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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Εκτίμηση του ποσού των περιεχόμενων φωτοσυνθετικών χρωστικών σε καρπούς με τη χρήση φασμάτων της in vivo ανακλαστικότητας

Κυζερίδου, Αλεξάνδρα 03 May 2010 (has links)
Οι πράσινοι καρποί φέρουν ενεργούς χλωροπλάστες, οι οποίοι επιτελούν φωτοσύνθεση και αναπτύσσονται σε ένα ιδιαίτερο μικροπεριβάλλον, που διαφέρει σημαντικά από αυτό των φύλλων. Συγκεκριμένα, χαρακτηρίζεται από υποξία, πολύ υψηλές συγκεντρώσεις CO2 και χαμηλές εντάσεις φωτός, ιδιαίτερα στα εσώτερα σημεία του καρπού. Οι συνθήκες αυτές διαμορφώνονται από τα ανατομικά χαρακτηριστικά των καρπών και από τον υψηλό μεταβολικό ρυθμό που επιδεικνύουν. Τα ιδιαίτερα χαρακτηριστικά του εσωτερικού του καρπού επηρεάζουν αντίστοιχα τα επίπεδα των συνολικών χλωροφυλλών (Chla+b) και τις σχετικές αναλογίες των φωτοσυνθετικών χρωστικών του (Chla/b, Car/Chla+b). Στην παρούσα εργασία, το ενδιαφέρον μας εστιάζεται στη μελέτη των φωτοσυνθετικών χρωστικών των καρπών και στη σύγκριση του προτύπου που διαμορφώνεται μεταξύ φύλλων, περικαρπίων και σπερμάτων, σε όσο το δυνατόν περισσότερα φυτικά είδη. Για τον σκοπό αυτό επιλέξαμε να αξιοποιήσουμε τους αντίστοιχους δείκτες της in vivo ανακλαστικότητας (NDI, δείκτης Chla/b και PRI) ως μια γρήγορη, ευαίσθητη και μη καταστρεπτική μέθοδο εκτίμησης των φωτοσυνθετικών χρωστικών. Παράλληλα, θέλοντας να ελέγξουμε την αξιοπιστία των ανωτέρω δεικτών ανακλαστικότητας και στους καρπούς, προσδιορίσαμε τα επίπεδα των φωτοσυνθετικών χρωστικών και των σχετικών αναλογιών τους και με την παραδοσιακή μέθοδο της εκχύλισης-φασματοφωτομέτρησης. Τα αποτελέσματά μας έδειξαν ότι σε όλες τις περιπτώσεις, τα περικάρπια περιέχουν σαφώς λιγότερες συνολικές χλωροφύλλες και ακολουθούν τα σπέρματα με ακόμα λιγότερες. Η σχετική αναλογία Chla/b είναι χαμηλότερη στα περικάρπια και τα σπέρματα έναντι των φύλλων, γεγονός που μπορεί εν μέρει να ερμηνευθεί ως σκιόφιλη προσαρμογή (περίπτωση σπερμάτων). Ωστόσο, οι εξωτερικές (πλήρως φωτιζόμενες) και οι εσωτερικές (σκιαζόμενες) πλευρές των περικαρπίων εμφανίζουν ίδια επίπεδα του λόγου Chla/b στα περισσότερα είδη που μελετήθηκαν. Αυτό μας υποδεικνύει ότι, ενδεχομένως, άλλοι παράγοντες πέραν του φωτός επηρεάζουν τη σχετική αναλογία των δύο χλωροφυλλών. Επιπρόσθετα, παρατηρήθηκε μη αναμενόμενη, αυξημένη σχετική αναλογία των συνολικών καροτενοειδών σε σχέση με τις συνολικές χλωροφύλλες (Car/Chla+b) των περικαρπίων και των σπερμάτων έναντι των αντίστοιχων φύλλων, εύρημα που χρήζει επίσης περαιτέρω μελέτης. / Green fruits contain active chloroplasts, which are driving the reactions of photosynthesis and function in a particular microenvironment, completely different from that of leaves. This microenvironment is characterized by hypoxia, extremely high internal CO2 concentrations and low light intensity, especially in the inner part of the fruit. The above conditions are shaped by fruit anatomical features and their high metabolic rhythm. The special characteristics of the fruit’s internal affect the total chlorophyll concentration (Chla+b), the ratio of Chla to Chlb (Chla/b) and the carotenoid to chlorophylls ratio (Car/Chla+b). In this study, the photosynthetic pigment profile of green fruits (pericarps and seeds) of 15 different species was investigated, with the corresponding leaves serving as controls. To this aim, the appropriate in vivo spectral reflectance indices (NDI, Chla/b index and PRI) were used, as a rapid, sensitive and non-destructive method for photosynthetic pigment estimation. In order to assess the reliability of the above indices in fruits, we estimated in parallel the photosynthetic pigment levels and their ratios with traditional extracting methods. Our results indicated that compared to leaves, pericarps are characterized by lower levels of total chlorophylls followed by seeds with even lower. The Chla/b ratio is lower in pericarps and seeds. As a consequence the lower Chla/b ratio could only partly be attributed to a shade adaptation. However, the exposed and shaded sides of pericarps displayed similar values for Chla/b ratio in the most of the species tested. Moreover, pericarps and seeds showed unexpectedly, higher carotenoid/chlorophyll ratios.
272

