942 resultados para light feedback
Resumo:
Kansalliskirjaston ONKI-projektin ylläpitämä Finto-palvelu käyttää projektissa kehitettävää Skosmos-ohjelmaa (entinen ONKI Light). Skosmos on työkalu kontrolloitujen sanastojen, kuten asiasanastojen ja asiasanastotyyppisesti käytettävien ontologioiden julkaisuun. Työkalu tarjoaa selailu- ja hakukäyttöliittymän sanastoille sekä avoimet rajapinnat koneellista käyttöä varten. Käyttöliittymä on monikielinen sisältäen tällä hetkellä suomen-, ruotsin- sekä englanninkieliset käyttöliittymäversiot.
Skosmoksen edeltäjälle ONKI Lightille on tehty ONKI-projektissa jo aikaisempi käytettävyystesti, jonka raportti on luettavissa Doriassa.
Käytettävyystestien perusteella vaikuttaisi siltä, että ontologian selaamiseen asiasanoituksessa vaikuttaisi ainakin käyttäjän käyttämä järjestelmä, asiasanoitukseen käytettävä aika, asiasanoitustottumukset ja -kokemus sekä sanaston tuttuus. Jos aikaa ei ole juurikaan varattu asiasanoitukselle, ei käsitteitä juurikaan selailla, vaikka muuten tuki ontologioiden hyödyntämiselle olisi olemassa. Myöskään sanastoa ei juurikaan selailla, mikäli aihe ja sanasto ovat tuttuja, jolloin asiasanojen merkitykset ovat etukäteen tiedossa.
Light and storage on the germination of spores of Dicksonia sellowiana (Presl.) Hook., Dicksoniaceae
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Spores of Dicksonia sellowiana are positively photoblastic and reach the maximum percentage of germination at 23 ± 2°C in white light after seven days of imbibition. The pre-induction phase for spores induced by white or red light for 24 hours was 72 hours. Gametophytes grown in white light were plane and bidimensional, while those grown under red light were filamentous. The higher the number of hours of light applied per day during 10 days, the higher the percentage of germination. Germination was higher for long white light treatments applied on a daily basis. The effect of different light intensities on germination was also investigated here. The lower percentages of germination were observed for spores kept under 43% and 2% of full sunlight, while those kept under 26, 19 and 4% presented higher percentages. Spores presented circa 82% of germination after 731 days of storage under refrigeration at aproximately 10°C.
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Bidens gardneri is a very common herbaceous species in the cerrados of the state of São Paulo, whose seeds become light sensitive at 25°C only. Achenes of this species were stored in refrigerator at 4°C and in cerrado soil and in forest soil. The field experiments were carried out in the cerrado at the Reserva Biológica e Estação Experimental de Moji Guaçu, in Moji Guaçu and in the forest of the Instituto de Botânica, in São Paulo, Brazil. Achenes of B. gardneri vary in size and achenes from 7 to 12 mm long were used. Achenes stored for up to 6 months at 4°C showed light sensitivity; after 9 months storage, the difference in germination between light and darkness had disappeared for the smallest and the largest achenes used. Seeds of B. gardneri germinated during the period of storage in soil; the number of germinated seeds increased over the storage time, while the number of intact achenes decreased for the same period, no matter if the experiment was being carried out in the cerrado or in the forest. Therefore, the achenes germinated in soil in darkness. Light sensitivity was lost in intact achenes that had been stored in soil for three months.
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Vochysia tucanorum Mart. (Vochysiaceae) is a very widely distributed species in the cerrado and forests in Brazil, from the State of Bahia to Paraná. Its seed germination was analysed under eight treatments using different conditions of light and temperature. Up to 73 days, at least ca. 93% of the seeds germinated in all treatments, except under alternating temperatures of 35°/10°C (62%). Light enhanced germination, except under constant temperature of 25°C when seeds are not photoblastic. At this temperature, the highest percentage of germination was found. Initial vegetative growth was analysed by comparing the effects of shading, by means of different percentages of full daylight (100%, 45%, 10.6%, 4.8%), and soils from cerrado and forest. During 123 days, no mortality was recorded and cotyledons persisted on the seedlings of all treatments. In general, the seedlings of V. tucanorum were found to be more or less indifferent to the soil from cerrado or forest and shading seems to promote height increment. However, total dry mass was larger under a radiation of 45% full daylight and smaller under extreme conditions (100% or 4.8% full daylight).
