre as médias e pontuações de VAS e OASIS de acordo com a necessidade percebida de tratamento ortodôntico na escala AC de IOTN. A relação entre as várias escalas foi examinada utilizando ensaios de correlação. A significância estatística foi definida como p < 0,05. Resultados: As medias e desvios padrão de OASIS e VAS foram 13,61 ± 5,98 e 75,64 ± 18,40, respectivamente. De acordo com a escala AC de IOTN, 86,8% dos participantes se classificaram como não tendo necessidade de tratamento, 7,4% ficaram na situação limítrofe de necessidade, e 5,8% relataram grande necessidade de tratamento ortodôntico. A comparação entre as medias de OASIS e VAS de acordo com a categoria AC mostrou uma tendência de maior escore para OASIS e mais baixo escore para VAS, com maior necessidade de tratamento. ANOVA mostrou que houve diferenças significativas entre os grupos OASIS e VAS. Testes de correlação de Spearman entre as três escalas apresentaram resultados baixos. Conclusões: Houve uma baixa correlação entre o OASIS, VAS e escala de AC de IOTN na avaliação de autopercepção da estética dentária e necessidade de tratamento ortodôntico. OASIS e VAS foram capazes de discriminar entre os participantes com diferentes graus de necessidade de tratamento.

Orthodontic treatment need of children in Trinidad and Tobago / Necesidad de tratamiento ortodóntico de los niños en Trinidad y Tobago

OBJECTIVE: This prospective cross-sectional study was undertaken to determine the normative and perceived orthodontic treatment needs of children aged 11-12 years in a Caribbean country, Trinidad and Tobago. METHODS: One author, an experienced orthodontist, examined 367 children using the Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN) to assess the normative need. The same orthodontist administered the questionnaire to assess the patient's perceived needs using the Aesthetic Component (AC) of the IOTN and the Oral Aesthetic Subjective Impact Scale (OASIS). RESULTS: The DHC and the AC of the IOTN and the OASIS showed respectively that 61.4%, 2.5% and 0.6% of the children had definite need for orthodontic treatment. The female proportion of the sample was more than the target population but the perceived need and normative need for orthodontic treatment did not depend significantly (p < 0.05) on the gender or ethnicity of the subjects of this study. The perception of need for orthodontic treatment differed inversely from the normative need and this is seen to be significant (p < 0.05) when OASIS was used. CONCLUSIONS: Approximately three out of five children in Trinidad and Tobago have a great (or very great) need for orthodontic treatment for dental health reasons.

OBJETIVO: Este estudio prospectivo transversal fue emprendido con el objeto de determinar las necesidades del tratamiento ortodóntico normativo y percibido para niños de 11-12 años de edad en un país caribeño - Trinidad y Tobago. MÉTODOS: Un autor - ortodoncista experimentado - examinó a 367 niños usando el Componente de Salud Dental (DHC) del Índice de Necesidad del Tratamiento Ortodóntico (IOTN) para evaluar la necesidad normativa. El mismo ortodoncista aplicó la encuesta para evaluar las necesidades percibidas del paciente usando el Componente Estético (CA) del IOTN y Escala ortodóntica de impacto estético subjetivo (OASIS). RESULTADOS: El DHCy el CA del IOTNy el OASIS mostraron respectivamente que 61.4%, 2.5% y .6% de los ninos tenían una necesidad definida de tratamiento ortodóntico. La proporción de hembras de la muestra fue mayor que la población objetivo, pero la necesidad percibida y la necesidad normativa de tratamiento ortodóntico no dependia significativamente (p < 0.05) del género o etnicidad de los sujetos de este estudio. La percepción de la necesidad de tratamiento ortodóntico difería inversamente de la necesidad normativa y puede verse que es significativa (p < 0.05) cuando el OASIS fue usado. CONCLUSIONES: Aproximadamente tres de cada cinco ninos en Trinidad y Tobago tienen una necesidad grande (o muy grande) de tratamiento ortodóntico por razones de salud dental.

Seasonal diet composition of Fundulus lima (Cyprinodontiformes: Fundulidae) in two oasis systems of Baja California Sur, Mexico

Fundulus lima inhabits river drainage systems and is threatened after the introduction of cichlids in the area. To support conservation programs, the spatial and temporal variation of the diet composition of this endangered killifish, was determined in two oasis systems of Baja California Sur, Mexico (San Ignacio and La Purisima river drainages), during rainy and dry seasons. F. lima was captured by using passive and active capture techniques. A total of 192 stomach contents of F. lima was analyzed. The contribution of each prey item in the diet composition was quantified by means of the indices of occurrence frequency (% OF), numerical (%N) and volume (%V) percentages. The relative importance of each prey item was determined according to the percentage of the Relative Importance Index (%RII). The similarity of the diet was calculated between hydrological basins (populations combined by basin), seasons (rainy versus dry months), sexes and size classes, by using Schoener’s resource overlap index. We used two ecological indices to determine the type of feeding strategy exhibited by the fish: (1) niche breadth of Levins and (2) proportional similarity of Feisinger. Sand was the most abundant item in the stomach content of killifishes from both drainages (39% and 47%, respectively). Diet composition was similar for both drainages (74%) as well as among their respective size classes; however, it was different between sexes. In both drainages, F. lima predated mainly on diatom algae, dipterous and trichopteran larvae, and fish scales during the dry season; while it preferred dipterous larvae, filamentous algae and ostracods in the rainy season. A feeding strategy of opportunist type was exhibited by F. lima during the rainy season, changing to specialist type during the dry season. This information will be the basis for future investigations related to the conservation of this endangered species and its habitat. Rev. Biol. Trop. 59 (4): 1669-1678. ...

