Resumen Los hábitos de selección de refugios de los murciélagos de ventosas del género Thyroptera (Chiroptera: Thyropteridae) han sido desconocidos o muy poco conocidos, con excepción a los hábitos de T. tricolor, que es la especie que se encuentra comúnmente. Muchas publicaciones de literatura secundaria afirman que los hábitos de selección de refugio de los Thyroptera en general son los mismos que los de tricolor, que son conocidos por descansar casi exclusivamente en hojas grandes verticales y parcialmente enrolladas, especialmente hojas de Heliconia nativa y banano introducido (género Musa). Sin embargo, por el momento no se conoce ninguna otra especie de Thyroptera que elija este tipo de refugio. Hasta 1993, las únicas especies de Thyroptera conocidas eran tricolor y discifera y habían sido las únicas dos especies conocidas durante 139 años. Durante este largo período, los hábitos particulares de selección de refugios de tricolor frecuentemente se atribuyeron a todo género, como a veces todavía sucede hoy en día. Actualmente se conocen tres especies más en este género: lavali, devivoi y wynneae. En este artículo, corregimos los conceptos erróneos sobre selección de refugios en Thyroptera, resumimos lo que se conoce de las cinco especies y brindamos las primeras observaciones detalladas sobre la selección de refugios de discifera. Thyroptera discifera se ha encontrado descansando adherido a la parte inferior de un folíolo o folíolos de palma en Brasil y en porciones de hojas muertas de plátano enrolladas cónicamente en Costa Rica.

Abstract Roosting habits of disk-winged bats of the genus Thyroptera (Chiroptera: Thyropteridae) have been unknown to very poorly known except for those of the commonly encountered T. tricolor. Many secondary literature publications state that roosting habits of Thyroptera in general are those of tricolor, known to roost almost exclusively in vertical, unfurling large leaves, especially of native Heliconia and introduced banana (genus Musa). However, so far as known, no other species of Thyroptera chooses such roosts. Until 1993, the only species of Thyroptera known were tricolor and discifera-they had been the only two known for 139 years. During this long period, the unique roosting habits of tricolor often were attributed to the genus as a whole, as sometimes still happens today. Now there are three more known species-lavali, devivoi, and wynneae. In this paper, we correct misconceptions concerning roosting habits in Thyroptera, summarize what is known for all five species, and provide the first detailed observations on roosting in discifera. Thyroptera discifera has been found roosting attached to the underside of a palm leaflet or leaflets in Brazil and in conically curled portions of dead banana leaves in Costa Rica.

Resumo O objetivo deste trabalho foi avaliar o desenvolvimento e a sobrevivência de larvas de terceiro estágio (L3) de Haemonchus contortus em forrageiras na Amazônia Oriental. Foram utilizados quatro canteiros compostos por Megathyrsus maximus 'Massai', M. maximus 'Mombaça', Urochloa brizantha 'Marandu' e Urochloa humidicola, os quais foram divididos em 13 parcelas cada um. Fezes de ovinos com cerca de 10.000 ovos de H. contortus foram depositadas em cada parcela. Amostras de capim, fezes e solo foram coletadas no no sétimo, no décimo quinto e no trigésimo dia pós-contaminação (DPC) e, sequencialmente, a cada 30 dias até o trecentésimo trigésimo DPC. Foram determinados os seguintes dados das gramíneas: microclimáticos, como temperatura, umidade relativa do ar, umidade do solo e luminosidade do capim, e macroclimáticos, como pluviosidade, temperatura, umidade relativa do ar e radiação solar. As larvas do terceiro estágio foram recuperadas em todas as amostras de gramíneas e solo, em todas as parcelas, do sétimo ao trecentésimo trigésimo DPC. Os parâmetros microclimáticos mostram correlações entre a recuperação de L3 na grama e no solo, e os parâmetros macroclimáticos, entre a recuperação de L3 nas fezes e na grama. Urochloa humidicola e M. maximus 'Massai' favorecem o desenvolvimento e a sobrevivência de L3 de H. contortus, enquanto U. brizantha 'Marandu' e M. maximus 'Mombaça' apresentam menor biodisponibilidade dessas larvas.

