168 research outputs found

    THE EFFECT OF QUALITY OF FOOD SOURCE ON MACADAMIA NUT DAMAGE BY Gymnandrosoma aurantianum (LEPIDOPTERA: TORTRICIDAE)

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    RESUMEN Efecto de la calidad de la fuente de alimento sobre el daño a la nuez de macadamia por Gymnandrosoma aurantianum (Lepidoptera: Tortricidae). Se estudió el efecto del contenido de nitrógeno, de los compuestos secundarios (taninos y prohantocianidinas) y de la materia seca de 4 clones de macadamia y de los diferentes estados de desarrollo de la nuez, sobre la abundancia de Gymnandrosoma aurantianum. El contenido de nitrógeno varió entre clones y los estados de desarrollo de la nuez, siendo más alto en los clones más tolerantes 508>660>344>246. Los mayores contenidos de materia seca se encontraron en los clones tolerantes, 508 y 660, y en las capas externas de la nuez, que en los susceptibles 246 y 344 y en las capas internas (2 y 3). El contenido de proantocianidinas fue mayor en la segunda capa de los clones 508 y 660 que en la de los clones 246 y 344. Los resultados muestran cómo la calidad del alimento afecta el desempeño de las larvas del barrenador, donde éstas, para alimentarse de la almendra, deben superar primero una barrera física, seguida por una barrera química. ABSTRACT The effect of nitrogen content, the secondary compounds (tannin and proanthocyanidin) content, the dry matter content of 4 clones, and the different developmental stages of macadamia nuts, on the abundance of Gymnandrosoma aurantianum, was studied. Nitrogen content differed between clones and the stages of development of the nuts, being highest in the most tolerant clones 508>660>344>246. Highest dry matter contents were found in the tolerant clones, 508 and 660, and in the outer layer, than in the susceptible clones 246 and 344 and in the inner layers (2 and 3). Proanthocyanidin content was highest in layer 2 of clones 508 and 660 than in clones 246 and 344. Results show that food quality affects the performance of nutborer larvae, where the larvae have to overcome first a physical barrier, followed by a chemical barrier, to be able to feed on macadamia nuts

    Efecto de la calidad de la fuente de alimento sobre el daño a la nuez de macadamia por Gymnandrosoma aurantianum (Lepidoptera: Tortricidae)

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    The effect of nitrogen content, the secondary compounds (tannin and proanthocyanidin) content, the dry matter content of 4 clones, and the different developmental stages of macadamia nuts, on the abundance of Gymnandrosoma aurantianum, was studied. Nitrogen content differed between clones and the stages of development of the nuts, being highest in the most tolerant clones 508>660>344>246. Highest dry matter contents were found in the tolerant clones, 508 and 660, and in the outer layer, than in the susceptible clones 246 and 344 and in the inner layers (2 and 3). Proanthocyanidin content was highest in layer 2 of clones 508 and 660 than in clones 246 and 344. Results show that food quality affects the performance of nutborer larvae, where the larvae have to overcome first a physical barrier, followed by a chemical barrier, to be able to feed on macadamia nuts.Se estudió el efecto del contenido de nitrógeno, de los compuestos secundarios (taninos y prohantocianidinas) y de la materia seca de 4 clones de macadamia y de los diferentes estados de desarrollo de la nuez, sobre la abundancia de Gymnandrosoma aurantianum. El contenido de nitrógeno varió entre clones y los estados de desarrollo de la nuez, siendo más alto en los clones más tolerantes 508>660>344>246. Los mayores contenidos de materia seca se encontraron en los clones tolerantes, 508 y 660, y en las capas externas de la nuez, que en los susceptibles 246 y 344 y en las capas internas (2 y 3). El contenido de proantocianidinas fue mayor en la segunda capa de los clones 508 y 660 que en la de los clones 246 y 344. Los resultados muestran cómo la calidad del alimento afecta el desempeño de las larvas del barrenador, donde éstas, para alimentarse de la almendra, deben superar primero una barrera física, seguida por una barrera química

    Panoramic optical and near-infrared SETI instrument: prototype design and testing