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Considering the performance of CAM epiphytes under high levels of radiation or in shaded environments, with growth rate proportional to light intensity, the objective of this work was to evaluate the effects of long-term light stress on the growth of a Brazilian epiphytic orchid, Cattleya forbesii Lindl. X Laelia tenebrosa Rolfe. Two groups of plants were used in the first experiment, one under 90% (@ 1,650 µmol.m-2.s-1) of Photosynthetically Active Radiation (PAR) and the other maintained under 22.5% (@ 400 µmol.m-2.s-1). In the second experiment the diffusive resistance, transpiration rate and fluorescence levels were monitored for plants that were under 22.5% of PAR, under 90% and plants transferred from 22.5 to 90%. Our results show that light intensity interfered with growth and development of this orchid. Data on the changes in pseudobulb volume throughout the time course of growth suggest that water and reserves stored in the back shoots are translocated to the current shoot. Regarding stomatal resistance, plants under 22.5% of PAR reached a largest stomatal aperture during the night, whereas those under 90% only after dawn. After transfer from 22.5% PAR to 90% PAR the ratio of Fv/Fm decreased from approximately 0.8 to 0.7. This suggests the limitation of photoprotection mechanisms in the leaf and the results observed after the transfer of plants from 22.5% to 90% reinforce the possibility that a photoinhibition is reflected in a decrease in growth rate.
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Lianas are plants that depend on support to reach some appreciable height, and they represent an important structural component of tropical forests. Although they predominate in clearings and gaps, some species survive in the understory. Changes in irradiance between these environments can affect leaf morphology and absorption of photosynthetic active radiation (PAR). We had examined the effects of different light regimes on leaf optical properties, chlorophyll content, specific leaf area, and leaf surface morphology in young seedlings of Canavalia parviflora Benth. (Fabaceae) and Gouania virgata Reissk (Rhamnaceae). The seedlings were distributed on workbenches covered by different layers of neutral shade netting, thus creating three levels of light intensity corresponding to about 40%, 10% and 1.5% of solar irradiance. Plants growing in full sun were used as a control. Both species exhibited an increase in reflectance in full sun and alterations in leaf morphology. Reduction in irradiance induced an increase in absorptance (decrease in reflectance and transmittance) in C. parviflora leaves in the green due to higher chlorophyll content. In G. virgata the spectral leaf changes were less observable. However, the efficiency of absorption was more pronounced in G. virgata than in C. parviflora leaves under 40%, 10% and 1.5% photon flux density (PFD). The greater efficiency of absorption in G. virgata was due to a larger specific leaf area (SLA) under these conditions. The adjustments in leaf optical properties can aid these species in overall carbon gain under limited light conditions.
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In some literature variations in photosynthetic rates are considered to be of little relevance for individual fitness. This depends among other things on how one defines fitness, i.e. if one takes strictly Darwinian fitness as seed production or if one needs to evaluate particular traits and consider plant establishment. It also matters if one takes the Darwinian "organism individual" as the central entity in evolution ("individual fitness") or the "species individual" in a modified "Structure of Evolutionary Theory" sensu Stephen Jay Gould. A phenotypically expressed trait like photosynthetic rate, even if intra- and interspecific differences may be small, can matter in habitat performance and niche acquisition. Light dependence curves (LCs) of photosynthetic rates are now readily measured under field conditions using miniaturized equipment of pulse amplitude modulated fluorometers. In contrast to actual momentary measurements of quantum yield of photosynthesis under actually prevailing ambient conditions, LC measurements reflect the expressed intrinsic capacity of photosynthesis. In this review we explore the power of LC measurements yielding cardinal points such as maximum apparent electron transport rate of photosystem II (ETRmax) and saturating photosynthetically active radiation (PARsat) in making intra- and interspecific comparisons of plant performance and synecological fingerprinting in ecophysiological studies across species, sites, habitats and ecosystems.
