Academic literature on the topic 'Seasonal Selection'
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Journal articles on the topic "Seasonal Selection"
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Seong, Byeong-Chan, Sung-K. Ahn, and Sin-Sup Ch. "Semiparametric Seasonal Cointegrating Rank Selection." Korean Journal of Applied Statistics 24, no. 5 (October 31, 2011): 791–97. http://dx.doi.org/10.5351/kjas.2011.24.5.791.
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Morehouse, N. I., N. Mandon, J. P. Christides, M. Body, G. Bimbard, and J. Casas. "Seasonal selection and resource dynamics in a seasonally polyphenic butterfly." Journal of Evolutionary Biology 26, no. 1 (November 29, 2012): 175–85. http://dx.doi.org/10.1111/jeb.12051.
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Janjua, N. Z., D. M. Skowronski, T. S. Hottes, G. De Serres, N. S. Crowcroft, and L. C. Rosella. "Selection bias explains seasonal vaccine's protection." BMJ 339, no. 24 3 (November 24, 2009): b4972. http://dx.doi.org/10.1136/bmj.b4972.
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Zarebski, Alexander E., Peter Dawson, James M. McCaw, and Robert Moss. "Model selection for seasonal influenza forecasting." Infectious Disease Modelling 2, no. 1 (February 2017): 56–70. http://dx.doi.org/10.1016/j.idm.2016.12.004.
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Wittmann, Meike J., Alan O. Bergland, Marcus W. Feldman, Paul S. Schmidt, and Dmitri A. Petrov. "Seasonally fluctuating selection can maintain polymorphism at many loci via segregation lift." Proceedings of the National Academy of Sciences 114, no. 46 (October 30, 2017): E9932—E9941. http://dx.doi.org/10.1073/pnas.1702994114.
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Most natural populations are affected by seasonal changes in temperature, rainfall, or resource availability. Seasonally fluctuating selection could potentially make a large contribution to maintaining genetic polymorphism in populations. However, previous theory suggests that the conditions for multilocus polymorphism are restrictive. Here, we explore a more general class of models with multilocus seasonally fluctuating selection in diploids. In these models, the multilocus genotype is mapped to fitness in two steps. The first mapping is additive across loci and accounts for the relative contributions of heterozygous and homozygous loci—that is, dominance. The second step uses a nonlinear fitness function to account for the strength of selection and epistasis. Using mathematical analysis and individual-based simulations, we show that stable polymorphism at many loci is possible if currently favored alleles are sufficiently dominant. This general mechanism, which we call “segregation lift,” requires seasonal changes in dominance, a phenomenon that may arise naturally in situations with antagonistic pleiotropy and seasonal changes in the relative importance of traits for fitness. Segregation lift works best under diminishing-returns epistasis, is not affected by problems of genetic load, and is robust to differences in parameters across loci and seasons. Under segregation lift, loci can exhibit conspicuous seasonal allele-frequency fluctuations, but often fluctuations may be small and hard to detect. An important direction for future work is to formally test for segregation lift in empirical data and to quantify its contribution to maintaining genetic variation in natural populations.
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Thomas, Jessica L., Kathrine A. Handasyde, Peter Temple-Smith, and Marissa L. Parrott. "Seasonal changes in food selection and nutrition of captive platypuses (Ornithorhynchus anatinus)." Australian Journal of Zoology 65, no. 5 (2017): 319. http://dx.doi.org/10.1071/zo18004.
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Anecdotal observations of captive platypuses (Ornithorhynchus anatinus) suggest that they show a seasonal preference for particular foods, but this has never been rigorously measured. This study aimed to determine seasonal food preferences and energy consumption of captive platypuses so that better protocols for maintaining platypuses in captivity can be developed. Seven platypuses were fed an ad libitum diet with all food items weighed in and out of tanks. Food items were analysed for energy, fats, carbohydrates, proteins, vitamins and minerals. Platypuses preferred less mobile prey (mealworms, earthworms and fly pupae) over highly mobile prey (crayfish). There was no significant seasonal change in preference for different dietary items, which is more likely to be driven by prey behaviour. Crayfish contributed the largest percentage (mass) consumed and was highly nutritious. While the relative percentage of items in the diet did not change seasonally, the quantity eaten did. The mean energy intake of platypuses was 921 kJ kg–1 day–1 and varied seasonally, being lowest during the breeding season (810 kJ kg–1 day–1) and highest in the postbreeding season (1007 kJ kg–1 day–1). These changes were associated with preparation and recovery from the breeding season. We conclude that the platypus diet is influenced by nutrition and seasonal factors as well as by prey behaviour. This knowledge will contribute to improving the husbandry and management of platypuses, which are widely recognised as difficult to maintain in captivity.
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Milewski, Jarosław, Marcin Wołowicz, and Wojciech Bujalski. "Seasonal Thermal Energy Storage - A Size Selection." Applied Mechanics and Materials 467 (December 2013): 270–76. http://dx.doi.org/10.4028/www.scientific.net/amm.467.270.
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The paper presents a theoretical investigation of using a Seasonal Thermal Energy Storage facility (STES) to cover the heat demand of a complex of four buildings. The STES is placed in the ground and connected to both the local district heating network and solar panels. A number of scenarios were investigated to find an adequate size of the STES (tank size and solar panel area.) The results obtained show that the use of a STES could reduce heat consumption by 22100% depending on the architecture solution chosen.
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Cunningham, Frederick L., Guiming Wang, and D. Tommy King. "Seasonal Habitat Selection by American White Pelicans." Diversity 14, no. 10 (September 30, 2022): 821. http://dx.doi.org/10.3390/d14100821.
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Resource utilization strategies of avian migrants are a major concern for conservation and management. Understanding seasonal habitat selection by migratory birds helps us explain the ongoing continental declines of migratory bird populations. Our objective was to compare the second-order and third-order habitat selection by the American White Pelican (Pelecanus erythrorhynchos; hereafter pelican) between the breeding and non-breeding grounds. We tested the Lack hypothesis that habitat selection by migratory birds is stronger on the breeding grounds than on the non-breeding grounds. We used random-effect Dirichlet-multinomial models to estimate the second-order habitat selection between the seasons with the GPS locations of 32 tracked pelicans. We used Gaussian Markov random field models to estimate the third-order habitat selection by pelicans at the breeding and non-breeding grounds, accounting for spatial autocorrelation. Pelicans strongly selected waterbodies and wetlands at both non-breeding and breeding grounds, tracking their foraging habitats between the seasons at the home range level. However, pelicans exhibited seasonal differences in the strength of the third-order selection of wetlands and waterbodies with foraging habitat selection being stronger at the breeding grounds than at the non-breeding grounds, supporting the Lack hypothesis.
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Neely, B. C., M. A. Pegg, and G. E. Mestl. "Seasonal resource selection by blue suckersCycleptus elongatus." Journal of Fish Biology 76, no. 4 (March 2010): 836–51. http://dx.doi.org/10.1111/j.1095-8649.2009.02532.x.
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Wen, Frank, Sidney Bell, Trevor Bedford, and Sarah Cobey. "Estimating Vaccine-Driven Selection in Seasonal Influenza." Viruses 10, no. 9 (September 18, 2018): 509. http://dx.doi.org/10.3390/v10090509.
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Vaccination could be an evolutionary pressure on seasonal influenza if vaccines reduce the transmission rates of some (“targeted”) strains more than others. In theory, more vaccinated populations should have a lower prevalence of targeted strains compared to less vaccinated populations. We tested for vaccine-induced selection in influenza by comparing strain frequencies between more and less vaccinated human populations. We defined strains in three ways: first as influenza types and subtypes, next as lineages of type B, and finally as clades of influenza A/H3N2. We detected spatial differences partially consistent with vaccine use in the frequencies of subtypes and types and between the lineages of influenza B, suggesting that vaccines do not select strongly among all these phylogenetic groups at regional scales. We did detect a significantly greater frequency of an H3N2 clade with known vaccine escape mutations in more vaccinated countries during the 2014–2015 season, which is consistent with vaccine-driven selection within the H3N2 subtype. Overall, we find more support for vaccine-driven selection when large differences in vaccine effectiveness suggest a strong effect size. Variation in surveillance practices across countries could obscure signals of selection, especially when strain-specific differences in vaccine effectiveness are small. Further examination of the influenza vaccine’s evolutionary effects would benefit from improvements in epidemiological surveillance and reporting.
