Estudiantes con gratuidad en universidades prestigiosas: ajustes académicos para permanecer / Fee-free students at prestigious universities: academic adjustments so that they can remain in education

(analítico) La educación superior en Chile se ha masificado; sin embargo, se mantiene una alta segmentación en el sistema. En 2016 comienza a implementarse la política de gratuidad, dirigida a estudiantes de menores ingresos. Esta investigación buscó comprender las experiencias académicas de estudiantes con gratuidad en universidades prestigiosas y selectivas, espacios tradicionalmente de reproducción de las clases altas y élites. Se realizaron entrevistas biográficas a trece estudiantes de estas universidades, así como un análisis temático temporal. Los resultados muestran que la obtención de la gratuidad emerge como un facilitador en el acceso, pero los/as estudiantes experimentan fuertes sensaciones de inadecuación académica; se muestran activos en transformar sus disposiciones, realizando un fuerte trabajo sobre sí para permanecer. Las experiencias de jóvenes de menores capitales muestran la persistencia de desigualdades.

(analytical) Higher education in Chile has experienced massification during the last 30 years. However, a high level of segmentation in the system continues. In 2016, the fee-free policy began to be implemented and was designed for lower-income students. This research study sought to understand the academic experiences of fee-free students at prestigious and selective universities, which are considered spaces that reproduce power dynamics in favor of the country's upper classes. Biographical interviews were conducted with 13 fee-free students who are currently enrolled in these universities and a temporal thematic analysis was carried out. The results of the study show that: obtaining fee-free tuition facilitates access to education; both male and female fee-free students experience strong feelings of academic inadequacy; and these students take an active role in transforming their situations by adopting a strong work ethic that helps them continue with their studies. These experiences of young people from lower income backgrounds show the persistence of inequalities in the higher education sector.

(analítico) O Ensino Superior no Chile se massificou nos últimos 30 anos, porém, ainda há uma alta segmentação no sistema. No ano 2016 começa a implementação da política de gratuidade, destinada a estudantes de menor renda. Esta pesquisa buscou compreender as experiências acadêmicas de estudantes com gratuidade em universidades prestigiadas e seletivas, espaços de reprodução das classes altas e das elites. Foram realizadas entrevistas biográficas a treze estudantes destas universidades. Além disso, foi realizada uma análise temática temporal. Os resultados mostram que a obtenção da gratuidade surge como um facilitador no acesso, os e as estudantes experimentam fortes sentimentos de inadequação acadêmica, são ativos na transformação de suas disposições, trabalhando arduamente em si mesmos para permanecer. As experiências dos jovens de menores rendas mostram a persistência das desigualdades.

Targeting Metal Impurities for the Detection and Quantification of Carbon Black Particles in Water via spICP-MS.

Carbon black (CB) is a nanomaterial with numerous industrial applications and high potential for integration into nano-enabled water treatment devices. However, few analytical techniques are capable of measuring CB in water at environmentally relevant concentrations. Therefore, we intended to establish a quantification method for CB with lower detection limits through utilization of trace metal impurities as analytical tracers. Various metal impurities were investigated in six commercial CB materials, and the Monarch 1000 CB was chosen as a model for further testing. The La impurity was chosen as a tracer for spICP-MS analysis based on measured concentration, low detection limits, and lack of polyatomic interferences. CB stability in water and adhesion to the spICP-MS introduction system presented a challenge that was mitigated by the addition of a nonionic surfactant to the matrix. Following optimization, the limit of detection (64 µg/L) and quantification (122 µg/L) for Monarch 1000 CB demonstrated the applicability of this approach to samples expected to contain trace amounts of CB. When compared against gravimetric analysis and UV-visible absorption spectroscopy, spICP-MS quantification exhibited similar sensitivity but with the ability to detect concentrations an order of magnitude lower. Method detection and sensitivity was unaffected when dissolved La was spiked into CB samples at environmentally relevant concentrations. Additionally, a more complex synthetic matrix representative of drinking water caused no appreciable impact to CB quantification. In comparison to existing quantification techniques, this method has achieved competitive sensitivity, a wide working range for quantification, and high selectivity for tracing possible release of CB materials with known metal contents.

Soil and foliar exposure of soybean (Glycine max) to Cu: Nanoparticle coating-dependent plant responses.

