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• 11. [Article] Theorizing age and gender in the pursuit of love in late life

  In this dissertation, I explore how women and men in later life experience the world of dating and the pursuit of new intimate relationships. Although the mortality gap between women and men at older ages ...

  Citation × Citation Citation Abstract Copy Title: Theorizing age and gender in the pursuit of love in late life Author: Levaro, Elizabeth Bayler In this dissertation, I explore how women and men in later life experience the world of dating and the pursuit of new intimate relationships. Although the mortality gap between women and men at older ages is narrowing, as they enter their 70s, 80s, and 90s, there are still at least two unmarried women for every unmarried man. This gender imbalance is due to women's greater longevity and cultural norms based in gender relations that underlie men's preference for younger partners at all ages--and, throughout most of their lives, women's preference for older partners. Viewing the pursuit of new intimate relationships as embedded within intersecting systems of age and gender inequality, my goal was to explore how unmarried heterosexual women and men negotiate the world of dating in late life and how they view themselves and each other as aging men and women. This research focuses on White heterosexual women and men 70 years of age and older who were actively pursuing new dating relationships through personal newspaper ads and Internet dating and matching sites. Positioning the search for new intimate partners within the intersection of age relations and gender relations, I addressed two research questions. First, I sought to understand how unmarried—widowed, divorced, or always single—heterosexual women and men age 70 and older who are actively pursuing new intimate relationships view and describe their experience of the world of late-life dating, their place in it as aging men and women, and the dating partners they encounter. Second, I examined how, as men and women in aging bodies in a culture that devalues both old age and old people, they maintain, negotiate, or construct their sense of manhood and masculinity or womanhood and femininity in the context of dating, romance, and sexual intimacy. This dissertation consists of two studies, both grounded in a constructivist/interpretive paradigm and the thematic analysis of in-depth, semistructured interviews with 24 informants (11 women and 13 men) between the ages of 70 and 92. In the first study, using an intersectional framework of age relations and gender relations, I examined how internalized negative stereotypes of aging in general and one's own aging, in particular, shape the ways in which old men and women position themselves for finding romantic partners and how they manage identity to make themselves attractive romantic partners in an ageist society. Through their personal ads, Internet profiles, posted pictures, and within the interviews themselves, I found that informants both maintained and subverted age and gender expectations. They consistently resisted a self-identity as old by invoking claims and affirmations of neither looking nor acting their chronological age. Simultaneously, they communicated admonitions to potential dating partners that they should not look or act old. Both the men and the women were seeking new romantic partners younger than themselves, with the men's mean lower age 21 years younger and the women's, 10 years younger. In the second study, also grounded in considerations of age relations and gender relations, I examined informants' orientations to sexual activity and the importance of sex in their dating lives. Findings showed that, contrary to ageist stereotypes depicting old people as asexual and earlier research findings that older adults might settle for alternate intimate activities, the majority of the women and men in this study expressed interest in an intimate relationship that includes sex, and most interpreted this to mean penetrative intercourse. Nearly all of the men were sexually active with younger partners, with over half either using or holding samples of drugs for the treatment of erectile dysfunction (ED). A far smaller percentage of the women were currently dating or sexually active, and none had experience with partners who required the functional assistance of ED drugs. In conclusion, the informants present a picture of late-life dating in which individuals both consciously and unconsciously submit to, resist, and sometimes defy the structural constraints presented by societal ageism, age relations, and gender relations. The intersecting systems of inequality and oppression that impact these women and men as they pursue new love may seem only to privilege old men, offering them, for instance, advantage in terms of more lenience in showing their age and a broader age range in which to pursue dating partners. As a group, however, the women expressed more satisfaction with their lives and were less driven by the desire for an intimate partner, relishing the independence and autonomy their unattached status allowed them. Title: Theorizing age and gender in the pursuit of love in late life Author: Levaro, Elizabeth Bayler In this dissertation, I explore how women and men in later life experience the world of dating and the pursuit of new intimate relationships. Although the mortality gap between women and men at older ages is narrowing, as they enter their 70s, 80s, and 90s, there are still at least two unmarried women for every unmarried man. This gender imbalance is due to women's greater longevity and cultural norms based in gender relations that underlie men's preference for younger partners at all ages--and, throughout most of their lives, women's preference for older partners. Viewing the pursuit of new intimate relationships as embedded within intersecting systems of age and gender inequality, my goal was to explore how unmarried heterosexual women and men negotiate the world of dating in late life and how they view themselves and each other as aging men and women. This research focuses on White heterosexual women and men 70 years of age and older who were actively pursuing new dating relationships through personal newspaper ads and Internet dating and matching sites. Positioning the search for new intimate partners within the intersection of age relations and gender relations, I addressed two research questions. First, I sought to understand how unmarried—widowed, divorced, or always single—heterosexual women and men age 70 and older who are actively pursuing new intimate relationships view and describe their experience of the world of late-life dating, their place in it as aging men and women, and the dating partners they encounter. Second, I examined how, as men and women in aging bodies in a culture that devalues both old age and old people, they maintain, negotiate, or construct their sense of manhood and masculinity or womanhood and femininity in the context of dating, romance, and sexual intimacy. This dissertation consists of two studies, both grounded in a constructivist/interpretive paradigm and the thematic analysis of in-depth, semistructured interviews with 24 informants (11 women and 13 men) between the ages of 70 and 92. In the first study, using an intersectional framework of age relations and gender relations, I examined how internalized negative stereotypes of aging in general and one's own aging, in particular, shape the ways in which old men and women position themselves for finding romantic partners and how they manage identity to make themselves attractive romantic partners in an ageist society. Through their personal ads, Internet profiles, posted pictures, and within the interviews themselves, I found that informants both maintained and subverted age and gender expectations. They consistently resisted a self-identity as old by invoking claims and affirmations of neither looking nor acting their chronological age. Simultaneously, they communicated admonitions to potential dating partners that they should not look or act old. Both the men and the women were seeking new romantic partners younger than themselves, with the men's mean lower age 21 years younger and the women's, 10 years younger. In the second study, also grounded in considerations of age relations and gender relations, I examined informants' orientations to sexual activity and the importance of sex in their dating lives. Findings showed that, contrary to ageist stereotypes depicting old people as asexual and earlier research findings that older adults might settle for alternate intimate activities, the majority of the women and men in this study expressed interest in an intimate relationship that includes sex, and most interpreted this to mean penetrative intercourse. Nearly all of the men were sexually active with younger partners, with over half either using or holding samples of drugs for the treatment of erectile dysfunction (ED). A far smaller percentage of the women were currently dating or sexually active, and none had experience with partners who required the functional assistance of ED drugs. In conclusion, the informants present a picture of late-life dating in which individuals both consciously and unconsciously submit to, resist, and sometimes defy the structural constraints presented by societal ageism, age relations, and gender relations. The intersecting systems of inequality and oppression that impact these women and men as they pursue new love may seem only to privilege old men, offering them, for instance, advantage in terms of more lenience in showing their age and a broader age range in which to pursue dating partners. As a group, however, the women expressed more satisfaction with their lives and were less driven by the desire for an intimate partner, relishing the independence and autonomy their unattached status allowed them. Close

• 12. [Article] The effects of enhanced expression of the GluN2B (NR2B) subunit of the N-methyl-D-aspartate (NMDA) receptor on memory in aged animals

  As the aging population continues to grow worldwide, age-related complications are becoming more apparent within the aging population. One of the first age-related complications to become apparent is age-associated ...