Abstract The objective of this work was to evaluate the survival of third-stage larvae (L3) of Haemonchus contortus in forage species in the Eastern Amazon. Four paddocks composed of Megathyrsus maximus 'Massai', M. maximus 'Mombaça', Urochloa brizantha 'Marandu', and Urochloa humidicola were used and divided into 13 plots each. Sheep feces containing about 10,000 eggs of H. contortus were deposited in each plot. Grass, feces, and soil samples were collected on the seventh, fifteenth, and thirtieth day post-contamination (DPC), and, then, they were sequentially collected every 30 days until the three-hundredth and thirtieth DPC. The following data were determined for the grass species: microclimatic, such as temperature, relative humidity, soil moisture, and grass luminosity, as well as macroclimatic data for rainfall, temperature, relative humidity, and solar radiation. L3 were recovered on all grasses and soil samples, in all plots, from the seventh to the three-hundredth and thirtieth DPC. The microclimatic parameters show correlations between the L3 recovery on grass and in the soil, and the macroclimatic parameters, between the L3 recovery in feces and on grass. Urochloa humidicola and M. maximus 'Massai' favor the development and survival of L3 of H. contortus, while U. brizantha 'Marandu' and M. maximus 'Mombaça' show a lower bioavailability of these larvae.

Abstract: Genetic studies provide important insights into the evolutionary history and taxonomy of species, allowing us to identify lineages difficult to distinguish morphologically. The relationships among species in the genus Heteromys have been in flux as new species have been described, and candidate species have been suggested in the H. desmarestianus group. One new potential species may be in Costa Rica’s Caribbean lowlands. Herein, we test the phylogenetic relationships of individuals from Costa Rica’s Caribbean lowlands to individuals from throughout the species’ range using mitochondrial sequences from cytochrome-b (cytb). We captured 116 individuals from the lowlands, sequenced their cytb gene, and incorporated 74 GenBank sequences from throughout the species’ range to test if individuals from Costa Rica’s Caribbean lowlands potentially constitute an undescribed species. Our results document a distinct mitochondrial lineage in the Caribbean lowlands of Costa Rica. Our results from extensive sampling within the lowlands show a unique mitochondrial DNA lineage, which suggests the presence of an undescribed species. The Caribbean lowlands of Costa Rica may hold other cryptic diversity, and further phylogenetic studies should incorporate samples from this area, as it may have a unique evolutionary history.

Resumen: Los estudios genéticos proporcionan información importante sobre la historia evolutiva y la taxonomía de las especies, lo que nos permite identificar linajes difíciles de distinguir morfológicamente. Las relaciones filogenéticas entre las especies del género Heteromys han estado cambiando a medida que se han descrito nuevas especies y se han sugerido especies candidatas en el grupo H. desmarestianus. Una nueva especie potencial podría encontrarse en las tierras bajas del Caribe de Costa Rica. En este trabajo analizamos las relaciones filogenéticas entre individuos de las tierras bajas del Caribe de Costa Rica con individuos de todo el rango de la especie utilizando secuencias mitocondriales del citocromo-b (cytb). Capturamos 116 individuos de las tierras bajas, secuenciamos su gen cytb e incorporamos 74 secuencias GenBank de todo el área de distribución de la especie para probar si los individuos de las tierras bajas del Caribe de Costa Rica constituyen potencialmente una especie no descrita. Nuestros resultados indican la presencia de un linaje distinto basado en el ADN mitocondrial, que sugiere que los individuos de las tierras bajas del Caribe de Costa Rica probablemente son una especie distinta. Las tierras bajas del Caribe de Costa Rica pueden tener una diversidad críptica significativa. Por ello sugerimos que estudios filogenéticos adicionales deberían incorporar muestras de esta área, ya que puede tener una historia evolutiva única.

The use of chitosan biofilm in biomedical fields has a vast therapeutic potential due to useful properties such as biodegradability and antimicrobial activity, however, to achieve successful application some physicochemical properties need to be improved. In this context, the addition of glycerol to this biofilm is an alternative to improve its wettability and flexibility. Thus, low and high concentrations of plasticizer were added to this biomaterial for later characterization regarding its wettability, microstructure, mechanical and chemical properties. Glycerol addition to chitosan resulted in biofilms with more homogeneous surfaces, increased wettability, and increased flexibility, without significant changes in its chemical structure.

