Agronomic, economic and ecological aspects of the papaya (Carica papaya) production in Tabasco, Mexico

The cultivation of papaya is important in the tropic because it provides source of income to the farmer within a short time. Statistical data were obtained from farmers located in the Chontalpa, Rios and Centro-Sierra regions; the size of the survey was 67 farmers. The study shows the results of the farmers’ problem in a drastic reduction of their productivity because of the virosis and low prices in commercialization. The farmers were classified into three levels of technology, “low”, “middle” and “high”. The first one covers 88% of the farmers in seasonal conditions in contrast with the high technology that concentrates 4.5% in irrigation conditions. According to the technology used, the fertilizer shows more yields. Economically, the high technology had an internal tax return of 0.43 in comparison with the low technology of 0.25, which means that the investment is recovered with different yields. However, the use of high technology makes the system more competitive. Key words

Effect of Inoculation with Rhizobacteria and Arbuscular Mycorrhizal Fungi on Growth and Yield of Capsicum chinense Jacquin

We evaluated the effect of two rhizobacteria (Azotobacter chroococcum and Azospirillum brasilense) and a commercial product containing multiple strains of arbuscular mycorrhizal fungi (AMF) and an NPK fertiliser on the growth and yield of habanero chilli (Capsicum chinense Jacquin). All treatments were applied as single or combined inoculants, under nursery and field conditions, in a completely randomised design. The biofertilisers were applied to the roots by coating or dipping, with the inoculants in a solid or liquid support, respectively. At 30 days after inoculation, populations of 2.5×106 to 1.3×106 cfu g soil−1 of A. brasilense and 10.3×105 to 2.6×105 of A. chroococcum were detected in the rhizosphere of the crop. The prevalence of colonisation of plants inoculated with AMF ranged from 35 to 57%, with the greatest values recorded for the treatment involving single biofertilisation by root coating. In the nursery phase, single biofertilisation promoted a higher growth and nutrient content in the crop than combined biofertilisation. However, in the field phase the combined biofertilisation increased the nutrient content of the plant leaves, which was significantly greater than observed in the NPK treatment. The highest yields were recorded for the treatments involving a single inoculation of A. chroococcum and for those with the multi-strain of AMF, with average values of 2.5 and 2.3 kg plant−1 respectively, compared with 1.0 kg plant−1 obtained with the treatment in which NPK fertiliser was applied

Utilidad de la exploración física para el diagnóstico de neumonía infantil adquirida en la comunidad en un centro de atención primaria

ObjetivoDeterminar la utilidad diagnóstica de tres signos clínicos (fiebre, tos, estertores crepitantes) para el diagnóstico de neumonía en niños; evaluar la concordancia en la interpretación de la radiografía de tórax por dos radiólogosDiseñoEstudio de pruebas diagnósticasEmplazamientoAtención primariaMaterialTrescientas cincuenta historias clínicas de niños a los que se practicó una radiografía de tórax urgente para diagnosticar neumonía entre el 1 de enero de 1996 y el 30 de junio de 1999Mediciones principalesa) Prevalencia de neumonía en toda la muestra y en dos subgrupos de edad: igual o inferior a 5 años y superior a 5 años; b) cocientes de probabilidad positivo y negativo e intervalos de confianza del 95% (IC del 95%). Se consideró la radiografía de tórax como estándar de referencia, y c) concordancia interradiólogos-índice kappa (?)ResultadosLa prevalencia de neumonía en toda la muestra fue del 22,9% (IC del 95%, 18,5-27,3); en los niños de 5 años de edad o menores fue del 20,4% (IC del 95%, 15,6- 25,2), y en los mayores de 5 años, del 31,3% (IC del 95%, 21,1-41,4). Los signos estudiados sólo tuvieron alguna utilidad para confirmar el diagnóstico en mayores de 5 años: el cociente de probabilidad positivo fue de 3,52 (IC del 95%, 1,28-9,69) y los radiólogos coincidieron en el diagnóstico en el 93,1% de las radiografías de tórax (k=0,8; IC del 95%, 0,77-0,83)ConclusionesEn este estudio no se constató la presencia de un subconjunto de signos clínicos que aseguren de forma inequívoca el diagnóstico de neumonía en niñosObjectiveTo determine the diagnostic usefulness of three clinical signs (temperature, cough, crepitant stertor) for diagnosing pneumonia in children.To evaluate the agreement of two radiologists in evaluating thoracic x-rays (TXR)DesignStudy of diagnostic testsSettingPrimary careParticipants350 clinical histories of children who had an urgent TXR to diagnosis pneumonia between 1st January 1996 and 30th June 1999Main measurementsa) Prevalence of pneumonia in the entire sample and two age-based sub-groups: aged 5 years and under, and over 5; b) positive probability quotients (PQ+) and negative ones (PQ-) and 95% confidence intervals (95% CI). The TXR was seen as the reference standard, and c) kappa index (?) for inter-radiologist concordanceResultsPrevalence: the entire sample, 22.9% (95% CI, 18.5-27.3); children aged 5 or less, 20.4% (95% CI, 15.6-25.2); aged over 5, 31.3% (95% CI, 21.1-41.4). The signs studied were only of any use in confirming the diagnosis in children over 5: PQ+ was 3.52 (1.28-9.69). Radiologists coincided in their diagnosis in 93.1% of the TXR (k=0.8; 95% CI, 0.77-0.83)ConclusionsThis study did not prove that there was a sub-grouping of clinical signs which confirmed unmistakeably the diagnosis of pneumonia in childre