  Citation × Citation Citation Abstract Copy Title: The effects of enhanced expression of the GluN2B (NR2B) subunit of the N-methyl-D-aspartate (NMDA) receptor on memory in aged animals Author: Brim, Brenna L. As the aging population continues to grow worldwide, age-related complications are becoming more apparent within the aging population. One of the first age-related complications to become apparent is age-associated memory impairment and it can make the elderly more dependent on caregivers early on. The N-methyl-D-aspartate (NMDA) receptor is important to learning and memory and appears to be especially vulnerable to the process of aging. The density of NMDA receptors declines with age more than any other ionotropic glutamate receptor. Both the density of NMDA receptors and the mRNA and protein expression of its subunits decline with age. In particular, the GluN2B subunit of the NMDA receptor shows the greatest age-related declines in expression across multiple brain regions, including the frontal lobe (including the prefrontal and frontal cortices), caudate nucleus and hippocampus. These declines are strongly correlated to age-related declines in spatial memory. Specifically, age-related decreases in the protein expression of the GluN2B subunit within crude synaptosomes of the frontal cortex of C57BL/6 mice show a relationship to the declines in performance in a long-term spatial memory task across age groups. However, within the population of aged mice, there was a subpopulation of aged mice in which higher expression of the GluN2B subunit within the synaptic membrane of the hippocampus was associated with poorer performance in the same task. Moreover, transgenic mice designed to express higher levels of the GluN2B subunit from birth also possess superior memory, including spatial memory, across adulthood to middle-age. Taken together, these data led to the hypothesis that increasing the expression of the GluN2B subunit within the aged brain could potentially alleviate age-related declines in memory. However, increasing its expression regionally was first examined since higher expression of the GluN2B subunit within the hippocampus has been associated with poorer memory in aged animals. Since age-related decreases in the protein expression of the GluN2B subunit within the frontal cortex show a relationship to impaired memory function, the first study was designed to determine if increasing GluN2B subunit expression in the frontal lobe would improve memory in aged mice. Mice received bilateral injections of either an adenoviral vector, containing cDNA specific for the GluN2B subunit and enhanced Green Fluorescent Protein (eGFP) (GluN2B vector); an adenoviral vector containing only the cDNA for eGFP (control vector); or vehicle into their frontal lobe. Spatial memory, cognitive flexibility and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression in the frontal lobe, exhibited improved long-term spatial memory, comparable to young mice, in the second day of training. Moreover, a higher concentration of the specific GluN2B antagonist, Ro 25-6981, was required to impair long-term spatial memory in aged mice with enhanced GluN2B subunit expression, as compared to aged controls. The requirement for greater antagonism in aged mice to block memory performance suggests that the number of GluN2B-containing receptors in their frontal lobe was enhanced and contributed to the improved memory. This study provides suggestive evidence that therapies that enhance GluN2B subunit expression within the aged brain could have the potential to ameliorate age-related memory loss. Since higher expression of the GluN2B subunit within the hippocampus of aged mice is associated with poorer memory, the second study was designed to determine if increasing GluN2B subunit expression in the hippocampus would improve or further impair memory in aged mice. This would help to determine if a therapy aimed at enhancing the GluN2B subunit expression or function of GluN2B-containing receptors throughout the aged brain could help ameliorate age-associated memory loss. Mice were injected bilaterally with either the GluN2B vector, a control vector or vehicle into the hippocampus. Spatial memory, cognitive flexibility and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression in the hippocampus, exhibited improved long-term spatial memory, comparable to young mice, early in training. However, there was a trend for impaired memory later in the long-term spatial memory trials. Still, these data suggest that enhancing GluN2B subunit expression in the aged hippocampus could be more beneficial to memory than harmful. In addition, the results of this study suggest that enhancing GluN2B subunit expression in different brain regions may improve memory at different phases of learning. Therefore, therapies that enhance GluN2B subunit expression throughout the aged brain could help ameliorate age-related memory loss. The first two studies demonstrated that enhancing the expression of the GluN2B subunit within either the frontal lobe or hippocampus of the aged brain has the potential to reduce age-related memory declines. However, the increase was not global nor specific to the synapse. Therefore, a third study was developed with the intent of garnering a more global increase in GluN2B subunit expression that was localized to the synapse. Cyclin dependent kinase 5 (Cdk5) enhances endocytosis of the GluN2B subunit-containing NMDA receptors from the synapse. Previous research has shown that inhibiting Cdk5 increases the number of GluN2B subunits at the synapse and within the whole cell and improves memory in young mice. This study was designed to determine if using antisense phosphorodiamidate morpholino oligomers (Morpholinos) to decrease the expression of Cdk5 protein within the brain would improve memory in aged mice. Morpholinos were conjugated to a cell penetrating peptide, which enhances cellular uptake, and delivered bilaterally to the lateral ventricles of both young and aged mice via acute stereotaxic injection. Treatments consisted of equivalent volumes and concentrations of either vehicle, control Morpholino or a Morpholino targeting the mRNA of Cdk5 (Cdk5 Morpholino). Memory was evaluated in the Morris water maze and using a novel object recognition task. Aged mice treated with the Cdk5 Morpholino exhibited improved early acquisition and spatial bias in the long-term spatial memory trials, as well as improved performance overall, compared to control Morpholino-treated aged animals. However, aged mice treated with the Cdk5 Morpholino performed similarly to vehicle-treated aged animals. The presence of the peptide-conjugated Morpholinos within the brain may have worsened performance in the Morris water maze task since control Morpholino-treated animals performed significantly worse than vehicle-treated animals. In concurrence, there was significantly greater gliosis in peptide-conjugated Morpholino-treated animals over vehicle-treated brains, suggesting it was neurotoxic. In contrast, young mice treated with the Cdk5 Morpholino showed impaired early acquisition and spatial bias but a trend for improved later learning in the long-term spatial memory task compared to control Morpholino-treated animals. Treatment with the Cdk5 Morpholino had no significant effect on cognitive flexibility, associative memory or novel object recognition for young or aged animals. Immunohistochemistry revealed increased GluN2B subunit expression within cells with characteristics of neurons and astroglia in regions of the frontal lobe, caudate nucleus and hippocampus of aged mice who received the Cdk5 Morpholino compared to control treatments. However, the increased GluN2B subunit expression appeared to be greater within the hippocampus. These results suggest that inhibiting the translation of Cdk5 using Morpholinos increased GluN2B subunit expression in both young and aged mice and may have contributed to the improved long-term spatial memory observed in aged mice, despite the Morpholino being administered at a presumably toxic concentration. An additional group of mice was used to determine a non-neurotoxic dosage of the peptide conjugated Morpholino. However, future studies are needed to determine the efficacy of the Cdk5 Morpholino at this dosage. Taken together, the studies presented here suggest that increasing expression of the GluN2B subunit within the aged brain does improve age-associated memory declines. In addition, cell penetrating peptide- conjugated Morpholinos show promise as tools for genetic manipulation within the brain and Cdk5 could prove to be a novel target for enhancing GluN2B subunit expression within the aged brain. Though future studies are needed, the studies presented here do suggest that therapies that enhance GluN2B subunit expression within the aged brain have the potential to help ameliorate memory loss. However, since enhanced GluN2B subunit expression itself can increase the potential for excitotoxicity, an optimal dose of such a therapeutic would need