Ultrathin Single and Multi-Channel Fiberscopes for Biomedical Imaging

Kano, Angelique Lynn January 2009 (has links)
Ultrathin fiberscopes typically have an imaging channel and an illumination channeland are available in diameters ranging from 0.5 mm to 2.5 mm. The minimum diam-eter can be reduced by combining the illumination and imaging paths into a singlefiberoptic channel. Constructing a single channel fiberscope requires a technique ofilluminating the tissue, while minimizing the Fresnel reflections and scatter withinthe common illumination and detection channel.A single channel fiberscope should image diffusely reflected light from tissue illu-minated with light filtered for the visible wavelength range (450 - 650 nm). Simplycombining the illumination and collection paths via a beamsplitter results in a lowobject to background signal ratio. The low contrast image is due to a low collectionefficiency of light from the ob ject as well as a high background signal from the Fresnelreflection at the proximal surface of the fiber bundle, where the illumination enters thefiber bundle. The focus of the dissertation is the investigation of methods to reducethe background signal from the proximal surface of the fiber bundle. Three systemswere tested. The first system uses a coherent fiber bundle with an AR-coating on theproximal face. The second system incorporates crossed polarizers into the light path.In addition, a technique was developed, whereby a portion of the image numericalaperture is devoted to illumination and a portion to image signal detection. Thistechnique is called numerical aperture sharing (NA sharing).This dissertation presents the design, construction, testing, and comparison ofthe three single channel fiberscopes. In addition, preliminary results of a study aimedat the usefulness of broadband diffuse reflectance imaging for the identification andtracking of disease progression in mouse esophagus are presented.
273

Suitability of Canadian-bred and Native Plant Species for Extensive Green Roofs in Northern Nova Scotia

Grant, Jason J W 20 February 2013 (has links)
Research was conducted to determine individual suitability of native and Canadian-bred selected plants in terms of growth and survivability for local extensive green roofs. The experiment was single-factor (species) with 12 levels (two Sedum spp. [controls]; 10 Canadian-bred or native plant species) in a randomized complete block design with three blocks. Variables measured were percent survival and cover, height, fresh and dry weights, stomatal conductance, transpiration, photosynthetic rate, soil temperature, soil moisture, and reflectance. Artemisia stelleriana contributed more to cooling through transpiration than Sedum floriferum, and maintained similar soil moisture to Sedum acre. Lotus corniculatus was similar to the controls in photosynthetic rate and had higher reflectance than Sedum acre in July. With high biomass and photosynthetic rates, Aster novi-belgii may contribute more to carbon sequestration and insulation than the controls. Artemisia stelleriana , Lotus corniculatus, and Aster novi-belgii are suitable species for extensive green roofs in northern Nova Scotia.
274

Practical and Applied Reflectance Spectroscopy: Automated Drill Core Logging and Mineral Mapping

