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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Estudo da herdabilidade em genealogias de familias com portadores de psoriase cutanea e lingua geografica

Chaves, Marcelo Donizetti 28 March 2005 (has links)
Orientador: Heron Fernando de Souza Gonzaga / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T05:15:05Z (GMT). No. of bitstreams: 1 Chaves_MarceloDonizetti_D.pdf: 1424400 bytes, checksum: 35e88d5e057e2d0b7214de851a1b8e3f (MD5) Previous issue date: 2005 / Resumo: A psoríase é uma doença cutânea crônica, cuja condição bucal mais freqüentemente associada é a língua geográfica. Fatores genéticos e ambientais estão relacionados com as mesmas. A descrição destes fatores mostra a importância do estudo da herdabilidade para determinação quantitativa da influência do genótipo e do ambiente. Este trabalho foi realizado com o objetivo de estudar a herdabilidade da psoríase cutânea e língua geográfica, através do estudo de genealogias de famílias com portadores destas condições. Foram estudados 356 heredogramas de pacientes com estas doenças, a partir de prontuários de um ambulatório dermatológico, independente da idade, gênero e grupo étnico. A amostra foi constituída por 128 propósitos com psoríase cutânea, do tipo vulgar e 257 língua geográfica. Os propósitos com psoríase cutânea apresentavam ou não simultaneidade de língua geográfica e os propósitos com língua geográfica apresentavam ou não simultaneidade de psoríase cutânea. Para a determinação da herdabilidade, utilizou-se o método de Falconer. Este método foi desenvolvido em genética quantitativa, para avaliar o comportamento de características de limiar, aplicado para dados da incidência das doenças, a fim de responder a questão relativa à importância da herança e do ambiente no desenvolvimento das mesmas. A partir dos resultados obtidos destas análises, constatamos que: a) a herdabilidade dos pais em famílias de portadores de psoríase foi de 89,2%, sendo esta considerada alta; b) o mesmo foi observado com relação aos filhos (86,8%) e filhas (84,4%) do propósito; c) verificou-se herdabilidade maior nos grupos de irmãos e irmãs que nos grupos dos pais do propósito, sendo todas as herdabilidades consideradas altas; d) as herdabilidades das irmãs (97%) e irmãos (98%) foram as maiores obtidas, sendo muito semelhantes entre si e maiores do que a dos pais do propósito (89,2%); e) verificou-se a correlação entre filhos/propósito (86,8%) e filhas/propósito (84,4%), ambas com herdabilidade alta e muito semelhante; f) com relação à língua geográfica, observou-se que o valor da herdabilidade filhos/propósito (80,2%) foi maior que a dos pais/propósito (41,6%), sendo o mesmo verificado para a herdabilidade filhas/propósito (68,6%) que na herdabilidade pais/propósito (41,6%); g) a herdabilidade irmãos/propósito (56,8%) foi maior que o valor para pais/propósito (41,6%) e irmãs/propósito (41,6%); h) na comparação entre as herdabilidades filhos/propósito (80,2%) e filhas/propósito (68,6%), observamos que esta foi maior na primeira que na segunda; i) observou-se herdabilidade maior na relação irmãos/propósito (56,8%) que na irmãs/propósito (41,6%); j) o cálculo da herdabilidade total para o grupo com psoríase indicou uma herdabilidade alta (92,1%); k) com relação ao grupo com língua geográfica, também se observou uma herdabilidade alta (51,5%). A partir destes dados, conclui-se que tanto na psoríase, quanto na língua geográfica existe um fator genético determinante / Abstract: Psoriasis is a chronic cutaneous disease whose oral condition is more frequently associated to benign migratory glossitis. Aspects as epidemiological association, basic lesions and microscopic characteristics similarly support the idea that benign migratory glossitis is the true form of oral psoriasis. This study was done having the objective of study the heritability to cutaneous psoriasis and benign migratory glossitis through the genealogy of family with holder these diseases. Were studied 356 heredograms of patients from the records of the dermatological ambulatory, independently of age, gender or ethnic group. The sample was made up of 128 propositi with cutaneous psoriasis and 257 with benign migratory glossitis. The patients suffering from cutaneous psoriasis presented benign migratory glossitis simultaneous or not and the patients of benign migratory glossitis group presented or not psoriasis simultaneously. To determination of heritability were applied Falconer¿s methods. This method was developed in quantitative genetics to analyze the behavior of threshold characteristics. It was applied to date of the incidence of the diseases, so as to answer the question about the role of the inheritance and environmental factors in development the psoriasis and benign migratory glossitis. The following constations were taking from the observed results: a) the heritability of parents in families with patients suffering from cutaneous psoriasis was 89,2%, being considered high; b) high heritability was observed to sons (86,8%) and daughters (84,4%) from propositi; c) it was verified heritability higher in groups of brothers and sisters than groups of parents from propositi, that showed high heritabilities; d) the heritabities of sisters (97%) and brothers (98%) were the higher obtained, and very similar among these and higher than parents from propositi (89,2%); e) it was verified the correlation among sons/propositi (86,8%) and daughters/propositi (84,4%), both having high heritability and very similar; f) beside to benign migratory glossitis, observed that value to heritability sons/propositi (80,2%) was high than parents/propositi (41,6%), being the same verified beside to heritability daughters/propositi (68,6%) that to heritability parents/propositi (41,6%); g) the heritability brothers/propositi (56,8%) was higher than the value to parents/propositi (41,6%) and sisters/propositi (41,6%); h) beside the heritabilities sons/propositi (80,2%) and daughters/propositi (68,6%), it was observed that the heritability was higher in first than second; i) it was observed heritability higher beside brothers/propositi (56,8%) than sisters/propositi (41,6%); j) the total heritability to group with cutaneous psoriasis indicated high heritability (92,6%); k) comparing to group with benign migratory glossitis was also observed a high heritability (54,8%). These data allow the conclusion that, both psoriasis and benign migratory glossitis have a determinant genetic factor / Doutorado / Patologia / Doutor em Estomatopatologia
12