to be determined. Title: The effects of enhanced expression of the GluN2B (NR2B) subunit of the N-methyl-D-aspartate (NMDA) receptor on memory in aged animals Author: Brim, Brenna L. As the aging population continues to grow worldwide, age-related complications are becoming more apparent within the aging population. One of the first age-related complications to become apparent is age-associated memory impairment and it can make the elderly more dependent on caregivers early on. The N-methyl-D-aspartate (NMDA) receptor is important to learning and memory and appears to be especially vulnerable to the process of aging. The density of NMDA receptors declines with age more than any other ionotropic glutamate receptor. Both the density of NMDA receptors and the mRNA and protein expression of its subunits decline with age. In particular, the GluN2B subunit of the NMDA receptor shows the greatest age-related declines in expression across multiple brain regions, including the frontal lobe (including the prefrontal and frontal cortices), caudate nucleus and hippocampus. These declines are strongly correlated to age-related declines in spatial memory. Specifically, age-related decreases in the protein expression of the GluN2B subunit within crude synaptosomes of the frontal cortex of C57BL/6 mice show a relationship to the declines in performance in a long-term spatial memory task across age groups. However, within the population of aged mice, there was a subpopulation of aged mice in which higher expression of the GluN2B subunit within the synaptic membrane of the hippocampus was associated with poorer performance in the same task. Moreover, transgenic mice designed to express higher levels of the GluN2B subunit from birth also possess superior memory, including spatial memory, across adulthood to middle-age. Taken together, these data led to the hypothesis that increasing the expression of the GluN2B subunit within the aged brain could potentially alleviate age-related declines in memory. However, increasing its expression regionally was first examined since higher expression of the GluN2B subunit within the hippocampus has been associated with poorer memory in aged animals. Since age-related decreases in the protein expression of the GluN2B subunit within the frontal cortex show a relationship to impaired memory function, the first study was designed to determine if increasing GluN2B subunit expression in the frontal lobe would improve memory in aged mice. Mice received bilateral injections of either an adenoviral vector, containing cDNA specific for the GluN2B subunit and enhanced Green Fluorescent Protein (eGFP) (GluN2B vector); an adenoviral vector containing only the cDNA for eGFP (control vector); or vehicle into their frontal lobe. Spatial memory, cognitive flexibility and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression in the frontal lobe, exhibited improved long-term spatial memory, comparable to young mice, in the second day of training. Moreover, a higher concentration of the specific GluN2B antagonist, Ro 25-6981, was required to impair long-term spatial memory in aged mice with enhanced GluN2B subunit expression, as compared to aged controls. The requirement for greater antagonism in aged mice to block memory performance suggests that the number of GluN2B-containing receptors in their frontal lobe was enhanced and contributed to the improved memory. This study provides suggestive evidence that therapies that enhance GluN2B subunit expression within the aged brain could have the potential to ameliorate age-related memory loss. Since higher expression of the GluN2B subunit within the hippocampus of aged mice is associated with poorer memory, the second study was designed to determine if increasing GluN2B subunit expression in the hippocampus would improve or further impair memory in aged mice. This would help to determine if a therapy aimed at enhancing the GluN2B subunit expression or function of GluN2B-containing receptors throughout the aged brain could help ameliorate age-associated memory loss. Mice were injected bilaterally with either the GluN2B vector, a control vector or vehicle into the hippocampus. Spatial memory, cognitive flexibility and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression in the hippocampus, exhibited improved long-term spatial memory, comparable to young mice, early in training. However, there was a trend for impaired memory later in the long-term spatial memory trials. Still, these data suggest that enhancing GluN2B subunit expression in the aged hippocampus could be more beneficial to memory than harmful. In addition, the results of this study suggest that enhancing GluN2B subunit expression in different brain regions may improve memory at different phases of learning. Therefore, therapies that enhance GluN2B subunit expression throughout the aged brain could help ameliorate age-related memory loss. The first two studies demonstrated that enhancing the expression of the GluN2B subunit within either the frontal lobe or hippocampus of the aged brain has the potential to reduce age-related memory declines. However, the increase was not global nor specific to the synapse. Therefore, a third study was developed with the intent of garnering a more global increase in GluN2B subunit expression that was localized to the synapse. Cyclin dependent kinase 5 (Cdk5) enhances endocytosis of the GluN2B subunit-containing NMDA receptors from the synapse. Previous research has shown that inhibiting Cdk5 increases the number of GluN2B subunits at the synapse and within the whole cell and improves memory in young mice. This study was designed to determine if using antisense phosphorodiamidate morpholino oligomers (Morpholinos) to decrease the expression of Cdk5 protein within the brain would improve memory in aged mice. Morpholinos were conjugated to a cell penetrating peptide, which enhances cellular uptake, and delivered bilaterally to the lateral ventricles of both young and aged mice via acute stereotaxic injection. Treatments consisted of equivalent volumes and concentrations of either vehicle, control Morpholino or a Morpholino targeting the mRNA of Cdk5 (Cdk5 Morpholino). Memory was evaluated in the Morris water maze and using a novel object recognition task. Aged mice treated with the Cdk5 Morpholino exhibited improved early acquisition and spatial bias in the long-term spatial memory trials, as well as improved performance overall, compared to control Morpholino-treated aged animals. However, aged mice treated with the Cdk5 Morpholino performed similarly to vehicle-treated aged animals. The presence of the peptide-conjugated Morpholinos within the brain may have worsened performance in the Morris water maze task since control Morpholino-treated animals performed significantly worse than vehicle-treated animals. In concurrence, there was significantly greater gliosis in peptide-conjugated Morpholino-treated animals over vehicle-treated brains, suggesting it was neurotoxic. In contrast, young mice treated with the Cdk5 Morpholino showed impaired early acquisition and spatial bias but a trend for improved later learning in the long-term spatial memory task compared to control Morpholino-treated animals. Treatment with the Cdk5 Morpholino had no significant effect on cognitive flexibility, associative memory or novel object recognition for young or aged animals. Immunohistochemistry revealed increased GluN2B subunit expression within cells with characteristics of neurons and astroglia in regions of the frontal lobe, caudate nucleus and hippocampus of aged mice who received the Cdk5 Morpholino compared to control treatments. However, the increased GluN2B subunit expression appeared to be greater within the hippocampus. These results suggest that inhibiting the translation of Cdk5 using Morpholinos increased GluN2B subunit expression in both young and aged mice and may have contributed to the improved long-term spatial memory observed in aged mice, despite the Morpholino being administered at a presumably toxic concentration. An additional group of mice was used to determine a non-neurotoxic dosage of the peptide conjugated Morpholino. However, future studies are needed to determine the efficacy of the Cdk5 Morpholino at this dosage. Taken together, the studies presented here suggest that increasing expression of the GluN2B subunit within the aged brain does improve age-associated memory declines. In addition, cell penetrating peptide- conjugated Morpholinos show promise as tools for genetic manipulation within the brain and Cdk5 could prove to be a novel target for enhancing GluN2B subunit expression within the aged brain. Though future studies are needed, the studies presented here do suggest that therapies that enhance GluN2B subunit expression within the aged brain have the potential to help ameliorate memory loss. However, since enhanced GluN2B subunit expression itself can increase the potential for excitotoxicity, an optimal dose of such a therapeutic would need to be determined. Close

