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• 21. [Image] RA_PETR_TG_0685

  	Vertical wall, much damaged, with several layers of images: a tall, Bronze Age hunter (almost invisible) covered by an Iron Age goat, in the center; a long, anchor-shaped tamga in lower right, over and ...
  	Citation × Citation Citation Abstract Copy Title: RA_PETR_TG_0685 Year: 2003 Vertical wall, much damaged, with several layers of images: a tall, Bronze Age hunter (almost invisible) covered by an Iron Age goat, in the center; a long, anchor-shaped tamga in lower right, over and under other elements.; Bronze Age; Late Bronze Age; Iron Age Title: RA_PETR_TG_0685 Year: 2003 Vertical wall, much damaged, with several layers of images: a tall, Bronze Age hunter (almost invisible) covered by an Iron Age goat, in the center; a long, anchor-shaped tamga in lower right, over and under other elements.; Bronze Age; Late Bronze Age; Iron Age Close

• 22. [Image] RA_PETR_TG_0822

  	Three images, possibly all by different hands: tall figure with long staff, daluur, quiver (Bronze Age); crude goat Iron Age); boar done in an elaborate parcelled style (Arzhan or Pazyryk style).; Bronze ...
  	Citation × Citation Citation Abstract Copy Title: RA_PETR_TG_0822 Year: 1996 Three images, possibly all by different hands: tall figure with long staff, daluur, quiver (Bronze Age); crude goat Iron Age); boar done in an elaborate parcelled style (Arzhan or Pazyryk style).; Bronze Age; Late Bronze Age; Iron Age; varied Title: RA_PETR_TG_0822 Year: 1996 Three images, possibly all by different hands: tall figure with long staff, daluur, quiver (Bronze Age); crude goat Iron Age); boar done in an elaborate parcelled style (Arzhan or Pazyryk style).; Bronze Age; Late Bronze Age; Iron Age; varied Close

• 23. [Image] RA_PETR_OI_0152

  	Surface with images of small wolf and two ibex (Bronze Age) framed by long wolf (Iron Age). Small Iron Age goat on right.; Bronze Age; Iron Age; varied
  	Citation × Citation Citation Abstract Copy Title: RA_PETR_OI_0152 Year: 1997 Surface with images of small wolf and two ibex (Bronze Age) framed by long wolf (Iron Age). Small Iron Age goat on right.; Bronze Age; Iron Age; varied Title: RA_PETR_OI_0152 Year: 1997 Surface with images of small wolf and two ibex (Bronze Age) framed by long wolf (Iron Age). Small Iron Age goat on right.; Bronze Age; Iron Age; varied Close

• 24. [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

• 25. [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

• 26. [Article] Employee Age Differences in Formal Performance Feedback Reactions: Examining the Effects of Perceived Valence, Content, and Delivery

  As the nature of work is rapidly changing, organizations in developed nations all over the world are experiencing shifts in the age composition of their workforces. These changes, which include an aging ...

  Citation × Citation Citation Abstract Copy Title: Employee Age Differences in Formal Performance Feedback Reactions: Examining the Effects of Perceived Valence, Content, and Delivery Author: Burlacu, Gabriela Year: 2011 As the nature of work is rapidly changing, organizations in developed nations all over the world are experiencing shifts in the age composition of their workforces. These changes, which include an aging workforce that is becoming increasingly age-diverse, indicate that organizational researchers and practitioners need to be better aware of how age differences manifest themselves in the workplace and what implications this has for effective employee management. In the current study it is proposed that employees of different ages react differently to various elements of a formal performance feedback event. Specifically, Carstensen's developmental Socio-emotional Selectivity Theory is used as a theoretical backing for explaining how and why employees of different ages perceive and react to performance feedback differently based on their perceptions of the valence, content quality, and delivery quality of the feedback. The results show evidence of age differences in feedback reactions, with younger adults being particularly concerned with information that will benefit them in the future and older adults being particularly concerned with information that conveys a positive relationship with one's supervisor. These findings have both conceptual and practical implications as we seek to build workplace aging theory and find ways to better manage and retain valuable employees of all ages in a changing world of work. Title: Employee Age Differences in Formal Performance Feedback Reactions: Examining the Effects of Perceived Valence, Content, and Delivery Author: Burlacu, Gabriela Year: 2011 As the nature of work is rapidly changing, organizations in developed nations all over the world are experiencing shifts in the age composition of their workforces. These changes, which include an aging workforce that is becoming increasingly age-diverse, indicate that organizational researchers and practitioners need to be better aware of how age differences manifest themselves in the workplace and what implications this has for effective employee management. In the current study it is proposed that employees of different ages react differently to various elements of a formal performance feedback event. Specifically, Carstensen's developmental Socio-emotional Selectivity Theory is used as a theoretical backing for explaining how and why employees of different ages perceive and react to performance feedback differently based on their perceptions of the valence, content quality, and delivery quality of the feedback. The results show evidence of age differences in feedback reactions, with younger adults being particularly concerned with information that will benefit them in the future and older adults being particularly concerned with information that conveys a positive relationship with one's supervisor. These findings have both conceptual and practical implications as we seek to build workplace aging theory and find ways to better manage and retain valuable employees of all ages in a changing world of work. Close

