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1
Detoni, Cezar Ernesto. "Grain Sorghum Field Emergence and Seed Vigor Tests." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30649.
Full textAbstract:
Poor emergence of sorghum [(Sorghum bicolor (L) Moench] affects the stand and
potential yields. The major objective of this research was to find correlations
among field emergence data and laboratory seed vigor tests. Thirty-two and 30
hybrids of sorghum were planted at three Virginia locations in 1995 and 1996,
respectively. Field emergence was subsequently compared with results from
laboratory tests that included: 1) standard germination; 2) osmotic-stress using
polyethylene glycol 8000 (mw); 3) heat-shock using 2 hr at 50?C stress; 4)
electrical conductivity of steep water of germinating seeds; and 5) seed mass.
Field emergence of grain sorghum differed among hybrids, years and locations.
Mean emergence across years and locations was 67.5%, whereas mean
germination in the laboratory was 87.8%. There were interaction between hybrid
and location and between hybrid and year. Germination under optimal conditions
(standard germination test) and with osmotic or heat-shock stress differed among
hybrids. Regression analyses showed a weak correlation between laboratory
germination (with or without stress) and field emergence in both years. The fresh
weight of seedlings whether from standard germination or stress tests also
differed among hybrids in both years, and the associations with field emergence
were weakly correlated in 1996. Hybrids showed significant differences in radicle
length when grown under laboratory stress in both years following standard
germination. There was a weak correlation with field emergence and radicle
length following heat-shock treatment in 1996. The measurement of electrical
conductivity in the seed steep water showed significant differences among
hybrids. A weak correlation with field emergence was seen in 1996.
Conductivity values per gram of seed and per cm2 of seed area revealed
differences among hybrids. The correlation of these parameters with field
emergence was higher than conductivity per seed. Seed mass varied among
hybrids in both years , but was no correlation between seed mass and emergence.
Of the laboratory parameters examined, germination proved to be the most
consistent predictor of variations in field emergence of sorghum hybrids.Ph. D.
2
Schutte, Brian J. "Biology and ecology of Ambrosia Trifida L. seedling emergence." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1181937971.
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3
Dzomeku, Israel K. "Modelling seed dormancy, germination and emergence of Striga hermonthica." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252261.
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4
Sinclair, John. "Crusting, soil strength and seedling emergence in Botswana." Thesis, University of Aberdeen, 1985. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU363198.
Full textAbstract:
This thesis gives the results of an investigation of the strengths and particularly the crust forming potential of arable soils from Botswana and the relationship to seedling emergence of sorghum, the most important crop in Botswana and one that because of its small seed weight (about 2 0 mg) can fail to emerge through a hard soil crust. A review of the literature suggested that the soil factors which had to be considered were dispersibility of clay and factors which affect this, and the bulk density of the soils. Soils which are found in many tropical and sub-tropical regions, with low organic matter and inactive clays can set hard after a simple wetting and drying cycle. In these soils, the strength is very strongly dependent on the water content, showing a hyperbolic or exponential relationship-, and the strengths when dry may be very greatly increased by remoulding the wet soil. The crust strength required to prevent seedling emergence varies with the size of the seedling and for cotton (seed weight about 80 mg), 1-3 MPa penetration resistance measured with a penetrometer is sufficient to prevent emergence. Seedlings exert a total force proportional to their number. In the experimental programme, seedlings' forces were measured, seedling emergence observed in a field experiment under crusting conditions, and the strength characteristics of a group of soils, representative of arable soils in Botswana, studied. A sorghum seedling was found to exert a maximum force of about 1 N or dividing by the area of the plumule, a pressure of about 0,5 MPa. The field experiment showed that much better emergence was obtained from planting 15 seeds together than from planting 4 seeds together when a crust formed after planting. A study of 32 soils, most of them sand to sandy loam in texture but with a few clays and hydroirorphic soils, from arable areas in Botswana showed the sandy to sandy loam soils to have high bulk densities ( 1,45-1 ,75 Mg/m3) and extremely low organic carbon contents (0,12-0,85 g/100g). The bulk densities of all the soils were inversely related to the organic carbon content and this was itself related to the clay content of the soils. The bulk densities of the sands were dependent on the grading of the sand fraction. Many of the soils were sensitive to remoulding in the Emerson test and the sands to loany sands had 0,4-1,0 g/100 g water dispersible clay. Measurements of tensile strength on air-dry samples showed that all the soils, except for one sand, set hard after a wetting and drying cycle, giving for vacuum wet samples indirect tensile strengths 1,0-14,4 kPa. For the sands to sandy loams this strength was related to the water dispersible clay content. Samples wet at atmospheric pressure were weaker than the vacuum wet samples, the reduction in strength was related to the air porosity of the non-vacuum wet soils prior to drying. Remoulding the soils prior to drying them increased the strength by a factor of up to 50 times, giving strengths from 4 kPa to 600 kPa. The strength after remoulding was dependent on the Emerson index. Compacting the soils increased their strength greatly and to an extent that agreed with the hypothesis that the strength obtained was proportional to the area of contact between the particles. Experiments on penetration resistance at a range of water contents were performed on a few soils. A hyperbolic relationship between water content and penetration resistance of the surface soil was found for sand to sandy loam soils, with the maximum resistance of dry soils above 2 MPa. The penetration resistance of the sandy loam soil was Increased three times by disturbing it when wet. Sprinkler wetting the sieved soils was not found to affect the penetration resistance by a large amount compared and other methods of welting. Penetration resistance was measured on air-dry samples of most of the main group of soils following varying degrees of wetting with a rainfall simulator. The clays and hydromorphic soils gave very low values of penetration resistance under these conditions, showing that at organic carbon contents of about 1% and clay contents from 20 to 30%, the decreased bulk density and tendency to form aggregates' on drying overcame the tendency to set hard. The mean values for the sands to sandy loams were from 1 to 6 MPa so all these soils could offer significant resistance to a sorghum seedling. The penetration resistance of the sands and loam/ sands depended on their bulk densities and water dispersible clay contents, while the penetration resistance of the sandy loams depended only on the water dispersible clay content.
5
Khadka, Samida. "Environment and hormone effects on seed biology of kochia (Kochia scoparia)." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/36231.
Full textAbstract:
Master of ScienceDepartment of Agronomy
Johanna A. Dille
Understanding the impact of early spring environmental conditions on kochia seed biology as well as time from flowering to seed maturation could suggest effective control practices. Kochia seed accessions were exposed to moisture stress or different phytohormone combinations across a range of temperature conditions to evaluate cumulative seed germination. Base temperature (T[subscript b]) and base water potential (ψb) were determined and used to calculate thermal (TT), hydro (HT), and hydrothermal (HTT) time to describe cumulative percent kochia germination across the environmental conditions. Base temperature was 2.7 C and ψb was -1.70, -1.62, and -0.92 MPa at 11, 6, and 4 C, respectively. To reach 50% cumulative seed germination, more days (2 and 11 d) and more TT (16.7 and 74.8 Cd) were needed as temperature decreased from 11 to 4 C and as water potential decreased from 0.0 to -1.2 MPa. Using the HT and HTT scale helped to account for effect of moisture stress. A small fraction of seeds under low temperature and high moisture stress germinated faster (10% at 6 C and -1.2 MPa) compared to more seed germinated at higher temperature and less moisture stress (91% at 11 C and -0.0 MPa). Addition of abscisic acid (10 µM ABA) decreased germination by 16% at both 23 and 6 C, while addition of gibberellic acid (10 µM GA) increased germination by 14% at both 23 and 6 C. Addition of ABA delayed time to 50% germination at 6 C compared to water, with 3 days or 10 Cd. Similarly, addition of GA shortened time to 50% germination at 6 C as it took 8.9 d and 29.3 Cd as compared to 10 d and 33 Cd in water. Kochia seed development was observed visually in greenhouse conditions after controlled and natural pollination. Kochia flower buds changed color from light green to dark brown by 36 days after pollination (DAP). At 36 DAP, buds had seeds enclosed in them but a germination study showed they were not yet viable. Hence, seed germination decreased and seeds needed more time to accumulate enough thermal and hydro unit before germinating as temperature and moisture stresses increased from 11 to 4 C and -0.0 to -1.2 MPa. We conclude that kochia seeds can germinate under very low temperature and moisture potential. Hence, should be controlled very early in the growing season. Phytohormones ABA and GA decrease and increase the germination of seeds, respectively. Kochia takes more than 36 DAP to produce viable seeds. Information on flower bud changes after pollination have implications for both kochia management and research.
