1,051 research outputs found

    NEMATICIDAL POTENTIAL OF EXTRACTS OF NEEM (Azadirachta indica) AND LEMON GRASS (Cymbopogon citratus) ON ROOT-KNOT NEMATODES (Meloidogyne spp) INFECTING SWEET POTATO

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    The nematicidal potential of extracts of Azadirachta indica (neem) leaves and Cymbopogon citratus (lemon grass) on root-knot nematodes infecting sweet potato was evaluated between the months of June and November, 2012 at the Botanical Nursery of the University of Jos. The root-knot nematodes were obtained from galled roots of tomato and potato in Jos farms. A total of forty (40) sweet potato cultivar TIS 87/0087 were raised in steam-sterilized soil in clay pots and used for the study. Thirty (30) of the test plants were inoculated with 2250 juveniles of root-knot nematodes each while 10 were not inoculated serving as positive control. Ten of the inoculated plants were treated with extracts of neem leaves, 10 were treated with extracts of lemon grass while 10 were not treated, they served as negative control. Growth and yield parameters were then measured from 42 days after planting to 120 DAP using agronomic traits as a measure of growth and yield. Growth and yield parameters such as number of leaves, length of vines, number of tubers, weight of tubers etc were highest in the positive control, followed by sweet potato infected with nematodes and treated with lemon grass extract, then those treated with Neem leaves extract while those not treated with extract had the least growth and yield. Statistical analysis showed that the positive control produced significantly higher (PË‚ 0.05) growth and yield parameters than all the other treatments. Infected plants treated with the extracts were also found to have significantly higher growth and yield parameters than the plants that were infected but not treated with extracts (negative control) at 0.05 level of probability. Number of galls was highest among the plants from the negative control, followed by plants treated with lemon grass extracts. The findings indicated that extracts of Lemon grass and Neem leaves improved growth and yield data of nematodes infected sweet potato and thus could be utilized in the control of root-knot nematodes in garden

    Quasi-simultaneous observations of the BL Lac object MK 501 in X-ray, UV, visible, IR and radio frequencies

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    Quasi-simultaneous observations of the BL Lacertae (Lac) objects MK 501 were performed for the first time at X-ray, ultraviolet, visible, infrared, and radio frequencies. The observed spectral slope from the X-ray to UV regions is positive and continuous, but that from the mid UV to visible light region becomes gradually flat and possibly turns down toward lower frequencies; the optical radio emission can not be accounted for by a single power law. Several theoretical models were considered for the emission mechanism. A quantitative comparison was performed with the synchrotron-self-Compton model; the total spectrum is found consistent with this model. The spectrum from visible light to X-ray is consistent with synchrotron radiation or with inverse-Compton scattering by a hot thermal cloud of electrons. The continuity of the spectral slope from X-ray to UV implied by the current data suggests that the previous estimates of the total luminosity of this BL Lac object is underestimated by a factor of about three or four

    EFFECTS OF SUBSTITUTION OF FAT WITH MELON SEED MEAL ON QUALITY CHARACTERISTICS OF PORK SAUSAGES

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    A study was conducted in which melon seed meal (MSM) replaced fat at 0, 33, 66, and 100% levels in four batches of pork sausages. The chemical and storage properties, cooking weight losses, and sensory properties, of the sausages were determined in the meat processing laboratory. The results showed that MSM increased both ash and crude protein contents. The highest ether extract (36%) was obtained for batch 1 (control) while the lowest value (25.50%) was recorded for batch 4. The values obtained for refrigeration weight losses increased with increase in MSM while the results for dry matter were statistically insignificant. Batch 3 had the highest cooking weight loss of 0.83% whilebatch one had the lowest value of 0.30%. The values obtained for sensory properties increased with increase in the level of MSM up to 66%. It was concluded that pork back fat can be replaced with MSM in pork sausage without adverse effect on processing yield

    A Study of Nine High-Redshift Clusters of Galaxies: IV. Photometry and Sp ectra of Clusters 1324+3011 and 1604+4321

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    New photometric and spectroscopic observations of galaxies in the directions of three distant clusters are presented as part of our on-going high-redshift cluster survey. The clusters are CL1324+3011 at z = 0.76, CL1604+4304 at z = 0.90, and CL1604+4321 at z = 0.92. The observed x-ray luminosities in these clusters are at least a factor of 3 smaller than those observed in clusters with similar velocity dispersions at z <= 0.4. These clusters contain a significant population of elliptical-like galaxies, although these galaxies are not nearly as dominant as in massive clusters at z <= 0.5. We also find a large population of blue cluster members. Defining an active galaxy as one in which the rest equivalent width of [OII] is greater than 15 Angstroms, the fraction of active cluster galaxies, within the central 1.0 Mpc, is 45%. In the field population, we find that 65% of the galaxies with redshifts between z = 0.40 and z = 0.85 are active, while the fraction is 79% for field galaxies at z > 0.85. The star formation rate normalized by the rest AB B-band magnitude, SFRN, increases as the redshift increases at a given evolving luminosity. At a given redshift, however, SFRN decreases linearly with increasing luminosity indicating a remarkable insensitivity of the star formation rate to the intrinsic luminosity of the galaxy over the range -18 >= ABB >= -22. Cluster galaxies in the central 1 Mpc regions exhibit depressed star formation rates. We are able to measure significant evolution in the B-band luminosity function over the range 0.1 <= z <= 1. The characteristic luminosity increases by a factor of 3 with increasing redshift over this range.Comment: 64 pages, 18 figures, accepted for publication in the Astronomical Journal on May 25, 2001. Scheduled to appear in Sept 2001 issu