In this study, we investigated the effects of citric acid (CA) coated copper oxide nanoparticles (CuO NPs) and their application method (foliar or soil exposure) on the growth and physiology of soybean (Glycine max). After nanomaterials exposure via foliar or soil application, Cu concentration was elevated in the roots, leaves, stem, pod, and seeds; distribution varied by plant organ and surface coating. Foliar application of CuO NPs at 300 mg/L and CuO-CA NPs at 75 mg/L increased soybean yield by 169.5% and 170.1%, respectively. In contrast, foliar and soil exposure to ionic Cu with all treatments (75 and 300 mg/L) had no impact on yield. Additionally, CuO-CA NPs at 300 mg/L significantly decreased Cu concentration in seeds by 46.7%, compared to control, and by 44.7%, compared to equivalent concentration of CuO NPs. Based on the total Cu concentration, CuO NPs appeared to be more accessible for plant uptake, compared to CuO-CA NPs, inducing a decrease in protein content by 56.3% and inhibiting plant height by 27.9% at 300 mg/kg under soil exposure. The translocation of Cu from leaf to root and from the root to leaf through the xylem was imaged by two-photon microscopy. The findings indicate that citric acid coating reduced CuO NPs toxicity in soybean, demonstrating that surface modification may change the toxic properties of NPs. This research provides direct evidence for the positive effects of CuO-CA NPs on soybean, including accumulation and in planta transfer of the particles, and provides important information when assessing the risk and the benefits of NP use in food safety and security.

Flight system morphology and minimum flight temperature in North American cicadas (Insecta: Hemiptera: Cicadidae).

Thermal responses in cicadas have been studied for many years. The minimum flight temperature (MFT) does not show the same relationship to habitat and behavior as other thermal responses. We measured live mass, wing length, wingspan, wing area and wing loading in an attempt to correlate these morphological parameters to the MFT. We analyzed both intraspecific (in Magicicada cassinii (Fisher, 1852)) and interspecific relationships of the wing morphology and the ability of the cicadas to fly in a large number of North American cicada taxa (n=119). A total of 109 species and 10 subspecies from 17 genera, six tribes, and three subfamilies including all major North American habitats were studied. Analyses show that wing morphology (wing length, wingspan, wing area and wing loading) scales to body size as predicted by geometric similarity (all P<0.0001) for all species and wing area and wing loading (both P<0.0001) in M. cassinii. Mass (P=0.0105), wing length (P=0.0006), wingspan (P=0.0006), wing area (P=0.0055), and wing loading (P=0.0455) all demonstrate a significant correlation to MFT between species, as would be predicted by aerodynamic theory, but not within species. However, the low correlation coefficients suggest the flight system has minimal influence on the MFT of cicadas. Specific physiological adaptations appear to be responsible for the between species variability in MFT rather than being the result of modifications to the flight system morphology.

Antioxidant and defense genetic expressions in corn at early-developmental stage are differentially modulated by copper form exposure (nano, bulk, ionic): Nutrient and physiological effects.

In the present study, Zea mays seedlings grown under nano Cu(OH)2 (nCu), bulk Cu(OH)2 (bCu), and ionic CuSO4 (iCu) compound exposure were harvested after six days. The nutritional profile was determined to be significantly disrupted in the roots by 1000 ppm bCu treatment, resulting in a 58.7% reduction in potassium compared to the control. In the shoots, a significant decrease of manganese was observed for 10 and 1000 ppm iCu treatments with 55.7% and 64.2% reductions, respectively. The overall protein content and catalase (CAT) enzymatic activity, however, remained unaffected in either roots or shoots, while an absence of polyphenol oxidase (PPO) activity was observed for all samples. The genetic expression of defense-related genes, metallothionein (MT), CAT, ascorbate peroxidase (APX), and PPO was assessed. The genetic expression of MT was upregulated 50-fold in roots treated with 1000 ppm bCu. There were no significant differences in CAT transcripts among the various treatments, while APX was upregulated 28 and 19-fold in shoots treated with 10 ppm bCu and 10 ppm nCu, respectively. Meanwhile, APX mRNA levels were downregulated five-fold in shoots treated with 1000 ppm iCu. Thus, indicating that the role of APX in plant defense was reinforced in seedlings exposed to low concentration of particulate Cu compounds. Remarkably, no PPO expression was found in any of the treatments and controls, which suggests this enzyme is expressed only under specific external factors or seedlings have an "immature" cascade signaling activation of the PPO system. Taken together, these results show that bCu and nCu treatments at a low concentration do not compromise vital cell machinery but rather elicit the enhancement of defense responses as observed through the increase in APX expression. Furthermore, under optimal concentrations, these Cu treatments show promise in enhancing corn defense responses, which can ultimately lead to increases in future global crop yields.