6
Hofmann, Wallace C., David L. Kittock, B. Brooks Taylor, Peter T. Else, Joel Malcuit, and Carl Michaud. "Emergence and Yield from Six Seed Densities of DPL 90 Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/204031.
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7
Kittock, David L., Wallace C. Hofmann, B. Brooks Taylor, Peter T. Else, Joel Malcuit, and Carl Michaud. "Emergence and Yield from High and Low Quality Upland Cotton Seed." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/204030.
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8
Kittock, D. L., W. C. Hofmann, J. Malcuit, P. Else, and C. Michaud. "Emergence and Yield from High and Low Quality Upland Cotton Seed." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219704.
Full textAbstract:
The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.Low quality Deltapine (DP) 41 seed had lower germination, lower cold test germination, reduced stand, and reduced lint yield in four tests in Arizona in 1985.
9
Welling, P. (Pirjo). "Regeneration by seeds and vegetation structure in alpine plant communities, subarctic Finland." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:951426861X.
Full textAbstract:
Abstract
The aims were to examine the importance of regeneration by seeds, the
influence of plant traits and disturbances, and the role of seed-seedling
conflicts in regeneration and in the determination of vegetation structure.
The study was carried out at in a subarctic alpine area (Kilpisjärvi
69°01'N 20°50E', Finland).
Seed bank and seedling densities were high in many plant communities
(ranges 99 -1109 viable seeds/m2 and 0.2-227
seedlings/m2, respectively). Effective seedling
recruitment is reflected in vegetation as a high proportion of plants with
poor or no vegetative reproduction ability. This development may take place
in meadows and snowbeds where herbs (e.g. Gnaphalium
supinum, Sibbaldia procumbens,
Veronica alpina and Viola
biflora) are abundant. On the other hand, the low proportion of
these plants in heath vegetation reflects ineffective seedling
recruitment.
Floristic similarities between the consecutive phases in the
regeneration pathway may be low despite effective seedling recruitment.
Clonality, large and small seed sizes and appendaged diaspores limit the
movement of species from phase to phase.
Generally, disturbances facilitate effective regeneration by seeds.
Grazing promotes species with large seed banks and is therefore one reason
for high seed bank densities. Freezing and melting processes negate a
negative influence of altitude on seed bank densities in the phase of
seedlings. However, if disturbances are severe and continuous and the soil
is compact, unstable or dry, disturbances are not beneficial. The same is
true if there is a shift in the species composition of seedlings from gaps
to closed vegetation. This phenomenon occurred in a rich meadow.
Seed-seedling conflicts limit regeneration by seeds in low-herb
snowbeds and Ranunculus glacialis-Gymnomitrion
snowbeds. Vegetative reproduction and infrequent pulses of seedling
recruitment negate an influence of short-term seedling recruitment on the
spatial structure of vegetation. Extreme conditions, such as low
temperatures, instability of the soil and late snowmelt modify the
influence of factors that are important in more moderate conditions.
To conclude, all transitions limit regeneration by seeds. However,
favourable conditions (e.g. moist conditions in a meadow) partly eliminate
the obstacles against seedling emergence. Regeneration by seeds therefore
has a major impact on the dynamics and structure of vegetation. In heath
vegetation, where bare soils are dry and the moss cover is thick, large
seed banks and seed rains do not guarantee effective seedling recruitment.
The regeneration process is reduced in the early phases, and plants that reproduce primarily by seeds have a minor role in vegetation. The accumulation of seed banks is effective in these circumstances.
10
Hofmann, W. C., D. L. Kittock, J. Malcuit, P. Else, and C. Michaud. "Seedling Emergence and Lint Yield of DP-90 Seed of Different Densities." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219729.
Full textAbstract:
The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.Six lots of Deltapine (DP) 90 of different seed densities were planted at three planting rates in four tests in Arizona in 1985. The lowest density seed lot had significantly lower standard germination, cold test germination, field emergence, and lint yield than other seed lots. The highest density seed lot had slightly higher lint yield and field emergence than other lots on an average.
11
Kittock, David L., Wallace C. Hofmann, B. Brooks Taylor, Joel Malcuit, Carl Michaud, and Peter T. Else. "Seedling Emergence Studies on Upland Cotton in Arizona in 1984." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/203916.
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12
Kittock, D. L., W. C. Hofmann, J. Malcuit, P. Else, and C. Michaud. "Seedling Emergence Studies on Upland Cotton in Arizona in 1985." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219703.
Full textAbstract:
The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.Seed of 19 upland cotton varieties was planted early in the season at 3 locations to evaluate relative emergence. Variety comparisons for seedling emergence were consistent at the 3 locations. Comparison of performance of older varieties with past years showed consistent relative emergence in 7 comparisons and an apparent weak seed lot for one variety in 1985 and apparent weak seed lots for another variety in past years. Deltapine 41 has consistently been near the bottom in early season seedling emergence over years and Deltapine 61 has been below average.
13
Wheeler, Timothy R. "Seed quality and the germination, emergence and growth of onion (Allium cepa L.)." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278100.
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14
Taylor, Aimee R. "Seed vigour and the effects of soil physical conditions on sugar beet emergence." Thesis, University of Aberdeen, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248612.
Full textAbstract:
Sugar beet (Beta vulgaris. L.) is sown to a stand in commercial agriculture. Consequently establishment of < 70 % can lead to an important loss in final yield and it is essential to obtain seed quality and pellet types that can give consistently high percentage emergence even under adverse soil conditions. This depends on suitable field testing and in use of vigour tests that can adequately simulate soil physical conditions in the field. In this study field and laboratory experiments were carried out to determine the effects of seed vigour, pellet type and soil physical conditions on the emergence of different sugar beet (Beta vulgaris. L.) seed lots. Field experiments were performed at three contrasting sites with seed lots of three different levels of vigour usually in four different types of pellet. The importance of imposing a stress was identified after the first field trial, in which few significant differences in percentage emergence were found. Therefore field trials with irrigated plots were carried out to determine the effects of heavy rainfall immediately after sowing. The result was a decrease in emergence percentage in irrigated plots and more significant differences (P <0.05) were found between seed lots. All field trials discriminated between high and low vigour seed (in common with laboratory tests) and between pelleted and unpelleted high vigour seed, but field tests did not rank order or discriminate as consistently between variants as did laboratory tests. Results from laboratory tests that were designed to simulate field conditions were compared with field emergence. Laboratory tests in soil or an artificial mixture (Erd and Sand-peat) under non-stressed conditions produced between 97.5-89.9 % emergence and did not differentiate well between different seed lots. In contrast 'wet' Erd and Sand-peat tests that had similar matric suctions to the irrigated field trials, gave between 90.1 to 50.4 % emergence, discriminated between different seed lots, correlated well with irrigated and other more stressed field trials. A model (BeetEM) predicting seedling emergence is also described and applied to sugar beet. The input variables are soil temperature at seed depth and the depth of sowing. The time for the hypocotyl to reach the soil surface is calculated using a base temperature and thermal time for hypocotyl appearance, and base temperature and thermal time and controlling the rate of pre-emergent shoot growth. Predicted emergence times were shorter than the observed. When the conditions were not stressed or seed lots were high in vigour the prediction was closer to the observed (within ½ - 1d out of a total of 12-14 d). However, in irrigated field trials low vigour seed lots took > 2 d longer to emerge than predicted.
15
Parks, Geoffrey Richmond. "Longleaf pine sandhill seed banks and seedling emergence in relation to time since fire." [Gainesville, Fla.] : University of Florida, 2007. http://purl.fcla.edu/fcla/etd/UFE0021193.
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16
Campbell, Diane R., Alison K. Brody, Mary V. Price, Nickolas M. Waser, and George Aldridge. "Is Plant Fitness Proportional to Seed Set? An Experiment and a Spatial Model." UNIV CHICAGO PRESS, 2017. http://hdl.handle.net/10150/626253.