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In this study we evaluated photosynthetic characteristics and patterns of biomass accumulation in seedlings of two tree species from a Semideciduous Tropical Forest of Brazil. Seedlings of Trema micrantha (L.) Blum. (pioneer) and Hymenaea courbaril (L.) var. stilbocarpa (Hayne) Lee & Langenh. (climax) were grown for 4 months under low light (LL) (5%-8% of sunlight) and high light (HL) (100% of sunlight). Under HL, T. micrantha showed higher CO2 assimilation rates (A CO2) and light saturation than H. courbaril. Under LL, A CO2 were higher in H. courbaril. Under LL, total chlorophyll and carotenoid contents per unit leaf area were higher in H. courbaril. Chlorophyll a/b ratio was higher in T. micrantha under both light regimes. A CO2 and Fv/Fm ratio at both pre-dawn and midday in H. coubaril were lower in HL indicating chronic photoinhibition. Thus, the climax species was more susceptible to photoinhibition than the pioneer. However, H. courbaril produced higher total biomass under both treatments showing high efficiency in the maintenance of a positive carbon balance. Thus, both species expressed characteristics that favor growth under conditions that resemble their natural microenvironments, but H. courbaril also grew under HL. The ecophysiological range of responses to contrasting light levels of this climax plant seems to be broader than generally observed for other rainforest climax species. We propose that this could be related to the particular spatio-temporal light regime of the semideciduous forests.
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Tool center point calibration is a known problem in industrial robotics. The major focus of academic research is to enhance the accuracy and repeatability of next generation robots. However, operators of currently available robots are working within the limits of the robot´s repeatability and require calibration methods suitable for these basic applications. This study was conducted in association with Stresstech Oy, which provides solutions for manufacturing quality control. Their sensor, based on the Barkhausen noise effect, requires accurate positioning. The accuracy requirement admits a tool center point calibration problem if measurements are executed with an industrial robot. Multiple possibilities are available in the market for automatic tool center point calibration. Manufacturers provide customized calibrators to most robot types and tools. With the handmade sensors and multiple robot types that Stresstech uses, this would require great deal of labor. This thesis introduces a calibration method that is suitable for all robots which have two digital input ports free. It functions with the traditional method of using a light barrier to detect the tool in the robot coordinate system. However, this method utilizes two parallel light barriers to simultaneously measure and detect the center axis of the tool. Rotations about two axes are defined with the center axis. The last rotation about the Z-axis is calculated for tools that have different width of X- and Y-axes. The results indicate that this method is suitable for calibrating the geometric tool center point of a Barkhausen noise sensor. In the repeatability tests, a standard deviation inside robot repeatability was acquired. The Barkhausen noise signal was also evaluated after recalibration and the results indicate correct calibration. However, future studies should be conducted using a more accurate manipulator, since the method employs the robot itself as a measuring device.
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Spectral sensitivities of visual systems are specified as the reciprocals of the intensities of light (quantum fluxes) needed at each wavelength to elicit the same criterion amplitude of responses. This review primarily considers the methods that have been developed for electrophysiological determinations of criterion amplitudes of slow-wave responses from single retinal cells. Traditional flash methods can require tedious dark adaptations and may yield erroneous spectral sensitivity curves which are not seen in such modifications as ramp methods. Linear response methods involve interferometry, while constant response methods involve manual or automatic adjustments of continuous illumination to keep response amplitudes constant during spectral scans. In DC or AC computerized constant response methods, feedback to determine intensities at each wavelength is derived from the response amplitudes themselves. Although all but traditional flash methods have greater or lesser abilities to provide on-line determinations of spectral sensitivities, computerized constant response methods are the most satisfactory due to flexibility, speed and maintenance of a constant adaptation level