• 27. [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

• 28. [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

• 29. [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

• 30. [Article] The effects of different otolith ageing techniques on estimates of growth and mortality for two species of rockfishes, Sebastes pinniger and Sebastes diploproa

  The use of some age determination methods may result in the incorrect age structure of fish populations. This in turn may lead to incorporation of inappropriate data into models used for stock management. ...

  Citation × Citation Citation Abstract Copy Title: The effects of different otolith ageing techniques on estimates of growth and mortality for two species of rockfishes, Sebastes pinniger and Sebastes diploproa Author: Wilson, Christopher D. The use of some age determination methods may result in the incorrect age structure of fish populations. This in turn may lead to incorporation of inappropriate data into models used for stock management. Otoliths are commonly used for determining the age of fishes, and ages based on the whole otoliths (surface ages) are often lower than those based on otolith sections of long-lived, slow-growing fishes such as rockfishes (Sebastes spp.). Therefore, significant overestimates in growth and mortality may occur when surface ages are used for these species. This study provides estimates of growth and total instantaneous mortality for Sebastes diploproa and S. pinniger based on ages determined from the otolith surface versus those determined from otolith sections. For both species, estimates of mortality were reduced by more than half when section rather than surface ages were used. Estimates of growth based on surface rather than section ages were nearly identical for S. diploproa but appeared higher for S. pinniger. The inclusion of posterior otolith projections in the surface counts of S. diploproa and not S. pinniger are suspected of producing these differences. Because of these revised estimates of mortality and growth the life history features and response to exploitation of these species must be re-evaluated. Maximum sustainable yields of S. ninniger and S. diploproa based on surface ages are 2 to 5 times greater for either species than yields based on section ages. Mistaken estimates such as these can lead to management errors resulting in overexploitation and may thus explain the depletion of some stocks of Sebastes spp.. Title: The effects of different otolith ageing techniques on estimates of growth and mortality for two species of rockfishes, Sebastes pinniger and Sebastes diploproa Author: Wilson, Christopher D. The use of some age determination methods may result in the incorrect age structure of fish populations. This in turn may lead to incorporation of inappropriate data into models used for stock management. Otoliths are commonly used for determining the age of fishes, and ages based on the whole otoliths (surface ages) are often lower than those based on otolith sections of long-lived, slow-growing fishes such as rockfishes (Sebastes spp.). Therefore, significant overestimates in growth and mortality may occur when surface ages are used for these species. This study provides estimates of growth and total instantaneous mortality for Sebastes diploproa and S. pinniger based on ages determined from the otolith surface versus those determined from otolith sections. For both species, estimates of mortality were reduced by more than half when section rather than surface ages were used. Estimates of growth based on surface rather than section ages were nearly identical for S. diploproa but appeared higher for S. pinniger. The inclusion of posterior otolith projections in the surface counts of S. diploproa and not S. pinniger are suspected of producing these differences. Because of these revised estimates of mortality and growth the life history features and response to exploitation of these species must be re-evaluated. Maximum sustainable yields of S. ninniger and S. diploproa based on surface ages are 2 to 5 times greater for either species than yields based on section ages. Mistaken estimates such as these can lead to management errors resulting in overexploitation and may thus explain the depletion of some stocks of Sebastes spp.. Close