Copper nanowires as nanofertilizers for alfalfa plants: Understanding nano-bio systems interactions from microbial genomics, plant molecular responses and spectroscopic studies.

The recent application of nano copper (Cu) compounds in the agrosystem has shown potential to improve the physiological performance and agronomical parameters of crops. We grew alfalfa (Medicago sativa) in potting mix amended with bulk, nano, and ionic Cu compounds at 80 and 280 mg Cu/kg; then, we evaluated plant performance at physiological and molecular levels. Plants treated with bulk/nano Cu presented better agronomical responses. The P and S content was reduced in bulk and ionic Cu-exposed plants, compared to controls (p ≤ .05). All Cu forms increased the content of Fe and Zn in roots and Fe in leaves, compared to controls (p ≤ .05). Leaf-superoxide dismutase expression was augmented ~27-fold and rubisco mRNA was unaffected in bulk/nano Cu-treated plants, compared to controls (p ≤ .05). Bulk/nano Cu incremented the relative abundance of microorganisms involved in the elemental uptake. These results indicate that nano Cu improved the physiology of alfalfa and can be considered as potential nanofertilizers.

Probiotic Bacterium and Microalga Interaction on Rearing Kumamoto Oyster Crassostrea sikamea Spat.

This study assessed in vitro interaction between Bacillus bacteria and microalgae and their posterior in vivo effect on rearing Kumamoto oyster Crassostrea sikamea. The probiotic strains Bacillus licheniformis (MAt32), B. subtilis (MAt43) and B. subtilis (GAtB1) were individually inoculated in triplicate into 250 mL flasks containing 1 × 104 colony forming units (CFU) mL-1 of bacteria and 4.5 × 104 cell mL-1 of microalgae (Isochrysis galbana or Chaetoceros calcitrans) to evaluate their growth during a 7-day culture. Single cultures of microalgae or bacilli served as control. Additionally, C. sikamea spat was treated for 28 days with four single/combined bacillus treatments in triplicate at a concentration of 1 × 106 CFU mL-1 as follows: (a) control, without treatments; (b) combination of two antibiotics (10 mg L-1); (c) B. licheniformis; (d) B. subtilis; (e) B. subtilis subtilis and (f) mixed bacilli. The results showed a significantly (P < 0.05) increased growth of Bacillus strains co-cultured with microalgae, while the growth of I. galbana co-cultured with bacteria was not reduced significantly (P > 0.05) compared with the control group. C. sikamea spat treated with Bacillus showed significantly (P < 0.05) higher growth and survival than the control group. In this study, C. calcitrans microalgae were susceptible to the presence of probiotic bacteria. Nonetheless, this reduction in microalgal growth observed in vitro increased growth and survival of C. sikamea spat exposed to probiotic bacteria when compared to spat without probiotics.

Investigation into the thermodynamics and kinetics of the binding of Cu2+ and Pb2+ to TiS2 nanoparticles synthesized using a solvothermal process.

In the present study, titanium (IV) sulfide (TiS2) was synthesized and investigated for the removal of Cu2+ and Pb2+ ions from aqueous solutions. TiS2 nanoparticles synthesized through a solvothermal synthesis were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The average particle size for the TiS2 material was determined to be 8.03 ± 0.98 nm from the diffraction pattern. Studies were performed to examine the effects of pH, temperature, time, and interfering ions on the binding of Cu2+ and Pb2+ to the TiS2. As well isotherm studies were performed to determine the binding capacity of TiS2 for both Cu2+ and Pb2+ ions. The pH profile studies showed optimal binding occurred at pH 2 for the sorption of both Cu2+ and Pb2+ to the TiS2. The isotherm studies showed the adsorption capacities at temperatures of 4, 22, and 45°C for Cu2+ were 243, 222, and 153 mg/g, respectively. An opposite trend in the adsorption was observed for Pb2+ binding to the TiS2. The observed binding capacities for Pb2+ were 32, 166, and 357 mg/g, at temperatures of 4, 22, and 45°C, respectively. The thermodynamic parameters for binding showed a non-spontaneous process for the sorption of Cu2+ whereas a spontaneous binding process was observed for the sorption of Pb2+. Additionally, the binding of Cu2+ on TiS2 in the presence of interfering ions (Na+, K+, Mg2+, and/or Ca2+) was observed to decrease at high concentrations; however, the binding of Pb2+ was unaffected by the presence of the same cations.