• 13. [Article] Effect of consumers' and salespersons' age on perceptions of salespeople

  Physical appearance is one of the most important cues that an individual uses in forming an impression of another person. Researchers have found that perceptions of age are negatively related to perceptions ...

  Citation × Citation Citation Abstract Copy Title: Effect of consumers' and salespersons' age on perceptions of salespeople Author: Cho, Shi Jean Physical appearance is one of the most important cues that an individual uses in forming an impression of another person. Researchers have found that perceptions of age are negatively related to perceptions of physical attractiveness. Because salespeople are influential in affecting a store's sales, especially for nondurable goods (Undell, 1972), consumers' perceptions of salespeople may influence the store's image and sales outcomes. The purpose of the present study was to investigate consumers' perceptions of salespeople of different ages and to determine if differences in these perceptions were related to consumers' age and salespersons' age. Two groups of subjects were investigated - younger adults (between 18 and 28 years of age) and older adults (55 years of age and older) . Younger adult subjects were recruited from university classrooms (n = 41). Older adult subjects were the recipients of Oregon Horne Economics Extension Newsletter (n = 46). The total sample size was 87. A questionnaire was used in the present study to investigate a consumer's perceptions. The questionnaire included three parts questions on the respondent's shopping patterns, a consumer shopping scenario which included the salesperson's age manipulation, and questions asking demographic information. Three dependent variables were measured in the questionnaire: perceptions of the salesperson's fashionability, product knowledge, and job performance. The data were analyzed using the chi-square statistic and content analysis. Results indicated that consumers' perceptions of a salesperson's fashionability was related to the age of the salesperson. Perceptions of a salesperson's fashionability was also related to the age of consumer and the age of the salesperson. Perceptions of the salesperson's product knowledge and performance were not related to the age of salesperson nor to the age of the consumers. Title: Effect of consumers' and salespersons' age on perceptions of salespeople Author: Cho, Shi Jean Physical appearance is one of the most important cues that an individual uses in forming an impression of another person. Researchers have found that perceptions of age are negatively related to perceptions of physical attractiveness. Because salespeople are influential in affecting a store's sales, especially for nondurable goods (Undell, 1972), consumers' perceptions of salespeople may influence the store's image and sales outcomes. The purpose of the present study was to investigate consumers' perceptions of salespeople of different ages and to determine if differences in these perceptions were related to consumers' age and salespersons' age. Two groups of subjects were investigated - younger adults (between 18 and 28 years of age) and older adults (55 years of age and older) . Younger adult subjects were recruited from university classrooms (n = 41). Older adult subjects were the recipients of Oregon Horne Economics Extension Newsletter (n = 46). The total sample size was 87. A questionnaire was used in the present study to investigate a consumer's perceptions. The questionnaire included three parts questions on the respondent's shopping patterns, a consumer shopping scenario which included the salesperson's age manipulation, and questions asking demographic information. Three dependent variables were measured in the questionnaire: perceptions of the salesperson's fashionability, product knowledge, and job performance. The data were analyzed using the chi-square statistic and content analysis. Results indicated that consumers' perceptions of a salesperson's fashionability was related to the age of the salesperson. Perceptions of a salesperson's fashionability was also related to the age of consumer and the age of the salesperson. Perceptions of the salesperson's product knowledge and performance were not related to the age of salesperson nor to the age of the consumers. Close

• 14. [Article] A model of fall chinook salmon (Onchorhynchus tshawytscha) life history

  The research involved development of two ecological simulation models to explain the complex dimensionality of chinook salmon (Oncorhynchus tshawytscha) life history structure (represented by the age composition ...

  Citation × Citation Citation Abstract Copy Title: A model of fall chinook salmon (Onchorhynchus tshawytscha) life history Author: Hirai, Takayuki The research involved development of two ecological simulation models to explain the complex dimensionality of chinook salmon (Oncorhynchus tshawytscha) life history structure (represented by the age composition of the spawning stock) and management difficulties entailed in the complexity. Since different sizes of chinook salmon are thought to adapt differently to heterogeneous habitats, age composition of the spawning stock is determined by characteristics of the habitats of the substocks. Numerical properties of substocks result from the incorporation of individual spawners in different age classes and each substock performs differently because their age compositions are distinctive. A stock or population consists of substocks whose age compositions are concordant with their habitats. The productive capacity of a population will result from the incorporation of substocks. If habitat structures of streams are different, the age and size compositions and productive capacity of the populations may differ. Selective harvesting affects spawners in different ways, so that age compositions must be deformed differently by fishing pressure. Once the age composition deviates from the natural age composition, the productivity of the population will decrease. Population dynamics are strongly correlated with substock structure which is determined by habitat structure in a stream system. Hierarchical population structure make fisheries management difficult and requires not only quantitative but also qualitative analysis on the populations in relation to habitat classification. Title: A model of fall chinook salmon (Onchorhynchus tshawytscha) life history Author: Hirai, Takayuki The research involved development of two ecological simulation models to explain the complex dimensionality of chinook salmon (Oncorhynchus tshawytscha) life history structure (represented by the age composition of the spawning stock) and management difficulties entailed in the complexity. Since different sizes of chinook salmon are thought to adapt differently to heterogeneous habitats, age composition of the spawning stock is determined by characteristics of the habitats of the substocks. Numerical properties of substocks result from the incorporation of individual spawners in different age classes and each substock performs differently because their age compositions are distinctive. A stock or population consists of substocks whose age compositions are concordant with their habitats. The productive capacity of a population will result from the incorporation of substocks. If habitat structures of streams are different, the age and size compositions and productive capacity of the populations may differ. Selective harvesting affects spawners in different ways, so that age compositions must be deformed differently by fishing pressure. Once the age composition deviates from the natural age composition, the productivity of the population will decrease. Population dynamics are strongly correlated with substock structure which is determined by habitat structure in a stream system. Hierarchical population structure make fisheries management difficult and requires not only quantitative but also qualitative analysis on the populations in relation to habitat classification. Close

• 15. [Article] Correction of deposit ages for inherited ages of charcoal: implications for sediment dynamics inferred from random sampling of deposits on headwater valley floors

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.sciencedirect.com/science/journal/0277...