Dissertations / Theses on the topic "Seasonal Selection"
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PENG, SISI. "Evaluating Automatic Model Selection." Thesis, Uppsala universitet, Statistiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-154449.
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In this paper, we briefly describe the automatic model selection which is provided by Autometrics in the PcGive program. The modeler only needs to specify the initial model and the significance level at which to reduce the model. Then, the algorithm does the rest. The properties of Autometrics are discussed. We also explain its background concepts and try to see whether the model selected by the Autometrics can perform well. For a given data set, we use Autometrics to find a “new” model, and then compare the “new” model with a previously selected one by another modeler. It is an interesting issue to see whether Autometrics can also find models which fit better to the given data. As an illustration, we choose three examples. It is true that Autometrics is labor saving and always gives us a parsimonious model. It is really an invaluable instrument for social science. But, we still need more examples to strongly support the idea that Autometrics can find a model which fits the data better, just a few examples in this paper is far from enough.
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Peck, Riley D. "Seasonal Habitat Selection by Greater Sage Grouse in Strawberry Valley Utah." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3180.
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This study examined winter habitat use and nesting ecology of greater sage grouse (Centrocercus urophasianus) in Strawberry Valley (SV), Utah located in the north-central part of the state. We monitored sage grouse with the aid of radio telemetry throughout the year, but specifically used information from the winter and nesting periods for this study. Our study provided evidence that sage grouse show fidelity to nesting areas in subsequent years regardless of nest success. We found only 57% of our nests located within the 3 km distance from an active lek typically used to delineate critical nesting habitat. We suggest a more conservative distance of 10 km for our study area. Whenever possible, we urge consideration of nest-area fidelity in conservation planning across the range of greater sage grouse. We also evaluated winter-habitat selection at multiple spatial scales. Sage grouse in our study area selected gradual slopes with high amounts of sagebrush exposed above the snow. We produced a map that identified suitable winter habitat for sage grouse in our study area. This map highlighted core areas that should be conserved and will provide a basis for management decisions affecting Strawberry Valley, Utah.
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McGeachy, David N. C. "Population Distribution and Seasonal Resource Selection by Elk (Cervus elaphus) in Central Ontario." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2181.
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Understanding population structure and resource selection are essential for wildlife management and conservation. I assessed the population structure and resource selection of elk (Cervus elaphus) in central Ontario. I used fuzzy and hierarchical cluster analyses to elucidate elk population structure based on spatial data collected from 41 radio-collared elk. I assessed impacts of habitat quality on space use using the minimum convex polygon (MCP) and fixed kernel methods. I evaluated resource selection by elk in winter, spring, summer, and fall, from December 2011 to August 2013, using resource selection functions (RSF’s). I used a generalized linear mixed model (GLMM) to evaluate resource selection functions and used Akaike information criterion (AICc ) to select the best model of 20 candidate models constructed a priori. Models included parameters representing resources known to be important to elk: elevation, aspect, slope, distance to roads and water, and habitat. Both fuzzy and hard clustering indicated that elk in Central Ontario occur in a metapopulation that includes 5 subpopulations. The largest cluster consisted of a core group of 22 radio-collared elk located in Burwash with several satellite subpopulations spread along a 50km long north-south axis and a small subpopulation to the west located in Worthington. Survival rates among subpopulations were similar ranging from 0.71 to 0.83; however, anthropogenic causes of mortality were predominant only in the Burwash subpopulation. Space use and density of elk differed between core and satellite subpopulations. Resource selection by elk differed by time of day and season. In all seasons, elk selected open habitats at night and more forested areas during the day. Elk avoided areas close to roads in spring, but selected them in winter at night. Elk selected higher elevations in winter and for south facing slopes in spring and fall. Elk displayed strong crepuscular activity patterns in all seasons; however, movements were limited in winter. Understanding population structure is important in order to develop appropriate management plans. My results support the conclusion that population structure can be reliably assessed using spatial data. Resource selection is a dynamic process that changes with seasons, as well as animal activity across the diel period. Resource selection should include time of day in order to obtain a complete picture of resources important to a particular species and to support the conservation of habitats used for various animal activities.
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Hill, Gregory J. "Examining Movement and Habitat Selection of Everglades Fishes in Response to Seasonal Water levels." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3209.
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Fish distribution patterns and seasonal habitat use play a key role in the food web dynamics of aquatic ecosystems, including the Florida Everglades. In this study I examined the fine scale habitat shifts and movements of spotted sunfish, Lepomis punctatus across varying seasons and hydrologic conditions using in-situ field enclosures and Passive Integrated Transponder (PIT) systems. Data on fish use of three dominant Everglades marsh habitats and activity level were recorded continuously from January to August, 2015. Fish were more active and had the highest use of higher elevation habitats when water levels rose during an experimental reversal in mid-April. Fish activity was higher at increasing water levels relative to decreasing. Fish activity also varied with the rate of change, with the highest activity occurring during rapid increases in depth. Findings from this study provide insight on how fish response to changing water levels may affect foraging for wading birds, a key performance measure for Everglades restoration.
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Jordan, Katherine Mead. "Characterization of seasonal reproduction in Virginia Tech Selection Line, St. Croix, and Suffolk ewes." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/28663.
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This dissertation research contained three studies. The first two studies were conducted to investigate the ability of ewes to rebreed while lactating during seasonal anestrus. Breeds studied included the Virginia Tech Out-of-season (OOS) Line, which is a wool line genetically selected to lamb in the fall, and the St. Croix, a hair breed of tropical origin thought to be lowly seasonal. When January-lambing ewes were exposed to rams while lactating in April, significantly more OOS than St. Croix ewes were marked by rams in the first 21 d and total 39 d of ram exposure (58.3 vs. 8.7%, P = 0.0003 and 95.8 vs. 43.5%, P < 0.0001). Percentages of ewes diagnosed pregnant (53.2%) and percentages of ewes lambing (41.3%) were not different between breeds. When March-lambing OOS ewes were exposed to rams while lactating in May, 52.9% of ewes were marked though only 20% of ewes exposed to rams gave birth to viable lambs. Both OOS and St. Croix ewes appear to be well suited to accelerated production systems involving 7 to 8 mo lambing intervals. However, reduction of lambing intervals to 6 to 7 mo appeared to have detrimental effects on fetal survival in OOS ewes.
In a third study, alterations in endocrine profiles associated with differing degrees of hypothalamic sensitivity to estradiol-negative feedback and changing daylength in OOS, St. Croix, and Suffolk ewes in the absence of rams were investigated for 1 yr. The results show for the first time that based on progesterone profiles from intact ewes, St. Croix ewes do not have shorter anestrous periods than ewes of wool breeds, as previously thought. Based on luteinizing hormone profiles from ovariectomized ewes treated with estradiol implants, the duration of luteinizing hormone inhibition was shorter in OOS than Suffolk ewes (68 vs. 170.2 d, P = 0.02), but was not different from that found in St. Croix ewes (124.8 d). Specific roles for thyroxine and prolactin in timing the breeding season could not be assigned. This study was the first known use of the ovariectomized, estradiol-implanted ewe model to compare degree of reproductive seasonality in different breeds.Ph. D.