    Ciliary Body Tumour Occurring in a Nigerian - A case report

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    Objective: To report the rare case of a 33-year-old female Nigerian who presented to our retina clinic with a chronic total retinal detachment and visual acuity of no light perception in her left eye. Re-attachment surgery in the eyewas not attempted as prognosis for return of vision was poor. She was later noted to harbor a progressively enlarging ciliarybody mass in the inferotemporal quadrant. Method: An observational case report was performed, withdocumentation of findings as patient was seen in the clinic.Conclusion: This is the first report of a ciliary body mass lesionin a Nigerian. The ciliary body mass could be a ciliary melanoma (ciliary body lesion being rarer than a choroidal mass) but other benign differential diagnoses must be borne in mind. Enucleation and histological assessment of the specimen will give the definitive diagnosis. Difficulties with patientacceptance of enucleating a non seeing eye though harboring a potentially harmful disease still abound in our environment

    Assessing the impact of observations on ocean forecasts and reanalyses: Part 2, Regional applications

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    The value of global (e.g., altimetry, satellite sea-surface temperature, Argo) and regional (e.g., radars, gliders, instrumented mammals, airborne profiles, biogeochemical) observation-types for monitoring the mesoscale ocean circulation and biogeochemistry is demonstrated using a suite of global and regional prediction systems and remotely-sensed data. A range of techniques is used to demonstrate the value of different observation-types to regional systems and the benefit of high- resolution and adaptive sampling for monitoring the mesoscale circulation. The techniques include Observing System Experiments, Observing System Simulation Experiments, adjoint sensitivities, representer matrix spectrum, observation footprints, information content and spectral analysis. It is shown that local errors in global and basin-scale systems can be significantly reduced when assimilating observations from regional observing systems

    A multi-object fiber spectrograph for The Hale Telescope

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    A new faint-object spectrograph has been designed around the capabilities of fiber optics. This instrument, the Norris Spectrograph, is for exclusive use at the Cassegrain focus (f/16) of The Hale Telescope and is optimized for faint galaxy spectroscopy. There are 176 independently positionable fibers that are serially manipulated by a single robotic system. Each of these fibers sees 1.6 arcsec on the sky and the total positionable area is in excess of 300 arcmin^2. Unlike most multiobject spectrographs which utilize fibers that are several tens of meters long, the philosophy of the design of the Norris was quite the antithesis, i.e., to minimize the fiber lengths; hence, it is an entirely self-contained telescope-mounted instrument for the Cassegrain focus. The instrument consists of an integrated xy stage, for the fiber positioning, and an attached optical spectrograph. The design of the spectrograph is basically classical: spherical collimator mirror, standard reflection grating, and a newly designed all-transmissive-optics camera lens. The detector currently used is a thinned, AR-coated 2048 X 2048 Tektronix CCD. Fibers are arranged in two linear opposing banks that can access the 20 arcmin diameter field-of-view (FOV) of the instrument. The accuracy of fiber placement (assuming errorless coordinates) is less than 0.1 arcsec over the entire FOV. Fibers may be placed as close as 16 arcsec. This permits close pairings of fibers for very faint-object spectroscopy. Beam switching between paired fibers, as was done with two-channel spectrographs of yesteryear, will help average out temporal and spatial variations of the light of the night sky. Actual observations performed in this mode of operation indicate that the quality of the sky subtraction improves, as would be expected. The density of paired fibers within the Norris FOV matches the approximate density of faint field galaxies expected to a blue magnitude of 21. Software exists to take object lists (α,δ) and convert them to rectilinear (x,y) values (mm) on the xy stage by gnomonic projection and to assign fibers. This software also corrects for precession of the equinoxes, proper motion if epoch differences exist, and corrects for differential atmospheric refraction. To place a single fiber takes approximately 5 s on the average. A lower limit to the efficiency of the spectrograph plus telescope has been estimated to be 6.8% at 5500 Å. In order to derive the throughput of the instrument, the efficiency of the telescope, estimated to be approximately 56%, must be divided out. This value is consistent with the expectation that the reduction in efficiency from that of a standard CCD spectrograph such as The Hale Telescope's Double Spectrograph will be about a factor of 2. This results from the 60%-70% transmittance of the fibers and other losses. The spectra produced are linear with little distortion. With 10 A spectral resolution, fitting residuals on the order of 100 km s^(-1) are easily obtainable by modeling the dispersion by a third-order polynomial. The resolutions currently available range from 1 to about 20 Å. The spectra have a FWHM in the direction perpendicular to that of the dispersion of about 90 µm, or equivalently about three 27 pixels found in the older Tektronix 2048 CCDs. The interorder spacing of 250 µm is large enough to permit clean spectrum extractions. The instrument has been in use for several years. The scientific programs vary from high resolution (1 Å resolution) spectroscopy of stars in nearby globular clusters to a low spectral resolution (10 Å) survey of faint field galaxies. In this latter survey, with typical 2-hr exposures, absorption-line redshifts as high as z ~ 0.5 have been routinely measured. Several heretofore unknown quasars with redshifts around three have also been discovered serendipitously