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    The Pulsed All-sky Near-infrared Optical Search for ExtraTerrestrial Intelligence (PANOSETI) is an instrument program that aims to search for fast transient signals (nano-second to seconds) of artificial or astrophysical origin. The PANOSETI instrument objective is to sample the entire observable sky during all observable time at optical and near-infrared wavelengths over 300 - 1650 nm1^1. The PANOSETI instrument is designed with a number of modular telescope units using Fresnel lenses (\sim0.5m) arranged on two geodesic domes in order to maximize sky coverage2^2. We present the prototype design and tests of these modular Fresnel telescope units. This consists of the design of mechanical components such as the lens mounting and module frame. One of the most important goals of the modules is to maintain the characteristics of the Fresnel lens under a variety of operating conditions. We discuss how we account for a range of operating temperatures, humidity, and module orientations in our design in order to minimize undesirable changes to our focal length or angular resolution.Comment: 12 pages, 8 figures, 1 tabl

    Efecto del manejo de las malezas en macadamia sobre la población del barrenador de la nuez Ecdytolopha torticornis Meyrick (Lep: Tortricidae).

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    Entre junio y setiembre de 1992 se evaluó el efecto de tres sistemas de manejo de malezas; cobertura de cáscara de macadamia, chapia al ras del suelo y malezas creciendo libremente, sobre la población del barrenador de la nuez (Ecdytolopha torticornis) en plantaciones de macadamia en Turrialba, Costa Rica. El menor número de huevos del barrenador se registró en el tratamiento de suelo limpio, seguido por el tratamiento de malezas creciendo libremente y el de cobertura con cáscara. Aunque se ha utilizado este tipo de cobertura como una solución al problema de los desechos en el procesamiento de la nuez, el aumento de la población del barrenador bajo dicho tratamiento sugiere que podría estar actuando como atrayente del insecto adulto o bien confundiendo la población de parasitoides y depredadores. Es necesario probar otros sistemas de manejo de malezas con otros sus tratos, así como el uso de cultivos de cobertura entre las hileras de árboles, lo cual además podría incrementar las poblaciones de organismos benéficos

    Network Analysis Reveals Distinct Clinical Syndromes Underlying Acute Mountain Sickness

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    Acute mountain sickness (AMS) is a common problem among visitors at high altitude, and may progress to life-threatening pulmonary and cerebral oedema in a minority of cases. International consensus defines AMS as a constellation of subjective, non-specific symptoms. Specifically, headache, sleep disturbance, fatigue and dizziness are given equal diagnostic weighting. Different pathophysiological mechanisms are now thought to underlie headache and sleep disturbance during acute exposure to high altitude. Hence, these symptoms may not belong together as a single syndrome. Using a novel visual analogue scale (VAS), we sought to undertake a systematic exploration of the symptomatology of AMS using an unbiased, data-driven approach originally designed for analysis of gene expression. Symptom scores were collected from 292 subjects during 1110 subject-days at altitudes between 3650 m and 5200 m on Apex expeditions to Bolivia and Kilimanjaro. Three distinct patterns of symptoms were consistently identified. Although fatigue is a ubiquitous finding, sleep disturbance and headache are each commonly reported without the other. The commonest pattern of symptoms was sleep disturbance and fatigue, with little or no headache. In subjects reporting severe headache, 40% did not report sleep disturbance. Sleep disturbance correlates poorly with other symptoms of AMS (Mean Spearman correlation 0.25). These results challenge the accepted paradigm that AMS is a single disease process and describe at least two distinct syndromes following acute ascent to high altitude. This approach to analysing symptom patterns has potential utility in other clinical syndromes

    Avoiding Decline: Fostering Resilience and Sustainability in Midsize Cities

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    Eighty-five percent of United States citizens live in urban areas. However, research surrounding the resilience and sustainability of complex urban systems focuses largely on coastal megacities (\u3e1 million people). Midsize cities differ from their larger counterparts due to tight urban-rural feedbacks with their immediate natural environments that result from heavy reliance and close management of local ecosystem services. They also may be less path-dependent than larger cities due to shorter average connection length among system components, contributing to higher responsiveness among social, infrastructural, and ecological feedbacks. These distinct midsize city features call for a framework that organizes information and concepts concerning the sustainability of midsize cities specifically. We argue that an integrative approach is necessary to capture properties emergent from the complex interactions of the social, infrastructural, and ecological subsystems that comprise a city system. We suggest approaches to estimate the relative resilience of midsize cities, and include an example assessment to illustrate one such estimation approach. Resilience assessments of a midsize city can be used to examine why some cities end up on sustainable paths while others diverge to unsustainable paths, and which feedbacks may be partially responsible. They also provide insight into how city planners and decision makers can use information about the resilience of midsize cities undergoing growth or shrinkage relative to their larger and smaller counterparts, to transform them into long-term, sustainable social-ecological systems

