Plan de muestreo secuencial para el gusano de la mazorca, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), en siembras de maíz de la costa sur de Puerto Rico.

The corn earworm, Helicoverpa zea (Boddie), is the major insect pest of corn, Zea mays L., in Puerto Rico. The objective of this study was to design a sequential sampling plan with fixed precision levels for H. zea (Boddie) in corn fields on the south coast of Puerto Rico. For determining the presence (= 1) or absence (= 0) of H. zea eggs, 25 corn plants were randomly sampled from December 2003 to March 2004. Data were analyzed by using the beta binomial distribution. Critical density levels of 0.10 and 0.08 infested plants, before and after the emergence of ear silks, were used for Iwao's and converging lines formulae. A converging line sampling plan is recommended because it selected a smaller average sample size. This plan can be used to make cost effective control decisions on field corn in Puerto Rico.El gusano de la mazorca, Helicoverpa zea (Boddie), es la plaga más importante del maíz, Zea mays L., en Puerto Rico. El objetivo de este estudio fue diseñar un plan de muestreo secuencial con niveles fijos de precisión para Helicoverpa zea en campos de maíz en la costa sur de Puerto Rico. Para determinar la presencia (= 1) o ausencia (= 0) de huevos de H. zea, se examinaron 25 plantas de maíz desde diciembre de 2003 hasta marzo de 2004. Los datos se analizaron utilizando una distribución beta binomial. Se utilizaron niveles de densidad crítica de 0.10 y 0.08 plantas infestadas, antes y después de la emergencia de los filamentos de la mazorca, en las fórmulas de Iwao y de líneas convergentes. Se recomienda el plan de muestreo secuencial de líneas convergentes porque seleccionó un menor número promedio de muestras. Este plan puede ser utilizado para tomar decisiones de control costo efectivas en siembras de maíz de campo en Puerto Rico

Effects of land-use change on Nitisols properties in a tropical climate

Land use change, especially conversion of native forests to cultivated land, exerts an impact on the physical, chemical and hydrophysical soils properties. To quantify and better understand responses, this study was aimed at evaluating the influence of different tropical soil management systems reflected in some physic, chemical and hydro-physical properties. Nine Nitisol profiles were evaluated and grouped in three categories: (I) native forest (Benchmark 30 years); (II) soils formerly cultivated then turned to pasture (Conservation 10 years); and (III) soils under continuous cultivation (Agrogenic 50 years). The analyzed variables were organic matter, bulk density, soil particle density, porosity, field capacity, texture and structural index. Results determine that the action of traditional farming techniques in tropical environments produces excessive soil degradation. Organic matter content and the structural index showed a linear relationship with high degree of dependence (R2=0.99). Bulk density average for (I) and (II) profile were lower (P0.05) than the bulk density values for (III). In the regression analyses the bulk density increased, the field capacity decreased, and the tendency for profile (I) and (II) were of a linear type. While the profile for (III) was of a polynomial type with (R2=0.83), being able to be influenced by the higher values of bulk density, greater soil compaction, lower structural index, organic matter and porosity in correspondence with the other profiles.El cambio en el uso de la tierra, especialmente la conversión de bosques nativos en tierras cultivadas ejerce un impacto sobre las propiedades físicas, químicas e hidrofísicas de los suelos. El objetivo de este estudio fue evaluar la influencia de diferentes sistemas de manejo de un suelo tropical reflejado en algunas de sus propiedades físicas, químicas e hidrofísicas. Se evaluaron nueve perfiles de un suelo Nitisol agrupado en tres categorías: (I) bosque nativo (Referencia 30 años); (II) suelos anteriormente cultivados y luego convertidos en pastizales (Conservados 10 años); y (III) suelos bajo cultivo continuado (Agrogénicos 50 años). Las variables analizadas fueron materia orgánica, densidad aparente, densidad real, porosidad, capacidad de campo, textura e índice estructural. Los resultados determinaron que la acción de las técnicas agrícolas tradicionales en ambientes tropicales produce una excesiva degradación de las propiedades del suelo. El contenido de materia orgánica e índice estructural muestran una relación lineal con un alto grado de dependencia (R2=0,99). La densidad aparente promedio para los perfiles (I) y (II) fue menor (P0,05) que los valores de densidad aparente del perfil (III). En los análisis de regresión a medida que aumenta la densidad aparente disminuye la capacidad de campo y la tendencia observada para (I) y (II) es lineal, mientras que para (III) es polinómica con (R2=0,83), pudiendo estar influenciado por los valores más altos de la densidad aparente, mayor compactación, menor índice estructural, materia orgánica y porosidad en correspondencia con los otros perfiles

Identification and Role of Regulatory Non-Coding RNAs in Listeria monocytogenes

Bacterial regulatory non-coding RNAs control numerous mRNA targets that direct a plethora of biological processes, such as the adaption to environmental changes, growth and virulence. Recently developed high-throughput techniques, such as genomic tiling arrays and RNA-Seq have allowed investigating prokaryotic cis- and trans-acting regulatory RNAs, including sRNAs, asRNAs, untranslated regions (UTR) and riboswitches. As a result, we obtained a more comprehensive view on the complexity and plasticity of the prokaryotic genome biology. Listeria monocytogenes was utilized as a model system for intracellular pathogenic bacteria in several studies, which revealed the presence of about 180 regulatory RNAs in the listerial genome. A regulatory role of non-coding RNAs in survival, virulence and adaptation mechanisms of L. monocytogenes was confirmed in subsequent experiments, thus, providing insight into a multifaceted modulatory function of RNA/mRNA interference. In this review, we discuss the identification of regulatory RNAs by high-throughput techniques and in their functional role in L. monocytogenes

Significados del envejecimiento desde la perspectiva de los ancianos

Introduction: Aging is a natural and integral part of life, and although all persons aim to be members of this process, different representations merge into it, whether the preceptors are different. Objective: To understand the meaning that a group of elderly people give to the process of aging. Material and methods: Qualitative research conducted in six focus groups, in people aged 60 years or older, from both sexes, and residents in the area of "Ana Betancourt" Polyclinic in Playa Municipality. Results: The participants expressed that aging is not necessarily considered to be a synonym of suffering. From their perspectives, aging gives them the possibility to reorganize their lives daily, and beside this, to enjoy their family, their free time, and although suffering from some diseases which can be controlled, to feel well.  Conclusions: Even though the testimonies of the participants (elderly women and men) could be different in the meaning that they give to aging, such change is argued on the fact that aging is a complex process that differs from person to person, and is also influenced by all the factors that exist in their daily lives, being the economic and the affective ones the most relevant.Keywords: aging, perception, old age, qualitative methodology.</p

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161