    Multi-color Classification in the Calar Alto Deep Imaging Survey

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    We use a multi-color classification method introduced by Wolf, Meisenheimer & Roeser (2000) to reliably identify stars, galaxies and quasars in the up to 16-dimensional color space provided by the filter set of the Calar Alto Deep Imaging Survey (CADIS). The samples of stars, galaxies and quasars obtained this way have been used for dedicated studies published in separate papers. The classification is good enough to detect quasars rather completely and efficiently without confirmative spectroscopy. The multi-color redshifts are accurate enough for most statistical applications, e.g. evolutionary studies of the galaxy luminosity function. We characterize our current dataset on the CADIS 1h-, 9h- and 16h-fields. Using Monte-Carlo simulations we model the classification performance expected for CADIS. We present a summary of the classification results and discuss unclassified objects. More than 99% of the whole catalog sample at R<22 (more than 95% at R<23) are successfully classified matching the expectations derived from the simulations. A small number of peculiar objects challenging the classification are discussed in detail. Spectroscopic observations are used to check the reliability of the multi-color classification (6 mistakes among 151 objects with R<24). We also determine the accuracy of the multi-color redshifts which are rather good for galaxies (sigma_z = 0.03) and useful for quasars. We find the classification performance derived from the simulations to compare well with results from the real survey. Finally, we locate areas for potential improvement of the classification.Comment: 18 pages, 13 figures included, accepted for publication in Astronomy & Astrophysic

    Identification of blue high proper motion objects in the Tycho-2 and 2MASS catalogues using Virtual Observatory tools

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    With available Virtual Observatory tools, we looked for new bright blue high proper motion objects in the entire sky: white dwarfs, hot subdwarfs, runaway OB stars, and early-type stars in nearby young moving groups. We performed an all-sky cross-match between the optical Tycho-2 and near-infrared 2MASS catalogues with Aladin, and selected objects with proper motions >50mas/yr and colours Vt-Ks<-0.5mag with TOPCAT. We also collected multi-wavelength photometry, constructed the spectral energy distributions and estimated effective temperatures from fits to atmospheric models with VOSA for the most interesting targets. We assembled a sample of 32 bright blue high proper motion objects, including ten sdO/B subdwarfs, nine DA white dwarfs, five young early-type stars (two of which are runaway stars), two blue horizontal branch stars, one star with poor information, and five objects reported for the first time in this work. These last five objects have magnitudes Bt~11.0-11.6mag, effective temperatures ~24,000-30,000K, and are located in the region of known white dwarfs and hot subdwarfs in a reduced proper motion-colour diagram. We confirmed the hot subdwarf nature of one of the new objects, Albus 5, with public far-ultraviolet spectroscopic data obtained with FUSE.Comment: Published in Astronomy & Astrophysic

    Common carotid segmentation in 18F-sodium fluoride PET/CT scans: Head-to-head comparison of artificial intelligence-based and manual method

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    Background: Carotid atherosclerosis is a major cause of stroke, traditionally diagnosed late. Positron emission tomography/computed tomography (PET/CT) with 18F-sodium fluoride (NaF) detects arterial wall micro-calcification long before macro-calcification becomes detectable by ultrasound, CT or magnetic resonance imaging. However, manual PET/CT processing is time-consuming and requires experience. We compared a convolutional neural network (CNN) approach with manual segmentation of the common carotids. Methods: Segmentation in NaF-PET/CT scans of 29 healthy volunteers and 20 angina pectoris patients were compared for segmented volume (Vol) and mean, maximal, and total standardized uptake values (SUVmean, SUVmax, and\ua0SUVtotal). SUVmean was the average of SUVmeans within the VOI, SUVmax the highest SUV in all voxels in the VOI, and SUVtotal the SUVmean multiplied by the Vol of the VOI. Intra\ua0and Interobserver variability with manual segmentation was examined in 25 randomly selected scans. Results: Bias for Vol, SUVmean, SUVmax, and SUVtotal were 1.33 \ub1 2.06, −0.01 \ub1 0.05, 0.09 \ub1 0.48, and 1.18 \ub1 1.99 in the left and 1.89 \ub1 1.5, −0.07 \ub1 0.12, 0.05 \ub1 0.47, and 1.61 \ub1 1.47, respectively, in the right common carotid artery. Manual segmentation lasted typically 20 min versus 1 min with the CNN-based approach. Mean Vol deviation at repeat manual segmentation was 14% and 27% in left and right common carotids. Conclusions: CNN-based segmentation was much faster and provided SUVmean values virtually identical to manually obtained ones, suggesting CNN-based analysis as a promising substitute of slow and cumbersome manual processing
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