Full textAbstract:
Individual differences in fecundity often serve as proxies for differences in overall fitness, especially when it is difficult to track the fate of an individual's offspring to reproductive maturity. Using fecundity may be biased, however, if density-dependent interactions between siblings affect survival and reproduction of offspring from high- and low-fecundity parents differently. To test for such density-dependent effects in plants, we sowed seeds of the wildflower Ipomopsis aggregata (scarlet gilia) to mimic partially overlapping seed shadows of pairs of plants, one of which produced twice as many seeds. We tested for differences in offspring success using a genetic marker to track offspring to flowering multiple years later. Without density dependence, the high-fecundity parent should produce twice as many surviving offspring. We also developed a model that considered the geometry of seed shadows and assumed limited survivors so that the number of juvenile recruits is proportional to the area. Rather than a ratio of 2:1 offspring success from high- versus low-fecundity parents, our model predicted a ratio of 1.42:1, which would translate into weaker selection. Empirical ratios of juvenile offspring and of flowers produced conformed well to the model's prediction. Extending the model shows how spatial relationships of parents and seed dispersal patterns modify inferences about relative fitness based solely on fecundity.
17
Malcuit, Joel, David L. Kittock, B. Brooks Taylor, and Carl Michaud. "The Effect of Pregermination of Cotton Seed in Oxygen on Seedling Emergence and Lint Yield." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/204033.
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18
Silva, Josué Bispo da. "Testes para avaliar o potencial fisiológico de sementes de beterraba /." Jaboticabal : [s.n.], 2006. http://hdl.handle.net/11449/105115.
Full textAbstract:
Orientador: Roberval Daiton VieiraBanca: Teresinha de Jesus Deléo Rodrigues
Banca: Arthur Bernardes Cecílio Filho
Banca: Júlio Marcos Filho
Banca: Ana Dionisia da Luz Coelho Novembre
Resumo: O uso de testes de vigor é imprescindível na avaliação do potencial fisiológico das sementes produzidas e comercializadas por uma empresa. O trabalho, dividido em duas etapas, teve por objetivo estudar diferentes testes para avaliar o potencial fisiológico de sementes de beterraba. Com base nos resultados, concluiu-se que os testes de EA, EASS-20, EASS-40 e DC podem ser utilizados para avaliar o potencial fisiológico de sementes de beterraba; o uso de soluções salinas apresenta vantagem sobre o procedimento tradicional; o ajuste do TA das sementes no teste de deterioração controlada deve ser feito pelo método do substrato úmido.
Abstract: The use of vigor tests is essential to evaluate the physiological potential of seed lots produced and selled by a company. The work, separated in two stages, aimed to study different vigor tests to evaluate the physiological potential of beetroot seeds. With base in the results, it was concluded that EA, EASS-20, EASS-40 and DC tests can be used to evaluate the physiological potential of beet seeds; the use of solutions presents advantage on the traditional procedure; the adjustment of seed MC in the controlled deterioration test would be done by the method of humid substratum.
Doutor
19
Figueroa, Rodrigo. "Biology and management of common groundsel (senecio vulgaris L.) in strawberry." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1069953083.
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20
Watts, Jason Christopher. "The effect of seed priming on the germination, emergence, and development of five different grass species." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62864.pdf.
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21
Kittock, D. L., W. C. Hofmann, J. Malcuit, P. Else, and C. Michaud. "The Effect of Pregerminating DP-90 Cotton Seed in Oxygen and Drying on Seedling Emergence and Lint Yield." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219705.
Full textAbstract:
The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.Partial pre-germination of Deltapine 90 seed under oxygen and then drying prior to planting tended to speed and increase emergence in two tests in 1985, but did not increase lint yield.
22
Alemayehu, Makonnen. "Germination and emergence salt tolerance of sorghum (Sorghum bicolor L.) as influenced by seed quality and generations." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184933.
Full textAbstract:
Artificially aged and non-aged seeds of 22 grain sorghum (Sorghum bicolor L.) F₁ hybrids and their F₂ and F₃ generations were evaluated for germination salt tolerance. Six of the hybrids, along with their F₂ and F₃ generations, were tested for emergence salt tolerance. Effects of seed production environments on germination salt tolerance were also studied using F₂ generations of 12 sorghum hybrids produced under full-season irrigation, limited irrigation, and double-cropping conditions. Germination tests were conducted in a growth chamber, on trays, while the emergence test was conducted in a greenhouse in flats filled with sand. The experiments were conducted under non-saline and saline conditions in randomized complete block designs. Artificial seed aging resulted in significant reductions in germination percentages under both non-saline and saline environments. The overall mean reduction in germination caused by seed aging was more than twice as much under salinity stress as under the non-stress conditions (48 vs. 17%), indicating differential effects of salinity on different quality seeds. Entries that appeared to be resistant to seed aging also had higher germination percentages under salinity stress. Seed production environment influenced germination performance in both non-saline and saline environments. The overall mean germination percentages of sorghum seeds produced under three different field environments were significantly different from one another. Significant differences were observed in germination and emergence percentages within F₁, F₂, and F₃ generations. Except for the F₁ entries, however, emergence index differences within the F₂ and F₃ generations were not significant. Correlations between germination and emergence percentages in the non-saline and saline treatments were generally nonsignificant. This suggests that germination and emergence responses of sorghum may vary under different salinity levels and different environments.
23
Mogollones, Barrera Sol C. "Seed dispersal, seedling emergence and bird community structure in a human-modified landscape mosaic in Sri Lanka." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=202126.
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24
Taab, Alireza. "Seed dormancy and germination in Solanum nigrum and S. physalifolium as influenced by temperature conditions /." Uppsala : Dept. of Crop Production Ecology, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200949.pdf.
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Pamuk, Gunnar Sven. "Controlling water dynamics in Scots pine (Pinus sylvestris L.) seeds before and during seedling emergence /." Umeå : Dept. of Silviculture, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/s305.pdf.
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26
Burleson, Sarah Ann. "Development of New and Alternative Resources for Breeding Low Phytate Soybeans." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/32162.
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Soybean (Glycine max (L.) Merr) cultivars with genetic reduction in seed phytate concentration will be a valuable resource to livestock producers both nutritionally and economically, as well as in the preservation of the environment. However, due to association with reduced seed germination and field emergence potential, low phytate (LP) soybean cultivars are not being advanced to commercialization. Soybean breeders of LP lines must adjust their techniques and resources in order to efficiently select LP germplasm. Reduced seed germination and field emergence potential associated with LP germplasm eliminates many individuals with the desired LP trait during early generation population development, making improvement of agronomic performance among LP lines difficult. Thus, development of resources for improved phenotyping, genotyping, and early generation population development will facilitate the commercialization of LP cultivars.
Discovery of variation for field emergence potential among F2-derived LP families suggests the potential for using a pedigree method for early generation population development in LP germplasm, as it preserves diversity and allows selection for improved field emergence. Integration of markers into a pedigree method will be useful to breeder. An example is BARCSOYSSR_11_1495 with 90-93% selection efficiency in various V99-5089-derived populations. Another resource for improved LP selection is a time-efficient, high-throughput modified iron (Fe) colorimetric phytate assay that does not suffer from inorganic phosphorus (P) concentration interference. Together these tools will provide breeders more accurate selection of LP lines.
Master of Science
27
Sagra, Javier, Daniel Moya, Pedro Plaza-Álvarez, Manuel Lucas-Borja, Raquel Alfaro-Sánchez, Las Heras Jorge De, and Pablo Ferrandis. "Predation on Early Recruitment in Mediterranean Forests after Prescribed Fires." MDPI AG, 2017. http://hdl.handle.net/10150/625399.
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Wildfires play a significant role in many different elements of Mediterranean forest ecosystems. In recent years, prescribed fires have started being used more often as a fuel reduction tool, and also as silvicultural treatment to help the regeneration and health improvement of stands. Apart from the fact that fire may alter microsite conditions, very little is known about the impact of prescribed burning on natural regeneration or plant species renewal in Mediterranean pine forests. Likewise, knowledge about the influence of seedling predators on post-fire regeneration is still scarce. In this study, we aimed to compare the effects of seedling predation on recruitment in earlier stages after prescribed burnings in three pine stands in Central Spain: a pure stand of Pinus nigra; a mixed stand of Pinus halepensis and Pinus pinaster and a mixed stand P. nigra with P. pinaster. In situ we superficially sowed seeds from two different species. In the sowing experiment, we tested two different seed provenances (drier and more humid spanish regions) for each species. In all, 60 plots (30 burned, 30 unburned) per site, with 10 seeding units per plot and more than 20,000 seeds, were used in the whole study. Seedling predation was evaluated by replicating the seeding units inside and outside a wire cage as protection for rodents and birds. Our results showed that prescribed fires alter initial seedling predation intensity: predation was significantly higher in the seedlings grown in the plots affected by prescribed fire. The individuals sown before the fire passed showed slightly more predation than those sown after fire passage. Provenances did not appear as an important predation drive. Understanding the role of the predation associated with these treatments can help improve Mediterranean pine forest management.