Abstract: Background: The genus Hampea (Malvaceae: Gossypieae) has 21 reported species and occurs in Mexico, Central America and Colombia. Mexico has eleven species, of which seven are endemic. Hampea is of special conservation interest because its members are wild relatives of cultivated cotton and several species are apparently threatened by anthropogenic activities. Questions: What is the conservation status of species of Hampea in Mexico? Study site and years of study: Observations were made in the field during 1991-1995, 2012 and 2016 in southern Mexico. Specimen data was obtained from the CONABIO data base and from national and international herbaria from 2014-2016. Methods: The conservation status of species of Hampea in Mexico was evaluated using criteria given in the Methods of the Evaluation of Risk of Extinction of Plants (MER-Plantas) (NOM-059-SEMARNAT-2010). The potential distribution was calculated using Maximum Entropy Algorithm and biological data for species were obtained from literature and field observations. Results: Seven species of the genus Hampea were considered to be in a category of risk under the MER-Plantas criteria. Hampea montebellensis, H. breedlovei, and H. longipes were categorized as “at Risk of Extinction,” (En Peligro de Extinción ); H. latifolia was categorized as “Threatened” (Amenazada) and H. stipitata, H. mexicana, and H. tomentosa categorized as “Subject to Special Protection” (Sujeto a Protección Especial). Conclusions: The species H. breedlovei, H. montebellensis, H. longipes, H. latifolia, H. mexicana, H. stipitata and H. tomentosa need to be included in ex situ and in situ conservation programs.

Resumen: Antecedentes: El género Hampea (Malvaceae: Gossypieae) está compuesto por 21 especies y se encuentra en México, América Central y Colombia. México tiene once especies de las cuales, siete son endémicas. Hampea es de interés especial para la conservación porque son plantas silvestres parientes del algodón cultivado y algunas especies son amenazadas por actividades antropogénicos. . Preguntas: ¿Cuál es el estatus de conservación de las especies de Hampea en México? Sitio y años de estudio: Se realizaron observaciones en el campo en el sur de México durante 1991-1995, 2012 y 2016. Se obtuvieron datos de especímenes de los base de datos de CONABIO y datos de herbarios nacionales e internacionales de 2014-2016. Métodos: El estatus de conservación del género Hampea en México fue evaluado usando los criterios de Método de Evaluación del Riesgo de Extinción de Plantas (MER-Plantas) de NOM-059-SEMARNAT-2010. La distribución potencial y de las especies fueron evaluadas con el algoritmo Maximum Entropy y datos biológicos fueron obtenidos de una revisión de la literatura y de observaciones en el campo. Resultados: Siete especies del género Hampea fueron consideradas entre un criterio de riesgo de MER-Plantas. Hampea montebellensis, H. breedlovei y H. longipes fueron categorizadas como “En Peligro de Extinción”; H. latifolia como “Amenazada” y H. stipitata, H. mexicana y H. tomentosa fueron consideradas como “Sujeto a Protección Especial.” Conclusiones: Las especies H. breedlovei, H. montebellensis, H. longipes, H. latifolia, H. mexicana, H. stipitata, y H. tomentosa requieren ser incorporadas en programas de conservación ex situ e in situ.