  Citation × Citation Citation Abstract Copy Title: Correction of deposit ages for inherited ages of charcoal: implications for sediment dynamics inferred from random sampling of deposits on headwater valley floors Author: Frueh, W. Terry, Lancaster, Stephen T. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.sciencedirect.com/science/journal/02773791. Title: Correction of deposit ages for inherited ages of charcoal: implications for sediment dynamics inferred from random sampling of deposits on headwater valley floors Author: Frueh, W. Terry, Lancaster, Stephen T. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.sciencedirect.com/science/journal/02773791. Close

• 16. [Article] Mitochondrial decay in the aging rat heart : changes in fatty acid-supported bioenergetics and macromolecular organization of the electron transport system

  Decline in cardiac pump function is a hallmark of aging where mitochondrial decay is an important underlying cause. Although certainly multifactorial in nature, both dysfunction of the machinery involved ...

  Citation × Citation Citation Abstract Copy Title: Mitochondrial decay in the aging rat heart : changes in fatty acid-supported bioenergetics and macromolecular organization of the electron transport system Author: Gomez Ramirez, Luis A. (Luis Alejandro) Decline in cardiac pump function is a hallmark of aging where mitochondrial decay is an important underlying cause. Although certainly multifactorial in nature, both dysfunction of the machinery involved in the chemiosmotic process of energy transduction and lower capacity to maintain fatty acid-driven respiration are identified as intrinsic factors of mitochondrial decay in the aged myocardium. Age-associated destabilization of electron transport supercomplexes as a potential factor of mitochondrial decay in the rat heart. Defective operation of the electron transport chain (ETC) constitutes a key mechanism involved in the age-associated loss of mitochondrial energy metabolism. Nevertheless, the molecular events underlying inefficient electron flux that ultimately leads to higher superoxide appearance and impaired respiration are not fully known. As recent biophysical evidence shows that the ETC may form large macromolecular assemblies (i.e. supercomplexes) that disintegrate in certain pathologies (e.g. heart failure or Barth syndrome) reminiscent of aging, we investigated the hypothesis that alterations in supercomplexes are partly responsible for the age-related loss of cardiac ETC function. In this dissertation, age-associated changes in supercomplex organization and stability were investigated in subsarcolemmal (SSM) and interfibrillary (IFM) mitochondria isolated from cardiac tissue from young (3-5 months) and old (24-28 months) male Fischer 344 rats. Blue native-PAGE (BN-PAGE) analysis of digitonin-solubilized mitochondrial membranes coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to investigate supercomplex organization. Results show that both SSM and IFM display supercomplexes comprised of various stoichiometries of complexes I, III and IV (never complex II), which typically organize as high mass (1500-2300 kDa) assemblies containing up to four copies of complex IV (i.e. I₁III₂IV[subscript N]-type supercomplexes). Interestingly, analysis of IFM proteins showed that, in general, supercomplex levels declined by up to 15 % (p < 0.05) with age; however, different degrees of supercomplex deterioration were observed, depending on the particular supercomplex investigated. Supercomplexes of the highest molecular weights (i.e. 1900-2300 kDa), which were also composed of the most complex stoichiometries (i.e. I1III2IVN, N ≥ 2), were primarily lost with age. In particular, I₁III₂IV₂, I₁III₂IV₃ and I₁III₂IV₄ supercomplexes were found to decline by 13% (p < 0.05), 30% (p < 0.05) and 45% (p < 0.05), respectively, on an age basis. Therefore, the age-associated loss of supercomplexes in IFM stems from destabilization of the assemblies that comprise several copies of complex IV, which could partially limit proper electron transfer to O₂ for its reduction, affecting mitochondrial respiratory capacity. In contrast to IFM, the aging defects of SSM supercomplexes appeared to be confined to the assembly comprised of only one copy of complex IV (I₁III₂IV₁, 1700 kDa) (37% loss; p = 0.06), while the higher molecular weight supercomplex sub-types that were most affected in IFM (i.e. I₁III₂IV[subscript N], N ≥ 2) were not significantly altered with age. Thus, the results from this dissertation indicate that mitochondria from different subcellular locations in the myocyte show different degrees of supercomplex destabilization in the aging rat heart. The more robust supercomplex deficits noted for IFM fit well with previous observations that electron transport characteristics of this subpopulation are more adversely affected with age than SSM. Although the underlying factor(s) of supercomplex deterioration are not fully known, the hypothesis that age-related alterations of certain constituents of the IMM (e.g. cardiolipin) may be important factors of supercomplex destabilization in cardiac mitochondria was investigated in this dissertation. To this end, LC-MS/MS characterization of supercomplex proteins and HPLC analysis of cardiolipin were used as approaches to elucidate potential factor(s) of supercomplex destabilization in the aging rat heart. Age-related alterations of cardiolipin levels and its acyl-chain content showed a strong parallel to the age-associated destabilization of supercomplexes. Specifically, cardiolipin levels declined by 10% (p < 0.05) in IFM, the mitochondrial subpopulation displaying the highest degree of supercomplex deterioration. In addition, the content of (18:2)₄-cardiolipin, the predominant species in the heart, was found to decline by 50% (p < 0.05) on average in both populations of cardiac mitochondria. Therefore, the data presented in this dissertation indicate that changes in cardiolipin may be at least one of the factors involved in supercomplex destabilization in the aging heart. Age-related decline in carnitine palmitoyltransferase I (CPT1) activity as a mitochondrial lesion that limits fatty acid catabolism in the rat heart. Loss of fatty acid utilization, another intrinsic factor of mitochondrial decay in the aged myocardium, has been associated with age-related alterations in the activity of carnitine palmitoyltransferase 1 (CPT1), the rate-controlling enzyme for overall fatty acid β-oxidation. Nevertheless, the exact molecular mechanism involved in the age-related loss of fatty acid-driven bioenergetics is not fully understood. In this dissertation, it was also investigated whether the aging lesion for fatty oxidation lies in a particular mitochondrial subpopulation or more generally results from cardiac decrements in L-carnitine levels. In order to clarify the role of each one of these factors, the effect of long-term dietary supplementation with the L-carnitine analogue, acetyl-L-carnitine (ALCAR), was also investigated. Results show that aging selectively decreases CPT1 activity in IFM by reducing enzyme catalytic efficiency for palmitoyl-CoA. IFM displayed a 28% (p < 0.05) loss of CPT1 activity, which correlated with a decline (41%, p < 0.05) in palmitoyl-CoA-driven state 3 respiration. Interestingly, SSM had preserved enzyme function and efficiently utilized palmitate. Analysis of IFM CPT1 kinetics showed both diminished V[subscript max] and K[subscript m] (60% and 49% respectively, p < 0.05) when palmitoyl-CoA was the substrate. However, no age-related changes in enzyme kinetics were evident with respect to L-carnitine. ALCAR supplementation restored CPT1 activity in heart IFM, but not apparently through remediation of L-carnitine levels. Rather, ALCAR influenced enzyme activity over time, potentially by modulating conditions in