A Range-wide Assessment of Migratory Connectivity for the Prothonotary Warbler Using Stable Hydrogen Isotopes

Reese, Jessica 01 January 2017 (has links)
Populations of many species of migratory birds are declining, and an understanding of how populations are linked between the breeding and nonbreeding grounds is necessary in order to determine drivers of declines. While all current tracking technologies to study the movements of small songbirds are limited by their coarse resolution, tracking birds by measuring stable isotopes in keratin offers an advantage because it requires only a single capture and is cost-effective, which leads to robust sample sizes. While this tracking method is accurate, stable hydrogen isotope values measured in feathers (δ2Hf) are known to be variable within a site, and may be influenced by the hydrology of a site. In this study, we assessed sources of variation in δ2Hf values in a wetland-associated Neotropical migratory bird, the prothonotary warbler (Protonotaria citrea), by comparing δ2Hf values among ages, sexes, years and feather type. We found that age and year significantly influence δ2Hf values, and that differences between primaries and rectrices are statistically significant but generally small. We also tested the accuracy and precision of models to assign prothonotary warblers to their breeding origin using known-origin feathers. We assigned birds in a spatially-explicit manner using an interpolated surface of stable hydrogen values measured in precipitation (δ2Hp), and developed a species-specific calibration equation to account for the offset between δ2Hf and δ2Hp, which explained 51% of the variation in δ2Hf values. We incorporated breeding bird abundance as prior information in our assignment model, and compared two sources of abundance data: the Breeding Bird Survey and a spatio-temporal exploratory model developed with eBird data. The assignment model with no prior information was accurate (83% of birds correctly assigned to their true location of origin), but imprecise (50% of grid cells assigned as likely locations of origin). Incorporating abundance as prior information led to a decrease in accuracy (9-14% of birds correctly assigned) but higher precision (1% of grid cells assigned as likely). We also assigned prothonotary warblers to their breeding origin using feathers collected from across the nonbreeding range. We found that all nonbreeding sampling locations contained a mixture of birds whose origins spanned the majority of the breeding range, with no evidence of strong connectivity between the seasons. In the absence of strong connectivity, the influence of events occurring at one nonbreeding location will be widespread and diffuse across the breeding range. For prothonotary warblers, understanding connectivity can help conservation planners understand how nonbreeding season habitat destruction and other processes influence population dynamics. We recommend that future studies account for age and year variation in δ2Hf values when possible, and continue to examine the trade-off between precision gained and accuracy lost when using abundance as prior information.
13

Evaluation of insect monitoring radar technology for monitoring locust migrations in inland Eastern Australia