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Baigas, Phillip E. "Winter habitat selection, winter diet, and seasonal distribution mapping of moose (Alces alces shirasi) in southeastern Wyoming." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1797714121&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Ross, Monica Ann. "Seasonal and Diel Patterns of Manatee Habitat Use." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2209.
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State and Federal agencies have created sanctuaries and speed zones to help reduce manatee mortality while incorporating the recreational and commercial resource needs of these same habitats for humans. Specific habitat resources are considered necessary to increase manatee survivorship. We have only recently begun to address how manatees use some of these resources based on physiological or reproductive strategies. In this study, I quantified patterns of habitat use during seasonal and diel periods for different sex and reproductive manatee classes using data from a radio-telemetry study conducted by the Florida Fish and Wildlife Conservation Commission during 1991-1996. I used five environmental geographic data layers: bathymetry, distance to seagrass, distance to shoreline, distance to warm water refuge sites, and distance to fresh water sources, to discriminate seasonal and diel habitat use patterns for different manatee classes: males (M), females with calves (FWC), and females without calves (FNC). Mean occupancy values were calculated for environmental variable locations and seasonal, diel, and manatee class differences were tested using a Multi-Response Permutation Procedure (MRPP). Nonmetric Multidimensional Scaling (NMS) was used to visualize the ordination patterns of the manatee classes and to assess importance of correlated environmental variables. Significant differences in habitat use were noted between summer and winter based on distances to warm water, seagrass, and fresh water sources but similar habitat use patterns were exhibited within summer diel periods among manatee classes. All manatee classes appeared to have used a higher proportion of locations closer in proximity to seagrass at night than day in winter indicating a disproportionate difference in feeding bouts between diel periods. These differences may be attributed to adjusting feeding strategies to reduce thermoregulatory costs or to decrease human interactions. Differences in patterns were exhibited for the winter diel periods specifically for the FWC manatee classes during winter days. FWC had a higher proportion of locations within the warm water refuges during the day indicating a possible trade off situation between food consumption and thermal exposure. This study demonstrates coarse and fine scale patterns of variation in habitat use for manatees both seasonally and daily within winter. It also suggests that during winter months, manatees were not just utilizing their habitat but they appeared to have preferences and selection for certain habitat types. Recovery of a species is greatly enhanced when patterns of habitat use within the species' environment has been clearly defined. Understanding more specifically what types of habitats manatees choose might allow management to adjust strategies for protection of key habitats while encouraging further recovery of this species.M.S.
Department of Biology
Sciences
Biology MS
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Wyness, William. "Home range use by Southern Ground-Hornbills (Bucorvus leadbeateri) - quantifying seasonal habitat selection and vegetation characteristics." Bachelor's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/25599.
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The habitat of an animal is extremely important as it provides that animal with the necessary resources for fulfilling its life-history requirements (Brennan & Block, 1993; Beyer et al. 2010). A habitat is defined as a region in environmental space which comprises of multiple abiotic and biotic variables influencing an animal's location (Krausman, 1999; Beyer et al. 2010). Animals tend to utilise discrete areas within a habitat, constituting part of their home range. Home range analysis helps to delineate the area used by an animal habitually and areas of concentrated use (Samuel et al. 1985; Seaman & Powell, 1996; Moorcroft et al. 1999; Mitchell, 2007; Rodgers & Kie, 2011). Patterns of differential use of space within an animal's home range are the result of competing demands and trade-offs. In this study, a kernel technique was used to determine the home range of four satellitetracked groups of Southern Ground-Hornbills Bucorvus leadbeateri in the Associated Private Nature Reserves (APNR) in the South African lowveld. Satellite data were analysed in ArcGIS® 9.3 to quantify habitat selectivity by groups of ground-hornbills at different times of the year to determine a) favoured habitat types, and b) the resolution with which they perceive their environment. Each of the I groups showed variation in the utilisation and extent of their home ranges on a seasonal basis. Home range sizes contracted towards the nest during the summer breeding season (December to March) and expanded during the dry season (April to September). Within the home range of one of the groups the physical characteristics of habitat types (i.e. vegetation types) were sampled at 250 random co-ordinates in order to assess whether habitat preference at the meso-scale can be explained by the physical attributes of that vegetation type. By profiling and quantifying the vegetation of areas in the home range that are used by Southern Ground-Hornbills to differing degrees, this information could be used as a proxy to facilitate re-introduction efforts, by providing a tool to identify optimal landscape configurations.
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Garner, Nathan Paul. "Seasonal movements, habitat selection, and food habits of black bears (Urus americanus) in Shenandoah National Park, Virginia." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/50059.
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The seasonal movements, food habits, and habitat selection of black bears (Ursus americanus) in Shenandoah National Park, Virginia were studied from May 1982 to April 1985. A total of 47 collared bears, including 25 adult females, 17 adult males, and 5 subadult males < 3.5 years old, was located 3973 times during the study.
Adult males had larger (P<0.001) home ranges (100% X=195 km², 95% X=116 km²) than adult females (100% X=38 km², 95% X=22 km²). Subadult males had larger (P<0.10) home ranges (100% X=542 km², 95% X=289 km²) than adult males and females. Extensive home range overlap occurred among each sex and age group. At least three subadult males dispersed from the Park during the study. Female bears with cubs were less mobile than solitary females during the spring. Fall cubs were large and did not restrict females' movements. Large fall home ranges for females were related to the scattered supply of acorns relative to the concentrated sources of soft mast used in the summer. Two females with cubs and 2 subadult males remained active during the winter months.
Adult and subadult males generally had less stable home ranges than adult females. Female bears displayed infidelity to given areas during the fall from year-to-year due to variation in the distribution of hard mast (acorns). Male bears made long excursions onto the Piedmont Plateau east of the Park mainly during the spring and early fall. Females were not exposed to as much human induced mortality as males because they were located within the Park 17% more frequently than males.
Males avoided fire roads (P<0.001), light duty roads (P<0.001), and primary roads (P<0.01) year around. Female bears preferred fire roads during summer (P< 0.001) and early fall (P<0.01) and avoided heavier traveled roads such as light duty roads (P<0.001) and primary roads (P<0.001) year around. Both male and female bears preferred foot trails for travel (P<0.05). Bears rarely came within 100 meters of campgrounds, picnic areas, and other human disturbance areas within the Park. Both sexes used low (P<0.10) elevations during the summer and high (P<0.10) elevations during early and late fall. Bears showed the greatest use of small rivers and streams during the driest months of summer. Geographic land forms of specific aspects, contours, and varying steepness were used differently by male and female bears.
Twelve stomachs and 854 scats were analyzed for food content. Forbs, graminoids, squawroot (Conopholis americana), corn, and the fruits of trees, shrubs, and vines composed 90 percent volume of the annual diet. Eight percent of the food consumed was animal matter from mammals, birds, and invertebrates.
During all seasons, females used yellow poplar (Liriodendron tulipifera) forests more (P<0.05) than males while males used yellow poplar forests less (P<0.05) than expected; males used black locust (Robinia pseudoacacia) \ black cherry (Prunus serotina) forests more (P<0.05) than females and more (P<0.05) than expected. Shifts in use of chestnut oak (Quercus prinus) \ northern red oak (Q. rubra) forests and northern red oak \ white oak (Q. alba) forests by both males and females in early and late fall was attributed to annual variation in oak mast production, preference for white oak acorns, foraging strategy, and the importance of mountain laurel (Kalmia latifolia) shrub cover in late fall.
Seasonal use of domestic fruits at 330 abandoned homesites was determined. Distance-to-nearest-homesite measurements indicated that males were never closer (P>0.10) to homesites than females or random points during any season while females were closer (P<0.001) to homesites than males and random points during summer. Only females were located at homesites (≤ 100m) more (P<0.001) than expected during summer and early fall. Bears consumed apples (Malus spp.) and sweet cherries (Prunus avium) at abandoned homesites mainly in summer, early fall, and late fall. Bears used homesites in late fall more than distance measures indicated. Domestic fruits were an important nutritional food for black bears in relation to total soft fruits eaten.Master of Science
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Kennish, Robin. "Seasonal patterns of algal availability, influences on diet selection and fitness of the tropical crab grapsus albolineatus." Thesis, Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17591533.