28
Silva, Josué Bispo da [UNESP]. "Testes para avaliar o potencial fisiológico de sementes de beterraba." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/105115.
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Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
O uso de testes de vigor é imprescindível na avaliação do potencial fisiológico das sementes produzidas e comercializadas por uma empresa. O trabalho, dividido em duas etapas, teve por objetivo estudar diferentes testes para avaliar o potencial fisiológico de sementes de beterraba. Com base nos resultados, concluiu-se que os testes de EA, EASS-20, EASS-40 e DC podem ser utilizados para avaliar o potencial fisiológico de sementes de beterraba; o uso de soluções salinas apresenta vantagem sobre o procedimento tradicional; o ajuste do TA das sementes no teste de deterioração controlada deve ser feito pelo método do substrato úmido.
The use of vigor tests is essential to evaluate the physiological potential of seed lots produced and selled by a company. The work, separated in two stages, aimed to study different vigor tests to evaluate the physiological potential of beetroot seeds. With base in the results, it was concluded that EA, EASS-20, EASS-40 and DC tests can be used to evaluate the physiological potential of beet seeds; the use of solutions presents advantage on the traditional procedure; the adjustment of seed MC in the controlled deterioration test would be done by the method of humid substratum.
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Averitt, Benjamin James. "A Survey of the Agronomic and End Use Characteristics of Low Phytic Acid Soybeans." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71335.
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Phytic acid (PA) accounts for up to 75% of the P in soybean (Glycine max L. Merr.) seeds, but it is indigestible by mono- and agastric animals resulting in economic and environmental detriment. Soybean lines with genetically reduced PA contents have been developed using three distinct mutant alleles at the MIPS1, LPA1, and LPA2 genes resulting in up to a 75% reduction in PA. Low PA (LPA) soymeal-based feeds have been tested on several agricultural species and shown to reduce the P in the animal effluent, but they have not been tested on any aquacultural species. However, LPA soybean lines often exhibit low field emergence making them commercially inviable. The cause of this phenomenon is widely debated with possibilities ranging from increased disease pressure to decreased seedling vigor. The objectives of this research were to 1) enhance field emergence of LPA soybean varieties through pre-planting seed treatments, 2) study the impact of the LPA mutant alleles on agronomic, quality, and seed composition traits, and 3) design a low-error method for studying the effect of LPA soymeal-based feeds on aquatic animals using Pacific White Shrimp (Litoenaeus vannamei). These results describe a variety of agronomic and genetic strategies with which the low field emergence of LPA soybeans can be addressed, reveal a heretofore not reported interaction between the mips1 and lpa2 alleles to further increase the digestibility of soymeal, and a possible method for studying LPA soymeal based feed on aquacultural animals.Master of Science
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Leeks, C. R. F. "Determining seed vigour in selected Brassica species." Lincoln University, 2006. http://hdl.handle.net/10182/1274.
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Variables for the accelerated ageing (AA) test, methods for reducing fungal contamination during the AA test, using the conductivity test as a vigour test, the effect of seed size on seed vigour and the relationship between laboratory test results and field perfonnance in selected Brassica spp were investigated. In the first experiment, three seed lots of turnip rape hybrid (B. rapa x campestris), turnip (B. campestris) and forage rape (B. napus); and seven seed lots of Asian rape (B. napus), six seed lots of Asian kale (B. oleraceae var. alboglabra L.) and five seed lots of choisum (B. rapa var. pekinensis) with germinations above 90% were aged at two different temperatures (41 and 42°C ± 0.3°C) and three ageing times (24, 48 and 72 ± 15 minutes). The second experiment was divided into three sections. In the first, the same seed lots and species were aged at one temperature (41°C) and time (72 h), but either 40 ml of saturated salts; KCl (83%RH), NaCl (76%RH), NaBr (55%RH); or distilled water (96%RH) were used as the ageing solutions. In the second, one turnip rape hyprid seed lot was aged at three temperatures (41, 42 and 45°C) and two times (72 and 96h), again using the three saturated salts and distilled water as ageing solutions. In the third, three turnip rape hybrid seed lots and three Asian kale seed lots were surface sterilised (1 % sodium hypochlorite) prior to ageing at one temperature (41°C) and time (72 h). In the third experiment, the same species and seed lots used in experiment one at their original seed moisture content (SMC) were tested for conductivity after soaking in deionised water for 4, 8, 12, 16, 20 and 24 h. They were then re-tested after the SMC had been adjusted to 8.5%. In the fourth experiment, three seed lots of forage rape and three seed lots of Asian kale were graded into three seed size categories; large (retained on a 2.0 mm screen), medium (retained on a 1.7 mm screen) and small (passed through a 1.7 mm screen). Graded seeds were then tested for standard germination, AA (41°C/48 h) and conductivity (measured at 16 and 24 h). In the final experiment, the relationships between laboratory tests for the six species (each consisting of three seed lots), field emergence from three sowings, and cold room emergence were evaluated. Both time and temperature influenced post-AA germination. Increasing the ageing period from 48 to 72 hours at 41°C, and 24 to 48 hours at 42°C resulted in decreased mean germination percentage for all species but not always clear separation of seed lots. While there were sometimes few differences between ageing at 41°C and 42°C, the former is preferred because it is already the temperature used for other species. For Asian rape, choisum and turnip, the previously recommended testing conditions of 41°C/72 h provided good seed lot separation, but for Asian kale and turnip rape hybrid, AA testing at 41°C/48 h provided better results. Seed moisture content after ageing ranged from 29-37% depending on species. Fungal growth on seeds during the ageing period appeared to reduce post-ageing germination in some seed lots . Substituting saturated salts for distilled water did not stress seed lots in the AA test, due to the lowered RH%, the exception being seed lots 1210 and 1296. For forage and Asian species, seed lot germination mostly remained above 90% when aged for 72 h at lowered RH%. Increasing the ageing duration from 72 to 96 hours resulted in some decreases in post-AA germination but no clear separation of seed lots. Surface sterilising the seeds prior to the AA test resulted in a lower incidence of contaminant fungi which was associated with a lower percentage of abnormal seedlings. The conductivity test was mostly able to identify vigour differences among forage and Asian vegetable brassica seed lots. Differences in conductivity readings were observed among seed lots in all species. Increasing the period of imbibition resulted in increased conductivity from most seed lots but radicle emergence occurred after 16-20 h of imbibition. Variation was observed in the time to reach 95% maximum of the imbibition curve for most species. Conductivity readings at 16 h would avoid possible influences of radicle emergence on results. Adjusting the SMC to 8.5% resulted in reduced variation in conductivity among replicates of seed lots, due to a reduction in imbibition damage. Seed size had a significant effect on both post-AA germination and conductivity results. In forage rape, large size seeds had higher post-AA germination cf. medium cf. small size seeds. In Asian kale, large size seeds had higher post-AA germination compared with small size seeds. For both forage rape and Asian kale, large size seeds had lower conductivity readings cf. small size seeds. The correlation analyses demonstrated significant relationships between AA testing and field emergence parameters (percentage emergence, emergence index and emergence rate). Significant relationships were also observed between conductivity testing and these field emergence parameters. Based on the correlation analysis, AA testing at 41°C/48 hand/or 42°C/48 h could be recommended to be used as an AA test for turnip and Asian rape; and 41°C/48 hand/or 41°C/72 h for Asian kale and choisum. Based on the correlation analysis, conductivity testing at 16 h can be used to predict the field emergence potential of forage and Asian vegetable seed lots. Vigour tests were consistently able to provide better indicators of field perfonnance than the standard germination test, although these relationships did vary with the different field sowings.