Wang, Haikou, Physical, Environmental & Mathematical Sciences, Australian Defence Force Academy, UNSW January 2008 (has links)
To evaluate the utility of insect monitoring radar (IMR) technology for long-term monitoring of insect migration, a mini-network of two IMR units in Bourke, NSW, and Thargomindah, Qld, and a base-station server in Canberra, ACT, was set up in eastern Australia. The IMR operated automatically every night under the control of a personal computer that also conducted data acquisition and processing. Digitisation of radar signals, their analysis (delimitation of echoes from background noise and adjoining echoes, followed by extraction of estimates for each target's speed, displacement direction, body alignment, radar cross-section, and wingbeat frequency and modulation pattern), and generation of observation summaries were implemented as a fully automated procedure. Wingbeat frequency was found to be retrievable from the IMR's rotary-beam signals, and this allowed each individual target to be characterised by its wingbeat as well as its size and shape. By drawing on ancillary information from the Australian Plague Locust Commission's database of field survey and light trap records, the echo characters indicative of Australian plague locust, Chortoicetes terminifera (Walker), were identified. Using these, about 140 nights with detectable plague locust migrations were identified for the Bourke IMR site during 1998 - 2001 and 31 nights for Thargomindah during 1999 - 2000. Analysis of these nights confirmed that C. terminifera migrates in association with disturbed weather, especially tropical troughs, in eastern Australia. Trajectory simulation based on IMR-derived displacement directions and flight speeds allowed the identification of population movements likely to reach favourable habitats and thus to develop rapidly and possibly cause a plague. The outbreak during 1999 - 2001 most likely originated from the southeastern agricultural belt after migrations and multiplications over several generations. The IMR observations demonstrated that C. terminifera migrates over long distances with the wind at night and indicated that it may have an orientation behaviour that prevents it from being taken too far into the arid inland, a trait that could be highly adaptive in this environment. The two IMRs were operational for more than 85% of scheduled time during the study period and provided a wealth of information of potential value for locust management and migration research
14

Avian community structure and diversity in relation to coastal development in the Sian Ka’an Biosphere Reserve and Riviera Maya, Quintana Roo, Mexico

Raymundo Sanchez, Angeles A 01 May 2010 (has links)
Habitat loss and fragmentation caused by tourist development along the eastern coast of the Yucatan Peninsula of Mexico represents a big threat to the survival of Nearctic-Neotropical migratory songbirds. This habitat plays a crucial role for successful migration for many migratory birds. However, the effects of habitat loss and fragmentation on these birds have not been well documented in the region. From September- December, 2006-2008, we mist-netted and conducted transect surveys to assess the variation in the avian community among three different levels of development (high, medium and low). The study area included two small reserves (10-20 ha) in the hotel zone associated with the Riviera Maya (high development), two sites with limited development within the Sian Ka’an Biosphere Reserve associated with small fishing camps (medium development), and two undeveloped sites located on a private ranch within Sian Ka’an (low development). I assessed species richness and abundance of four avian groups: the entire community, year-round residents, winter residents, and transients. Species richness and abundance decreased significantly with the greatest levels of disturbance. The high development level had the least species richness and abundance, whereas the medium development level had the greatest richness for all bird classes. However, my results suggest that small reserves in the hotel zone can be important compliments to the large, undisturbed reserves (Sian Ka’an) for both resident and migrant birds. Forty-six percent of all birds species captured in mist nets were Nearctic-Neotropical migrants; thus this group composed a significant component of the avian community. The dominance in the year-round resident community by the endemic Black Catbird (Dumetella glabrirostris) at medium and low development sites showed that coastal dune vegetation is also important in maintaining populations of endemic species, which are sensitive to levels of disturbance. The use of two different survey methods (mist-netting and transect surveys) produced complimentary descriptions of community composition. Because many year-round resident species and migrants depend on this scarce and discontinuous coastal habitat, and because of the intense development pressure on this coastal zone, better conservation strategies are needed to successfully sustain the avian community of this region.
15

Mechanism of the Heck reaction: nature of oxidative addition and migratory insertion