Full textBooks on the topic "Seasonal Selection"
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Franses, Philip Hans. Model selection and seasonality in time series. Amsterdam: Thesis/Tinbergen Instituut, 1991.
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Gibson, John. How pro-poor is the selection of seasonal migrant workers from Tonga under New Zealand's recognized Seasonal Employer Program ? [Washington, D.C: World Bank, 2008.
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BookElves anthology: Volume 1 : a selection of seasonal tales for Middle Grade Readers. [Unknown]: Princelings Publications / Createspace, 2014.
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Fargey, Patrick J. Seasonal patterns of forage selection by wapiti (Cervus elaphus) in relation to land reclamation. Vegreville, AB: Alberta Environmental Centre, 1989.
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Lisa, Shelkin, ed. A year of flowers: Fresh flower arranging : a seasonal guide to selection, design, and arrangement. Philadelphia, Pa: Running Press, 1994.
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Ngana, J. Selection of a probability distribution for estimating reliably seasonal rainfall in semi-arid central Tanzania. [Dar es Salaam]: Institute of Resource Assessment, University of Dar es Salaam, 1991.
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Henderson, R. E. The Lower Clark Fork elk study: Final report 1985-1990 : the social structure and seasonal habitat selection of a northwest Montana elk population with an analysis of population characteristics, harvest rates, and survey techniques. Helena, Mont: Montana Dept. of Fish, Wildlife and Parks, 1993.
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1927-, Green William B., ed. Seasons of the heart: A selection of sermons. Cincinnati, Ohio: Forward Movement Publications, 1994.
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Emma, Wood, ed. Antique dinner recipes: For all seasons : an 18th century selection. Mount Vernon, NY: Constantia Books, 1987.
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Kara, Saurībandhu. A man for all seasons: Selections from Souribandhu Kar. Edited by Mohapatra Chandra Kishore and Panigrahi Pradeep. Bhubaneswar: Book Point, 2008.
Find full textBook chapters on the topic "Seasonal Selection"
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Seong, Byeongchan, Sung K. Ahn, and Sinsup Cho. "Semiparametric Seasonal Cointegrating Rank Selection." In Proceedings of COMPSTAT'2010, 297–304. Heidelberg: Physica-Verlag HD, 2010. http://dx.doi.org/10.1007/978-3-7908-2604-3_27.
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Zaremba, Adam, and Jacob “Koby” Shemer. "Januaries, Mays, and Lunar Cycles: Stock Selection with Seasonal Anomalies." In Price-Based Investment Strategies, 195–212. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-91530-2_6.
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Belmecheri, Soumaya, William E. Wright, and Paul Szejner. "Sample Collection and Preparation for Annual and Intra-annual Tree-Ring Isotope Chronologies." In Stable Isotopes in Tree Rings, 103–34. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_4.
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AbstractThis chapter provides guidance for conducting studies based on stable isotope measurements in tree rings to infer past and present climate variability and ecophysiology. Balancing theoretical perspectives of stable isotope variations recorded in tree rings, intended research applications (paleoclimate or ecophysiology) and resource limitations, this chapter describes key aspects of field sampling strategies and laboratory sample processing. It presents an overview of factors influencing variations and thus interpretations of carbon and oxygen isotopes, including juvenile/age effects, canopy status and stand characteristicsto inform sampling strategies that optimize a robust paleoenvironmental and physiological signal with statistically defined confidence limits. Fieldwork considerations include the selection of a study site and trees, field equipment, and sample requirements to recover sufficient material for isotopic measurements, and the desired environmental signal. Aspects of laboratory sample processing include choosing a sampling resolution (e.g. whole ring, earlywood/latewood, thin section, etc.), sample pooling within and between trees, and particle size requirements for chemical extraction and analytical repeatability. Finally, this chapter provides a case study highlighting the potential benefits and limitations of high-resolution sub-seasonal sampling.
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Belmecheri, Soumaya, William E. Wright, and Paul Szejner. "Sample Collection and Preparation for Annual and Intra-annual Tree-Ring Isotope Chronologies." In Stable Isotopes in Tree Rings, 103–34. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_4.
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AbstractThis chapter provides guidance for conducting studies based on stable isotope measurements in tree rings to infer past and present climate variability and ecophysiology. Balancing theoretical perspectives of stable isotope variations recorded in tree rings, intended research applications (paleoclimate or ecophysiology) and resource limitations, this chapter describes key aspects of field sampling strategies and laboratory sample processing. It presents an overview of factors influencing variations and thus interpretations of carbon and oxygen isotopes, including juvenile/age effects, canopy status and stand characteristicsto inform sampling strategies that optimize a robust paleoenvironmental and physiological signal with statistically defined confidence limits. Fieldwork considerations include the selection of a study site and trees, field equipment, and sample requirements to recover sufficient material for isotopic measurements, and the desired environmental signal. Aspects of laboratory sample processing include choosing a sampling resolution (e.g. whole ring, earlywood/latewood, thin section, etc.), sample pooling within and between trees, and particle size requirements for chemical extraction and analytical repeatability. Finally, this chapter provides a case study highlighting the potential benefits and limitations of high-resolution sub-seasonal sampling.
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Yusop, Mohd Rafii, Yusuff Oladosu, Abdul Rahim Harun, Asfaliza Ramli, Ghazali Hussin, Mohd Razi Ismail, and Norhani Abdullah. "Application of mutation techniques and genotype × environment interaction for grain yield in ion beam induced mutant rice lines tested in multiple locations in Malaysia." In Mutation breeding, genetic diversity and crop adaptation to climate change, 226–34. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0023.
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Abstract Genotype evaluation for stability and high yield in rice is an important factor for sustainable rice production and food security. These evaluations are essential, especially when the breeding objective is to release rice with high yields, adaptability and stability for commercial cultivation. To achieve this objective, this study was carried out to select high-yielding rice genotypes induced by ion beam irradiation. Seeds of the rice variety 'MR219' were subjected to different doses of 320 MeV carbon-ion beam irradiation to determine the optimum dose to produce high mutant frequency and spectrum. The optimum dose was 60 Gy. After several cycles of selection and fixation between 2009 and 2014 (M0-M6), six prospective lines with desirable characters were selected at the M6 generation. The selected mutant lines along with other mutant varieties were then tested at five locations in two planting seasons to select high-yielding and stable genotypes. The experiment was conducted in a randomized complete block design with three replications across the locations and seasons. The pooled analysis of variance revealed highly significant differences (p ≤ 0.01, 0.05) among genotypes, among locations and among genotypes by location by season (G×L×S interaction) for the yield traits except for seasons and genotype by season (G×S interaction). Based on univariate and multivariate stability parameters, rice genotypes were classified into three main categories. The first group comprised genotypes with high yield stability along with high yield per hectare. These genotypes include ML4 and ML6 and are widely adapted to diverse environmental conditions. One line exhibited high yield per hectare but low stability; this genotype (ML9) is suitable for specific environments. The last group had low yield per hectare and high stability and included 'MR220', 'Binadhan4' and 'Binadhan7'. This final group is more suitable for breeding specific traits or perhaps has yield component compensation. Hence, rice mutant lines ML4 and ML6 were recommended for commercial cultivation in Malaysia.
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Vogel, Kenneth P. "Improving Warm-Season Forage Grasses Using Selection, Breeding, and Biotechnology." In Native Warm-Season Grasses: Research Trends and Issues, 83–106. Madison, WI, USA: Crop Science Society of America and American Society of Agronomy, 2015. http://dx.doi.org/10.2135/cssaspecpub30.c6.