the aging heart that ultimately affect palmitoyl-CoA binding and CPT1 kinetics. In conclusion, this dissertation presents a characterization of age-associated alterations in the macromolecular organization of the IMM components that could partly explain the loss of mitochondrial oxidative capacity that affects the aging heart. In addition, the characterization of an age-related lesion of the controlling enzyme for β-oxidation is presented as another important factor that limits mitochondrial function and energy metabolism in cardiac mitochondria. Title: Mitochondrial decay in the aging rat heart : changes in fatty acid-supported bioenergetics and macromolecular organization of the electron transport system Author: Gomez Ramirez, Luis A. (Luis Alejandro) Decline in cardiac pump function is a hallmark of aging where mitochondrial decay is an important underlying cause. Although certainly multifactorial in nature, both dysfunction of the machinery involved in the chemiosmotic process of energy transduction and lower capacity to maintain fatty acid-driven respiration are identified as intrinsic factors of mitochondrial decay in the aged myocardium. Age-associated destabilization of electron transport supercomplexes as a potential factor of mitochondrial decay in the rat heart. Defective operation of the electron transport chain (ETC) constitutes a key mechanism involved in the age-associated loss of mitochondrial energy metabolism. Nevertheless, the molecular events underlying inefficient electron flux that ultimately leads to higher superoxide appearance and impaired respiration are not fully known. As recent biophysical evidence shows that the ETC may form large macromolecular assemblies (i.e. supercomplexes) that disintegrate in certain pathologies (e.g. heart failure or Barth syndrome) reminiscent of aging, we investigated the hypothesis that alterations in supercomplexes are partly responsible for the age-related loss of cardiac ETC function. In this dissertation, age-associated changes in supercomplex organization and stability were investigated in subsarcolemmal (SSM) and interfibrillary (IFM) mitochondria isolated from cardiac tissue from young (3-5 months) and old (24-28 months) male Fischer 344 rats. Blue native-PAGE (BN-PAGE) analysis of digitonin-solubilized mitochondrial membranes coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to investigate supercomplex organization. Results show that both SSM and IFM display supercomplexes comprised of various stoichiometries of complexes I, III and IV (never complex II), which typically organize as high mass (1500-2300 kDa) assemblies containing up to four copies of complex IV (i.e. I₁III₂IV[subscript N]-type supercomplexes). Interestingly, analysis of IFM proteins showed that, in general, supercomplex levels declined by up to 15 % (p < 0.05) with age; however, different degrees of supercomplex deterioration were observed, depending on the particular supercomplex investigated. Supercomplexes of the highest molecular weights (i.e. 1900-2300 kDa), which were also composed of the most complex stoichiometries (i.e. I1III2IVN, N ≥ 2), were primarily lost with age. In particular, I₁III₂IV₂, I₁III₂IV₃ and I₁III₂IV₄ supercomplexes were found to decline by 13% (p < 0.05), 30% (p < 0.05) and 45% (p < 0.05), respectively, on an age basis. Therefore, the age-associated loss of supercomplexes in IFM stems from destabilization of the assemblies that comprise several copies of complex IV, which could partially limit proper electron transfer to O₂ for its reduction, affecting mitochondrial respiratory capacity. In contrast to IFM, the aging defects of SSM supercomplexes appeared to be confined to the assembly comprised of only one copy of complex IV (I₁III₂IV₁, 1700 kDa) (37% loss; p = 0.06), while the higher molecular weight supercomplex sub-types that were most affected in IFM (i.e. I₁III₂IV[subscript N], N ≥ 2) were not significantly altered with age. Thus, the results from this dissertation indicate that mitochondria from different subcellular locations in the myocyte show different degrees of supercomplex destabilization in the aging rat heart. The more robust supercomplex deficits noted for IFM fit well with previous observations that electron transport characteristics of this subpopulation are more adversely affected with age than SSM. Although the underlying factor(s) of supercomplex deterioration are not fully known, the hypothesis that age-related alterations of certain constituents of the IMM (e.g. cardiolipin) may be important factors of supercomplex destabilization in cardiac mitochondria was investigated in this dissertation. To this end, LC-MS/MS characterization of supercomplex proteins and HPLC analysis of cardiolipin were used as approaches to elucidate potential factor(s) of supercomplex destabilization in the aging rat heart. Age-related alterations of cardiolipin levels and its acyl-chain content showed a strong parallel to the age-associated destabilization of supercomplexes. Specifically, cardiolipin levels declined by 10% (p < 0.05) in IFM, the mitochondrial subpopulation displaying the highest degree of supercomplex deterioration. In addition, the content of (18:2)₄-cardiolipin, the predominant species in the heart, was found to decline by 50% (p < 0.05) on average in both populations of cardiac mitochondria. Therefore, the data presented in this dissertation indicate that changes in cardiolipin may be at least one of the factors involved in supercomplex destabilization in the aging heart. Age-related decline in carnitine palmitoyltransferase I (CPT1) activity as a mitochondrial lesion that limits fatty acid catabolism in the rat heart. Loss of fatty acid utilization, another intrinsic factor of mitochondrial decay in the aged myocardium, has been associated with age-related alterations in the activity of carnitine palmitoyltransferase 1 (CPT1), the rate-controlling enzyme for overall fatty acid β-oxidation. Nevertheless, the exact molecular mechanism involved in the age-related loss of fatty acid-driven bioenergetics is not fully understood. In this dissertation, it was also investigated whether the aging lesion for fatty oxidation lies in a particular mitochondrial subpopulation or more generally results from cardiac decrements in L-carnitine levels. In order to clarify the role of each one of these factors, the effect of long-term dietary supplementation with the L-carnitine analogue, acetyl-L-carnitine (ALCAR), was also investigated. Results show that aging selectively decreases CPT1 activity in IFM by reducing enzyme catalytic efficiency for palmitoyl-CoA. IFM displayed a 28% (p < 0.05) loss of CPT1 activity, which correlated with a decline (41%, p < 0.05) in palmitoyl-CoA-driven state 3 respiration. Interestingly, SSM had preserved enzyme function and efficiently utilized palmitate. Analysis of IFM CPT1 kinetics showed both diminished V[subscript max] and K[subscript m] (60% and 49% respectively, p < 0.05) when palmitoyl-CoA was the substrate. However, no age-related changes in enzyme kinetics were evident with respect to L-carnitine. ALCAR supplementation restored CPT1 activity in heart IFM, but not apparently through remediation of L-carnitine levels. Rather, ALCAR influenced enzyme activity over time, potentially by modulating conditions in the aging heart that ultimately affect palmitoyl-CoA binding and CPT1 kinetics. In conclusion, this dissertation presents a characterization of age-associated alterations in the macromolecular organization of the IMM components that could partly explain the loss of mitochondrial oxidative capacity that affects the aging heart. In addition, the characterization of an age-related lesion of the controlling enzyme for β-oxidation is presented as another important factor that limits mitochondrial function and energy metabolism in cardiac mitochondria. Close

