Tile Packing Tomography is NP-hard

Discrete tomography deals with reconstructing finite spatial objects from lower dimensional projections and has applications for example in timetable design. In this paper we consider the problem of reconstructing a tile packing from its row and column projections. It consists of disjoint copies of a fixed tile, all contained in some rectangular grid. The projections tell how many cells are covered by a tile in each row and column. How difficult is it to construct a tile packing satisfying given projections? It was known to be solvable by a greedy algorithm for bars (tiles of width or height 1), and NP-hardness results were known for some specific tiles. This paper shows that the problem is NP-hard whenever the tile is not a bar

Eficiencia de uso de agua en quince genotipos de papa (Solanum tuberosum L.) bajo condiciones de estrés hídrico por sequía

Universidad Nacional Agraria La Molina. Facultad de Agronomía. Departamento Académico de FitotecniaLa papa (Solanum tuberosum L.) es un cultivo sensible a la sequía debido a que posee un sistema radicular poco profundo y requiere disponibilidad constante de agua en el suelo para asegurar su máximo rendimiento y calidad en el tubérculo. La eficiencia de uso de agua (EUA) se define como la producción por unidad de agua consumida, esta variable es considerada importante para determinar el rendimiento bajo condiciones limitadas de agua. Si logramos entender la relación entre EUA y el rendimiento bajo condiciones de estrés puede ayudarnos a encontrar estrategias que nos ayuden a minimizar la perdida de rendimiento debido a la disponibilidad de agua y asegurar una alta producción. Se llevó acabo un experimento en invernadero con condiciones controladas , para caracterizar la respuesta y entender la relación entre la EUA, el rendimiento y la tolerancia en 15 genotipos de papa de la población avanzada de mejoramiento del Centro Internacional de la Papa (CIP). El experimento fue llevado acabo baja el diseño experimental de parcelas divididas teniendo como factor principal dos tipos de riego, sequía regulada y riego normal y como factor secundario los quince genotipos. A través del experimento se evaluaron variables morfológicas y fisiológicas tales como contenido relativo de clorofila (SPAD), contenido relativo de agua (CRA), Potencial Osmótico (PO), Área foliar (AF), transpiración y parámetros de rendimiento tales como el peso de la biomasa, Índice de Cosecha (IC) e Índice de tolerancia a la reducción de agua (TRA). Los resultados de la investigación muestran diferencias significativas entre tratamientos, y en general las plantas sometidas a limitaciones de agua muestran un rendimiento menor, existiendo una reducción en la biomasa y el área foliar. Existe una correlación alta entra la EUA y el IC (r = 0.98), indicando que este último puede ser una herramienta útil para la selección prematura de genotipos con buen rendimiento y tolerante al estrés por sequía. Los genotipos, CIP398190.89, CIP397077.16, CIP392797.22, CIP398208.620 mostraron una mayor eficiencia en el uso de agua bajo condiciones de sequía sin que esto produzca una reducción drástica en su rendimiento.The potato (Solanum tuberosum L.) is a sensitive crop to drought because it has a shallow root system and requires constant availability of water in the soil to ensure maximum performance and quality in the tuber. The water use efficiency (EUA) is defined as production per unit of water consumed, this variable is considered important in determining the performance under limited water conditions. If we understand the relationship between the EUA and yield under stress conditions may help us find strategies that help to minimize the loss of yield due to water availability and ensure high production. It was performed an experiment in greenhouse with controlled conditions, to characterize the response and understanding the relationship between the EUA, performance and tolerance in 15 potato genotypes from advanced breeding population of the International Potato Center (CIP). The experiment was carried in a split plot experimental design with the main factor the two types of irrigation, drought and normal watering and as a secondary factor the fifteen genotypes. Through the experiment morphological and physiological variables were evaluated such as relative chlorophyll content (SPAD), leaf area (AF), transpiration and yield parameters such as the weight of biomass, harvest index (IC) and tolerance index (TRA). The research results show significant differences between treatments, plants subjected to water shortages show a lower yield, and there was a reduction in the biomass and leaf area. There was a high correlation enters the EUA and IC (r = 0.98), indicating that the IC can be a useful tool for early selection of genotypes with good performance and tolerant to drought. Genotypes CIP398190.89, CIP397077.16, CIP392797.22, CIP398208.620 showed greater efficiency in the use of water under drought conditions without producing a drastic reduction in yield.Tesi