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Bliss, F. A., and J. C. Miller. "Selecting and breeding grain legumes for enhanced nitrogen fixation." In World crops: Cool season food legumes, 1001–12. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2764-3_79.
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Bell, Michael J., Antonio P. Mallarino, Jeff Volenec, Sylvie Brouder, and David W. Franzen. "Considerations for Selecting Potassium Placement Methods in Soil." In Improving Potassium Recommendations for Agricultural Crops, 341–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-59197-7_12.
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AbstractPlacement strategies can be a key determinant of efficient use of applied fertilizer potassium (K), given the relative immobility of K in all except the lightest textured soils or high rainfall environments. Limitations to K accessibility by plants caused by immobility in the soil are further compounded by the general lack of K-stimulated root proliferation in localized soil zones enriched with K alone, compared with root proliferation due to concentrated N and P. Further, effects of K fixation reactions in soils with certain clay mineralogies and the declining concentration and activity of soil solution K with increasing clay content can also limit plant K acquisition. Variation in root system characteristics among crops in a rotation sequence and fluctuating soil moisture conditions in fertilized soil horizons in rain-fed systems increase the complexity of fertilizer placement decisions to ensure efficient K recovery and use. This complexity has resulted in extensive exploration of fertilizer K application strategies, with this chapter focusing on K applications to the soil. Issues discussed include comparisons of broadcast versus banded applications, depth of fertilizer placement, and the impacts of co-location of K with other nutrients. While research findings are often specific to the crop, soil, and seasonal conditions under which they are conducted, we attempt to identify strategies that most consistently deliver improved crop recovery and utilization of fertilizer K.
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Miningou, Amos, Appolinaire S. Traoré, Essegbemon Akpo, Issoufou Kapran, Bertin M. Zagré, Gabriel A. Diasso, Yamba Kienthéga, and Apolinaire Zoungrana. "An Analysis of Groundnut Innovation Platform Achievements in Brokering Improved Varieties to Communities in TL III Project in Burkina Faso." In Enhancing Smallholder Farmers' Access to Seed of Improved Legume Varieties Through Multi-stakeholder Platforms, 31–49. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8014-7_3.
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AbstractAccess to seeds of improved groundnut varieties is the most critical problem of farmers in Burkina Faso. Firstly, majority do not know the existence of improved varieties and secondly the price is not affordable to them. Based on the above, the INERA groundnut breeders’ team established four innovation platforms on groundnut in the Region of Centre-East, Region of Centre-North, Region of Centre-West and Region de la Boucle of Mouhoun. Through these platforms, Quality Declared Seeds (QDS) were produced for the first time in Burkina Faso in 2016 with support from the Tropical Legumes phase III (TL III) project. Since then, QDS and certified seeds are produced and sold to the local communities at affordable small packs in order to make improved seeds accessible to the poor farmers. So far about 10,000 persons have been reached with small packs. Farmers, agricultural extension and NGO staff have been trained in groundnut seed production, demonstrations, field days and Farmer Participatory Variety Selection (FPVS) to promote the improved varieties and the best agronomic practices. Farmers’ yields increased from 500–700 kg/ha to 1200–1500 kg/ha increasing women and youth incomes from 200 USD to 800 USD/year only for those who grow groundnut during the rainy season. Those who grow during rainy and off-seasons their incomes can reach 1200–1500 USD. Links with financial institutions have facilitated access to credit for these farmers. In the future, the Platform sustainability will be assured through members’ annual financial contributions and strong production contracts among traders, processors and farmers.
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Crespo-Herrera, Leonardo A., José Crossa, Mateo Vargas, and Hans-Joachim Braun. "Defining Target Wheat Breeding Environments." In Wheat Improvement, 31–45. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-90673-3_3.
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AbstractThe main objective of a plant breeding program is to deliver superior germplasm for farmers in a defined set of environments, or a target population of environments (TPE). Historically, CIMMYT has characterized the environments in which the developed germplasm will be grown. The main factors that determine when and where a wheat variety can be grown are flowering time, water availability and the incidence of pests and diseases. A TPE consists of many (population) environments and future years or seasons, that share common variation in the farmers’ fields, it can also be seen as a variable group of future production environments. TPEs can be characterized by climatic, soil and hydrological features, as well as socioeconomic aspects. Whereas the selection environments (SE) are the environments where the breeder does the selection of the lines. The SE are identified for predicting the performance in the TPE, but the SE may not belong to the TPE. The utilization of advanced statistical methods allows the identification of GEI to obtain higher precision when estimating the genetic effects. Multi-environmental testing (MET) is a fundamental strategy for CIMMYT to develop stable high grain yielding germplasm in countries with developing economies. An adequate MET strategy allows the evaluation of germplasm in stress hotspots and the identification of representative and correlated sites; thus, breeders can make better and targeted decisions in terms of crossing, selection and logistic operations.
Conference papers on the topic "Seasonal Selection"
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Hendaus, Mohamed A., Ahmed Alhammadi, Mohamed Khalifa, and Prem Chandra. "Seasonal Variation in Respiratory Syncytial Virus Infection in a Desert Climate." In Selection of Abstracts From NCE 2016. American Academy of Pediatrics, 2018. http://dx.doi.org/10.1542/peds.141.1_meetingabstract.436.
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DeFroda, Steven F., Joseph A. Gil, Kalpit N. Shah, Neill Li, Aristides I. Cruz, and Jonathan Schiller. "Seasonal Variation in Lyme Arthritis Evaluated in a Northeastern State with a Single Pediatric Emergency Department." In Selection of Abstracts From NCE 2016. American Academy of Pediatrics, 2018. http://dx.doi.org/10.1542/peds.141.1_meetingabstract.645.
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Moskvitina, Anna. "SELECTION OF HEAT ACCUMULATING MATERIALS FOR SEASONAL SOLAR HEATING SYSTEMS." In Scientific Development of New Eastern Europe. Publishing House “Baltija Publishing”, 2019. http://dx.doi.org/10.30525/978-9934-571-89-3_118.
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Dalum Hansen, Niels, Kåre Mølbak, Ingemar J. Cox, and Christina Lioma. "Seasonal Web Search Query Selection for Influenza-Like Illness (ILI) Estimation." In SIGIR '17: The 40th International ACM SIGIR conference on research and development in Information Retrieval. New York, NY, USA: ACM, 2017. http://dx.doi.org/10.1145/3077136.3080760.
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Tran, Thien Q., and Jun Sakuma. "Seasonal-adjustment Based Feature Selection Method for Predicting Epidemic with Large-scale Search Engine Logs." In KDD '19: The 25th ACM SIGKDD Conference on Knowledge Discovery and Data Mining. New York, NY, USA: ACM, 2019. http://dx.doi.org/10.1145/3292500.3330766.
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Ившин, Георгий, Georgy IVSHIN, Вера Ившина, and Vera IVSHINA. "EFFICIENCY OF THE CORRELATION ANALYSIS AT THE FINAL STAGE OF SELECTION A COMMON VETCH." In Multifunctional adaptive feed production. ru: Federal Williams Research Center of Forage Production and Agroecology, 2019. http://dx.doi.org/10.33814/mak-2019-21-69-5-14.
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By estimation of selection numbers of a common vetch a sowing campaign on the basis of correlation matrixes at the final stage of selection are revealed genotype features of mutual relations of attributes of efficiency of plants during their formation. Distinctions between selection samples on number and intensity of correlation communications are established, testifying about specificity of mechanisms of their adaptation to Wednesday of growth are established. Any law in the ratio number and intensity of correlation com-munications with direct attributes of efficiency of vegetative weight and seeds it is not re-vealed. Precisely expressed return tendency in the ratio number and intensity of correlations of attributes of efficiency of a plant with a level of seasonal variability of productivity of dry weight and seeds of a common vetch is established.