BACKGROUND: Xpert® MTB/RIF is a molecular test for the detection of Mycobacterium tuberculosis and rifampicin resistance. It is considered to be a great advance over smear microscopy and culture. However, there is very little information regarding the performance characteristics of Xpert MTB/RIF in Malawi. OBJECTIVE: We aimed to evaluate the performance of Xpert MTB/RIF in a Malawian setting. METHODS: Stored sputum pellets were processed on Xpert MTB/RIF between June 2012 and May 2014. Results were compared to mycobacteria growth indicator tube and Löwenstein-Jensen cultures, LED fluorescent microscopy and GenoType® MTBDRplus assay. Rifampicin resistance was confirmed by DNA sequencing. RESULTS: Of the 348 specimens with valid Xpert MTB/RIF results, 129/348 (37%) were smear-positive and 198/348 (57%) were culture-positive. Xpert MTB/RIF demonstrated a sensitivity of 93.8% (95% CI 89.4% - 96.8%) and specificity of 97.4% (95% CI 93.5% - 99.3%), with a positive predictive value of 97.8% (95% CI 94.6% - 99.4%) and a negative predictive value of 92.6% (95% CI 87.4% - 96.1%). Xpert MTB/RIF correctly identified 185/186 (99.5%) rifampicin-sensitive and 2/2 (100%) rifampicin-resistant M. tuberculosis strains. Mutations were not detected by sequencing in one isolate which was rifampicin resistant on Xpert MTB/RIF but sensitive on MTBDRplus. Four non-tuberculous mycobacteria grew from four smear-negative specimens, namely, M. avium (n = 1) and M. intracellulare (n = 3). No cross-reactivity was observed with any of the non-tuberculous mycobacteria when using Xpert MTB/RIF. CONCLUSION: When fully implemented, Xpert MTB/RIF may have an impact on patient care in Malawi. The increased diagnostic yield of Xpert MTB/RIF over smear microscopy can increase laboratory-confirmed tuberculosis detection and ensure that treatment is given to appropriate individuals or groups.

ABSTRACT The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions.

We used genus/species specific PCRs to determine the temporal persistence of host DNA in Triatoma infestans experimentally fed on blood from six common vertebrate species: humans, domestic dogs, guinea pigs, chickens, mice, and pigs. Twenty third or fourth instar nymphs per animal group were allowed to feed to engorgement, followed by fasting-maintenance in the insectary. At 7, 14, 21, or 28 days post-feeding, the midgut contents from five triatomines per group were tested with the respective PCR assay. DNA from all vertebrate species was detected in at least four of five study nymphs at seven and 14 days post-feeding. DNA of humans, domestic dogs, guinea pigs, pigs, and chickens were more successfully detected (80-100%) through day 21, and less successfully (20-100%) at day 28. Findings demonstrate that species-specific PCRs can consistently identify feeding sources of T. infestans within two weeks, a biologically relevant time interval.

Se utilizó pruebas PCR género o especie específicas para determinar la persistencia temporal de ADN del hospedero en el contenido intestinal de Triatoma infestans que fueron alimentados experimentalmente con sangre de seis vertebrados muy frecuentemente asociados a enfermedad de Chagas: humano, perro, cobayo, pollo, ratón, y cerdo. Se emplearon 20 ninfas de tercer y cuarto estadio por cada especie de hospedero. Fueron alimentados a saciedad y mantenidas en el insectario sin alimentación posterior. Se obtuvo el contenido intestinal de cinco triatominos por cada grupo a los 7, 14, 21 y 28 días post - alimentación, que fueron evaluados con los respectivos PCRs específicos. El ADN de todos los vertebrados fue detectado en al menos 4 de 5 ninfas evaluadas a los 7 y 14 días post - alimentación. El ADN de humano, perro, cobayo, cerdo y pollo fue detectado exitosamente (80-100%) hasta el día 21 y con menos éxito (20-100%) en el día 28. Estos resultados demuestran que PCRs específicos para cada especie de hospedero pueden identificar consistentemente la fuente de alimentación de T. infestans dentro de las dos semanas post - alimentación, siendo un intervalo de tiempo biológicamente relevante.

Foram avaliados os efeitos da estrutura física de habitats em comunidades de macroinvertebrados bentônicos em três reservatórios: Serra Azul (SA), Vargem das Flores (FV) e Ibirité (IB). Mensurações de variáveis físicas e químicas e comunidade bentônica foram realizadas em 30 estações de amostragem em cada reservatório. Em SA, foram coletados 12 táxons com predomínio de Melanoides tuberculatus Müller, 1774 (15,2%) e Chaoboridae (63,8%). Em VF foram coletados 11 táxons sendo M. tuberculatus (34,2%) e Oligochaeta (33,6%) os dominantes. Em IB foram coletados 7 táxons com domínio de M. tuberculatus (91,2%) e Chaoboridae (6,27%). Em Serra Azul foi observada influência significativa do sub-bosque arbustivo e do ângulo de inclinação do barranco. Nos reservatórios de Ibirité e Vargem das Flores as variáveis significativas foram cobertura do solo, influência humana e macrófitas aquáticas. Concluímos que as ações humanas reduzem a cobertura da vegetação terrestre e a complexidade de habitats físicos na região litorâneos dos reservatórios, levando a uma redução na qualidade de água. Essas mudanças, por sua vez, reduzem a riqueza taxonômica dos macroinvertebrados bentônicos.