Toxicity of copper hydroxide nanoparticles, bulk copper hydroxide, and ionic copper to alfalfa plants: A spectroscopic and gene expression study.

Bulk Cu compounds such as Cu(OH)2 are extensively used as pesticides in agriculture. Recent investigations suggest that Cu-based nanomaterials can replace bulk materials reducing the environmental impacts of Cu. In this study, stress responses of alfalfa (Medicago sativa L.) seedlings to Cu(OH)2 nanoparticle or compounds were evaluated. Seeds were immersed in suspension/solutions of a Cu(OH)2 nanoform, bulk Cu(OH)2, CuSO4, and Cu(NO3)2 at 25 and 75 mg/L. Six days later, the germination, seedling growth, and the physiological and biochemical responses of sprouts were evaluated. All Cu treatments significantly reduced root elongation (average = 63%). The ionic compounds at 25 and 75 mg/L caused a reduction in all elements analyzed (Ca, K, Mg, P, Zn, and Mn), excepting for S, Fe and Mo. The bulk-Cu(OH)2 treatment reduced K (48%) and P (52%) at 75 mg/L, but increased Zn at 25 (18%) and 75 (21%) mg/L. The nano-Cu(OH)2 reduced K (46%) and P (48%) at 75 mg/L, and also P (37%) at 25 mg/L, compared with control. Confocal microscopy images showed that all Cu compounds, at 75 mg/L, significantly reduced nitric oxide, concurring with the reduction in root growth. Nano Cu(OH)2 at 25 mg/L upregulated the expression of the Cu/Zn superoxide dismutase gene (1.92-fold), while ionic treatments at 75 mg/L upregulated (∼10-fold) metallothionein (MT) transcripts. Results demonstrated that nano and bulk Cu(OH)2 compounds caused less physiological impairments in comparison to the ionic ones in alfalfa seedlings.

La construcción de generación en los discursos juveniles del Chile actual / The making of a generation in the current discourse of Chilean youth / A construção da geração nos discursos juvenis no Chile atual

El artículo busca identificar los elementos que caracterizan a la juventud chilena actual, a partir de la noción o nociones de generación que los y las jóvenes construyen. Para ello, se analizan 14 grupos de discusión realizados a estudiantes de educación secundaria, en las ciudades de Punta Arenas, Concepción, Talcahuano, Talca, San Fernando y Santiago. Los resultados sugieren una relación entre el contexto socio-histórico en el que se desenvuelven los jóvenes y las jóvenes, la diferenciación/distinción que realizan con generaciones precedentes y la marca generacional de las movilizaciones estudiantiles del año 2011.

This article seeks to identify the elements that currently characterize Chilean youth, describing the notions of generation that are present in the discourse of young people. To achieve this, we analyze 14 discussion groups with secondary school students from the cities of Punta Arenas, Concepcion, Talcahuano, Talca, San Fernando and Santiago. The results suggest a relationship with the socio-historical context in which young people act the differentiation and distinction they make between themselves and previous generations and the generational milestone of the 2011 student movement.

O artigo busca identificar os elementos que caracterizam a atual juventude chilena a partir da noção ou noções de geração que os jovens constroem. Para esse propósito, 14 grupos de discussão para alunos do ensino secundário nas cidades de Punta Arenas, Concepción, Talcahuano, Talca, San Fernando e Santiago, foram analisados. Os resultados sugerem uma relação entre o contexto sócio-histórico em que operam os jovens, a diferenciação/distinção feita com as gerações anteriores e marca geracional das manifestações estudantis de 2011.

Imaginarios sociales sobre lo juvenil en el Chile contemporáneo / Social imaginaries of youth in contemporary Chile / Imaginários sociais sobre o juvenil no Chile contemporâneo

En este artículo, se presentan los resultados de una investigación cuyo objetivo fue identificar imaginarios sociales emergentes sobre lo juvenil en el Chile contemporáneo. Es un estudio cualitativo basado en el análisis de trece grupos de discusión realizados en cinco regiones del país. La selección de los participantes en el estudio consideró a estudiantes que cursan su último año de educación secundaria en Chile. Entre los resultados más relevantes se encuentra la identificación de un imaginario social sobre lo juvenil como un desafío de escolarización, que se estructura conflictivamente con énfasis en varias dimensiones y procesos claves en la configuración de la condición social de las juventudes chilenas contemporáneas.