Romifidina ou xilazina associadas à quetamina em cães premedicados com levomepromazina

The cardiorespiratory and analgesic effects of romifidine or xylazine combined with ketamine was investigated in dogs. Dogs were premedicated with 1.0 mg/kg of methotrimeprazine IV, followed by 0.1 mg/kg of romifidine (n = 8) or 1.0 mg/kg of xylazine (n = 8) and 15 mg/kg of ketamine IM, using a double blind randomised design. Dogs of both groups developed hypothermia, bradycardia, slight hypotension and reduction in respiratory rate and minute volume. There were minimal changes in end tidal CO2 and O2 saturation. There were no differences either in time or between the groups in pH, PaO2, and blood biochemistry. The reflexes to pain were reduced until 30-45 minutes of anaesthesia in both groups. Twelve bitches were divided in two groups as above and underwent ovariohysterectomy. Recovery was longer after romifidine/ketamine when compared to xylazine/ketamine in both studies. Although these anaesthetic protocols produced minimal cardiorespiratory changes, the quality of anaesthesia was not ideal for ovariohysterectomy.Investigaram-se neste estudo os efeitos cardiorrespiratório e analgésico da associação de romifidina ou xilazina com a quetamina em cães. Dezesseis cães receberam como medicação pré-anestésica 1,0 mg/kg de levomepromazina IV, seguido de 0,1 mg/kg de romifidina (n = 8) ou 1,0 mg/kg de xilazina (n = 8) associadas a 15 mg/kg de quetamina IM, utilizando-se protocolo aleatório de seleção dos grupos, em estudo duplo cego. Os cães de ambos os grupos apresentaram hipotermia, bradicardia, leve hipotensão e redução da freqüência respiratória e volume minuto. Poucas alterações foram observadas na concentração de CO2 expirada e na saturação de O2 na hemoglobina. Os valores de pH, PaO2 e bioquímica sangüínea não apresentaram diferenças ao longo do tempo em cada grupo ou entre os grupos. Os reflexos dolorosos permaneceram reduzidos por até 30 a 45 minutos após a aplicação dos alfa-2 agonistas e quetamina. Doze cadelas foram divididas em dois grupos, anestesiadas como acima e foram submetidas a ovarioisterectomia. A recuperação foi mais longa nas cadelas tratadas com romifidina/quetamina. Embora estes protocolos anestésicos tenham produzido mínimas alterações cardiorrespiratórias, a qualidade da anestesia não foi ideal para ovarioisterectomia

Implementación del marketing digital para mejorar el posicionamiento de la empresa CONSIABSA S.A.

La investigación “Implementación de Marketing Digital para mejorar el posicionamiento de la empresa Consiabsa” tuvo como problema la falta de aplicación de nuevas estrategias digitales con direccionamiento al posicionamiento de la empresa, correspondiendo a la necesidad de posicionar de manera efectiva en el mercado industrial, como objetivo general se determinó cómo la implementación de Marketing digital influyó en el posicionamiento de la empresa. La investigación fue de tipo aplicada, enfoque cuantitativo, nivel explicativo y diseño pre experimental. Se delimitó como población 200 clientes actuales que por lo menos hayan adquirido algún producto o servicio. La muestra fue lamisma cantidad de población en estudio. La técnica utilizada fue la encuesta y análisis documentario. Asimismo, el instrumento fue el cuestionario y el registro de datos. Para obtener los resultados se realizó el análisis inferencial, se aplicó a losmismos clientes en el prestest y postest, para contrastar las hipótesis a través del estadígrafo de Wilcoxon. Se obtuvo una significancia de 0,000 obteniendo como resultado que el marketing digital influyó sobre el posicionamiento de la empresa en estudio. Se concluyó que, la implementación mejoró la posición de la empresa Consiabsa, al pasar de un nivel medio a un nivel alto

Uso de meta-topolina, una citoquinina no convencional en la multiplicación in vitro de Opuntia stricta Haw.