We assessed the effects of physical habitat structure on benthic macroinvertebrate communities in 3 reservoirs: Serra Azul (SA), Vargem das Flores (VF) and Ibirité (IB). We sampled physical and chemical habitat and benthic macroinvertebrates at 30 systematic sites in each reservoir. In SA, the dominant taxa out of 12 were Melanoides tuberculatus Müller, 1774 (15.2%) and Chaoboridae (63.8%). In VF, the dominant taxa, out of 11 were M. tuberculatus (34.2%) and Oligochaeta (33.6%). In IB, M. tuberculatus (91.2%) and Chaoboridae (6.27%) dominated and we collected only 7 taxa. In SA, benthos were significantly influenced by the deciduous shrub understory and bank angle. In IB and VF, the significant physical habitat variables were: land cover, human influence, and aquatic macrophytes. We conclude that human disturbances reduced terrestrial vegetation cover and riparian and littoral physical habitat structural complexity, leading to worse water quality. Those changes, in turn, reduced the taxonomic richness of the benthic macroinvertebrate communities.

OBJECTIVES: To estimate the effect of sex-related alcohol expectancies (SRAE) on hazardous drinking prevalence and examine gender differences in reporting SRAE. METHODS: Trained research assistants administered part of a questionnaire to 393 men and 400 women between 18 and 30 years old from a peri-urban shantytown in Lima, Peru. The remaining questions were self-administered. Two measuring instruments-one testing for hazardous drinking and one for SRAE-were used. Multivariate data analysis was performed using logistic regression. RESULTS: Based on odds ratios adjusted for socio-demographic variables (age, marital status, education, and employment status) (n = 793), men with one or two SRAE and men with three or more SRAE were 2.3 (95% confidence interval (CI) = 1.4-3.8; p = 0.001) and 3.9 (95% CI = 2.1-7.3; p < 0.001) times more likely than men with no SRAE, respectively, to be hazardous drinkers. Reporting of SRAE was significantly higher in men versus women. CONCLUSION: In a shantytown in Lima, SRAE is associated with hazardous drinking among men, but not among women, and reporting of SRAE differs by gender.

OBJETIVOS: Estimar el efecto de las expectativas generadas por el consumo de alcohol relacionadas con el sexo (SRAE) sobre la prevalencia del consumo peligroso y analizar las diferencias en la información sobre las SRAE según el género. MÉTODOS: Asistentes entrenados aplicaron parte de un cuestionario a 393 hombres y 400 mujeres de 18 a 30 años de edad residentes en un barrio marginal periurbano de Lima, Perú. Los participantes respondieron las preguntas restantes de forma individual. Se emplearon dos instrumentos de evaluación: uno sobre el consumo peligroso y otro sobre las SRAE. Se realizó un análisis multifactorial de los datos mediante regresión logística. RESULTADOS: Según las razones de posibilidades (odds ratios) ajustadas por algunas variables sociodemográficas (edad, estado marital, educación y situación laboral) (n = 793), los hombres con una o dos SRAE y los que tenían tres SRAE o más presentaron 2,3 (intervalo de confianza de 95% [IC95%]: 1,4 a 3,8; P = 0,001) y 3,9 (IC95%: 2,1 a 7,3; P < 0,001) veces más probabilidades, respectivamente, de ser bebedores peligrosos que los hombres sin SRAE. Los hombres informaron SRAE en una proporción significativamente mayor que las mujeres. CONCLUSIONES: En un barrio periférico pobre de Lima, las SRAE se asociaron significativamente con el consumo peligroso de bebidas alcohólicas en hombres, pero no en mujeres, y se observaron diferencias en la información sobre las SRAE según el género.