Evans, Anthony Steven 15 November 2004 (has links)
The mechanism of carbon coupling reactions is traditionally represented in a very broad schematic. This thesis seeks to explore the mechanism of these reactions by focusing on Heck olefination. The Heck reaction has become a powerful tool in synthetic labs but the mechanism of this reaction has remained a topic of debate since the reaction's discovery. The catalytic cycle that has come to be accepted, while accurate in its own right, is not nearly as detailed as the complexity of the various stages of the Heck reaction suggest it should be. This study seeks to elucidate the nature of the oxidative addition of aryl halide to a palladium catalyst using a ligand that has been shown to have high activity in facilitating oxidative addition of aryl chlorides and bromides in other coupling reactions. This information is then compared to other studies in the field so that conclusions can be drawn about the oxidative addition. Also, selectivity studies seek to determine the nature of the migratory insertion of an olefin into the Pd-Ar bond. Again, comparison of results obtained in this study are compared to previous results so that a more definitive conclusion can be drawn about the oxidative addition.
16

The spring reverse migration of landbirds in the Pelee region: 2010-2012

Burrell, Kenneth 20 September 2013 (has links)
The spring reverse migration of landbirds (i.e., birds flying in the direction opposite to be expected), within the Great Lakes region is controversial because it is not understood if the extent or reversal of flight direction in spring is truly a change in migratory patterns or a brief anomaly. It is also not clear what the fitness and community level impacts are. My objective was to determine what and how weather influences reverse migration and to determine which species and families of birds participate the most frequently in this form of flight. I examined species which are participatory (and those that are not) as well as the impacts of specific weather covariates on the abundance of landbirds and focused explicitly on the putative reverse migration of landbirds. Field sites were located at the extreme southern tip of Fish Point, Pelee Island (2010-2012) and Point Pelee National Park (2012), where my field assistant and I visually recorded the total number of birds observed to be reverse migrating, while identifying all birds to species or family as best possible. This study was conducted over 97 days during April 26 – May 20, in 2010-2012. Information pertaining to potential reverse migration has only been formally documented twice in the Great Lakes region, most recently in 1951. I undertook a descriptive analysis to compare the numbers of individuals of bird species and families. Temperate and neotropical migrants were examined, compared, and divided into sub-sets based on their geographic ranges. I identified species at risk and vagrants which I observed during reverse migrations. Based on provincial population estimates, I determined the proportion of all reverse migrants where ≥200 individuals were observed. A descriptive analysis was undertaken to determine differences between sites (i.e., Point Pelee and Fish Point) in the final year of surveys (2012). Species and abundance were comparatively differentiated between each site and subsequently compared. While very few birds were observed flying anything but south, a total of 61,677 birds of 80 species was documented flying south. My results indicate temperate migrants vastly outnumbered neotropical migrants (as much as 4:1) and numbers of birds varied between study sites. Temperate migrants were noted to be more common (in the final study year) at Point Pelee compared to Fish Point, while neotropical migrants were more numerous at Fish Point than Point Pelee. Despite the fact that most migrant species participated in reverse migrations (i.e., of the species regularly occurring in the Pelee region at this time of year), complete absences were noted, most notably in Catharus thrushes, while species such as Rose-breasted Grosbeak and Scarlet Tanager, and families such as Tyrant Flycatchers, Vireos and Sparrows were observed to be less prevalent than anticipated. Species at risk and vagrants were noted relatively frequently during this study, suggesting that these surveys are an efficient and potentially important tool for migration monitoring in this region. Diurnal migrants, most notably Blackbirds, were observed to engage in reverse migration in higher numbers than nocturnal migrants, such as Wood Warblers. Seven weather covariates were measured and modeled with the total number of birds detected using R to determine which covariates explain the most amount of variation of the total number of birds during my surveys. I used an AICc approach to select the best model for each hypothesis. After selecting the top weather covariates with time lags according to the best (lowest) AICc values, I built general models by comparing all possible combinations of the covariates identified in the top models for each hypothesis. I included a random effect intercept for study site to discern any site difference or similarities between Point Pelee and Fish Point and specified a Poisson distribution (log-link function as implemented in the LMER package) because the data set was continuous (time-series) and count oriented. My adjusted time lag results show that most migrants tend to migrate during and ahead of inclement weather and/or periods of south winds. I also found that all identified covariates influence reverse migration to some degree. Wind direction and barometric pressure were the most significant of the covariates examined (β = 0.718 and -0.213, respectively). Specifically, wind direction is the most important covariate in explaining reverse migration, with days of south winds dramatically increasing the probability of higher numbers of birds during surveys. Low barometric pressure is also important for explaining the number of observed reverse migrants; therefore, days with lower barometric pressure have a greater likelihood of increased bird observations. Based on my observations and results I theorized that while reverse migration pertains to a distinct form of flight, it is likely not an actual form of migration. This form of flight at its simplest is likely a form of reorientation, whereby migratory birds take advantage of local weather conditions by flying south for extended distances. I anticipate that this form of flight must have serious consequences for the fitness levels and life-cycles of migratory birds. Studies looking at reverse migration provide a useful tool for migration monitoring, particularly as it is an underexplored phenomenon. Observations of thousands of birds, many of which are either species at risk or vagrants, collected in an efficient manner are vital for determining population trends related to migratory birds. Continuing this study would aid on-going monitoring programs assessing bird populations passing through the lower Great Lakes region. These studies will also help us understand the impacts of climate and climate change on migratory birds.
17