This paper presents the finding/results of an investigation that had theobjective of identifying emerging social imaginaries related to youth in contemporary Chile. Thisis a qualitative study based on the analysis of thirteen discussion groups, conducted in five regionsacross the country. Participants in the study were studying their last year of secondary education/high school in Chile. Among the most relevant results is the identification of a social imaginary ofyouth as a permanent challenge to be controlled by the education system, which is structured as aconflict into the foundation of emphasizing different dimensions and processes that are consideredessential in the configuration of the social condition of contemporary Chilean youth.

Neste artigo apresentam-se os resultados de uma pesquisa cujo objetivofoi identificar imaginários sociais emergentes sobre o juvenil no Chile contemporâneo. É um estudoqualitativo baseado na análise de treze grupos de discussão realizados em cinco regiões do país. Aseleção dos participantes no estudo considerou a estudantes que cursam seu último ano de educaçãosecundária em Chile. Entre os resultados mais relevantes se encontram a identificação de umimaginário social sobre o juvenil como um desafio permanente de escolarização, o qual se estruturaconflituosamente sobre a base de enfatizar diversas dimensões e processos chaves na configuraçãoda condição social das juventudes chilenas contemporâneas.

Microsatellite primers for two threatened orchids in Florida: Encyclia tampensis and Cyrtopodium punctatum (Orchidaceae).

PREMISE OF THE STUDY: The Million Orchid Project at Fairchild Tropical Botanic Garden is an initiative to propagate native orchids for reintroduction into Miami's urban landscapes. The aim of this study was to develop microsatellites for Encyclia tampensis and Cyrtopodium punctatum (Orchidaceae). METHODS AND RESULTS: Ten microsatellites were developed for each species. For E. tampensis sampled from the natural population, allele numbers ranged from one to four, with an average observed heterozygosity (H o) of 0.314 and average expected heterozygosity (H e) of 0.281. For the individuals from cultivation, allele numbers ranged from one to six, with an average H o of 0.35 and an average H e of 0.224. For C. punctatum, allele numbers ranged from one to three, with an average H o of 0.257 and an average H e of 0.272. CONCLUSIONS: These microsatellites will be used to assess the genetic diversity of natural and cultivated populations with the intention of guiding genetic breeding under the Million Orchid Project.

[Microorganisms effect with probiotic potential in water quality and growth of the shrimp Litopenaeus vannamei (Decapoda: Penaeidae) in intensive culture]. / Efecto de microorganismos con potencial probiótico en la calidad del agua y el crecimiento de camarón Litopenaeus vannamei (Decapoda: Penaeidae) en cultivo intensivo.

The use of probiotics has gained acceptance in aquaculture, particularly in maintaining water quality and enhancing growth in organisms. This study analyzed the effect of the commercial (EM, Japan) natural product composed by (Rhodopseudomonas palustris, Lactobacillus plantarum, Lactobacillus casei and Saccharomyces cerevisiae) added to the water, in order to determine its effect in water quality, sediment and growth of L. vannamei under intensive culture. The evaluation included three treatments with a weekly addition of EM: i) tanks without probiotics (C), ii) tanks with a dose of 4 L/ha (EM1) and iii) tanks with a dose of 10 L/ha (EM2). The treatment C was carried out three times, while treatments EM1 and EM2 were carried out four times. A total of 4 350 shrimps were measured for total length and weight, to calculate total and porcentual weight gain, daily weight gain, specific growth rate (TCE), and food conversion factor (FCA); besides, the survival rate was estimated. The use of probiotics allowed a shorter harvest time in treatments EM1 (90 d) and EM2 (105 d) with relation to the treatment C (120d). Treatments EM1 and EM2 were within the recommended intervals for culture, with respect to treatment C. The use of probiotic bacteria significantly regulated pH (EM1, 8.03 +/- 0.33; EM2, 7.77 +/- 0.22; C, 9.08 +/- 0.35) and reduced nitrate concentration (EM1, 0.64 +/- 0.25 mg/L; EM2, 0.39 +/- 0.26 mg/L; C, 0.71 mg/L). Water pH mostly explained the variance with respect to the treatments. Treatment EM2 presented the greatest removal of organic matter (1.77 +/- 0.45%), whereas the contents of extractable phosphorus increased significantly in treatment EM1 with 21.6 +/- 7.99 mg/kg and in treatment EM2 with 21.6 +/- 8.45 mg/kg with control relation (14.3 +/- 5.47). The shrimp growth was influenced by dissolved oxygen, salinity and pH in the sediment, establishing that salinity was the most important variable in the weight with a negative association. Treatment EM1 recorded an improved TCE (2.69 +/- 0.35%/d) and FCA (1.46 +/- 0.20) with relation to the control treatment (TCE, 1.88 +/- 0.25%/d; FCA, 2.13 +/- 0.48). Survival was significantly greater in treatments containing probiotics with 61 +/- 8.76% and 60 +/- 10.5% for EM1 and EM2, respectively. This study indicated the positive effect obtained with the use of this commercial probiotic, to improve culture conditions and growth parameters in an intensive culture of L. vannamei.