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Cortez, Paulo. "Sensitivity analysis for time lag selection to forecast seasonal time series using Neural Networks and Support Vector Machines." In 2010 International Joint Conference on Neural Networks (IJCNN). IEEE, 2010. http://dx.doi.org/10.1109/ijcnn.2010.5596890.
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King, Fraser, Katherine Ikeda-Cameron, Greg Van Boven, Tom Jack, Robert Sutherby, and Robert Worthingham. "In Situ Monitoring of Environmental Conditions for Stress Corrosion Cracking." In 2004 International Pipeline Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ipc2004-0371.
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TransCanada Pipelines have been involved with monitoring environmental conditions at pipe depth for almost 10 years. The purpose of this monitoring is to understand the mechanism of SCC as it occurs in the field and to assist in the development of site-selection models for identifying locations where SCC might be occurring. Monitoring can either be done at many locations along the right-of-way at a given time or continuously at discrete locations in order to observe seasonal variations. A range of environmental parameters can be monitored. Early work focussed on parameters relevant to corrosion, such as soil resistivity, redox potential, temperature, pH, and on- and off-potentials. More recently, parameters relevant to SCC have also been monitored, such as soil CO2 and permeable hydrogen concentrations. In addition, the extent to which these parameters change seasonally has been monitored to determine if the environment is conducive to SCC continuously or whether cracking might only occur at certain times of the year. In terms of implementation, the results of in situ monitoring can be used as part of a larger integrity management program to decide where and when to mitigate SCC. Correlations between soil parameters measured using the portable probe and known SCC sites can be used to identify other susceptible locations or to prioritize different lines for inspection. Seasonal variations at a particular location can be used to derive effective crack growth rates from accelerated laboratory testing in order to determine re-inspection intervals. Examples are provided of both portable and permanent NOVAProbe measurements for low-pH and high-pH SCC.
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Kujala, Pentti, Jorma Kämäräinen, and Mikko Suominen. "Analysis of a suitable ice class of ship hull for Antarctic operations." In SNAME 5th World Maritime Technology Conference. SNAME, 2015. http://dx.doi.org/10.5957/wmtc-2015-153.
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Shipping in ice covered Polar waters is increasing and new ice classed ships are built to replace older ice strengthened fleet. Selection of suitable ice class for ships operation is an important but not simple task. The process of selecting an appropriate ice class is of high importance both from a safety as well as an economical perspective, but the selection process is still based on accumulated experience and traditions within the areas of existing operations. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. Based on the full scale measurements of ice loads during summer 2013-2014 in the Antarctica, the structural strength of the South African research vessel S.A. Agulhas II has been evaluated to assess the suitability of the chosen ice class of the vessel. The new polar code and especially the new Polar Operational Limit Assessment Risk Indexing System (POLARIS)is applied on this vessel to evaluate the suitable ice class. It is found the PC 3 is the most suitable ice class for ships navigating in harsh Antarctic ice conditions.
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Neuburg, Harald, and Klaus D. Schmidt. "High Operation Flexibility and Reliability by Multi-Unit Compressor Arrangement for Gas Storage Applications." In ASME 1988 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1988. http://dx.doi.org/10.1115/88-gt-230.
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The growing gas market and the increasing ratio of imported gas to gas produced within a country requires an expanded capacity for buffer gas storage to compensate for differences between constant import gas flow and seasonal variances in consumption. For economical operation of the gas storage facility and for moving extensive quantities of gas, high operating flexibility as well as high availability and reliability of gas compression equipment are required. This paper will report on an underground gas storage project and indicate specific objectives for the project in reservoir engineering, gas compression and free-flow withdrawal duties. It will also deal with the sizing and selection of gas turbine driven centrifugal compressor sets, including the required station equipment. Finally, operating experience will be discussed.
Reports on the topic "Seasonal Selection"
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Tsur, Yacov, David Zilberman, Uri Shani, Amos Zemel, and David Sunding. Dynamic intraseasonal irrigation management under water scarcity, water quality, irrigation technology and environmental constraints. United States Department of Agriculture, March 2007. http://dx.doi.org/10.32747/2007.7696507.bard.
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In this project we studied optimal use and adoption of sophisticated irrigation technologies. The stated objectives in the original proposal were to develop a conceptual framework for analyzing intra-season timing of water application rates with implications for crop and irrigation technology selection. We proposed to base the analysis on an intra-seasonal, dynamic, agro-economic model of plants' water demand, paying special attention to contamination of groundwater and soil in intensively cultivated areas that increasingly rely on water of lesser quality. The framework developed in the project integrates (i) a bio-physical model of water flow in the vadose zone and water uptake by plants and yield response with (ii) a dynamic management model to determine the optimal intra-season irrigation policy. It consists of a dynamic optimization model to determine irrigation rates at each point of time during the growing season and aggregation relating harvested yield with accumulated water input. The detailed dynamic approach provides a description of yield production processes at the plant’s level, and serves to determine intra-season irrigation decisions. Data derived from extensive field experiments were used to calibrate the model's parameters. We use the framework to establish the substitution between irrigation technology (capital) and water inputs; this is an important property of irrigation water productivity that has been overlooked in the literature. Another important feature investigated is the possibility to substitute fresh and saline water with a minimal productivity loss. The effects of soil properties and crop characteristics on optimal technology adoption have also been studied. We find that sandy soil, with low water holding capacity, is more conducive to adoption of sophisticated drip irrigation, as compared to heavier soils in which drainage losses are significantly smaller.
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Veilleux, Richard, and David Levy. Potato Germplasm Development for Warm Climates. United States Department of Agriculture, October 1992. http://dx.doi.org/10.32747/1992.7561057.bard.
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Complex potato hybrids derived from crosses between cv. Atlantic and 11 clones of three genomic compositions, all with an unadapted component from previously identified heat tolerant accessions, were evaluated in the field in Israel and Virginia and in controlled environments in Israel. Heat tolerance was exhibited in the field by the ability of many of these hybrids to tuberize under severe heat stress when cv. Atlantic did not tuberize at all. The complex hybrids also exhibited fewer internal defects (heat necrosis, hollow heart) than Atlantic. Studies to determine if heat stress applied during anther culture or to pollen samples prior to pollination could affect gametic selection towards more heat tolerant progenies were also undertaken. There was some evidence of greater heat tolerance (longer survival under heat stress) in the anther-derived population that had been regenerated under heat stress. The seedlings resulting from crosses with heat-treated pollen also exhibited greater haulm growth under heat stress compared with controls. However, the poor adaption of the germplasm prevented a firm conclusion about gametic selection. The introduction of exotic germplasm into cultivated potato has considerable potential to adapt potato to nontraditional growing seasons and climates. However, such hybrids will require continued selection and evaluation to retain the traits required for commercial production.
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Abbo, Shahal, Hongbin Zhang, Clarice Coyne, Amir Sherman, Dan Shtienberg, and George J. Vandemark. Winter chickpea; towards a new winter pulse for the semiarid Pacific Northwest and wider adaptation in the Mediterranean basin. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7597909.bard.