Mechanism of the Heck reaction: nature of oxidative addition and alkene insertion

Evans, Anthony Steven 15 November 2004 (has links)
The mechanism of carbon coupling reactions is traditionally represented in a very broad schematic. This thesis seeks to explore the mechanism of these reactions by focusing on Heck olefination. The Heck reaction has become a powerful tool in synthetic labs but the mechanism of this reaction has remained a topic of debate since the reaction's discovery. The catalytic cycle that has come to be accepted, while accurate in its own right, is not nearly as detailed as the complexity of the various stages of the Heck reaction suggest it should be. This study seeks to elucidate the nature of the oxidative addition of aryl halide to a palladium catalyst using a ligand that has been shown to have high activity in facilitating oxidative addition of aryl chlorides and bromides in other coupling reactions. This information is then compared to other studies in the field so that conclusions can be drawn about the oxidative addition. Also, selectivity studies seek to determine the nature of the migratory insertion of an olefin into the Pd-Ar bond. Again, comparison of results obtained in this study are compared to previous results so that a more definitive conclusion can be drawn about the oxidative addition.
18

Avian community structure and diversity in relation to coastal development in the Sian Ka’an Biosphere Reserve and Riviera Maya, Quintana Roo, Mexico

Raymundo Sanchez, Angeles A 01 May 2010 (has links)
Habitat loss and fragmentation caused by tourist development along the eastern coast of the Yucatan Peninsula of Mexico represents a big threat to the survival of Nearctic-Neotropical migratory songbirds. This habitat plays a crucial role for successful migration for many migratory birds. However, the effects of habitat loss and fragmentation on these birds have not been well documented in the region. From September- December, 2006-2008, we mist-netted and conducted transect surveys to assess the variation in the avian community among three different levels of development (high, medium and low). The study area included two small reserves (10-20 ha) in the hotel zone associated with the Riviera Maya (high development), two sites with limited development within the Sian Ka’an Biosphere Reserve associated with small fishing camps (medium development), and two undeveloped sites located on a private ranch within Sian Ka’an (low development). I assessed species richness and abundance of four avian groups: the entire community, year-round residents, winter residents, and transients. Species richness and abundance decreased significantly with the greatest levels of disturbance. The high development level had the least species richness and abundance, whereas the medium development level had the greatest richness for all bird classes. However, my results suggest that small reserves in the hotel zone can be important compliments to the large, undisturbed reserves (Sian Ka’an) for both resident and migrant birds. Forty-six percent of all birds species captured in mist nets were Nearctic-Neotropical migrants; thus this group composed a significant component of the avian community. The dominance in the year-round resident community by the endemic Black Catbird (Dumetella glabrirostris) at medium and low development sites showed that coastal dune vegetation is also important in maintaining populations of endemic species, which are sensitive to levels of disturbance. The use of two different survey methods (mist-netting and transect surveys) produced complimentary descriptions of community composition. Because many year-round resident species and migrants depend on this scarce and discontinuous coastal habitat, and because of the intense development pressure on this coastal zone, better conservation strategies are needed to successfully sustain the avian community of this region.
19