The erect prickly pear (Opuntia stricta Haw) is an important alternative used to feed ruminants during prolonged periods of drought. The objective of this research was to evaluate the effect of different types and concentrations of cytokinins on the morphophysiological aspects of in vitro multiplication of O. stricta. Segments of O. stricta were grown in liquid and semisolid Murashige and Skoog (MS) medium supplemented with 2.22 or 1.11 µM l-1 of 6-benzylaminopurine (BAP) and 1.11 µMl-1 meta-Topolin (mT). The experiment was conducted in a growth room at 25±2 °C over a period of 45 days. It were evaluated multiplication rate, shoot formation index, rooting and callus formation, fresh biomass, height, activity of antioxidant enzymes, and content of hydrogen peroxide and malondialdehyde. The experiment was carry out in a completely randomized design with six treatments and twelve replicates. The results showed that the consistency of the medium had influence on the shoots development and roots emission. The increase in BAP concentrations resulted in a reduction in the length and fresh biomass of the shoots and in the root system. The enzymatic activity and oxidative stress were inducted with the use of 6-benzylaminopurine. The micropropagation of O. stricta was improved with the use of mT, verified through shoot with better morphophysiological quality for acclimatization, with longer shoot length, rooting and reduction in the occurrence of hyperhydricity, a morphophysiological disorder that leads to large losses in micropropagation of this specie. Keywords: antioxidant enzyme, hyperhydricity, in vitro stress, morphophysiological anomalies El nopal erecto (Opuntia stricta Haw) es una alternativa importante que se utiliza para alimentar a los rumiantes durante períodos prolongados de sequía. El objetivo de esta investigación fue evaluar el efecto de diferentes tipos y concentraciones de citoquininas en los aspectos morfofisiológicos de la multiplicación in vitro de O. stricta. Se cultivaron segmentos de O. stricta en medio de cultivo líquido y semisólido de Murashige y Skoog (MS) con 2.22 o 1.11 µM l-1 de 6-bencilaminopurina (BAP) y 1.11 µM l-1 de meta-Topolina (mT). El experimento se realizó en una sala de crecimiento a 25 ± 2 °C durante un período de 45 días. Se evaluaron la tasa de multiplicación, el índice de formación de brotes, la formación de raíces y callos, la biomasa fresca, la altura, la actividad de las enzimas antioxidantes y el contenido de peróxido de hidrógeno y malondialdehído. El experimento se realizó con un diseño completamente al azar con seis tratamientos y doce repeticiones. Los resultados mostraron que la consistencia del medio de cultivo influyó en el desarrollo de brotes y en la emisión de raíces. El aumento en las concentraciones de BAP resultó en una reducción en la longitud y la biomasa fresca de los brotes y en el sistema radicular. La actividad enzimática y el estrés oxidativo se indujeron con el uso de 6-bencilaminopurina. La micropropagación de O. stricta se mejoró con el uso de mT, verificado a través de brotes con mejor calidad morfofisiológica para la aclimatización con mayor longitud de brotes, enraizamiento y reducción en la aparición de hiperhidricidad, un trastorno morfofisiológico que conduce a grandes pérdidas de micropropagación de esta especie. Palabras clave: anomalías morfofisiológicas, enzima antioxidante, estrés in vitro, hiperhidricida

Tecnologías para una producción de arroz: Recomendaciones para el Perú basadas en investigaciones científicas

Los problemas futuros de producción de arroz están relacionados al calentamiento global y la escasez de agua producto del cambio climático. Para una producción eficiente y sustentable en el cultivo de arroz, el manejo de riego por inundación y altas aplicaciones de nitrógeno deben ser modificadas. Entre las principales recomendaciones incluyen la incorporación del fertilizante nitrogenado en las fases críticas del cultivo, y el uso de siembra directa en suelo seco en lugar del método de trasplante. El presente manuscrito reúne también recomendaciones para mejorar la eficiencia agronómica y el uso del nitrógeno en el cultivo de arroz.  Las recomendaciones técnicas mencionadas deben implementarse a fin de mejorar la productividad del cultivo y fortalecer la seguridad alimentaria