• 17. [Article] Influences of an Anti-inflammatory Drug, Ibuprofen, on Spatial Memory and NMDA Receptor Subunit Expression During Aging

  One of the first cognitive dysfunctions to arise with aging is memory loss, affecting an estimated 85% of elderly in the U.S. over the age of 80 with Age Associated Memory Impairment. A common feature ...

  Citation × Citation Citation Abstract Copy Title: Influences of an Anti-inflammatory Drug, Ibuprofen, on Spatial Memory and NMDA Receptor Subunit Expression During Aging Author: Marquez Loza, Alejandra One of the first cognitive dysfunctions to arise with aging is memory loss, affecting an estimated 85% of elderly in the U.S. over the age of 80 with Age Associated Memory Impairment. A common feature in humans and animals experiencing memory loss with aging is the decline in N-methyl-D-aspartate (NMDA) receptorbinding densities in the brain. Variability in the effects of aging on the GluN1 subunit suggests that inflammation may play a role in NMDA receptor aging. The purpose of the present study was to determine the effects of an anti-inflammatory drug, ibuprofen, on spatial long-term & short-term memory and cognitive flexibility in male C57BL/6 mice from four different age groups (5, 14, 20, and 26 months of age at the end of testing). Mice were fed either Ibuprofen (375 ppm) in NIH31 diet or NIH31 diet alone for 6 weeks prior to testing. This dose had been shown to reduce pathology in an Alzheimer’s disease mouse model. Behavioral testing using the Morris Water Maze showed a significant effect of age on acquisition of spatial reference memory, the formation of spatial memory bias in probe trials, cognitive flexibility in reversal trials, and working memory, with 20 and 26 month old mice performing significantly worse than 5 month old mice. Ibuprofen enhanced overall performance in the working memory task when data was collapsed across naïve and test trials and ages. The oldest mice receiving ibuprofen showed significantly better delayed working memory, but near significantly (p=0.08) worse spatial reference memory, as compared to age-matched controls. In situ hybridization assays showed significant decreases over all ages in the mRNA densities for the GluN2B subunit, all GluN1 splice variants, and the GluN1-1 splice forms in the frontal lobes of mice consuming ibuprofen. The GluN1-3 splice form mRNA was significantly increased across ages in the frontal lobes of the ibuprofen-treated mice. There was no effect of ibuprofen on IL-1beta expression in the brains or spleens of these mice. These findings suggest that inflammation may play a role in working memory declines in aged animals, but the reducing effects of ibuprofen across ages on several factors, without reducing age-related increases in cytokine expression suggests that ibuprofen has effects on mRNA for the NMDA receptor that are unrelated to aging or inflammation. Title: Influences of an Anti-inflammatory Drug, Ibuprofen, on Spatial Memory and NMDA Receptor Subunit Expression During Aging Author: Marquez Loza, Alejandra One of the first cognitive dysfunctions to arise with aging is memory loss, affecting an estimated 85% of elderly in the U.S. over the age of 80 with Age Associated Memory Impairment. A common feature in humans and animals experiencing memory loss with aging is the decline in N-methyl-D-aspartate (NMDA) receptorbinding densities in the brain. Variability in the effects of aging on the GluN1 subunit suggests that inflammation may play a role in NMDA receptor aging. The purpose of the present study was to determine the effects of an anti-inflammatory drug, ibuprofen, on spatial long-term & short-term memory and cognitive flexibility in male C57BL/6 mice from four different age groups (5, 14, 20, and 26 months of age at the end of testing). Mice were fed either Ibuprofen (375 ppm) in NIH31 diet or NIH31 diet alone for 6 weeks prior to testing. This dose had been shown to reduce pathology in an Alzheimer’s disease mouse model. Behavioral testing using the Morris Water Maze showed a significant effect of age on acquisition of spatial reference memory, the formation of spatial memory bias in probe trials, cognitive flexibility in reversal trials, and working memory, with 20 and 26 month old mice performing significantly worse than 5 month old mice. Ibuprofen enhanced overall performance in the working memory task when data was collapsed across naïve and test trials and ages. The oldest mice receiving ibuprofen showed significantly better delayed working memory, but near significantly (p=0.08) worse spatial reference memory, as compared to age-matched controls. In situ hybridization assays showed significant decreases over all ages in the mRNA densities for the GluN2B subunit, all GluN1 splice variants, and the GluN1-1 splice forms in the frontal lobes of mice consuming ibuprofen. The GluN1-3 splice form mRNA was significantly increased across ages in the frontal lobes of the ibuprofen-treated mice. There was no effect of ibuprofen on IL-1beta expression in the brains or spleens of these mice. These findings suggest that inflammation may play a role in working memory declines in aged animals, but the reducing effects of ibuprofen across ages on several factors, without reducing age-related increases in cytokine expression suggests that ibuprofen has effects on mRNA for the NMDA receptor that are unrelated to aging or inflammation. Close

• 18. [Article] Age at disability onset and self-reported health status

  This is the publisher’s final pdf. The published article is copyrighted by BioMed Central Ltd. and can be found at: http://www.biomedcentral.com/bmcpublichealth/.

  Citation × Citation Citation Abstract Copy Title: Age at disability onset and self-reported health status Author: Drum, Charles, Beatty, Phillip, Nosek, Margaret A., Hall, Trevor, Campbell, Vincent A., Jamoom, Eric W., Andresen, Elena M., Suzuki, Rie, Krahn, Gloria, Fujiura, Glenn, Horner-Johnson, Willi, Cardinal, Brad This is the publisher’s final pdf. The published article is copyrighted by BioMed Central Ltd. and can be found at: http://www.biomedcentral.com/bmcpublichealth/. Title: Age at disability onset and self-reported health status Author: Drum, Charles, Beatty, Phillip, Nosek, Margaret A., Hall, Trevor, Campbell, Vincent A., Jamoom, Eric W., Andresen, Elena M., Suzuki, Rie, Krahn, Gloria, Fujiura, Glenn, Horner-Johnson, Willi, Cardinal, Brad This is the publisher’s final pdf. The published article is copyrighted by BioMed Central Ltd. and can be found at: http://www.biomedcentral.com/bmcpublichealth/. Close

• 19. [Article] Persistence and age-age genetic correlations of stem defects in Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco)

  Stem defects, including sinuosity, large branches, and the occurrence of steep-angled branches (e.g., forks and ramicorns) can occur with high frequency in young plantations of Coastal Douglas-fir (Pseudotsuga ...