Fundulus lima habita sistemas de aguas continentales, y se encuentra amenazado tras la introducción de cíclidos en el área de estudio. Para poder llevar a cabo programas de conservación, fue determinada la dieta de la sardinilla peninsular en peligro de extinción, en dos sistemas de oasis de Baja California Sur, México (cuencas de los rios San Ignacio y La Purísima), durante las épocas secas y de lluvias. Una gran proporción de arena fue encontrada en el contenido estomacal de este pez para ambas cuencas (39% y 47%, respectivamente). La composición de la dieta fue similar entre ambas cuencas (74%), como también dentro de sus respectivas clases de tallas; sin embargo, fue diferente entre sexos. Durante la época de secas, F. lima consumió principalmente diatomeas, larvas de dípteros y tricópteros, además de escamas de peces; mientras que en la época de lluvias tuvo preferencia por las larvas de dípteros, algas filamentosas y ostrácodos. Este pez exhibe una estrategia alimentaria de tipo oportunista durante la época de lluvias, la cual cambia a tipo especialista en la época de secas. Esta información será la base para futuras investigaciones relacionadas con la conservación de esta especie, en peligro de extinción, y su hábitat.

Socioeconomic interest and valorization of medicinal plants from the Rissani oasis (SE of Morocco) / Interés socioeconómico y valorización de plantas medicinales del oasis de Rissani (SE de Marruecos)

The survival and sustenance of man depends largely on plants which generate directly 87 percent of its food needs and constitute a source of basic health care in developing countries. Based on socio-economic surveys and field observations led in the Rissani oasis (SE of Morocco), we have identified 109 species belonging to 45 botanical families and 102 genera. The distribution in families is: Lamiaceae (15.2 percent, Asteraceae (11.5 percent), Fabaceae (8.46 percent, Poaceae (8.12 percent) and Apiaceae (6.75 percent). The species used in traditional medicine correspond to 57.8 percent, for food 10.1 percent and for other uses 28.4 percent. Of these species, 10.1 percent are cultivated, naturalized, introduced and/or weeds. Byproducts of 46.8 percent of these species are imported from other regions of Morocco and locally marketed. Many medicinal species from this area are not recognized by the inhabitants, and their sensitization towards the use and conservation of local plant diversity is needed.

La supervivencia y sustentabilidad de la humanidad depende en gran medida de las plantas. Estas satisfacen directamente el 87 por ciento de sus necesidades alimenticias y constituyen, en países en desarrollo, una fuente para el cuidado de salud. Basados en estudios y observaciones de campo realizadas en el oasis de Rissani (SE de Marruecos), hemos identificado las 109 especies de plantas más utilizadas que pertenecen a 45 familias y 102 géneros. La distribución por familia es: Lamiaceae (15.2 por ciento), Asteraceae (11.5 por ciento), Fabaceae (8.46 por ciento), Proaceae (8.12 por ciento) y Apiaceae (6.75 por ciento). Las especies utilizadas en medicina tradicional corresponden al 57.8 por ciento, en alimentación 28.5 por ciento y para usos múltiples 28.4 por ciento. De estas especies el 10.1 por ciento son cultivadas, naturalizadas, introducidas y/o corresponden a malezas. Subproductos del 48.8 por ciento de estas especies son importados de otras regiones de Marrueco para su comercialización. Muchas de las especies medicinales no son reconocidas por los habitantes del oasis y es necesario sensibilizarlos en relación a su utilización y conservación.

Distribución de aves acuáticas en las lagunas de oxidación de la ciudad de La Paz, Baja California Sur, México

Distribution of aquatic birds in oxidation lagoons of La Paz city in South Baja California, Mexico. Taxonomic composition, spatial and temporal distribution of aquatic birds in oxidation lagoons (LO) of La Paz city in south Baja California, Mexico, were determined during 24 censuses realized in two-week intervals (April/98-March/99). There are five lagoons of 5 Ha each and 17 ha of terrains constantly flooded that serve as feeding areas for cattle and birds. One hundred twenty three species were observed, 75 of which were aquatic birds. A total of 46 041 observations were made (average 1 918 birds/census). Richness and abundance of aquatic birds were influenced mainly by migration of anatids and sandpipers. The first group had the greatest abundance due to its affinity towards fresh water bodies. The terrains were the favorite sites of dabbling ducks (Anas) and sandpipers. In contrast, two of the most abundant species (Oxyura jamaicensis, 12.5 % of all species, and Fulica americana, 8.8 %) restricted their presence to the oxidation lagoons. LO presented a bird structure of its own and atypical, according to the dryness of the region. Rev. Biol. Trop. 55 (2): 617-626. Epub 2007 June, 29.

Se determinó la composición taxonómica y la distribución espacial y temporal de aves acuáticas de las lagunas de oxidación (LO), de la ciudad de La Paz, Baja California Sur, México, durante 24 censos quincenales (abril/98marzo/99). Se trata de cinco lagunas, de cinco ha cada una y 17 ha de terrenos aledaños constantemente inundados que sirven como zona de alimentación para el ganado y las aves. Se observaron 123 especies de aves, de las cuales 75 fueron acuáticas. En total se realizaron 46 041 registros (promedio= 1 918 aves/censo). La riqueza y la abundancia estuvieron influenciadas por la migración, principalmente de anátidos y playeros, los primeros fueron el grupo más abundante, debido a su afinidad por cuerpos dulceacuícolas. Los terrenos aledaños fueron los preferidos por los patos vadeadores (Anas) y por los playeros. En contraste, dos de las especies más abundantes (Oxyura jamaicensis 12.5 % del total y Fulica americana 8.8 %), restringieron su presencia al espejo de agua. LO presentó un componente aviar propio y atípico, dada la aridez de la región.