Modelling Acacia saligna invasion in a large Mediterranean island using PAB factors: A tool for implementing the European legislation on invasive species

The present study aimed to investigate the role of propagule pressure (P), abiotic (A), and biotic (B) factors (collectively indicated as PAB) on the suitability of the Mediterranean island of Sardinia (Italy) to be invaded by the tree Acacia saligna, recently included in the list of invasive alien species of European Union concern. To this aim, a binomial Generalized Linear Model was applied for disentangling the relationship between 432 A. saligna occurrence records and 10 thematic layers, at high-resolution (10 x10 m), used as proxies for the 3 categories of PAB variables. The 432 occurrence records of A. saligna were periodically monitored (period 2000–2018) to check the persistence of the populations and their invasive status. The predictive power of the model was evaluated by computing the mean of the AUC scores, through cross-fold validation. The model adequately described how the PAB factors influence the presence of A. saligna which is mainly shaped by abiotic factors such as topography, and biotic factors such as the presence of woody dune vegetation, and to a lesser extent by other predictors. The projection of the model to the whole island clearly shows that suitability varies at the landscape level due to the variation of the PAB across the territory. The probability of A. saligna occurrence near the coast is higher in sand dunes. In the internal areas of the island it occurs close to the roads and urban areas. This study and the tested methodology could represent a suitable tool to prioritize areas for the monitoring of A. saligna to meet the requirements of the Regulation (EU) No. 1143/2014 on Invasive Alien Species (the IAS Regulation)

A relocatable ocean model in support of environmental emergencies

During the Costa Concordia emergency case, regional, subregional, and relocatable ocean models have been used together with the oil spill model, MEDSLIK-II, to provide ocean currents forecasts, possible oil spill scenarios, and drifters trajectories simulations. The models results together with the evaluation of their performances are presented in this paper. In particular, we focused this work on the implementation of the Interactive Relocatable Nested Ocean Model (IRENOM), based on the Harvard Ocean Prediction System (HOPS), for the Costa Concordia emergency and on its validation using drifters released in the area of the accident. It is shown that thanks to the capability of improving easily and quickly its configuration, the IRENOM results are of greater accuracy than the results achieved using regional or subregional model products. The model topography, and to the initialization procedures, and the horizontal resolution are the key model settings to be configured. Furthermore, the IRENOM currents and the MEDSLIK-II simulated trajectories showed to be sensitive to the spatial resolution of the meteorological fields used, providing higher prediction skills with higher resolution wind forcing.MEDESS4MS Project; TESSA Project; MyOcean2 Projectinfo:eu-repo/semantics/publishedVersio

Multiple QTLs linked to agro-morphological and physiological traits related to drought tolerance in potato.

Dissection of the genetic architecture of adaptation and abiotic stress-related traits is highly desirable for developing drought-tolerant potatoes and enhancing the resilience of existing cultivars, particularly as agricultural production in rain-fed areas may be reduced by up to 50 % by 2020. The “DMDD” potato progeny was developed at International Potato Center (CIP) by crossing the sequenced double monoploid line DM and a diploid cultivar of the Solanum tuberosum diploid Andigenum Goniocalyx group. Recently, a high-density integrated genetic map based on single nucleotide polymorphism (SNP), diversity array technology (DArT), simple sequence repeats (SSRs), and amplified fragment length polymorphism (AFLP) markers was also made available for this population. Two trials were conducted, in greenhouse and field, for drought tolerance with two treatments each, well-watered and terminal drought, in which watering was suspended 60 days after planting. The DMDD population was evaluated for agro-morphological and physiological traits before and after initiation of stress, at multiple time points. Two dense parental genetic maps were constructed using published genotypic data, and quantitative trait locus (QTL) analysis identified 45 genomic regions associated with nine traits in well-watered and terminal drought treatments and 26 potentially associated with drought stress. In this study, the strong influence of environmental factors besides water shortage on the expression of traits and QTLs reflects the multigenic control of traits related to drought tolerance. This is the first study to our knowledge in potato identifying QTLs for drought-related traits in field and greenhouse trials, giving new insights into genetic architecture of drought-related traits. Many of the QTLs identified have the potential to be used in potato breeding programs for enhanced drought tolerance