PURPOSE: To evaluate erectile function (EF) and voiding function following primary targeted cryoablation of the prostate (TCAP) for clinically localized prostate cancer (CaP) in a contemporary cohort. MATERIALS AND METHODS: We retrospectively reviewed all patients treated between 2/2000-5/2006 with primary TCAP. Variables included age, Gleason sum, pre-TCAP prostate specific antigen (PSA), prostate volume, clinical stage, pre-TCAP hormonal ablation, pre-TCAP EF and American Urologic Association Symptom Score (AUASS). EF was recorded as follows: 1 = potent; 2 = sufficient for intercourse; 3 = partial/insufficient; 4 = minimal/insufficient; 5 = none. Voiding function was analyzed by comparing pre/post-TCAP AUASS. Statistical analysis utilized SAS software with p < 0.05 considered significant. RESULTS: After exclusions, 78 consecutive patients were analyzed with a mean age of 69.2 years and follow-up 39.8 months. Thirty-five (44.9%) men reported pre-TCAP EF level of 1-2. Post-TCAP, 9 of 35 (25.7%) regained EF of level 1-2 while 1 (2.9%) achieved level 3 EF. Median pre-TCAP AUASS was 8.75 versus 7.50 postoperatively (p = 0.39). Six patients (7.7%) experienced post-TCAP urinary incontinence. Lower pre-TCAP PSA (p = 0.008) and higher Gleason sum (p = 0.002) were associated with higher post-TCAP AUASS while prostate volume demonstrated a trend (p = 0.07). Post-TCAP EF and stable AUASS were not associated with increased disease-recurrence (p = 0.24 and p = 0.67, respectively). CONCLUSIONS: Stable voiding function was observed post-TCAP, with an overall incontinence rate of 7.7%. Further, though erectile dysfunction is common following TCAP, 25.7% of previously potent patients demonstrated erections suitable for intercourse. While long-term data is requisite, consideration should be made for prospective evaluation of penile rehabilitation following primary TCAP.

Nove isolados de Botryosphaeria spp foram avaliados quanto ao crescimento e produção de enzimas líticas da parede celular (lacase, pectinase e beta-1,3-glucanase) quando cultivados em meio basal na ausência e presença do indutor de lacase álcool veratrílico (VA). As relações genéticas entre os nove isolados coletados de diferentes plantas hospedeiras foram determinadas por RAPD. A análise das seqüências de nucleotídeos da região ITS mostrou oito isolados estreitamente relacionados, os quais foram classificados como Botryosphaeria rhodina e um isolado como Botryosphaeria ribis. A análise por RAPD agrupou os isolados em três grupos principais condizentes com os níveis de atividades de lacase e beta-1,3-glucanase. Nenhuma correlação foi detectada entre a produção de pectinase e a diversidade genética nos nove isolados. Entretanto, a linhagem caracterizada como B. ribis, posicionada fora dos grupos principais, se mostrou maior produtora de pectinase na presença de álcool veratrílico.

Nine isolates of Botryosphaeria spp. were evaluated for their growth and the production of cell wall-lytic enzymes (laccase, pectinase and beta-1,3-glucanase) when grown on basal medium in the absence and presence of the laccase inducer, veratryl alcohol (VA). The genetic relationship among the nine isolates collected from different host plants was determined by RAPD analyses. ITS sequence analysis showed eight closely related isolates classified as Botryosphaeria rhodina, and one isolate classified as Botryosphaeria ribis. RAPD analysis resolved the isolates into three main clusters based upon levels of laccase and beta-1,3-glucanase activity. There appears to be no correlation between pectinase production and genetic diversity among the nine isolates. However, the strain characterized as B. ribis, positioned out of the main cluster, was found to be the highest producer of pectinases in the presence of VA.