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To assess relationships between neuropeptide-binding sites and receptor proteins in rat brain, the distribution of radioautographically labeled somatostatin and neurotensin-binding sites was compared to that of immunolabeled sst2A and NTRH receptor subtypes, respectively. By light microscopy, immunoreactive sst2A receptors were either confined to neuronal perikarya and dendrites or diffusely distributed in tissue. By electron microscopy, areas expressing somatodendritic sst2A receptors displayed only low proportions of membrane-associated, as compared to intracellular, receptors. Conversely, regions displaying diffuse sst2A labeling exhibited higher proportions of membrane-associated than intracellular receptors. Furthermore, the former showed only low levels of radioautographically labeled somatostatin-binding sites whereas the latter contained high densities of somatostatin-binding suggesting that membrane-associated receptors are preferentially recognized by the radioligand. In the case of NTRH receptors, there was a close correspondence between the light microscopic distribution of NTRH immunoreactivity and that of labeled neurotensin-binding sites. Within the substantia nigra, the bulk of immuno- and autoradiographically labeled receptors were associated with the cell bodies and dendrites of presumptive DA neurons. By electron microscopy, both markers were detected inside as well as on the surface of labeled neurons. At the level of the plasma membrane, their distribution was highly correlated and characterized by a lack of enrichment at the level of synaptic junctions and by a homogeneous distribution along the remaining neuronal surface, in conformity with the hypothesis of an extra-synaptic action of this neuropeptide. Inside labeled dendrites, there was a proportionally higher content of immunoreactive than radiolabeled receptors. Some of the immunolabeled receptors not recognized by the radioligand were found in endosome-like organelles suggesting that, as in the case of sst2A receptors, they may have undergone endocytosis subsequent to binding to the endogenous peptide
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In disuse atrophied skeletal muscle, the staircase response is virtually absent and light chain phosphorylation does not occur. The purpose of the present study was to determine if staircase could be restored in atrophied muscle with continued absence of myosin light chain phosphorylation, by reducing what appears to be an otherwise enhanced calcium release. Control (untreated) and sham-operated female Sprague-Dawley rats were compared with animals after 2 weeks of complete inactivity induced by tetrodotoxin (TTX) application to the left sciatic nerve. In situ isometric contractile responses of rat gastrocnemius muscle were analyzed before and after administration of dantrolene sodium (DS), a drug which is known to inhibit Ca2+ release in skeletal muscle. Twitch active force (AF) was attenuated by DS from 2.2 ± 0.2 N, 2.7 ± 0.1 N and 2.4 ± 0.2 N to 0.77 ± 0.2 N, 1.05 ± 0.1 N and 1.01 ± 0.2 N in TTX (N = 5), sham (N = 11) and control (N = 7) muscles, respectively. Following dantrolene treatment, 10 s of 10-Hz stimulation increased AF to 1.32 ± 0.2 N, 1.52 ± 0.1 N and 1.45 ± 0.2 N for the TTX, sham and control groups, respectively, demonstrating a positive staircase response. Regulatory light chain (R-LC) phosphorylation was lower for TTX-treated (5.5 ± 5.5%) than for control (26.1 ± 5.3%) and sham (20.0 ± 5%) groups. There was no significant change from resting levels for any of the groups after DS treatment (P = 0.88). This study shows that treatment with dantrolene permits staircase in atrophied muscle as well as control muscle, by a mechanism which appears to be independent of R-LC phosphorylation.
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The effects of the benzodiazepine1 (BZ1) receptor agonist SX-3228 were studied in rats (N = 12) implanted for chronic sleep procedures. Administration of 0.5, 1.0 and 2.5 mg/kg SX-3228, sc, to rats 1 h after the beginning of the light phase of the light-dark cycle induced a significant reduction of rapid-eye-movement sleep (REMS) during the third recording hour. Moreover, slow wave sleep (SWS) was increased during the fourth recording hour after the two largest doses of the compound. Administration of 0.5, 1.0 and 2.5 mg/kg SX-3228 one hour after the beginning of the dark period of the light-dark cycle caused a significant and maintained (6-h recording period) reduction of waking (W), whereas SWS and light sleep (LS) were increased. REMS values tended to increase during the entire recording period; however, the increase was statistically significant only for the 1.0 mg/kg dose during the first recording hour. In addition, a significant and dose-related increase of power density in the delta and the theta regions was found during nonREM sleep (LS and SWS) in the dark period. Our results indicate that SX-3228 is a potent hypnotic when given to the rat during the dark period of the light-dark cycle. Moreover, the sleep induced by SX-3228 during the dark phase closely resembles the physiological sleep of the rat.