The spring reverse migration of landbirds in the Pelee region: 2010-2012

Burrell, Kenneth 20 September 2013 (has links)
The spring reverse migration of landbirds (i.e., birds flying in the direction opposite to be expected), within the Great Lakes region is controversial because it is not understood if the extent or reversal of flight direction in spring is truly a change in migratory patterns or a brief anomaly. It is also not clear what the fitness and community level impacts are. My objective was to determine what and how weather influences reverse migration and to determine which species and families of birds participate the most frequently in this form of flight. I examined species which are participatory (and those that are not) as well as the impacts of specific weather covariates on the abundance of landbirds and focused explicitly on the putative reverse migration of landbirds. Field sites were located at the extreme southern tip of Fish Point, Pelee Island (2010-2012) and Point Pelee National Park (2012), where my field assistant and I visually recorded the total number of birds observed to be reverse migrating, while identifying all birds to species or family as best possible. This study was conducted over 97 days during April 26 – May 20, in 2010-2012. Information pertaining to potential reverse migration has only been formally documented twice in the Great Lakes region, most recently in 1951. I undertook a descriptive analysis to compare the numbers of individuals of bird species and families. Temperate and neotropical migrants were examined, compared, and divided into sub-sets based on their geographic ranges. I identified species at risk and vagrants which I observed during reverse migrations. Based on provincial population estimates, I determined the proportion of all reverse migrants where ≥200 individuals were observed. A descriptive analysis was undertaken to determine differences between sites (i.e., Point Pelee and Fish Point) in the final year of surveys (2012). Species and abundance were comparatively differentiated between each site and subsequently compared. While very few birds were observed flying anything but south, a total of 61,677 birds of 80 species was documented flying south. My results indicate temperate migrants vastly outnumbered neotropical migrants (as much as 4:1) and numbers of birds varied between study sites. Temperate migrants were noted to be more common (in the final study year) at Point Pelee compared to Fish Point, while neotropical migrants were more numerous at Fish Point than Point Pelee. Despite the fact that most migrant species participated in reverse migrations (i.e., of the species regularly occurring in the Pelee region at this time of year), complete absences were noted, most notably in Catharus thrushes, while species such as Rose-breasted Grosbeak and Scarlet Tanager, and families such as Tyrant Flycatchers, Vireos and Sparrows were observed to be less prevalent than anticipated. Species at risk and vagrants were noted relatively frequently during this study, suggesting that these surveys are an efficient and potentially important tool for migration monitoring in this region. Diurnal migrants, most notably Blackbirds, were observed to engage in reverse migration in higher numbers than nocturnal migrants, such as Wood Warblers. Seven weather covariates were measured and modeled with the total number of birds detected using R to determine which covariates explain the most amount of variation of the total number of birds during my surveys. I used an AICc approach to select the best model for each hypothesis. After selecting the top weather covariates with time lags according to the best (lowest) AICc values, I built general models by comparing all possible combinations of the covariates identified in the top models for each hypothesis. I included a random effect intercept for study site to discern any site difference or similarities between Point Pelee and Fish Point and specified a Poisson distribution (log-link function as implemented in the LMER package) because the data set was continuous (time-series) and count oriented. My adjusted time lag results show that most migrants tend to migrate during and ahead of inclement weather and/or periods of south winds. I also found that all identified covariates influence reverse migration to some degree. Wind direction and barometric pressure were the most significant of the covariates examined (β = 0.718 and -0.213, respectively). Specifically, wind direction is the most important covariate in explaining reverse migration, with days of south winds dramatically increasing the probability of higher numbers of birds during surveys. Low barometric pressure is also important for explaining the number of observed reverse migrants; therefore, days with lower barometric pressure have a greater likelihood of increased bird observations. Based on my observations and results I theorized that while reverse migration pertains to a distinct form of flight, it is likely not an actual form of migration. This form of flight at its simplest is likely a form of reorientation, whereby migratory birds take advantage of local weather conditions by flying south for extended distances. I anticipate that this form of flight must have serious consequences for the fitness levels and life-cycles of migratory birds. Studies looking at reverse migration provide a useful tool for migration monitoring, particularly as it is an underexplored phenomenon. Observations of thousands of birds, many of which are either species at risk or vagrants, collected in an efficient manner are vital for determining population trends related to migratory birds. Continuing this study would aid on-going monitoring programs assessing bird populations passing through the lower Great Lakes region. These studies will also help us understand the impacts of climate and climate change on migratory birds.
20

Studies of insect connective tissue, with special reference to its development in the Lepidoptera and Orthoptera

Ashhurst, Doreen E. January 1964 (has links)
No description available.

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