Correlation between magnetic interactions and domain structure in A1 FePt ferromagnetic thin films

We have investigated the relationship between the domain structure and the magnetic interactions in a series of FePt ferromagnetic thin films of varying thickness. As-made films grow in the magnetically soft and chemically disordered A1 phase that may have two distinct domain structures. Above a critical thickness $d_{cr}\sim 30$ nm the presence of an out of plane anisotropy induces the formation of stripes, while for $d<d_{cr}$ planar domains occur. Magnetic interactions have been characterized using the well known DCD-IRM remanence protocols, $\delta M$ plots, and magnetic viscosity measurements. We have observed a strong correlation between the domain configuration and the sign of the magnetic interactions. Planar domains are associated with positive exchange-like interactions, while stripe domains have a strong negative dipolar-like contribution. In this last case we have found a close correlation between the interaction parameter and the surface dipolar energy of the stripe domain structure. Using time dependent magnetic viscosity measurements, we have also estimated an average activation volume for magnetic reversal, $\langle V_{ac}\rangle \sim 1.37\times 10^{4}$ nm$^{3},$ which is approximately independent of the film thickness or the stripe period.Comment: 25 pages, 11 figure

Quality of thawed deepwater pink shrimp (Parapenaeus longirostris) treated with melanosis-inhibiting formulations during chilled storage

This work investigates how the treatment of thawed deepwater pink shrimp (Parapenaeus longirostris) with several melanosis-inhibiting formulations, affects the quality of the shrimp during chilled storage. Formulations were as follows: a formulation containing 4-hexylresorcinol (0.1 and 0.05%), in combination with organic acids and chelating agents, a commercial formula based on sulphites, and a mixture of gluconic acid and commercial sulphites. No noticeable differences were observed for both trimethylamine and total volatile bases during chilled storage. pH evolution was irrespective of the treatment condition. Microbial load enlarged after the sixth day of chilled storage. Higher total bacteria counts were associated with the control and sulphite treatment conditions, while lactic acid bacteria growth seemed to be favoured under formulations based on 4-hexylresorcinol. The appearance of melanosis occurred more rapidly in control shrimp or in shrimp treated with commercial sulphites. 4-hexylresorcinol formulations preserved the quality of thawed shrimp and could replace traditional sulphites. © 2007 The Authors. Journal compilation 2007 Institute of Food Science and Technology Trust Fund.Peer Reviewe

Recurrence of the blue wing enhancements in the high ionization lines of SDSS 1004+4112 A

We present integral field spectroscopic observations of the quadruple-lensed QSO SDSS 1004+4112 taken with the fiber system INTEGRAL at the William Herschel Telescope on 2004 January 19. In May 2003 a blueward enhancement in the high ionization lines of SDSS 1004+4112A was detected and then faded. Our observations are the first to note a second event of similar characteristics less than one year after. Although initially attributed to microlensing, the resemblance among the spectra of both events and the absence of microlensing-induced changes in the continuum of component A are puzzling. The lack of a convincing explanation under the microlensing or intrinsic variability hypotheses makes the observed enhancements particularly relevant, calling for close monitoring of this object.Comment: 4 pages, 5 figure

Contaminantes emergentes: determinación de fármacos antihipertensivos en aguas superficiales