Tappert, Michelle C. Unknown Date
No description available.
275

Reflectance measurements in the Sydney coalfield

Lasalle, Eric. January 1982 (has links)
No description available.
276

Innovative approaches to assessing seed quality in Brassicas

Larkin, Jodi 02 April 2012 (has links)
Brassica napus is grown as an edible oil (canola) and an industrial oil (HEAR). Its fatty acid profile and chlorophyll concentration affect the quality. It is important to develop accurate and efficient methods to evaluate these traits. The first objective of this study was to improve the single nucleotide polymorphism (SNP) and sequence characterized amplified region (SCAR) molecular markers for erucic acid genotypes in the Bn-FAE1.1 and Bn-FAE1.2 genes in the A and C genomes in Brassica napus originally developed by Rahman et al. (2008). When put into practice, the error rate was unacceptably high. With the modifications that were made to the protocols, the overall accuracy remained relatively consistent indicating that further improvements are still required. The second objective was to develop a near infrared reflectance (NIR) based calibration equation for chlorophyll concentration in whole Brassica napus seeds. In this case, an equation was successfully created.
277

Fourier transform infrared microspectroscopy, with attenuated total reflectance, as a detection method for fusarium in whole wheat kernels

Starr, Karen 24 September 2012 (has links)
The purpose of this study was to investigate the feasibility of using Fourier transform mid-infrared (FT-IR) microspectroscopy, with attenuated total reflectance (ATR), to detect the presence of Fusarium spp., classify differences in ability to detect Fusarium spp. among the Canadian soil zones, determine whether Fusarium spp. can serve as an indicator for the concentration of deoxynivalenol (DON), and develop an equation that can predict DON within wheat kernels. Canadian Western Red Spring wheat kernels were pressed against an ATR crystal to obtain spectra. Five chemical functional groups were investigated. The ability of FT-IR-ATR microspectroscopy to detect the presence of Fusarium spp. was confirmed. The chemical composition, and the ability to identify Fusarium spp., differed in kernels grown among the soil zones. Several methods to use Fusarium spp. as an indicator for the concentration of DON content within the wheat kernels were attempted and found to be unsuccessful.
278

Growth initiation processes for GaAs and AlGaAs in CBE

Hill, Daniel January 2000 (has links)
No description available.
279

Innovative approaches to assessing seed quality in Brassicas

Larkin, Jodi 02 April 2012 (has links)
Brassica napus is grown as an edible oil (canola) and an industrial oil (HEAR). Its fatty acid profile and chlorophyll concentration affect the quality. It is important to develop accurate and efficient methods to evaluate these traits. The first objective of this study was to improve the single nucleotide polymorphism (SNP) and sequence characterized amplified region (SCAR) molecular markers for erucic acid genotypes in the Bn-FAE1.1 and Bn-FAE1.2 genes in the A and C genomes in Brassica napus originally developed by Rahman et al. (2008). When put into practice, the error rate was unacceptably high. With the modifications that were made to the protocols, the overall accuracy remained relatively consistent indicating that further improvements are still required. The second objective was to develop a near infrared reflectance (NIR) based calibration equation for chlorophyll concentration in whole Brassica napus seeds. In this case, an equation was successfully created.
280

Fourier transform infrared microspectroscopy, with attenuated total reflectance, as a detection method for fusarium in whole wheat kernels

Starr, Karen 24 September 2012 (has links)
The purpose of this study was to investigate the feasibility of using Fourier transform mid-infrared (FT-IR) microspectroscopy, with attenuated total reflectance (ATR), to detect the presence of Fusarium spp., classify differences in ability to detect Fusarium spp. among the Canadian soil zones, determine whether Fusarium spp. can serve as an indicator for the concentration of deoxynivalenol (DON), and develop an equation that can predict DON within wheat kernels. Canadian Western Red Spring wheat kernels were pressed against an ATR crystal to obtain spectra. Five chemical functional groups were investigated. The ability of FT-IR-ATR microspectroscopy to detect the presence of Fusarium spp. was confirmed. The chemical composition, and the ability to identify Fusarium spp., differed in kernels grown among the soil zones. Several methods to use Fusarium spp. as an indicator for the concentration of DON content within the wheat kernels were attempted and found to be unsuccessful.

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