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Harris, Kumuthini D. "Effect of crop height, relative time of weed emergence, seed vigour and dormancy on yield maintenance and weed suppression by Rht lines of winter wheat." Thesis, University of Reading, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553173.
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The effects of crop plant height, relative time of weed emergence (RTE) and crop seed vigour and dormancy on the ability of Rht (Reduced height) lines of winter wheat to maintain yield and suppress weeds, were investigated. Near Isogenic Lines (NILs) of Rht lines in Mercia cultivar background were planted with oat as a model weed. As NILs were genetically similar apart from the Rht genes, actions and interaction of RTE and crop height were assessed without confounding effects of other traits associated with competitive ability. Seed vigour and dormancy were included in case they influenced RTE. In competition with oat, the crop yield increased and yield losses decreased as the oat emergence was delayed. The yield loss was greater in the dwarf NILs (Rht-Bl c: 49% and Rht12: 64%) compared to the Mercia control (18%) and semi-dwarfNILs (25%). RTE had no effect on crop height or biomass or light interception in both the years. Yield increased linearly with the crop height both in the presence and absence of weeds. Weed-free yields were always exceeding the weedy yields irrespective ofRTE. Whether the Rht lines were sensitive or insensitive to gibberellins, did not make any difference to yield maintenance and weed suppression, but their weed suppressive ability was generally poor. High vigour cv. Mercia and Rht-Bl c seed lots competed better against weeds than low vigour ones, but the effect related to a ,higher crop plant population as the effect of R TE of weeds was the same for low and high vigour lots. The acquisition of germinability and dormancy during maturation of grams and subsequent field emergence was studied in 19 winter wheat NILs in cv. Mercia, Maris Huntsman and Maris Widgeon backgrounds. High levels of dormancy were found in the dwarf allele Rht-Bl c in all three backgrounds and also in Rht-Dl b + Rht-Bl c in Maris Huntsman and Maris Widgeon backgrounds. Longer mean time of emergence, lower percentage of emergence, shorter coleoptile length, higher Hagberg Falling Number and GA insensitivity were the causes for the delay in emergence which slightly reduced the ability of Rht-Blc and Rht-Dlb+Rht-Blc to compete against weeds. Upright with erect leaf NIL's early season height, maximum height were positively correlated with grain yield and weed suppression, and negatively correlated with crop yield loss and weed seed production. Overall, crop height was found to be more important in achieving weed suppression than relative time of weed emergence.
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Maree, Pieter Hermanus. "Prediction of field emergence of maize (Zea mays L.) hybrids exposed to cold and wet conditions." Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-08122009-183953.
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Basso, Denise Puntel 1984. "Contribution to the characterization of the acquisition of the emergency vigor during seed maturation /." Botucatu, 2018. http://hdl.handle.net/11449/154563.
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Orientador: Edvaldo Aparecido Amaral da SilvaCoorientador: Olivier Leprince
Banca: Julia Buitink
Banca: Thierry Joet
Banca: José Baldin Pinheiro
Resumo: The stable production of high vigorous seeds regardless of the environment is a key lever to increase crop production. Seed vigor is defined as the sum of the physiological properties that lead to homogenous and vigorous seedling establishment. It includes longevity, defined as the capacity to remain viable for long periods during dry storage and the capacity to elongate after germination. However, how these traits are acquired during seed development and how the environment impacts their acquisition remain poorly understood. Yet this information is important to determine the harvest stage corresponding to maximum vigor. Using agronomy and physiological approaches on soybean and Medicago truncatula, we confirm that longevity is progressively acquired during seed maturation. In soybean, our data suggest that the climate influenced longevity whereas in Medicago, heat applied during seed maturation had no significant impact. This work also showed that HEAT SHOCK FACTOR A2.2, a homologue of HSFA9 and hub gene involved in seed maturation does not play a role in seed longevity but acts as negative regulator of embryonic dormancy. Longevity is evaluated by the ability to germinate after storage, which represents only a part of the success of crop establishment. How seed maturation affects the loss of seedling establishment capacity during storage was evaluated in soybean using an experimental system set up to assess elongation capacity. The pattern of acquisition of elongation capac... (Resumo completo, clicar acesso eletrônico abaixo)
Resumo: La production de semences vigoureuses est un levier pour augmenter les rendements. La vigueur est définie comme la somme des propriétés physiologiques conduisant à l'établissement homogène et vigoureux du peuplement végétal. Elle comprend la longévité, définie comme la capacité à rester viable pendant le stockage et la capacité de la plantule à s'allonger après germination. Cependant, comment ces caractéristiques sont acquises au cours du développement de la graine et comment l'environnement influence leur acquisition restent mal compris. Ces informations sont importantes pour déterminer le stade de récolte correspondant à une vigueur maximale. En utilisant des approches agronomique et physiologique sur le soja et Medicago truncatula, nous montrons que la longévité est progressivement acquise au cours de la maturation. Chez le soja, le climat influence la longévité de manière complexe alors que chez Medicago, la chaleur pendant la maturation ne l'impacte pas significativement. Nous montrons également que HEAT SHOCK FACTOR A2.2, un homologue de HSFA9 impliqué dans la survie à l'état sec ne joue pas de rôle dans la longévité chez Medicago mais agit comme régulateur négatif de la dormance. La longévité se mesure par la perte de la germination pendant le stockage et ne représente qu'une partie du succès de l'établissement de la culture. Donc, l'influence de la maturation sur la perte de capacité d'établir une plantule lors du stockage a été évaluée chez le soja. L'acquisition de la capacité d'élongation pendant la maturation varie entre les années de culture et selon les conditions de croissance des plantules. Le temps nécessaire pour diminuer la capacité d'élongation de 50% pendant le stockage augmente constamment pendant la maturation après la maturité de masse. Ceci démontre l'importance des phases tardives de la maturation dans ...
Doutor
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Asary, Melanie. "An investigation into the poor emergence of Pinus elliottii and Pinus taeda seeds." Thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26349.
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Yang, Peter Chih-chi. "Why do patients seek emergency psychiatric care? their reasons and characteristics /." [New Haven, Conn. : s.n.], 2007. http://ymtdl.med.yale.edu/theses/available/etd-08292007-113051/.
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Moolla, Zuraida. "Case mix and workload of patients seen at three private emergency centres in Cape Town, South Africa." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25467.
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Objectives: To determine the case mix and workload of patients presenting to three private emergency centres in Cape Town Design: A Prospective cross sectional observational study was undertaken Setting and subjects: A convenience sample of all prospective patients that presented to three private emergency centres namely Melomed Gatesville, Melomed Bellville and Melomed Mitchell's plain during the month of September 2013 The outcome measures included the following:- ● Determining basic metrics across all three units over study time ● Determining the triage parameters for patients sampled across three units ● Direct time study of patients through unit ● Determining Doctor to patient workloads ● Determining Nurse to patient workloads ● Determining average number of patients receiving special investigations Results: Third party funding was responsible for 91 % of patients seen. The patient profiles consisted primarily of lower acuity presentations. There were clear peaks of attendance with lower acuity presentations decreasing after 10 pm. The majority of patients were discharged and very few required specialist follow up. Conclusions: This study provides valuable information with regards to private emergency centres in the predominantly low income and low socio economic sectors of the Western Cape, Cape town thus allowing a greater focus on the operational aspects of Emergency Centres In these areas and to assist with future planning of the management and running of similar Emergency Centres.
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Boccia, Jennifer L. "Characteristics of individuals with asthma who seek care in the emergency room (ER)." Thesis, California State University, Long Beach, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1523054.
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Asthma is one of the most prevalent chronic diseases in the United States. If diagnosed asthma is highly treatable. However, diagnoses of asthma can be the hardest part of treatment. This study was conducted to examine the characteristics of asthma patients in the emergency room (ER). The dependent variable used use of ER in the past 12 months among was individuals who are currently diagnosed with asthma. I used the following independent variables to determine any characteristics that these individuals might share; age, race, insurance status/type, number of doctors' visits per year, geographic location and whether these particular patients use daily medication to control their asthma.
Data from the California Health Interview Survey (CHIS) 2009 was used. An association was found between the dependent variables; age, race, insurance status and number of doctors' visits per year. However, no association was found between geographic location and ER usage for individuals who have asthma.