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The induction of nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME) in etiolated maize (Zea mays) seedlings by UV-B and UV-A radiation, and different levels of photosynthetically active radiation (PAR, 400-700 nm) was investigated by measuring changes in activity, protein quantity and RNA levels as a function of intensity and duration of exposure to the different radiations. Under low levels of PAR, exposure to UV-B radiation but not UV-A radiation for 6 to 24 h caused a marked increase in the enzyme levels similar to that observed under high PAR in the absence of UV-B. UV-B treatment of green leaves following a 12-h dark period also caused an increase in NADP-ME expression. Exposure to UV-B radiation for only 5 min resulted in a rapid increase of the enzyme, followed by a more gradual rise with longer exposure up to 6 h. Low levels of red light for 5 min or 6 h were also effective in inducing NADP-ME activity equivalent to that obtained with UV-B radiation. A 5-min exposure to far-red light following UV-B or red light treatment reversed the induction of NADP-ME, and this effect could be eliminated by further treatment with UV-B or red light. These results indicate that physiological levels of UV-B radiation can have a positive effect on the induction of this photosynthetic enzyme. The reducing power and pyruvate generated by the activity of NADP-ME may be used for respiration, in cellular repair processes and as substrates for fatty acid synthesis required for membrane repair.
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The aim of this three phase study was to develop quality of radiotherapy care by the e-Feedback knowledge of radiotherapy -intervention (e-Re-Know). In Phase I, the purpose was to describe the quality of radiotherapy care and its deficits experienced by cancer patients. Based on the deficits in patient education in Phase II, the purpose was to describe cancer patients’ e-knowledge expectations in radiotherapy. In Phase III, the purpose was to develop and evaluate the outcomes of the e-Re-Know among breast cancer patients. The ultimate aim was to develop radiotherapy care to support patients’ empowerment with patient e-education. In Phase I (2004-2005), the descriptive design was used, and 134 radiotherapy patients evaluated their experiences by Good Nursing Care Scale for Patients (GNCS-P) in the middle of RT period. In Phase II (2006-2008), the descriptive longitudinal design was used and 100 radiotherapy patients’ e-knowledge expectations of RT were evaluated using open-ended questionnaire developed for this study before commencing first RT, in the middle of the treatment, and concluding RT period. In Phase III, firstly (2009-2010), the e-Re-Know intervention, i.e. knowledge test and feedback, was developed in terms of empowering knowledge and implemented with e-feedback approach based on literature and expert reviews. Secondly (2011-2014), the randomized controlled study was used to evaluate the e-Re-Know. Breast cancer patients randomized to either the intervention group (n=65) receiving the e-Re-Know by e-mail before commencing first RT and standard education or the control group (n=63) receiving standard education. The data were collected before commencing first RT, concluding last RT and 3 months after last RT using RT Knowledge Test, Spielberger’s State Trait Inventory (STAI) and Functional Assessment of Cancer Therapy - Breast (FACT-B) –instruments. Data were analyzed using statistical methods and content analysis. The study showed radiotherapy patients experienced quality of care high. However, there were deficits in patient education. Furthermore, radiotherapy patients’ multidimensional e-knowledge expectations through Internet covered mainly bio-physiological and functional knowledge. Thus, the e-Re-Know was developed and evaluated. The study showed when breast cancer patients’ carried out the e-Re-Know their knowledge of side effects self-care was significantly increased and quality of life (QOL) significantly improved in line with decrease in anxiety from time before radiotherapy period to three months after. In addition, the e-Re-Know has potential to have positive effects on anxiety and QOL, regardless of patient characteristics or knowledge level. The results support the theory of empowering patient education suggesting that empowerment can be supported by confirming patients’ understanding of own knowledge level. In summary, the e-Feedback knowledge of radiotherapy (e-Re-Know) intervention can be recommended in development of quality of radiotherapy care experienced by breast cancer patients. Further research is needed to assess and develop patient-centred quality of care by patient education among cancer patients.