Efecto de microorganismos con potencial probiótico en la calidad del agua y el crecimiento de camarón Litopenaeus vannamei (Decapoda: Penaeidae) en cultivo intensivo / Microorganisms effect with probiotic potential in water quality and growth of the shrimp Litopenaeus vannamei (Decapoda: Penaeidae) in intensive culture

The use of probiotics has gained acceptance in aquaculture, particularly in maintaining water quality and enhancing growth in organisms. This study analyzed the effect of the commercial (EM TM, Japan) natural product composed by (Rhodopseudomonas palustris, Lactobacillus plantarum, Lactobacillus casei and Saccharomyces cerevisiae) added to the water, in order to determine its effect in water quality, sediment and growth of L. vannamei under intensive culture. The evaluation included three treatments with a weekly addition of EM: i) tanks without probiotics (C), ii) tanks with a dose of 4L/ha (EM1) and iii) tanks with a dose of 10L/ha (EM2). The treatment C was carried out three times, while treatments EM1 and EM2 were carried out four times. A total of 4 350 shrimps were measured for total length and weight, to calculate total and porcentual weight gain, daily weight gain, specific growth rate (TCE), and food conversion factor (FCA); besides, the survival rate was estimated. The use of probiotics allowed a shorter harvest time in treatments EM1 (90d) and EM2 (105d) with relation to the treatment C (120d). Treatments EM1 and EM2 were within the recommended intervals for culture, with respect to treatment C. The use of probiotic bacteria significantly regulated pH (EM1, 8.03±0.33; EM2, 7.77±0.22; C, 9.08±0.35) and reduced nitrate concentration (EM1, 0.64±0.25mg/L; EM2, 0.39±0.26mg/L; C, 0.71mg/L). Water pH mostly explained the variance with respect to the treatments. Treatment EM2 presented the greatest removal of organic matter (1.77±0.45%), whereas the contents of extractable phosphorus increased significantly in treatment EM1 with 21.6±7.99mg/kg and in treatment EM2 with 21.6±8.45mg/kg with control relation (14.3±5.47). The shrimp growth was influenced by dissolved oxygen, salinity and pH in the sediment, establishing that salinity was the most important variable in the weight with a negative association. Treatment EM1 recorded an improved TCE (2.69±0.35%/d) and FCA (1.46±0.20) with relation to the control treatment (TCE, 1.88±0.25%/d; FCA, 2.13±0.48). Survival was significantly greater in treatments containing probiotics with 61±8.76% and 60±10.5% for EM1 and EM2, respectively. This study indicated the positive effect obtained with the use of this commercial probiotic, to improve culture conditions and growth parameters in an intensive culture of L. vannamei.

Los probióticos han ganado aceptación en la acuicultura para mantener la calidad del agua y aumentar el crecimiento de los organismos. En este estudio se analizó el efecto de una mezcla comercial de microorganismos eficientes (EM) (Rhodopseudomonas palustris, Lactobacillus plantarum, Lactobacillus casei y Saccharomyces cerevisiae) sobre la calidad del agua, sedimento y el crecimiento en un cultivo intensivo de camarón L. vannamei. La evaluación consistió en tres tratamientos: i) estanques sin EM (C), ii) estanques con dosis de 4L/ha (EM1) y iii) estanques con dosis de 10L/ha (EM2). Los resultados demostraron menor tiempo de cosecha en los tratamientos EM1 (90d) y EM2 (105d). Los tratamientos EM1 y EM2 mantuvieron significativamente regulados los valores del pH (EM1, 8.03±0.33; EM2, 7.77±0.22) y redujeron las concentraciones de nitrato (EM1, 0.64±0.25mg/L; EM2, 0.39±0.26mg/L). El tratamiento EM2 presentó la mayor remoción de materia orgánica (1.77±0.45%). El tratamiento EM1 mejoró la TCE (2.69±0.35%/d) y FCA (1.46±0.20). Los tratamientos EM1 y EM2 presentaron mayor supervivencia con 61±8.76% y 60±10.5%, respectivamente. Este estudio demostró el efecto benéfico del uso de la mezcla comercial en los parámetros ambientales y de crecimiento en un cultivo intensivo de L. vannamei.