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Coons, Robyn. "Characteristics of Young People Seen in the Emergency Department for Assault-Related Injuries." ScholarWorks, 2019. https://scholarworks.waldenu.edu/dissertations/7374.
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Violence is among the most serious threats to the health and safety of young people between the ages of 10 and 24 in the United States. The purpose of this cross-sectional quantitative study using secondary data from the CDC's 2015 National Hospital Ambulatory Medical Care Survey (NHAMCS) data set was to examine the characteristics (age, sex, race and ethnicity, insurance or payer source, and housing status) of young people between the ages of 10 and 24 who seek medical care for assault-related injuries through the emergency department (ED). The social ecological model was used to examine the complex interplay between individual, relationship, community, and societal factors, which allows for a better understanding of the range of factors that put people at risk for or protect them from being a victim of or engaging in violence. Chi-square and logistic regression with clustered robust standard errors was used to analyze the differences and the relationships between 6 characteristic variables and the likelihood of ED visits among young people between the ages of 10 and 24 for assault-related injuries. The results of this study provide researchers with a better understanding of the demographics of young people who seek care in the ED for assault-related injuries. Understanding this population is critical in examining the effectiveness of ED-based youth violence prevention programs. Future research is needed to understand the value and outcomes of existing ED-based youth violence prevention programs. Should public health practitioners use these results, positive social change can occur by empowering social norms that value equality, safety, and human rights instead of valuing power over another and the acceptance of violent behaviors as normal.
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Hoskins, R. "Why do patients seek unplanned follow up after treatment in the emergency department?" Thesis, University of the West of England, Bristol, 2014. http://eprints.uwe.ac.uk/22758/.
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Aims: This study explored why patients seek unplanned follow up after treatment in an emergency department, if participants could identify the healthcare professional they were treated by, and whether the patient’s perception of, and confidence in, the healthcare professional had an impact on their subsequent decision to seek follow up. Methods: A mixed method pragmatic approach was used in order to quantify and explore the aims of the study. Participants were followed up two weeks later by telephone and finally invited to take part in a focus group to explore their experience and perceptions of their visit to the emergency department. Results: 18% of patients sought unplanned follow up in the 2 weeks following their initial visit, with no statistically significant difference between healthcare professional groups. 19% of patients incorrectly identified the healthcare professional treating them, with evidence of a gender bias. Discussion: The qualitative elements of the study explored the quantitative results. Participants were more likely to believe the healthcare professional was a doctor if they were male and had effective communication skills. A number of practical issues were identified in reducing unplanned follow up rates. The most common were issuing fitness to work certificates, explaining the trajectory of an illness or injury and addressing specific pain management issues. A change in policy would be required for non –medical health care professionals to be able to issue fitness to work certificates but in this study it was found to be the single most effective strategy to reduce reconsultantion rates. Conclusion: Patients seek unplanned follow up for a variety of reasons. This study shows that non-medical HCPs do not have a higher planned or unplanned follow-up rate, and they may have some advantages over junior medical staff in terms of effective consultation skills, high patient satisfaction and reduced reconsultation rates.
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Legras, Elaine C. "Microhabitat is critical for sugar pine seedlings emergence and survival in a xeric Jeffrey pine dominated forest /." abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1455660.
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Thesis (M.S.)--University of Nevada, Reno, 2008."May, 2008." Includes bibliographical references (leaves 39-44). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.
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Winkel, Von Kenneth. "Effects of seedbed modification, sowing depth and soil water on emergence of warm-season grasses." Diss., The University of Arizona, 1990. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1990_108_sip1_w.pdf&type=application/pdf.
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Chapnick, Marie. "Hourly Roudning in th Emergency Department." ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/3593.
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The Affordable Care Act of 2010 increased the number of patients seen in a northeast, urban trauma emergency department by 34%. This created a problem as it occurred simultaneously with a nursing shortage. Consequently, patient satisfaction scores fell below the national average benchmark. The rate patients left the emergency department without being seen was 2.6% higher than the national average and patient fall rates increased by 20%. A review of the literature to search for solutions led to the support of an hourly rounding project and an educational workshop promoting proactive nurse behaviors as a way to address the quality and safety gap. The goal of this scholarly project was to develop this evidence based, theory supported project and to conduct a formative and summative evaluation by an expert review panel in order to achieve consensus before implementation. An executive team was formed and led through the process of development of a detailed hourly rounding protocol and workshop, which will be implemented at the facility at a later time. A 10 member expert panel was formed. The panel members consented to participate in an explanatory session, to review all project materials, and to complete an anonymous 20 question survey tool. The panel also consented to review any changes made to materials as part of a summative evaluation. Descriptive analysis of the formative data demonstrated a 90% overall agreement that the workshop was comprehensive and covered key concepts within 5 categories. Minor requested revisions were made in response to formative results. The summmative review demonstrated 100% consensus on the revisions. This project will bring about social change by engaging nurses in proactively caring for patients in a safe and efficient manner.
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Marsella, Sarah A. "Emergency department visits for mental health: an examination of wait times to see a provider." Thesis, Boston University, 2014. https://hdl.handle.net/2144/21212.
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Thesis (M.S.H.P.)BACKGROUND: Emergency department (ED) visits for psychiatric issues have grown at a disproportionately higher rate than other visits. This has been attributed to factors including severe cuts in mental health (MH) services and identified as a culprit in ED overcrowding. Little is known, however, about how mental health reason-for-visit (MHRFV) interacts with patient and hospital characteristics to affect wait times to see an ED provider. OBJECTIVE: To determine if wait time (WT) to see a provider at the ED differs for those presenting with MHRFV and how various patient and hospital-level characteristics interact to affect it. METHODS: Data were obtained from the National Hospital Ambulatory Medical Care Survey (NHAMCS) for visits to EDs throughout the United States. We examined data for patients ≥ 18 years of age who visited an ED in years 2009 and 2010. Patient weights were used to generate national estimates. Patients’ primary reasons-for-visit were used to identify the MH group for analysis and comparison to all other RFVs. Predictors of WT were chosen based on the Andersen Behavioral and ED overcrowding models. WTs were log-transformed for initial bivariate and final multivariate regression models to assure a more normal distribution. RESULTS: Mean WT was 56.5 and 55.8 minutes for MHRFV and all others respectively with a shared median of 31 minutes. As expected with our large sample (n = 47,831), all variables of interest were significantly associated with WT. Adjusting for patient and hospital level characteristics, a multivariate regression revealed that MHRFV prolonged WT by about 50%. After adjustment for independent variables, interactions with MHRFV were tested as the main outcomes of interest. Blacks with MHRFV had WTs 62% longer, patients age 41-64 31% longer, payer status of Medicare/Medicaid or no coverage had WTs about 24% and 14% longer than private insurance. Conversely, patients at government owned hospitals had WTs 145%, and non-profits 42%, lower than private hospitals. CONCLUSIONS: This is the first time that ED WT has been examined in this depth with a sample of patients presenting with MH issues. The results indicate that disparities are more pronounced in this subgroup of ED patients.
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Dickson, Ross L. "Seed production in Pinus radiata D. Don : Impact of climate and site on numbers of emergent female strobili." Thesis, University of Canterbury. Forestry, 1995. http://hdl.handle.net/10092/7190.
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This thesis describes a study undertaken to improve the capacity of seed orchard managers to select productive sites for the production of Pinus radiata seed. It is applied in its approach, with the major intent being to explore the relationship between environmental variables, and numbers of emergent female strobili at anthesis.
Following the development of a sampling methodology for counting strobili, data were collected from 52 open grown stands of Pinus radiata ranging in age from 10 to 12 years located over a range of latitudes and altitudes east of the main dividing range of the South Island. Stands were selected to be reasonably close to a meteorological station.
Based on existing knowledge of when environmental variables impact on the numbers of strobili carried at the time of anthesis, monthly temperature and water stress data for the spring months of the year prior to anthesis, and also for subsequent summer months, were correlated with numbers of strobili across sites. Winter temperatures prior to anthesis were also correlated with the strobilus data.
The variables that were significantly correlated with strobilus number were then included in a stepwise multiple regression analysis with the intent of developing a statistical model for strobilus production. The multiple regression analysis selected the following variables into the model equation (with the percentage of the variance accounted for by each variable shown in brackets):
(i) Mean minimum temperature for February (around the time of seed-cone bud
differentiation) (54%).