    Discovery and Follow-up Observations of the Young Type Ia Supernova 2016coj

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    The Type~Ia supernova (SN~Ia) 2016coj in NGC 4125 (redshift z=0.004523z=0.004523) was discovered by the Lick Observatory Supernova Search 4.9 days after the fitted first-light time (FFLT; 11.1 days before BB-band maximum). Our first detection (pre-discovery) is merely 0.6±0.50.6\pm0.5 day after the FFLT, making SN 2016coj one of the earliest known detections of a SN Ia. A spectrum was taken only 3.7 hr after discovery (5.0 days after the FFLT) and classified as a normal SN Ia. We performed high-quality photometry, low- and high-resolution spectroscopy, and spectropolarimetry, finding that SN 2016coj is a spectroscopically normal SN Ia, but with a high velocity of \ion{Si}{2} λ\lambda6355 (12,600\sim 12,600\,\kms\ around peak brightness). The \ion{Si}{2} λ\lambda6355 velocity evolution can be well fit by a broken-power-law function for up to a month after the FFLT. SN 2016coj has a normal peak luminosity (MB18.9±0.2M_B \approx -18.9 \pm 0.2 mag), and it reaches a BB-band maximum \about16.0~d after the FFLT. We estimate there to be low host-galaxy extinction based on the absence of Na~I~D absorption lines in our low- and high-resolution spectra. The spectropolarimetric data exhibit weak polarization in the continuum, but the \ion{Si}{2} line polarization is quite strong (0.9%±0.1%\sim 0.9\% \pm 0.1\%) at peak brightness.Comment: Submitte

    Characterizing and Improving the Data Reduction Pipeline for the Keck OSIRIS Integral Field Spectrograph

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    OSIRIS is a near-infrared (1.0--2.4 μ\mum) integral field spectrograph operating behind the adaptive optics system at Keck Observatory, and is one of the first lenslet-based integral field spectrographs. Since its commissioning in 2005, it has been a productive instrument, producing nearly half the laser guide star adaptive optics (LGS AO) papers on Keck. The complexity of its raw data format necessitated a custom data reduction pipeline (DRP) delivered with the instrument in order to iteratively assign flux in overlapping spectra to the proper spatial and spectral locations in a data cube. Other than bug fixes and updates required for hardware upgrades, the bulk of the DRP has not been updated since initial instrument commissioning. We report on the first major comprehensive characterization of the DRP using on-sky and calibration data. We also detail improvements to the DRP including characterization of the flux assignment algorithm; exploration of spatial rippling in the reduced data cubes; and improvements to several calibration files, including the rectification matrix, the bad pixel mask, and the wavelength solution. We present lessons learned from over a decade of OSIRIS data reduction that are relevant to the next generation of integral field spectrograph hardware and data reduction software design.Comment: 18 pages, 16 figures; accepted for publication in A

    Size–Luminosity Scaling Relations of Local and Distant Star-forming Regions

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    We investigate star forming scaling relations using Bayesian inference on a comprehensive data sample of low- (z < 0.1) and high-redshift (1 < z < 5) star forming regions. This full data set spans a wide range of host galaxy stellar mass (M∗∼10^6−10^(11)M⊙) and clump star formation rates (SFR ∼10^(−5)−10^2M⊙yr^(−1)). We fit the power-law relationship between the size (r_(Hα)) and luminosity (L_(Hα)) of the star forming clumps using the Bayesian statistical modeling tool Stan that makes use of Markov Chain Monte Carlo (MCMC) sampling techniques. Trends in the scaling relationship are explored for the full sample and subsets based on redshift and selection effects between samples. In our investigation we find no evidence of redshift evolution of the size-luminosity scaling relationship, nor a difference in slope between lensed and unlensed data. There is evidence of a break in the scaling relationship between high and low star formation rate surface density (Σ_(SFR)) clumps. The size-luminosity power law fit results are L_(Hα) ∼ r^(2.8)_(Hα) and L_(Hα) ∼ r^(1.7)_(Hα) for low and high Σ_(SFR) clumps, respectively. We present a model where star forming clumps form at locations of gravitational instability and produce an ionized region represented by the Strömgren radius. A radius smaller than the scale height of the disk results in a scaling relationship of L ∝ r^3 (high Σ_(SFR) clumps), and a scaling of L ∝ r2^ (low Σ_(SFR) clumps) if the radius is larger than the disk scale height
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