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Original objectives: [a] Screen an array of chickpea and wild annual Cicer germplasm for winter survival. [b] Genetic analysis of winter hardiness in domesticated x wild chickpea crosses. [c] Genetic analysis of vernalization response in domesticated x wild chickpea crosses. [d] Digital expression analysis of a core selection of breeding and germplasm lines of chickpea that differ in winter hardiness and vernalization. [e] Identification of the genes involved in the chickpea winter hardiness and vernalization and construction of gene network controlling these traits. [f] Assessing the phenotypic and genetic correlations between winter hardiness, vernalization response and Ascochyta blight response in chickpea. The complexity of the vernalization response and the inefficiency of our selection experiments (below) required quitting the work on ascochyta response in the framework of this project. Background to the subject: Since its introduction to the Palouse region of WA and Idaho, and the northern Great Plains, chickpea has been a spring rotation legume due to lack of winter hardiness. The short growing season of spring chickpea limits its grain yield and leaves relatively little stubble residue for combating soil erosion. In Israel, chilling temperatures limit pod setting in early springs and narrow the effective reproductive time window of the crop. Winter hardiness and vernalization response of chickpea alleles were lost due to a series of evolutionary bottlenecks; however, such alleles are prevalent in its wild progenitor’s genepool. Major conclusions, solutions, achievements: It appears that both vernalization response and winter hardiness are polygenic traits in the wild-domesticated chickpea genepool. The main conclusion from the fieldwork in Israel is that selection of domesticated winter hardy and vernalization responsive types should be conducted in late flowering and late maturity backgrounds to minimize interference by daylength and temperature response alleles (see our Plant Breeding paper on the subject). The main conclusion from the US winter-hardiness studies is that excellent lines have been identified for germplasm release and continued genetic study. Several of the lines have good seed size and growth habit that will be useful for introgressing winter-hardiness into current chickpea cultivars to develop releases for autumn sowing. We sequenced the transcriptomes and profiled the expression of genes in 87 samples. Differential expression analysis identified a total of 2,452 differentially expressed genes (DEGs) between vernalized plants and control plants, of which 287 were shared between two or more Cicer species studied. We cloned 498 genes controlling vernalization, named CVRN genes. Each of the CVRN genes contributes to flowering date advance (FDA) by 3.85% - 10.71%, but 413 (83%) other genes had negative effects on FDA, while only 83 (17%) had positive effects on FDA, when the plant is exposed to cold temperature. The cloned CVRN genes provide new toolkits and knowledge to develop chickpea cultivars that are suitable for autumn-sowing. Scientific & agricultural implications: Unlike the winter cereals (barley, wheat) or pea, in which a single allelic change may induce a switch from winter to spring habit, we were unable to find any evidence for such major gene action in chickpea. In agricultural terms this means that an alternative strategy must be employed in order to isolate late flowering – ascochyta resistant (winter types) domesticated forms to enable autumn sowing of chickpea in the US Great Plains. An environment was identified in U.S. (eastern Washington) where autumn-sown chickpea production is possible using the levels of winter-hardiness discovered once backcrossed into advanced cultivated material with acceptable agronomic traits. The cloned CVRN genes and identified gene networks significantly advance our understanding of molecular mechanisms underlying plant vernalization in general, and chickpea in particular, and provide a new toolkit for switching chickpea from a spring-sowing to autumn-sowing crop.
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Jurkevitch, Edouard, Carol Lauzon, Boaz Yuval, and Susan MacCombs. role of nitrogen-fixing bacteria in survival and reproductive success of Ceratitis capitata, the Mediterranean fruit fly. United States Department of Agriculture, September 2005. http://dx.doi.org/10.32747/2005.7695863.bard.
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Objectives: to demonstrate nitrogen fixation in the gut of Ceratitiscapitata, the Mediterranean fruit fly and that fixed nitrogen is important for the fly. Background: Fruit flies (Diptera: Tephritidae) are a highly successful, widespread group of insects causing enormous economic damage in agriculture. They are anautogenous, i.e. the acquisition of nitrogenous compounds by both male and female is essential for the realization of their reproductive potential. Nitrogen, although abundant in the atmosphere, is paradoxically a limiting resource for multicellular organisms. In the Animalia, biological nitrogen fixation has solely been demonstrated in termites. Major achievements and conclusions: We found that all individuals of field-collected medflies harbor large diazotrophicenterobacterial populations that express dinitrogenreductase in the gut. Moreover, nitrogen fixation was demonstrated in isolated guts and in live flies and may significantly contribute to the fly’s nitrogen intake. Specific components of these communities were shown to be transmitted vertically between flies. Moreover, we found that the gut bacterial community changes during the fly’s active season both in composition and complexity. Moreover, strong changes in community structure were also observed between the fly's various developmental stages. An initial analysis using SuPERPCR, a technology enabling the detection of minor populations by selective elimination of the dominant 16S rDNA sequences revealed that Pseudomonasspp. may also be part of the gut community. Implications: The presence of similar bacterial consortia in additional insect orders suggests that nitrogen fixation occurs in vast pools of terrestrial insects. On such a large scale, this phenomenon may have a considerable impact on the nitrogen cycle.
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Seginer, Ido, James Jones, Per-Olof Gutman, and Eduardo Vallejos. Optimal Environmental Control for Indeterminate Greenhouse Crops. United States Department of Agriculture, August 1997. http://dx.doi.org/10.32747/1997.7613034.bard.
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Increased world competition, as well as increased concern for the environment, drive all manufacturing systems, including greenhouses, towards high-precision operation. Optimal control is an important tool to achieve this goal, since it finds the best compromise between conflicting demands, such as higher profits and environmental concerns. The report, which is a collection of papers, each with its own abstract, outlines an approach for optimal, model-based control of the greenhouse environment. A reliable crop model is essential for this approach and a significant portion of the effort went in this direction, resulting in a radically new version of the tomato model TOMGRO, which can be used as a prototype model for other greenhouse crops. Truly optimal control of a very complex system requires prohibitively large computer resources. Two routes to model simplification have, therefore, been tried: Model reduction (to fewer state variables) and simplified decision making. Crop model reduction from nearly 70 state variables to about 5, was accomplished by either selecting a subset of the original variables or by forming combinations of them. Model dynamics were then fitted either with mechanistic relationships or with neural networks. To simplify the decision making process, the number of costate variables (control policy parametrs) was recuced to one or two. The dry-matter state variable was transformed in such a way that its costate became essentially constant throughout the season. A quasi-steady-state control algorithm was implemented in an experimental greenhouse. A constant value for the dry-matter costate was able to control simultaneously ventilation and CO2 enrichment by continuously producing weather-dependent optimal setpoints and then maintaining them closely.
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Tuller, Markus, Asher Bar-Tal, Hadar Heller, and Michal Amichai. Optimization of advanced greenhouse substrates based on physicochemical characterization, numerical simulations, and tomato growth experiments. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7600009.bard.
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Over the last decade there has been a dramatic shift in global agricultural practice. The increase in human population, especially in underdeveloped arid and semiarid regions of the world, poses unprecedented challenges to production of an adequate and economically feasible food supply to undernourished populations. Furthermore, the increased living standard in many industrial countries has created a strong demand for high-quality, out-of-season vegetables and fruits as well as for ornamentals such as cut and potted flowers and bedding plants. As a response to these imminent challenges and demands and because of a ban on methyl bromide fumigation of horticultural field soils, soilless greenhouse production systems are regaining increased worldwide attention. Though there is considerable recent empirical and theoretical research devoted to specific issues related to control and management of soilless culture production systems, a comprehensive approach that quantitatively considers all relevant physicochemical processes within the growth substrates is lacking. Moreover, it is common practice to treat soilless growth systems as static, ignoring dynamic changes of important physicochemical and hydraulic properties due to root and microbial growth that require adaptation of management practices throughout the growth period. To overcome these shortcomings, the objectives of this project were to apply thorough physicochemical characterization of commonly used greenhouse substrates in conjunction with state-of-the-art numerical modeling (HYDRUS-3D, PARSWMS) to not only optimize management practices (i.e., irrigation frequency and rates, fertigation, container size and geometry, etc.), but to also “engineer” optimal substrates by mixing organic (e.g., coconut coir) and inorganic (e.g., perlite, pumice, etc.) base substrates and modifying relevant parameters such as the particle (aggregate) size distribution. To evaluate the proposed approach under commercial production conditions, characterization and modeling efforts were accompanied by greenhouse experiments with tomatoes. The project not only yielded novel insights regarding favorable physicochemical properties of advanced greenhouse substrates, but also provided critically needed tools for control and management of containerized soilless production systems to provide a stress-free rhizosphere environment for optimal yields, while conserving valuable production resources. Numerical modeling results provided a more scientifically sound basis for the design of commercial greenhouse production trials and selection of adequate plant-specific substrates, thereby alleviating the risk of costly mistrials.