(ii) Integrated soil water stress for February and March (6%).
(iii) Accumulated growing degree days weighted against rainfall for the spring prior to seed-cone bud differentiation (4%).
(iv) Mean minimum temperature for May (between differentiation and anthesis) (1%).
Overall the model was able to account for around 65% of between-site variability in strobilus number. The model variables suggested that predominantly temperature and to some extent rainfall govern the number of seed-cone buds that begin differentiating; and the number that finally reach antl1esis in the spring. Two years later in 1994 the statistical model was validated across 12 new South Island sites. It was found that the model estimates were in close agreement with actual counts, with 75% of the residual values falling within the 95% confidence limit bounds.
Considering that mean February temperature was so highly correlated with strobilus number it was considered appropriate, whilst validating the model in the South Island, to extend sampling into the North Island. 11 stands were sampled, situated along both east and west coasts, where warmer summer temperatures prevail. However, the model estimates were less accurate in the North Island than the South. Both the data for 1992 and 1994 (total 74 sites) were combined and strobilus data were remodelled. Again the multiple regression analysis selected the mean minimum temperature of February as the variable that explained most of the between-site variance. The mean number of strobili at sites in the North Island was 1.4 times greater than that for the sites in the South Island, with trees at the best North Island site carrying 38% more strobili than those at the best site in the South Island.
Considering that long-term data for the February temperature variable were readily available and that the relationship between temperature and strobilus production is likely to have an upper-limit, the Schumacher sigmoid growth function was fitted to the strobilus data for the 74 sites in the both the 1992 and 1994 studies. This function was found to satisfactorily describe the relationship between strobilus number and February temperature, although due to the lack of data points at the high end of the temperature range, the response curve was not typically sigmoid with a flattening off at higher temperatures.
Using both a GIS mapping system and a climate surface model, mean minimum February temperatures for New Zealand were mapped to assist with the selection of potential seed orchard sites.
It was apparent from the maps that prime sites for strobilus production are likely to be those that have a mean minimum February temperature >15°C, and that those sites tend to be on northern coastal headlands and capes with insular climates. The majority of the sites meeting the temperature criteria are in the North Auckland region. It is likely that a reproductive environment for Pinus radiata is one where the temperature does not vary greatly, either diurnally or seasonally. Assessments of conelet abortion and cone seed yield and weight, made at the time of counting strobili, showed that the levels of conelet abortion were independent of the numbers of strobili carried by trees. Seed weight was also unrelated to strobilus production, but seed number was correlated. The high strobilus-producing sites tended to yield more full seeds per cone.
To verify the significance of the variables in the statistical model experimental studies were undertaken using clonal graft material at Amberley seed orchard, Canterbury.
Firstly, an experimental study confirmed the importance in the model of February as a time to influence strobilus numbers. Grafts put into a low-intensity-light building for 2 week periods during February and early March produced no strobili the following spring, while strobilus production was unaffected on grafts moved at other times between January and the 26th of March.
In a further experiment, cooling grafts during the summer months reduced the number of strobili per whorl by 44% and the number of grafts carrying strobili by up to 80%. Siting grafts at cool inland sites during the winter on the Canterbury plain caused a loss of up to 61% in seed-cone buds. However, neither warming grafts in a polyethylene house during long shoot primordial initiation/differentiation; or in a heated glasshouse during the winter months leading up to anthesis, increased strobilus production. The reasons for this are discussed. In hindsight it would appear that the maximum temperatures in the polyethylene house were too high for strobilus production, whilst in the heated glasshouse there was insufficient diurnal temperature variation, along with an interruption to the normal seasonal cooling pattern. Nonetheless, considering both the site predictions of the strobilus model and findings of these experiments it is proposed that an optimal reproductive environment for radiata pine is probably one where warm temperatures are relatively constant and do not vary greatly diurnally or seasonally.
Summer soil water stress was implicated with strobilus production, although to a lesser extent compared to mean minimum February temperature. That is, the sites more water stressed during February and March tended to produce more strobili than those that were less water stressed. This effect was borne out by an irrigation pot trial in 1993 which showed that irrigation reduced the numbers of strobili carried by grafts by up to 45%. However, due to persistent summer rain this effect was not satisfactorily demonstrated in an irrigation field trial conducted at Amberley seed orchard.
The temperature and moisture conditions during the spring of the year prior to anthesis were found to indirectly impact on strobilus production by modifying the number of branches produced by grafts. When graft shoot growth was increased by modifying spring growing conditions, more branches developed per whorl.
Finally, the effect of nitrogen fertiliser applications on strobilus production was tested across a range of sites and climates. There was no significant direct effect of N-fertiliser on strobilus production, regardless of N-form applied. It is unlikely that the use of nitrogen fertilisers in a well managed radiata pine seed orchard will enhance strobilus production; or that the inclusion of a soil-N variable in the model would improve its predictability.
The statistical model developed in this thesis has added to knowledge regarding the identification and the importance of site environmental variables associated with female strobilus production in Pinus radiata. Further the model identified mean minimum February temperature as a key variable, for which long term data is readily available across New Zealand. These data were used to construct 2 mean minimum February temperature maps for New Zealand which can now be used to assist with seed orchard site screening. Experimentally it was demonstrated that temperature and moisture conditions govern the number of seed-cone buds that are differentiated and reach anthesis. It is recognised that environmental variables can impact on strobilus formation in both direct and indirect ways.
The possibilities for extending the databases developed in this thesis to develop further
understanding of seed production processes is advocated.
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Nelson, J. M., and C. C. Sharples. "Effect of Treatment of Lettuce Seeds with Fusicoccin and Other Growth Regulators on Seedling Emergence at High Temperature." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/214109.
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Lettuce stand problems in desert production areas are, in many instances, related to high seedbed temperatures and the use of seed coatings. We evaluated the use of fusicoccin and other growth regulators to improve the performance of naked and coated lettuce seeds at high temperature. Treatment of both naked and coated seeds with fusicoccin markedly increased the rate and total emergence of seedlings incubated at 35 °C for 10 hours alternating with 23 °C for 14 hours.
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Abreu, Mariana da Silva Sequeira Marques. "Cutaneous and renal glomerular vasculopathy : a review of cases seen at an emergency veterinary practices in UK." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2019. http://hdl.handle.net/10400.5/18689.
Full textAbstract:
Dissertação de Mestrado Integrado em Medicina VeterináriaCutaneous and renal glomerular vasculopathy (CRGV), more commonly known as Alabama rot is a disease first reported in racing greyhounds in 1988 but recognised since 1995 in the USA, and with increasing occurrence, since 2012, in the UK. This disease is characterised with acute erythema and oedema progressing rapidly to cutaneous ulcers of the extremities, thrombocytopenia and clinically relevant acute renal failure (AKI). When acute renal failure develops it is usually fatal. The cause of this cutaneous and renal glomerular vasculopathy is not yet known. Thrombotic microangiopathy (TMA) is the main renal histopathological change that confirms CRGV and has been described in humans and dogs. It is currently undefined if CRGV is a new canine disease or if it is a variation of the haemolytic uremic syndrome, atypical haemolytic uremic syndrome, thrombotic thrombocytopenic purpura or disseminated intravascular coagulation which are the TMA’s reported in humans. The objectives of this present study are to review cases of dogs suspected with CRGV evaluating if the cutaneous lesions correlate with the developing of AKI and if this is associated with a worse outcome of CRGV. 40 cases from 26 first opinion emergency providers were analysed and their history, clinical signs, clinicopathological findings, diagnostics, treatment plan, and outcome observed. 27 dogs presented with only skin lesions and 13 with skin lesions and AKI. The most common macroscopic aspects of the skin lesions were superficial abrasions and cutaneous ulcers, particularly in the group of dogs with AKI, presence of inflammation and dermatitis, characterized by different sizes. Alopecia, erythema, and oedema were also observed, mainly when located in the limbs and digits. Lesions wider than five centimetres were significantly correlated with development of AKI (p=0.029). The median time between the presence of skin lesions and the diagnosis of AKI was 3 ± 5 days. Besides the azotaemia, dogs with AKI presented with anaemia, proteinuria, haematuria, hyposthenuria, hypocalcaemia, thrombocytopenia and neutrophilia, high serum liver enzyme activity, and hyperbilirubinaemia. Five animals were submitted to euthanasia (38.5%), due to azotaemia, no response to intravenous fluid therapy and oligoanuria. The remain survived. This study reveals that having azotaemia (0.001), oligoanuria (p<0.001), hypocalcaemia (p=0.003) and hypophosphatemia (p<0.001) was significantly correlated with a worse outcome. Nevertheless, intensive medical therapy is designated in these patients because successful outcomes with full recovery from AKI have been achieved as observed in seven dogs (53.8%) in this study.