Correlación entre test de Conners para padres y profesores en niños con trastorno de déficit atencional e hiperactividad en el Servicio de Psiquiatría Infanto Juvenil del Hospital Barros Luco Trudeau / Correlation between Conners parents and teachers rating Scale in children with attention deficit hyperactivity disorder in Barros Luco Trudeau´s Hospital Child and Adolescent Psychiatry Service

Introducción: En el Trastorno por Déficit Atencional e Hiperactividad (TDAH) se han observado diferencias en los reportes de cuestionarios entre padres y profesores. Objetivos: Observar la concordancia entre padres y profesores en el test de Conners abreviado (TCA) en el TDAH. Métodos: Se evaluó con TCA para profesores y para padres a niños atendidos por becados de primer año, con diagnóstico clínico de TDAH. Resultados: De 57 pacientes, 21por ciento mujeres y 78,9 por ciento hombres, el promedio de los TCA de profesores fue de 16,85 puntos y el de padres de 16,98, existiendo mayor diferencia al separarlos por género. El coeficiente de correlación fue de 0,41. Las únicas variables significativamente asociadas al puntaje fueron edad y comorbilidad con Trastorno Oposicionista Desafiante (TOD). Conclusión: No existe correlación entre Conners de padres y profesores, lo que recalca la importancia de objetivar los síntomas en más de un ambiente, para llegar a un diagnóstico certero.

Introduction: There has been observed in the Attention Deficit and Hyperactivity Disorder (ADHD) differences in the reports between parental and teachers questionnaires. Objectives: Observe concordance between parents and teachers in the abbreviated Conners Test (TCA) in ADHD. Methods: Children with clinical diagnosis of ADHD were evaluated by first year residents with parental and teachers TCA. Results: From a total of 57 patients, 21percent were women and 78, 9 percent men, the average of the TCA from teachers was 16, 85 points and from parents 16, 98, there was more difference if separated by sex. The correlation coefficient was 0, 41. And the only significant association between variables was TCA scores with child’s age and comorbidity with Oppositional Defiant Disorder. Conclusions: There is no correlation between parental and teachers TCA scores, which enhances the importance of objetivation of symptoms in more than one setting to get an accurate diagnosis.

Maloclusiones y su impacto psicosocial en estudiantes de un liceo intercultural / Malocclusions and its psychosocial impact in intercultural highschool students

Las maloclusiones están consideradas como la tercera patología oral de mayor prevalencia e impacto en el mundo, a pesar de esto son pocos los estudios en Chile que abordan el tema y consideran sus consecuencias en la calidad de vida o su relación con grupos poblacionales específicos. El objetivo de este estudio es determinar la prevalencia y su impacto psicosocial en jóvenes que estudian en un liceo con población indígena. Se realizó un estudio descriptivo de corte transversal, en 129 alumnos, 73,6 por ciento pehuenche, del Liceo de Ralco; se utilizó el Índice Estético Dental para cuantificar la magnitud de las maloclusiones y un Cuestionario de Autoimagen para evaluar el aspecto psicosocial. Los resultados muestran una prevalencia del 67,4 por ciento y un 21,7 por ciento para el nivel discapacitante de maloclusiones, siendo significativamente mayor en población pehuenche y rural, valores por sobre el de estadísticas nacionales e internacionales. A más de la mitad de los jóvenes las maloclusiones le ocasionan problemas para relacionarse con sus pares. Todo lo anterior hace necesario implementar estrategias preventivas y curativas que den solución a este problema.

Malocclusions are regarded as the third oral disease with most prevalence and impact in the world, despite this there are few studies in Chile that address the issue and consider their impact on the quality of life and relationship to specific population groups. The aim of this study is to determine the prevalence and psychosocial impact on young people studying in a high school with indigenous people. We performed a descriptive cross-sectional study in 129 students, 73.6 percent pehuenche, of Ralco High-school; Dental Aesthetic Index was used to quantify the malocclusion magnitude and a Selfimage Questionnaire for assessing psychosocial aspect. The results show a prevalence of 67.4 percent and 21.7 percent for disabling malocclusions level, was significantly higher in pehuenche and rural population, this values are over national and international statistics. More than half of youngs have troubles to relating with their peers to cause of malocclusion. This requires the implementation of preventive and curative strategies providing a solution to this problem.