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Firon, Nurit, Prem Chourey, Etan Pressman, Allen Hartwell, and Kenneth J. Boote. Molecular Identification and Characterization of Heat-Stress-Responsive Microgametogenesis Genes in Tomato and Sorghum - A Feasibility Study. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7591741.bard.
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Exposure to higher than optimal temperatures - heat-stress (HS) - is becoming increasingly common to all crop plants worldwide. Heat stress coinciding with microgametogenesis, especially during the post-meiotic phase that is marked by starch biosynthesis, is often associated with starch-deficient pollen and male sterility and ultimately, greatly reduced crop yields. The molecular basis for the high sensitivity of developing pollen grains, on one hand, and factors involved in pollen heat-tolerance, on the other, is poorly understood. The long-term goal of this project is to provide a better understanding of the genes that control pollen quality under heat-stress conditions. The specific objectives of this project were: (1) Determination of the threshold heat stress temperature(s) that affects tomato and sorghum pollen quality whether: a) Chronic mild heat stress conditions (CMHS), or b) Acute heat stress (AHS). (2) Isolation of heat-responsive, microgametogenesis-specific sequences. During our one-year feasibility project, we have accomplished the proposed objectives as follows: Objectrive 1: We have determined the threshold HS conditions in tomato and sorghum. This was essential for achieving the 2nd objective, since our accumulated experience (both Israeli and US labs) indicate that when temperature is raised too high above "threshold HS levels" it may cause massive death of the developing pollen grains. Above-threshold conditions have additional major disadvantages including the "noise" caused by induced expression of genes involved in cell death and masking of the differences between heatsensitive and heat-tolerant pollen grains. Two different types of HS conditions were determined: a) Season-long CMHS conditions: 32/26°C day/night temperatures confirmed in tomato and 36/26°C day maximum/night minimum temperatures in sorghum. b) Short-term AHS: In tomato, 2 hour exposure to 42-45°C (at 7 to 3 days before anthesis) followed by transfer to 28/22±2oC day/night temperatures until flower opening and pollen maturation, caused 50% reduced germinating pollen in the heat-sensitive 3017 cv.. In sorghum, 36/26°C day/night temperatures 10 to 5 days prior to panicle emergence, occurring at 35 days after sowing (DAS) in cv. DeKalb28E, produced starch-deficient and sterile pollen. Objective 2: We have established protocols for the high throughput transcriptomic approach, cDNA-AFLP, for identifying and isolating genes exhibiting differential expression in developing microspores exposed to either ambient or HS conditions and created a databank of HS-responsivemicrogametogenesis-expressed genes. A subset of differentially displayed Transcript-Derived Fragments (TDFs) that were cloned and sequenced (35 & 23 TDFs in tomato and sorghum, respectively) show close sequence similarities with metabolic genes, genes involved in regulation of carbohydrate metabolism, genes implicated in thermotolerance (heat shock proteins), genes involved in long chain fatty acids elongation, genes involved in proteolysis, in oxidation-reduction, vesicle-mediated transport, cell division and transcription factors. T-DNA-tagged Arabidopsis mutants for part of these genes were obtained to be used for their functional analysis. These studies are planned for a continuation project. Following functional analyses of these genes under HS – a valuable resource of genes, engaged in the HS-response of developing pollen grains, that could be modulated for the improvement of pollen quality under HS in both dicots and monocots and/or used to look for natural variability of such genes for selecting heat-tolerant germplasm - is expected.
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Goetsch, Arthur L., Yoav Aharoni, Arieh Brosh, Ryszard (Richard) Puchala, Terry A. Gipson, Zalman Henkin, Eugene D. Ungar, and Amit Dolev. Energy Expenditure for Activity in Free Ranging Ruminants: A Nutritional Frontier. United States Department of Agriculture, June 2009. http://dx.doi.org/10.32747/2009.7696529.bard.
Full textAbstract:
Heat production (HP) or energy expenditure for activity (EEa) is of fundamental nutritional importance for livestock because it determines the proportion of ingested nutrients available for productive functions. Previous estimates of EEa are unreliable and vary widely with different indirect methodologies. This leads to erroneous nutritional strategies, especially when intake on pasture does not meet nutritional requirements and supplementation is necessary for acceptable production. Therefore, the objective of this project was to measure EEa in different classes of livestock (beef cattle and goats) over a wide range of ecological and management conditions to develop and evaluate simple means of prediction. In the first study in Israel, small frame (SF) and large frame (LF) cows (268 and 581 kg) were monitored during spring, summer, and autumn. Feed intake by SF cows per unit of metabolic weight was greater (P < 0.001) than that by LF cows in both spring and summer and their apparent selection of higher quality herbage in spring was greater (P < 0.10) than that of LF cows. SF cows grazed more hours per day and walked longer distances than the LF cows during all seasons. The coefficient of specific costs of activities (kJ•kg BW-0.75•d-1) and of locomotion (J•kg BW-0.75•m-1) were smaller for the SF cows. In the second study, cows were monitored in March, May, and September when they grazed relatively large plots, 135 and 78 ha. Energy cost coefficients of standing, grazing, and horizontal locomotion derived were similar to those of the previous study based on data from smaller plots. However, the energy costs of walking idle and of vertical locomotion were greater than those found by Brosh et al. (2006) but similar to those found by Aharoni et al. (2009). In the third study, cows were monitored in February and May in a 78-ha plot with an average slope of 15.5°, whereas average plot slopes of the former studies ranged between 4.3 and 6.9°. Energy cost coefficients of standing, grazing, and walking idle were greater than those calculated in the previous studies. However, the estimated energy costs of locomotion were lower in the steeper plot. A comparison on a similar HP basis, i.e., similar metabolizable energy (ME) intake, shows that the daily energy spent on activities in relation to daily HP increased by 27% as the average plot slope increased from 5.8 and 6.02 to 15.5°. In the fourth study, cows grazing in a woodland habitat were monitored as in previous studies in December, March, and July. Data analysis is in progress. In the first US experiment, Boer and Spanish does with two kids were used in an experiment beginning in late spring at an average of 24 days after kidding. Two does of each breed resided in eight 0.5-ha grass/forb pastures. Periods of 56, 60, 63, 64, and 73 days in length corresponded to mid-lactation, early post-weaning, the late dry period, early gestation, and mid-gestation. EEa expressed as a percentage of the ME requirement for maintenance plus activity in confinement (EEa%) was not influenced by stocking rate, breed, or period, averaging 49%. Behavioral activities (e.g., time spent grazing, walking, and idle, distance traveled) were not highly related to EEa%, although no-intercept regressions against time spent grazing/eating and grazing/eating plus walking indicated an increase in EEa% of 5.8 and 5.1%/h, respectively. In the second study, animal types were yearling Angora doeling goats, yearling Boer wether goats, yearling Spanish wether goats, and Rambouilletwether sheep slightly more than 2 yr of age. Two animals of each type were randomly allocated to one of four pastures 9.3, 12.3, 4.6, and 1.2 ha in area. The experiment was conducted in the summer with three periods, 30, 26, and 26 days in length. EEa% was affected by an interaction between animal type and period (Angora: 16, 17, and 15; Boer: 60, 67, and 34; Spanish: 46, 62, and 42; sheep: 22, 12, and 22% in periods 1, 2, and 3, respectively (SE = 6.1)). EEa% of goats was predicted with moderate accuracy (R2 = 0.40-0.41) and without bias from estimates of 5.8 and 5.1%/h spent grazing/eating and grazing/eating plus walking, respectively, determined in the first experiment; however, these methods were not suitable for sheep. These methods of prediction are simpler and more accurate than currently recommended for goats by the National Research Council.