RESUMO - VASCULOPATIA CUTÂNEA E GLOMERULAR RENAL: UMA REVISÃO DE CASOS EM CLÍNICAS DE EMERGÊNCIA VETERINÁRIA NO REINO UNIDO - A vasculopatia cutânea e glomerular renal (CRGV), mais conhecida por Alabama Rot, é uma doença que foi descrita pela primeira vez em galgos de corrida em 1988, mas reconhecida desde 1995 nos Estados Unidos da América. No Reino Unido, a sua ocorrência tem aumentado desde 2012. Esta doença manifesta-se sobretudo por eritema e edema das extremidades, progredindo rapidamente para úlceras cutâneas, trombocitopénia e insuficiência renal aguda (IRA). Quando o quadro de insuficiência renal aguda se instala, geralmente é fatal. A causa desta doença ainda não é conhecida. A principal alteração histopatológica renal que confirma CRGV é a Microangiopatia trombótica (TMA), descrita nos humanos e cães. Atualmente, é desconhecido se a CRGV é uma nova doença da espécie canina ou se é uma modificação da síndrome hemolítica urémica, síndrome atípica hemolítica urémica, púrpura trombótica trombocitopénica e coagulação intravascular disseminada, que são as microangiopatias descritas nos humanos. Este estudo tem como objetivo sistematizar casos de cães com suspeita de CRGV avaliando se as lesões cutâneas se correlacionam com o aparecimento de IRA e se esta está associada a um pior prognóstico da doença. Foi realizado um estudo retrospetivo que consistiu na análise de 40 casos consultados em 26 clínicas com uma unidade de cuidados intensivos analisando a anamnese, sinais clínicos, exames complementares de diagnóstico, tratamento e prognóstico. Vinte e sete cães exibiam apenas lesões de pele e 13 lesões de pele e IRA. As lesões mais comuns encontradas foram abrasões superficiais e úlceras cutâneas, sendo estas mais prevalentes no grupo com IRA, presença de inflamação e dermatite, variando no tamanho. Foram observados alopécia, eritema e edema, em especial quando localizados nos membros e dígitos. Lesões com dimensão igual ou superior a 5 cm estão significativamente correlacionadas com o aparecimento de IRA (p=0.029). A mediana do tempo decorrido entre o aparecimento das lesões e o diagnóstico de IRA foi de 3 dias ± 5 dias. Além da azotémia, os cães com IRA apresentaram anemia, proteinúria, hematúria, hipostenúria, hipocalcémia, trombocitopénia, neutrofilia, enzimas hepáticas elevadas e hiperbilirrubinémia. Cinco cães foram submetidos a eutanásia (38,5%), devido a azotémia, não-resposta á fluidoterapia e oligoanúria, sendo que os restantes sobreviveram. Este estudo revela que os cães com azotémia (p=0.001), oligoanúria (p<0.001), hipocalcémia (p=0.003) e hipofosfatémia (p<0.001) estão associados a um prognóstico reservado. Contudo, o tratamento médico intensivo é indicado nestes casos, uma vez que existem resultados positivos com recuperação de IRA completa, como analisado em sete cães (53.8%) neste estudo.
N/A
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Gustafson, David Brett. "Follow-up rates and predictors for follow-up of patients seen in the emergency department for dental trauma." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1241798159.
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Russomano, John. "A Grounded-Theory Study Exploring the Emergence of Leadership in Dispersed Teaming as Organizations Seek Effectiveness in an Increasingly Complex World." Thesis, The Chicago School of Professional Psychology, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10838984.
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Complexity and turbulence create intensifying pressures on 21 st-century organizations seeking growth through globalization and operating efficiencies. Organizations are responding by engaging dispersed teams in expanding operations and enabling efficiencies from “anywhere, any time, any form” teaming. The use of dispersed teaming enables new opportunities for organizational growth; however, may introduce the need for change in the organization’s leadership mindset and approach to leading. The purpose of this qualitative grounded theory research study is to explore and seek a deeper understanding of the emergence of leadership in dispersed teams and the resulting points of tension that potentially affect the process of leading and team effectiveness as organizations address complexity. Findings from the study are based on the lived experiences of virtual team leaders and members and provide insights on the theoretical and practical guiding practices exploring the supportive and hindering forces that enable an ideal environment for the act of leading shifting from an entity or person to a shared process with members of dispersed teams. The findings explore the importance of relational leadership and the role of appointed leaders when fostering shared leading. The outcomes of the research provide insight to organizations, leaders, and members of dispersed teams on the importance of operating collectively in an environment where individuals can maximize their capabilities despite geographical separation; while understanding the importance of situational readiness and adaptability when seeking team effectiveness. The research study provides theory describing the ideal aspirational environment that will enable shared leading and guiding principles that introduce practical considerations reflecting the situational realities, ambiguities, and humanistic complexities influencing today’s organization when seeking growth and effective outcomes through dispersed teaming.
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Yuyes, Ruiz Luis Giovanni. "Crisis hipertensivas en el Servicio de Emergencia de la Clínica San Pablo Sede Norte Lima-Perú." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2006. https://hdl.handle.net/20.500.12672/15756.
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La crisis hipertensiva es una condición clínica donde ocurre un incremento súbito en los niveles de presión arterial asociada a
manifestaciones como cefalea, alteraciones visuales, vómitos y vértigo. Se realizó un estudio observacional de corte transversal, en el Servicio de Emergencia de la Clínica San Pablo Sede Norte, entre el 1º de enero y el 30 de Junio del 2003. Los datos se
recolectaron de las historias clínicas de emergencia. Como resultado, se recogieron datos de 101 pacientes mayores de 18 años con elevación de presión arterial más manifestaciones clínicas de crisis hipertensivas, que representaron el 1.55 % del total de atenciones por emergencia adultos. Dos pacientes (1.98 %) cursaron con emergencia hipertensiva, cuyo cuadro clínico fue trastorno de conciencia y déficit motor (accidente cerebrovascular). El 75.24 % fueron mujeres. El 51.88 % fueron mayores de 60 años. Es importante señalar que el tratamiento administrado en emergencia fue predominantemente los Inhibidores de la Enzima Convertidora de Angiotensina con el 98.02 %. Concluye que las emergencias hipertensivas representaron el 1.98 %. El tratamiento administrado en emergencia los Inhibidores de la Enzima Convertidora de Angiotensiva (captopril) fueron los mas usados con el 98.02 %. Además, la cefalea fue la manifestación clínica mas frecuente 56.43 %.
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Lejerdal, Ronja, and Alva Nilsson. "Att känna sig sedd oavsett vad : Äldre multisjuka människors erfarenheter av att söka vård på en akutmottagning." Thesis, Mälardalens högskola, Akademin för hälsa, vård och välfärd, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-37220.
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Background: People are living longer and more people suffer from age-related illnesses. Multiple illness is when a person have more than one disease. It is a high flow of patients on the emergency departments. The nurses work conditions are stressful and this causes less time for the nurses to take care of patients. Purpose: Describe older people with multiple illnessess experience of seeking care in emergency departments. Method: A systematic literature study with descriptive synthesis with a qualitative approach based on Evans (2002). Results: The results is based on two different main themes. One main theme was “left to ones own destiny” with two related subthemes “feel forgotten” and “feel uncertain”. Another identified main theme was “give over the responsibility to staff” with two related subthemes “feel safe” and “feel seen”. Conclusion: Older people with multiple illness are a vulnerable group of patients and they have a desire for contact of staff and to feel safe. When staff are safe in their profession, the older people with multiple illness feel seen from the staff. Then the older people also feel that their self-consciousness is strengthened. Keywords: Elderly patients, emergency department, multiple illness, patient experiences and qualitative study.