Estudios recientes han mostrado la presencia de un amplio grupo de principios activos farmacológicos en el medioambiente procedentes principalmente de la descarga de estaciones depuradoras de aguas residuales. Entre ellos, son de especial interés aquellos empleados en el tratamiento de enfermedades crónicas, como los fármacos antihipertensivos, no sólo debido a su consumo continuado, sino además a su potente mecanismo de acción, lo que los hace especialmente peligrosos para el medioambiente. En este trabajo se ha optimizado y validado una metodología analítica, basada en la extracción en fase sólida y determinación mediante cromatografía líquida con detector de espectrometría de masas de triple cuadrupolo, para la determinación de los tres fármacos antihipertensivos más consumidos (irbesartán, telmisartán y valsartán) en aguas superficiales. Las recuperaciones obtenidas se situaron entre el 84 y el 101 %. La precisión, medida en unidades de desviación estándar relativa, fue inferior al 10 % y los límites de detección se situaron entre 0.24 y 2.01 ng/L.Recent studies have reported the presence of a broad spectrum of pharmaceutical compounds in several environmental compartments, where they mainly end up due to discharges of effluent wastewater. Among them, pharmaceuticals designed to treat chronic diseases, including hypertensive pharmaceuticals, are of special interest, not only due to its continued consumption, but also for their potent mechanism of action, which makes them especially dangerous for the environment. In this work, an analytical method, based on solid phase extraction and determination by liquid chromatography with triple quadrupole mass spectrometry detector, has been optimized and validated for the determination of three of the most consumed antihypertensive pharmaceuticals (irbesartan, telmisartan and valsartan) on surface water samples. The recoveries obtained were between 84 and 101%. Precision, expressed as relative standard deviation, was < 10%, and limits of detection were between 0.24 and 2.01 ng/L.Ministerio de Economía y Competitividad. Proyecto CGL2013-44402-

Non-contact ultrasonic resonant spectroscopy resolves the elastic properties of layered plant tissues

This paper describes the application of the wide-band non-contact ultrasonic resonant spectroscopy technique to layered plant tissues (leaves), a method to extract the properties of main component tissues: palisade parenchyma and spongy mesophyll, a verification of the obtained properties, and a discussion of the implications of the observed elastic anisotropy. Transmission coefficient spectra of Ligustrum lucidum leaves with the thickness in the range of 250-850 µm revealing several order thickness resonances have been measured. A leaf acoustic model based on a two-layered structure and a metaheuristic (simulated annealing algorithm) is used to solve the inverse problem. The extracted parameters of these two layers of tissue are consistent with cross-sectional cryo-SEM images and other independent measurements. The extracted resonant frequency and the impedance of each layer explain the origin of the observed resonances. Finally, the elastic modulus of each layer is extracted and analyzed. The presented technique is a unique tool to study (in vivo and in a completely non-invasive way) the ultrasonic, elastic, and viscoelastic properties of layered plant tissues which could lead to a better understanding of the relationship between the tissue microstructure and the tissue function with macroscopic properties and how this may affect water relations

Evaluación del contenido de esteviósido y rebaudiósido A en una población de Stevia rebaudiana Bertoni (kaâ heê) cultivada comercialmente. Estudio preliminar

Stevia rebaudiana Bertoni (kaâ heê) es un arbusto originario de la Región Oriental de Paraguay. Sus hojas contienen glucósidos diterpénicos que producen un sabor dulce, pero sin valor calórico y son de 150 a 300 veces más dulces que la sacarosa (solución al 0,4%). Durante las temporadas agrícolas 1998 y 1999 se establecieron sembrados de selección individual, en el Instituto Agronómico Nacional (Caacupé, Paraguay).El objetivo de este trabajo fue determinar el contenido de esteviósido y rebaudiósido A en plantas seleccionadas en campo a fin de evaluar la variabilidad existente en la población e identificar clones con alto contenido de dichos glucósidos. De una población original de 2000 individuos, se seleccionaron fenotípicamente 140 plantas por características agronómicas superiores y se cosecharon en etapa de prefloración y libres de polinización. En los Laboratorios del Instituto Nacional de Tecnología Normalización y Metrología (INTN) fueron evaluados los contenidos de esteviósido y rebaudiósido A por detección por cromatografía liquida de alta resolución. El contenido de esteviósido fluctuó entre 0 y 21 % concentrándose el 92 % de la población entre valores del 5 al 15 % .En cuanto al contenido de rebaudiósido A se obtuvieron valores entre 0 y 12 % correspondiendo al 68 % de la población un contenido entre 3 y 9 %. La demanda actual de stevia se halla en creciente aumento, por lo que las acciones orientadas a establecer líneas clonales con alto contenido de principios edulcorantes permitirá a los productores primarios la obtención de cultivos más productivos e incrementara el rendimiento de obtención de glucósidos