RESUMEN Se analizó la relación entre la reflectancia y el contenido de clorofila (Chl) y nitrógeno (N) en hojas de maíz con el fin de identificar índices espectrales útiles para diagnosticar el estado nutricional del cultivo en términos de N. Se realizó un experimento en bloques al azar con cinco tratamientos de fertilizante nitrogenado (0, 50, 100, 150, 200 kg ha-¹) y cuatro repeticiones y se midieron las respuestas espectrales foliares con un espectro-radiómetro FieldSpec 4 en tres etapas fenológicas, varios índices espectrales se calcularon al igual que los valores de posición del borde rojo (REP) mediante varios métodos. La posición del borde del rojo por el método de la Interpolación lineal (REP-L), por el método de la extrapolación lineal de (REP-LE), la técnica de ajuste de gaussiano invertido REP (REP-IG), la posición del borde del rojo mediante el ajuste de polinomio (REP-P) y el indicie normalizado de vegetación (NDVI) tuvieron la mejor relación con el contenido de clorofila y nitrógeno. La primera derivada de la reflectancia, entre 560 y 760 nm, transformada median la variable de estado normal (SNV) también tuvo coeficientes de correlación altamente significativos con N, Chl y rendimiento. Adicionalmente, el rendimiento de maíz mostró correlaciones altamente significativas con los contenidos de N y Chl. Desde el punto de vista del diagnóstico del estado nutricional del maíz, los índices espectrales y valores de REP fueron apropiados para establecer el estado nutricional del maíz con relación al N en los estados fenológicos V8 y R1.

ABSTRACT The relationship between reflectance and chlorophyll (Chl) and nitrogen (N) contents in maize leaves was analyzed to identify useful spectral indices for diagnosing the nutritional status of crops in terms of N. An experiment was carried out in random blocks with five treatments of nitrogen fertilizer (0, 50, 100, 150, 200 kg ha-¹) and four repetitions and the foliar spectral responses were measured with a FieldSpec 4 spectroradiometer in three phenological stages. Several spectral indices and values of red edge position (REP) were calculated using various methods. Red-edge position linear interpolation (REP-L), Red-edge position linear extrapolation (REP-LE), REP-Inverted Gaussian fitting technique (REP-IG), REP-Polynomial fitting technique (REP-P) and NDVI had the best relationship with chlorophyll and nitrogen contents. The first derivative of reflectance, between 560 and 760 nm, transformed by the normal state variable (SNV) also had highly significant correlation coefficients with the N, Chl, and yield. Additionally, the corn yield showed highly significant correlations with the N and Chl contents. From the point of view of the diagnosis of the nutritional status of corn, the spectral indices and REP values were suitable for establishing the nutritional status of corn in relation to N in the phenological stages V8 and R1.

Objective. To analyze the characteristics of pneumococcal meningitis in children < 14 years old following the market introduction of pneumococcal conjugate vaccines in our community. Methods. Retrospective study of pneumococcal meningitis cases with a two-period analysis: pre-13-valent pneumococcal conjugate vaccine (PCV13) (2001-2010) and post-PCV13 (2010-2015). Patient demographic and clinical data, and microbiological data were collected. Results. Eighteen cases were diagnosed. The mean incidence in the pre-PCV13 period was 2.3/100 000, which reduced to 0.5/100 000 after the PCV13 introduction. The most commonly identified serotypes were 6A and 10A (pre-PCV13); 6B and 15B (post-PCV13, only 2 cases). Out of 18 patients, 13 were admitted to the intensive care unit. All cases were treated with cefotaxime, and 14/18 received dexamethasone. Six patients survived with sequelae, and 1 died. Conclusion. A major reduction has been observed in the incidence of pneumococcal meningitis since the introduction of the PCV13 to the market, so an even greater reduction is expected following its systematic introduction.

Objetivo. Analizar las características de la meningitis neumocócica en < 14 años tras la comercialización de vacunas antineumocócicas conjugadas en nuestra comunidad. Métodos. Estudio retrospectivo de los casos de meningitis neumocócica en el que se analizaron dos períodos: pre vacuna antineumocócica trecevalente (VNC13v) (2001-2010) y post-VNC13v (2010-2015). Se recogieron datos demográficos y clínicos de los pacientes y datos microbiológicos. Resultados. Se diagnosticaron 18 casos. La incidencia media pre-VNC13v fue de 2,3/100 000, y disminuyó a 0,5/100 000 tras la VNC13v. Los serotipos más frecuentemente identificados fueron 6A y 10A (pre-VNC13v); 6B y 15B (post-VNC13v, solo dos casos). Trece de dieciocho pacientes ingresaron en la Unidad de Cuidados Intensivos. Todos los casos fueron tratados con cefotaxima y recibieron dexametasona 14/18. Seis pacientes sobrevivieron con secuelas y uno falleció. Conclusión. Se observa un importante descenso en la incidencia de meningitis neumocócica desde la comercialización de la VNC13v, por lo que cabe esperar que tras su introducción sistemática se produzca un descenso aún mayor.

An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosaisolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosaisolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.