  Citation × Citation Citation Abstract Copy Title: Persistence and age-age genetic correlations of stem defects in Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) Author: Temel, Fatih Stem defects, including sinuosity, large branches, and the occurrence of steep-angled branches (e.g., forks and ramicorns) can occur with high frequency in young plantations of Coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco). The importance of including these stem defects as criteria in early selection depends, in great part, on their persistence over time, and the efficiency of early selection for these traits. In this study, 90 open-pollinated families of Douglas-fir growing on three test sites in the Oregon Coast Range, and originally measured in 1984 at age 12, were remeasured in 1996, at age 24 (approximate mid-rotation age for managed plantations in this region). While the majority (62%) of trees scored as having ramicoms at age 12 still had them at age 24, most forks (53%) had become ramicorns by the second measurement. Thus, there does not seem to be a need to score forks and ramicorns separately. Although branch size was highly correlated between the two measurement dates, sinuosity scores were poorly correlated. Estimated heritabilities and genetic correlations between stem defect traits, and between stem defect traits and bole diameter at breast height (DBH), were similar at the two ages. Due to low heritabilities, estimated genetic gains for DBH and individual stem defect traits were low but consistent with earlier studies. Both branch size and the number of whorls with steep-angled branches had positive genetic correlations with DBH, indicating that selection for stem size alone will indirectly increase stem defects. Thus, it may be prudent to include these traits along with DBH as selection criteria. Sinuosity was nearly uncorrelated with DBH. With the exception of sinuosity, genetic correlations between comparable traits at the two ages were very high (>0.75), and predicted correlated responses in these traits at age 24, from selection at age 12, were nearly as great as those expected if selection was delayed until age 24. Title: Persistence and age-age genetic correlations of stem defects in Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) Author: Temel, Fatih Stem defects, including sinuosity, large branches, and the occurrence of steep-angled branches (e.g., forks and ramicorns) can occur with high frequency in young plantations of Coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco). The importance of including these stem defects as criteria in early selection depends, in great part, on their persistence over time, and the efficiency of early selection for these traits. In this study, 90 open-pollinated families of Douglas-fir growing on three test sites in the Oregon Coast Range, and originally measured in 1984 at age 12, were remeasured in 1996, at age 24 (approximate mid-rotation age for managed plantations in this region). While the majority (62%) of trees scored as having ramicoms at age 12 still had them at age 24, most forks (53%) had become ramicorns by the second measurement. Thus, there does not seem to be a need to score forks and ramicorns separately. Although branch size was highly correlated between the two measurement dates, sinuosity scores were poorly correlated. Estimated heritabilities and genetic correlations between stem defect traits, and between stem defect traits and bole diameter at breast height (DBH), were similar at the two ages. Due to low heritabilities, estimated genetic gains for DBH and individual stem defect traits were low but consistent with earlier studies. Both branch size and the number of whorls with steep-angled branches had positive genetic correlations with DBH, indicating that selection for stem size alone will indirectly increase stem defects. Thus, it may be prudent to include these traits along with DBH as selection criteria. Sinuosity was nearly uncorrelated with DBH. With the exception of sinuosity, genetic correlations between comparable traits at the two ages were very high (>0.75), and predicted correlated responses in these traits at age 24, from selection at age 12, were nearly as great as those expected if selection was delayed until age 24. Close

• 20. [Article] Age determination of corvina reina (Cynoscion albus) in the Gulf of Nicoya, based on otolith surface readings and microincrement analysis

  The corvina reina (Cynoscion albus) is an important part of the artisanal fishery in the Gulf of Nicoya, Costa Rica. Stock assessment on this sciaenid species has been restricted to the use of length-based ...

  Citation × Citation Citation Abstract Copy Title: Age determination of corvina reina (Cynoscion albus) in the Gulf of Nicoya, based on otolith surface readings and microincrement analysis Author: Mug-Villanueva, Moises The corvina reina (Cynoscion albus) is an important part of the artisanal fishery in the Gulf of Nicoya, Costa Rica. Stock assessment on this sciaenid species has been restricted to the use of length-based methods because of the lack of age data. Direct age determination methodologies for tropical species often encounter serious difficulties such as poorly defined hyaline and opaque zones and lack of adequate techniques of ageing. This thesis presents the results of an age-determination study of Cynoscion albus based on otolith surface readings and microincrement analysis. Age estimates were obtained from counts of hyaline zones from surface readings using the light microscope and from microincrement readings from cross sections of the otolith using the scanning electron microscope. Validation of age estimates from surface readings was based on a linear regression of the age estimates from surface readings on age estimates from integrated daily increment readings. Growth of the otolith was studied using linear and multivariate regression methods and the results were used to construct multivariate models for prediction of age. Consistent estimates of age and fish growth parameters were obtained from surface and microincrement analysis. This study showed that Cynoscion albus is a slow-growing fish (K = 0.121) and reaches a large size (L∞ = 127.5 cm) and therefore is likely to suffer overfishing in the Gulf of Nicoya fishery. Title: Age determination of corvina reina (Cynoscion albus) in the Gulf of Nicoya, based on otolith surface readings and microincrement analysis Author: Mug-Villanueva, Moises The corvina reina (Cynoscion albus) is an important part of the artisanal fishery in the Gulf of Nicoya, Costa Rica. Stock assessment on this sciaenid species has been restricted to the use of length-based methods because of the lack of age data. Direct age determination methodologies for tropical species often encounter serious difficulties such as poorly defined hyaline and opaque zones and lack of adequate techniques of ageing. This thesis presents the results of an age-determination study of Cynoscion albus based on otolith surface readings and microincrement analysis. Age estimates were obtained from counts of hyaline zones from surface readings using the light microscope and from microincrement readings from cross sections of the otolith using the scanning electron microscope. Validation of age estimates from surface readings was based on a linear regression of the age estimates from surface readings on age estimates from integrated daily increment readings. Growth of the otolith was studied using linear and multivariate regression methods and the results were used to construct multivariate models for prediction of age. Consistent estimates of age and fish growth parameters were obtained from surface and microincrement analysis. This study showed that Cynoscion albus is a slow-growing fish (K = 0.121) and reaches a large size (L∞ = 127.5 cm) and therefore is likely to suffer overfishing in the Gulf of Nicoya fishery. Close