This study aimed to evaluate tidal and seasonal variations in concentrations and fluxes of nitrogen (NH4+, NO2+NO3, total nitrogen) and phosphorus (soluble reactive phosphorus, total phosphorus) in a riverine mangrove forest using the flume technique during the dry (May, December 2003) and rainy (October 2003) seasons in the Shark River Estuary, Florida. Tidal water temperatures during the sampling period were on average 29.4 (± 0.4) ºC in May and October declining to 20 ºC (± 4) in December. Salinity values remained constant in May (28 ± 0.12 PSU), whereas salinity in October and December ranged from 6-21 PSU and 9-25 PSU, respectively. Nitrate + nitrite (N+N) and NH4+ concentrations ranged from 0.0 to 3.5 µM and from 0 to 4.8 µM throughout the study period, respectively. Mean TN concentrations in October and December were 39 (±0.8) µM and 37 (±1.5) µM, respectively. SRP and N+N concentrations in the flume increased with higher frequency in flooding tides. TP concentrations ranged between 0.2-2.9 µM with higher concentrations in the dry season than in the rainy season. Mean concentrations were <1. 5 µM during the sampling period in October (0.75 ± 0.02) and December (0.76 ± 0.01), and were relatively constant in both upstream and downstream locations of the flume. Water residence time in the flume (25 m²) was relatively short for any nutrient exchange to occur between the water column and the forest floor. However, the distinct seasonality in nutrient concentrations in the flume and adjacent tidal creek indicate that the Gulf of Mexico is the main source of SRP and N+N into the mangrove forest.

El objetivo de este estudio fue evaluar los cambios en las concentraciones y flujos de nitrógeno (NH4+, NO2+NO3, nitrogeno total) y fósforo (fósforo reactivo soluble, fósforo total) asociados al regimen climatico y de marea en un manglar riverino, usando la técnica del flume durante las epocas seca (Mayo, Diciembre) y de lluvias (Octubre) del 2003 en Shark River Estuary. La temperatura promedio de la columna de agua fue 29.4 (± 0.4) ºC durante Mayo y Diciembre, y disminuyó a 20 (± 4) ºC en Diciembre. Los valores de salinidad permanecieron constantes durante Mayo (28 ± 0.12 PSU), mientras que en Octubre y Diciembre variaron entre 6-21 PSU y 9-25 PSU, respectivamente. Las concentraciones de nitrato + nitrito (N+N) y amonio (NH4+) fluctuaron entre 0.0±3.5 µM y 0.0-4.8 µM, respectivamente. Las concentraciones de nitrógeno total en Octubre y Diciembre fueron en promedio 39 (± 0.8) µM y 37 ± 1.5) µM, respectivamente. Las concentraciones de fósforo reactivo soluble y N+N en el flume incrementaron con mayor frequencia durante los períodos de marea alta. Las concentraciones de fósforo total variaron entre 0.2-2.9 µM, con máximos valores durante la época seca. En promedio, las concentraciones de fósforo total fueron <1.5 µM durante Octubre (0.75 ± 0.02) y Diciembre (0.78 ± 0.01), y se mantuvieron relativamente constantes en ambos extremos del flume. El tiempo de residencia delagua en el flume (25 m²) fue relativamente corto para permitir algún intercambio de nutrientes entre la columna de agua y el suelo del manglar. Sin embargo, la marcada estacionalidad en las concentraciones de nutrientes en el flume y en el canal mareal adjacente a éste, indican que el Golfo de México es la principal fuente de fósforo reactivo soluble y N+N hacia el bosque de manglar.

The introduction of epoxy groups into the main chain of elastomers has emerged as a promising alternative, considering the monitoring of polymer-filler interaction leading to changes in the properties of vulcanizates. The epoxidation reaction (in situ) was chosen to modify elastomers, such as polybutadiene (BR) and copolymer of styrene-butadiene-rubber (SBR), because it is a simple, easily controlled reaction, even considering the small epoxidation degree. The modification degree of the polymeric chain was studied with FT-IR and ¹H-NMR. The shift of the Tg to high temperatures with the increase of the epoxy group in the polymer chain was monitored through differential scanning calorimetry (DSC). An analysis of the dynamic modulus of the material in relation to its dependence on the amplitude and temperature was carried out. The interaction between epoxidized elastomeric matrix and silica as filler was extremely improved, even in the presence of very low content of epoxy groups into the polymer chain.