Is longitudinal pulse pressure a better predictor of 24-hour urinary albumin excretion than other indices of blood pressure?

The strong relationship between urinary albumin excretion (UAE) and pulse pressure (PP) in cross-sectional studies suggests that pressure pulsatility may contribute to renal microvascular injury. The longitudinal relationships between UAE and the various indices of blood pressure (BP) are not well studied. We compared the associations of UAE with the longitudinal exposure to PP and systolic, diastolic, and mean BPs. UAE was measured from 24-hour urine collections in 450 community-dwelling subjects (age: 57+/-15 years, 53% women, all with UAE <200 microg/min). For each subject, longitudinal indices of BP were estimated by dividing the area under the curve of serial measurements of BP (median: 5) during 1 to 22 years preceding UAE measurement by the number of follow-up years. Median (interquartile range) UAE was 4.7 microg/min (3.3 to 7.8 microg/min) in women and 5.2 microg/min (3.7 to 9.8 microg/min) in men. In women, UAE was not related to longitudinal indices of BP. In men, in multivariable-adjusted models that included either longitudinal systolic and diastolic BPs or longitudinal PP and mean BP, UAE was independently associated with systolic (standardized regression coefficient [beta]=0.227; P=0.03) but not with diastolic (beta=-0.049; P=0.59) BP and with PP (beta=0.216; P=0.01) but not with mean BP (beta=0.032; P=0.72). Comparisons of these 2 models and stepwise regression analyses both indicated that, of the 4 longitudinal indices of BP, PP was the strongest predictor of UAE in men. The pulsatile component of BP confers the highest risk for BP-induced renal microvascular injury. Future studies should examine whether PP reduction provides additional renoprotection beyond that attained by conventional BP goals alone.

Efecto en el patrón topográfico postoperatorio con y sin secado transoperatorio del lecho estromal en Lasik / Effect of \"in site\" stromal transoperative drines in postoperative topographic patterns after Lasik

Se estudiaron un total de 60 ojos con diagnóstico de miopía con equivalente esférico mayor o igual a 8 DP y menor o igual a 11 DP, los cuales fueron sometidos a queratectomía fotorrefractiva con técnica de Lasik utilizando el equipo láser excimer Technolas 217 de Chiron y el microqueratomo automatizado Hansatome de Chiron, dividiéndose en dos grupos, a uno de los cuales se le efectuó secado transoperatorio del lecho estromal al 50 por ciento del tratamiento con esponja de merocel, y al segundo grupo no. Se practicaron estudios topográficos de elevación (Orbsacan) preoperatoria, a las 24 horas y 7 días de postoperatorio, se empleó como parámetro de evaluación del patrón de irregularidades el mapa de mejor adaptación a una esfera, tomando como referencia la esfera preoperatoria de base

Tratamiento quirúrgico del prolapso rectal / Surgical treatment of rectal prolapse

Se presenta una revisión de los pacientes operados, por prolapso rectal con las técnicas de sacropromontofijación y rectopexia posterior cn malla según la técnica de Wells modificada, entre los años 1950 y 1994 en el Servicio de Cirugía del Hospital San Juan de Dios. La serie se compone de 82 pacientes, (60 mujeres y 22 hombres), con un promedio de edad de 55 años. Al 56 por ciento de los pacientes se les practicó sacropromontofijación y al 44 por ciento rectopexia posterior. Se hace una comparación entre los resultados obtenidos al aplicar cada una de las dos técnicas quirúrgicas, consignándose complicaciones postoperatorias inespecíficas y derivadas de la técnica desarrollada. Se realiza seguimiento de los pacientes por 7 años en promedio evaluando la recuperación del tono esfinteriano, recidiva de enfermedad y necesidad de reintervención quirúrgica. Las complicaciones postoperatorias son más frecuentes en la rectopexia posterior pero la sacropromontofijación presenta mayor frecuencia de recidivas, (diferencias estadísticamente significativas con un a = 0,05). Según los resultados de esta serie al comparar la sacropromontofijación con la rectopexia posterior ésta última sería el tratamiento definitivo para el prolapso rectal total